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Near Field Communication

1. C A 5 F i A 5 DIA MS 0D I gt 1 59us U v7 88800ps 10k points 19 Feb 2011 23 33 26 Figure 9 1 9 Pulse shape with cursors set to determine the positive overshoots b The modulation index is calculated as ws L where a and b are the peak and the minimum signal amplitude respectively with the value of the index expressed 872 16 mV as a percentage In this case the modulation index is 96 4 872 16 mV see Figure 9 1 10 58 Tek Prevu i 5 54us 16 0mY b e i O 10 3us 872mV 13 A4 80us A856mV i t dv dt 178kV s t TT ll mM I dd e
2. Bie _ 200mv goo a gt 1 59us U gt v7 94400us 10k points 19 Feb 2011 23 20 40 Figure 9 1 10 Pulse shape with cursors set to determine the modulation index The modulation index timings and overshoots are within the defined limits The test passes Summary Test Result Target RF level detection PASS Target passive communication mode PASS Initiator field strength FAIL Initiator modulation index and waveform PASS Table 9 4 Summary of test results for DUT A 9 1 2 DUT B Target RF Level Detection The DUT detects the external RF field from the test assembly at an output power of 45 4 dBm from the signal generator The voltage measured at the calibration coil is 76 mV rms which corresponds to a field strength value of 0 2375 A m The DUT fails on this test since the threshold value for RF level detection is 0 1875 A m 59 Target Passive Communication Mode The DUT is currently running Android 2 3 Gingerbread which does not support card emulation mode Initiator Field Strength Parameter Distance mm Voltage V Hmin 0 4 26 10 2 76 Hmaz Any 1 28 The test passes Initiator Modulation Index and Waveform Table 9 5 Field strength values for DUT B The timing results are illustrated in Figures 9 1 11 9 1 14 amp
3. RBW 3 MHz Att OdB VBW 10 MHz D2 1 25 06 dB Ref 31 6 mv SWT 8ps 2 817250000 us M1 1 74 323615651 mV 1Rr TRG 397 635 mV 2 257750000 ps eim TA 1 aaeoa Le 1 us 00 my D1 Mi POS 31 585 mn 10 mv a n i f 1 mv F Gat 4 vid A 100 pV Y y CF 13 56 MHz 800 0 ns Date Figure 9 1 11 Parameter t1 is acquired by reading the time value for D2 17 JAN 2011 15 37 01 60 RBW 3 MHz WALL O B VBW 10 MHz M1i 1 4 125494594 mV Ref_31 6 mV SWT 8jus 2 965500000 ys Ea 26 02 dB 1Rrr 397 635 mV 1 747380000 ys Clrw 0 05 dB 2 109500000 us Y POS 31 585 ma o k 4 Gat Vid CF 13 56 MHz 800 0 ns Date 17 JAN 2011 15 39 16 Figure 9 1 12 Parameter t2 is acquired by reading the time value for D2 amp RBW 3 MHz Att OdB VBW 10 MHz M1 1 74 271244203 mV Ref 31 6 mV SWT 8ps 5 533000000 us Ea 0 91 dB 1Rrr 397 635 mV 4 314880000 ps Clrw 25 05 dB ME 2e ain dar ns Y Gat Vid CF 13 56 MHz 800 0 ns Date 17 JAN 2011 15 40 07 Figure 9 1 13 Parameter t3 is acquired by reading the time value for D2 61 RBW 3 MHz Att OdB VBW 10 MHz M1 1 49 526371095 mV Ref 31 6 mV S
4. O 20 0 dB 5 00MH2 400ns 2 50GS s I gt s79ns Value Mean Min Max Std Dev Gv 244 680u5 10k points rus 533mY 533m 533m 533m 0 00 19 Feb 2011 22 36 58 Figure 9 1 3 The frequency response at Haz with cursors set to the peak amplitude of the sidebands 53 Tek Prevu O 14 400MHz 33 6 dB OO 12 700MHz 36 4 dB A1 7000MH2 A2 80 dB d dt 1 654dB H2 20 0aB 5 00MHz aeons EE 1 gt 879ns value Mean Min Max Std Dev Wty 244 680s 10k points rus 150mY_ 150m 150m 150m_ 0 00 19 Feb 2011 22 34 12 Figure 9 1 4 The frequency response at Hmin with cursors set to the peak amplitude of the sidebands The measured amplitude levels for the sidebands are converted from dBV to the corresponding voltage values in mV The results can be seen in Table 9 1 H Sideband Requirement mVp Measured values mVp Hmin Lower 18 44 21 41 Upper 18 44 29 55 maz Lower 2 67 49 03 Upper 2 67 79 22 Table 9 1 Minimum requirements on sidebands and measured amplitude levels The DUT fulfills the requirements for the minimum amplitude values for the sidebands at Hinin The test passes 54 Initiator Field Strength Parameter Distance mm Voltage V Amin 0 1 41 10 0 71 Hye Any 0 31 Table 9 2 Field strength values for DUT A The test
5. RBW 3 MHz Att OdB VBW 10 MHz M1 1 41 149025617 mv Ref 10 0 mv SWT 8ps 5 443500000 us a 0 91 dB IRF 4 225380000 ys Clrw Y POS 9 988 mV Gat vid 100 uv CF 13 56 MHz 800 0 ns Date 17 JAN 2011 15 29 00 Figure 9 1 7 Parameter t3 is acquired by reading the time value for D2 56 amp RBW 3 MHz Att OdB VBW 10 MHz M1 1 27 429591689 mV Ref 10 0 nV SWT 8ps 5 269000000 ys 1Rr Y TRG Clrw Bt A i nM JPOS 9 988 mV z Gat Vid 100 uv CF 13 56 MHz 800 0 ns Date 17 JAN 2011 15 29 54 Figure 9 1 8 Parameter t4 is acquired by reading the time value for D2 The results are summarized in table 9 3 Time parameter tl t2 t3 t4 Time 2 84 us 2 21 us 445 ns 270 ns Table 9 3 Parameter values for DUT A As mentioned in 5 1 3 the overshoots shall remain within 90 and 110 of 648 mV i 104 3 see Figure 9 1 9 Hinrrrar The overshoots reach n 57 la 5 49us 620mv O 10 3ps 648mV A4 80us A28 0mVY o dv dt 5 83kV s
6. OK m Measured 97 68 lt OK lt TC 9 2 Initiator 106kbps NFC A Succeeded 5 Test Name Calibration coil Test Type 18092_NFC IP1 normative tests 9 Functional test Initiator TC 9 2 Initiator modulation index and waveform in active and passive communication TC 9 2 212kbps NFC F 212 Test Result FAILED Test Log Measures tf Measured 5476 8 ns ERR tf not between 0 ns and 2000 0 ns NOK m Measured 2 78 ERR m not between 8 and 30 NOK tr Measured 4390 4 ns ERR tr not between 0 ns and 2000 0 ns NOK hf Measured 0 056 V ERR hf not between O V and 0 0004 V NOK hr Measured 0 01 V ERR hr not between 0 V and 0 0004 V NOK m Measured 3 15 ERR m not between 8 and 30 NOK ERR TC 9 2 Initiator 212kbps NFC F 212 Failed 6 Test Name Calibration coil Test Type 18092_NFC IP1 normative tests 9 Functional test Initiator TC 9 2 Initiator modulation index and waveform in active and passive communication TC 9 2 424kbps NFC F 424 Test Result FAILED Test Log Measures tf Measured 5476 8 ns ERR tf not between 0 ns and 1000 0 ns NOK m Measured 2 78 ERR m not between 8 and 30 NOK tr Measured 4390 4 ns ERR tr not between 0 ns and 1000 0 ns NOK hf Measured 0 056 V ERR hf not between 0 V and 0 0004 V NOK hr Measured 0 01 V 3 4 19 02 2011 16 39 MP3 11 05 01 DUT C Sony Ericsson ERR hr not between 0 V and 0 0004 V NOK m Measured 3 1
7. The modulation index timings and overshoots are within the defined limits The test passes For 212 kbps the results are seen in Table 9 18 Parameter ty te hy hr m Value 279 2 ns 624 8 ns 0 001 V 0 003 V 19 4 Table 9 18 Parameter values for DUT B 69 The modulation index timings and overshoots are within the defined limits The test passes For 424 kbps the results are seen in Table 9 19 Parameter tr tr hp hy m Value 242 ns 159 2 ns 0 V 0 001 V 17 9 Table 9 19 Parameter values for DUT B The modulation index timings and overshoots are within the defined limits The test passes Summary Test Result Target RF level detection FAIL Target passive communication mode N A Initiator field strength PASS Initiator modulation index and waveform PASS Table 9 20 Summary of test results for DUT B 9 2 3 DUT C Target RF Level Detection The DUT turns off its RF field when the external RF field has a field strength value of 0 6987 A m The test fails Target Passive Communication Mode The DUT is currently running Android 2 3 Gingerbread which does not support card emulation mode Initiator Field Strength Parameter Distance mm Voltage V Amin 0 2 4 10 1 2 A prec Any 0 52 Table 9 21 Field strength values for DUT C The test fails due to Hmin not reaching 3 V at any
8. NFC Forum Reference Polling Devices The NFC Forum Reference Polling Devices allow commands to be transferred to a Listening Device There are three different kinds of polling devices each with its own antenna coil de sign based on different standards Poller 0 is based on the standard EMVCo PCD whereas Poller 3 and Poller 6 are based on compensated versions of the ISO standardized PICC antenna coil design The NFC Forum Reference Polling Devices can be seen in Figures 6 2 1 6 2 3 UCZA _UCIA NFC FORUM POLLER O GIRT APR 2010 F5010 1132 01 Figure 6 2 1 NFC Forum Reference Poller 0 31 UC2A YCIA Ue2A _UCIA j R3 R4 RZ R8 E ME MAMA EATI RI R2 R5 R POLLER 6 Figure 6 2 3 NFC Forum Reference Poller 6 NFC Forum Reference Listening Devices The NFC Forum Refer ence Listening Devices allow the signals obtained by a Polling Device to be analyzed Like the NFC Forum Reference Polling Devices the NFC Forum Reference Listening Devices each have their own antenna coil design Listener 1 Listener 3 and Listener 6 are based on the outside envelope measurements of the ISO referenced PICC 1 PICC 3 and PICC 6 antenna designations respec tively The NFC Forum Reference Listening Devices come equipped with an integrated sense coil They can send back information through load modulation and be configured with a number of fixed resistive loads The NFC Forum Reference Listening De
9. Listener Tag Card An initiator is the term used in the ISO standards to describe a close coupling device that takes initiative to start any close coupling communication initiation sequence The name for initiator in the NFC Forum A reader is an active device that powers up and initiates contact with a passive close coupling device A reader can be seen as a subgroup of an initiator This is the term used in the ISO standards to indicate the respond ing device of any close coupling communication initiation sequence The reader and transponder are the main components of every RFID system The name for target in the NFC Forum A tag is a passive close coupling device without any specified phys ical layout A tag can be seen as a subgroup of a target A card is a passive close coupling device with ID 1 format i e typ ical credit card size A card can be seen as a subgroup of a target iv Contents Introduction LI Background e io 4 ct ede a le Ot ee RRS a 12 Thesis Objectives i e ae a AE ee ee gh LES Structures d pe SOE A AS Be sete os ee ee a RFID Basics 2 1 Historical Overview 2 0 20 00 A eee ee 2 2 Components of an RFID System 000 2 3 Passive and Active Communication 2 4 Coupling Techniques 4 Rd A a ee es 2 4 1 Backscatter Coupling 2 4 2 Capacitive Coupling s a a accra t eoe raa m e eea 2 4 3 Inductive Coupling ooa a Physi
10. Rev 3 4 edition 2009 Austrian Institute of Technology Test PCD Assembly Rev 3 4 edition 2009 A Paus Near Field Communication in Cell Phones July 2007 Ruhr Universitat Bochum J Pel NFC Tehnology from the IC to NFC Middleware NXP April 2008 Philips NFC vs ISO14443 vs Felica 02 2006 Confidential M Ilyas S Ahson RFID Handbook Applications Technology Security and Privacy CRC Press 2008 J R Williams S B Miles S E Sarma RFID Technology and Applications Cambridge 2008 Rohde amp Schwarz RFID Testing July 2009 Rohde amp Schwarz Measurements on RFID Components According to ISO IEC 14443 Standard Third edition January 2010 92 37 38 39 40 41 Rohde amp Schwarz Pulse Sequencer Software Software Manual September 2010 Tektronix Evaluating and Optimizing Radio Frequency Identification RFID Systems Using Real Time Spectrum Analysis April 2004 M Puglia V D Hunt A Puglia RFID A Guide to Radio Frequency Identification Wiley 2007 M Hadhoud W Ali W ElKilani Simulation of NFCIP 1 Protocol over NS 2 May 2010 S W Lee Y T Lo editor Antenna Handbook Volume II Antenna Theory Van Nostrand Reinhold 1993 93
11. The main idea is to replace people s wallets with digital payments through the mobile phone Mobile phones and SIM cards that can store and run various software applications make a powerful platform to be utilized together with NFC The three maybe most promising areas are public transport payment credit card replacement and advertising Further possi bilities are identity cards electronic keys configuration and setting up other communication protocols such as Bluetooth and WLAN 12 The magnetic strip and chip cards used today have limited lifetime and are vulnerable to demagnetizing and breakage These can be replaced by the card emulation mode of NFC and in that way the number of cards used in the ev eryday life will also be reduced Advertising in the form of smart posters is also an interesting feature For these services the phone acts as an NFC reader and collects information from the tags through load modulation The tag can contain all the information needed or the tag can give a URI combined with a phone command so that the user is redirected to a phone number or a website to complete the service 4 2 NFC Chip Suppliers The largest supplier of NFC chips today is NXP Semiconductors who supplies several handset manufacturers such as Nokia and Samsung with chips Current NFC solutions are all standalone chips but future chips will incorporate other wireless technologies such as Bluetooth or WLAN Other chip manufacturers includ
12. The test assembly was built according to the ECMA 356 standard as explained in 6 1 2 7 1 3 RF Amplifier While making the initial tests we realized that the 20 dBm output power de livered by the SMU 200A to the field generating antenna was not enough to generate the necessary field strength The maximum generated field strength was approximately 1 A m with no amplifier This was far from the maximum necessary value of 7 5 A m After thorough research it was decided that a 25 W amplifier would be sufficient for use in this setup The amplifier BSA 0125 25 from BONN Elektronik was chosen due to short delivery time While waiting for the amplifier to arrive another amplifier was borrowed from Perlos AB The output power of this amplifier was only 3 W but that was enough to perform some of the measurements 7 1 4 Spectrum Analyzer The spectrum analyzer was used for studying the rise and fall times using zero span Although this may seem a bit unorthodox the oscilloscope provided by Sony Ericsson during the thesis was not suitable for measuring the timings The spectrum analyzer gave us better precision since it allowed us to place markers at the desired amplitude levels on the rising and falling edges of the pulse 7 1 5 Digital Oscilloscope The oscilloscope was used to check the sent commands sequences and do all the required measurements The oscilloscope used was a Tektronix DPO 4054 7 1 6 Software The computer software used was R a
13. juL2 Roa E i 3 1 18 Rr The current flowing through L will vary when varying Rz Since the magnetic flux generated at L will counteract the flux from the reader there will be a change at the reader field This change can then be detected at the reader side and if the rate of which the load resistor switches on and off is controlled by data the same pattern will be detected at the reader Load modulation and its uses will be explained further in 5 3 1 11 Chapter 4 NFC Near Field Communication NFC technology development was initiated by Sony and Philips It consists of an interface and protocol developed on top of RFID which makes the NFC device part of this standard and compatible with already existing RFID tech nology The key feature that differentiates NFC from RFID is the possibility of bidi rectional transfer of information which allows bidirectional communication be tween NFC devices To connect two devices together one simply brings them very close together or makes them touch physically The NFC protocol then automatically configures them for communication in a peer to peer network In passive communication mode only one device generates an RF field the other device uses load modulation to transfer the data This is an ideal sce nario for mobile phones as it would allow them to interact with other devices such as laptops while keeping battery consumption low 4 1 NFC Applications NFC has several areas of use
14. 2 1 A reader typically contains an RF module transmitter and receiver a control unit and a coupling element to the tag The tag which represents the data carrying device of an RFID sys tem usually consists of a coupling element and an electronic microchip RFID typically operates at 13 56 MHz Data A er RFID Reader Ene gt Transponder Energy nooo Figure 2 2 1 The main components of every RFID system 2 3 Passive and Active Communication In active communication mode devices have their own power supplies and can generate their own RF signal on which data is carried Most RFID tags are passive which means that they have no power supply of their own Instead they are powered by the field generated by the reader Passive tags can therefore be much smaller and cheaper than active tags although the reading range is more limited Semi passive active tags have a battery dedicated exclusively to power the electronics on the chip 2 4 Coupling Techniques The way in which the RFID tag and reader communicate is known as the coupling mechanism and is categorized into three areas 2 4 1 Backscatter Coupling Backscatter coupling operates outside the near field region and the radio signal propagates away from the reader When the signal reaches the tag this interacts with the ingoing signal and some energy is reflected back towards the reader The properties of the tag affect the way in which the signal is reflected
15. ECMA 352 is a gateway between the existing interface standards In 2004 the NFC Forum was formed with its main objectives to promote the use of NFC technology in consumer devices and services provide an extensive framework for interoperable applications by developing standards based speci fications and ensure that products and devices claiming to be NFC compliant conform to the forum specifications The NFC forum is a non profit association with the aim to evaluate the technology and ensure interoperability Thus they have developed standards based on ISO ECMA and EMVCo 6 1 ISO IEC and ECMA The ISO IEC and ECMA NFC standards are the main focus of this thesis The reason for this is that the NFC Forum RF specifications have not yet been finalized The ISO EIC and ECMA standards for NFC are basically identical and will hereby only be referred to as ECMA 23 6 1 1 ECMA 340 NFC Interface and Protocol This standard defines the communication modes for Near Field Communication Interface and Protocol NFCIP 1 It defines both the active and the passive communication modes of NFC in order to realize a communication network us ing NFC devices The standard specifies RF field RF signal interface general protocol flow initialization transport protocol and includes CRC calculation methods in its appendix The testing specifications for ECMA 340 are ECMA 356 RF Interface Test Methods and ECMA 362 Protocol Test Methods The ISO variant
16. Load Modulation tool Figure 6 2 8 NFC Forum Test Bench Calibration requirements for the test bench and result evaluation are currently missing from the specification 35 Test Case Structure Each test contains the following information Section Explanation TC Id Name of test case RQ reference General Requirement reference in RF Analog Specification Section reference Specific section reference in RF Analog Specification Test Purpose Description of test case Comments If necessary specific information on test case Conditions All reference antennas to be used setup values and test positions Test Configuration Specific test bench configurations used to Functions achieve tests case Acceptance criteria Describes the acceptance criteria Step Detailed test case procedures Table 6 2 Structure of a test case Appendices Annex A contains all the specific numerical values for operating volume RF power and signal interface and is taken from the RF Analog Spec Annex B contains the acceptance conditions for the used measurement tool These conditions are not completely decided and are still under discussion by the NFC Forum Annex C to E are under construction 6 2 3 NFC Digital Protocol Technical Specification 1 0 The scope of this document covers the digital interface and the half duplex transmission protocol of the NFC Forum Device in its four roles Peer Initiator Pe
17. PCD PICC requirements how coding should be done how frames and commands should look like etc Since Card Emulation mode is not supported in Android 2 3 Gingerbread these tests aren t possible to make on handsets with Android until the software sup port is implemented Appendices Annex A contains specific and nominal values for the different parameters throughout the document Annex B and C contains measurement and position conventions as well as spec ifications for how the contactless symbol at a point of sale should look like Annex D contains a flowchart describing how a DUT in initiator mode distin guishes between any detectable disturbance and real transmission errors in the response from the DUT in target mode 1 The document actually uses the word PICC for a DUT in target mode and PCD for a DUT in initiator mode but it was decided to use DUT to be more consistent in the report 38 Chapter 7 Measurement Setup The main objective of the thesis was to assemble a measurement system for testing of NFC enabled devices In the beginning of the thesis two different suppliers were considered for the test assembly The first option was Micropross a French world leading provider of smartcard testing tools The other one was AIT an Austrian application oriented R amp D company Due to time constraints delivery time was a very important factor and since AIT had a shorter deliv ery time on the test assembly than Micropross a
18. a near field effect so the distance between the coils must be less than for the tag to operate Here it should be stated that no electromagnetic field is present in the near field region of a reader The field generated by the reader is purely magnetic until the transition to the far field Throughout the report the term RF field is used even though it actually is a magnetic field The range of the RFID system is broadly categorized into three areas e Close coupling within 1 cm e Remote coupling between 1 cm and 1 m e Long range coupling more than 1 m Of these types of RFID coupling inductive and capacitive types are normally used for close and remote range links and RFID backscatter coupling for long range links The type of used coupling affects not only the range of the RFID system but also operating frequency and other elements of the RFID hardware Chapter 3 Physical Principles The majority of RFID systems operate according to the principle of inductive coupling Therefore understanding of the procedures of power and data trans fer requires an understanding of the physical principles of magnetism This chapter therefore contains a short study of the theory of magnetic fields from an RFID point of view 3 1 Magnetic Field 3 1 1 Magnetic Field Strength H Moving electric charges i e flow of current generate a magnetic field The magnitude of the magnetic field is described by the magnetic field strength H In the
19. and 424 kbps the frame structure shown in Figure 5 2 3 is used Transport Data field 1 1 1 1 1 1 Figure 5 2 3 Frame format for 212 and 424 kbps The communication starts with the preamble sequence PA of minimum 48 bits with all logical ZERO encoded The synchronization SYNC contains two bytes and shall be set to 0xB2 and 0x4D The LEN byte shall be set to the length of the Transport Data field plus 1 The value of LEN shall be in the range of 3 to 255 E2 is the CRC for the Frame format of 212 and 424 kbps In active communication the frame format for initialization does not differ from the frame format for data exchange Communication at 106 kbps is done with the frame format shown in Figure 5 2 2 and communication at the higher bit rates is done with the frame format shown in Figure 5 2 3 5 3 Modulation 5 3 1 Load Modulation Using the principle of load modulation data from a passive target can be trans mitted back to the reader If a target with a resonance frequency equal to the 19 transmission frequency of the reader is placed within the magnetic alternating field of the reader s antenna the target will be powered by the magnetic field When a load resistor is switched on and off at the target the voltage changes at the reader s antenna due to the impedance change in the target resulting in amplitude modulation at the reader s antenna This is true when the target is l
20. expected ERR No Response ERR TC 8 2 212kbps NFC F Failed 4 Test Name Procedure for Hmax Test Type 18092_NFC IP1 normative tests 9 Functional test Initiator TC 9 1 Initiator Field strength in active and passive communication Test Result PASSED Test Log Results The maximum vale measured is 0 35 V lt TC 9 1 Initiator field strength in active and passive communication Hmax Succeeded 5 Test Name Procedure for Hmin Test Type 18092_NFC IP1 normative tests 9 Functional test Initiator TC 9 1 Initiator Field strength in active and passive communication Test Result FAILED Test Log Results The highest value is 1 44 V and is measured at 0 mm ERR TC 9 1 Initiator field strength in active and passive communication Hmin Failed 6 Test Name Calibration coil Test Type 18092_NFC IP1 normative tests 9 Functional test Initiator TC 9 2 Initiator modulation index and waveform in active and passive communication TC 9 2 106kbps NFC A Test Result PASSED Test Log 4 6 12 02 2011 17 47 MP3 11 05 01 DUT A Sony Ericsson Measures tl Measured 2847 2 ns lt OK t2 Measured 2088 8 ns lt OK t3 Measured 304 ns lt OK t4 Measured 185 6 ns lt OK overshoot Measured 107 48 lt OK m Measured 96 26 lt OK lt TC 9 2 Initiator 106kbps NFC A Succeeded 7 Test Name Calibration coil Test Type 18092_NFC IP1 norma
21. fails due to Hmin not reaching 3 V at any position Initiator Modulation Index and Waveform For 212 kbps the DUT does not provide a stable enough signal to trigger on Since no proper triggering can be done the tests for this bit rate have been omitted The DUT does not support communication at 424 kbps For 106 kbps the rise and fall times are determined by placing markers D1 M1 and D2 as described in 8 1 5 The envelope of the carrier amplitude and the definition of the time intervals are described in 5 1 3 The timing results are illustrated in Figures 9 1 5 9 1 8 amp 25 10 dB 2 842250000 us RBW 3 MHz Att OdB VBW 10 MHz D2 1 Ref 10 0 nv SWT 8us 1R Clrw Gat Vid Date TRG Dt A s nM JPOS 9 988 mV z 100 pV CF 13 56 MHz 800 0 ns i 17 JAN 2011 15 25 36 Figure 9 1 5 Parameter t1 is acquired by reading the time value for D2 55 RBW 3 MHz Att OdB VBW 10 MHz M1 1 2 280911878 mV Ref 10 0 mV SWT 8ps 2 789000000 us A 26 03 dB 1 570880000 ys 1Rr Y TRG H Clrw Bt A M JPOS 9 988 mV Gat vid 100 V CF 13 56 MHz 800 0 ns Date 17 JAN 2011 15 27 48 Figure 9 1 6 Parameter t2 is acquired by reading the time value for D2
22. fs f 16 847 5 kHz for the bit rate 106 kbps e Data is coded using Manchester coding e The Manchester coded data is then modulated at the subcarrier frequency e Finally the subcarrier load modulation is completed Two sidebands have now been generated due to the subcarrier load modulation The upper sideband is located at 14 0475 MHz and the lower one at 12 7125 MHz In Figure 5 3 2 the approach of load modulation with a subcarrier is illustrated Subcarrier Data stream baseband coded OS Modulated subcarrier Carrier signal 13 56 MHz OS Load modulated signal with subcarrier Figure 5 3 2 Step by step generation of a load modulated signal with a sub carrier 21 5 3 3 Digital modulation methods In NFC data transfer is made possible through ASK PSK or FSK modulation of the subcarrier in time with the data flow ASK Amplitude shift keying is a type of digital modulation that shows digital data in the form of variation in the amplitude of a carrier wave For binary levels a 1 is represented by the standard carrier wave and a 0 is represented by a carrier wave with zero amplitude This type of ASK is called 100 ASK or on off keying and is the most basic type of ASK The percentage defines how much the amplitude is reduced so e g 30 ASK would mean that a logical 0 reduces the amplitude level to 70 compared to the amplitude level of a logical 1 PSK Phase shift keying is another type of digital
23. general form we can say that the contour integral of magnetic field strength along a closed curve is equal to the sum of the current strengths of the currents within it as seen in equation 3 1 1 8 i pha 3 1 1 Two examples of how the magnetic flux behaves when a current passes a con ductor can be seen in Figure 3 1 1 In a straight conductor the field strength H along a circular flux line at a distance r is constant The field strength H can be expressed as H 3 1 2 rr Figure 3 1 1 Lines of magnetic flux around a conductor and a cylindrical coil Conductor loops are used as magnetic antennas to generate the magnetic alter nating field in the devices of inductively coupled RFID systems The magnetic field strength H decreases as the measuring point is moved away from the centre of the coil axis x axis in Figure 3 1 1 The field strength is reduced by 60 dB per decade in the near field of the coil The path of field strength along the x axis of a coil can be calculated by using Equation 3 1 3 2 es e a 3 1 3 24 r2 x2 Here N is the number of windings r is the circle radius and zx is the distance from the centre of the coil in the x direction This equation is only valid when d amp rand gx lt 2n The transition into the electromagnetic far field occurs when x exceeds A 2r At the centre of the antenna x 0 Equation 3 1 3 can be simplified to eN 2 3 1 4 3 1 2 Magnetic Flux an
24. homogeneous the mutual inductance Mj between two coils can be calculated using Equation 3 1 9 The resulting equation is as fol lows Bo Ih No a Ag _ Lo H 1 gt No Ag Mio 12 E E 3 1 11 By replacing H I with the expression in equation 3 1 3 and substituting A with r n Equation 3 1 12 is obtained 7 bo Nier No r3 7 2 ri 22 3 This equation is only valid when the x axes of the two coils lie on the same plane and Az lt Aj M2 3 1 12 3 1 5 Coupling Coefficient The coupling coefficient is a convenient way to specify the degree of electrical coupling that exists between two circuits The coupling coefficient k is expressed as M k 3 1 13 y L La where 0 lt k lt 1 A k value close to 0 equals high decoupling due to e g distance while a k value close to 1 equals high coupling If k 1 then both coils are subject to the same magnetic flux 3 1 6 Faraday s Law A change to the magnetic flux generates an electric field strength E and this is described by Faraday s law The effect of this electric field depends on the material of its surroundings Faraday s law in its general form is written as t For a coil with N windings Equation 3 1 14 can be expressed as dv dt A time variant current 1 t in the first coil generates a time variant magnetic flux delia which leads to a voltage being induced in both coils We can dif ferentiate between two cases self
25. inductance and mutual inductance For self inductance the flux change generated by the current change induces a voltage in the same conductor circuit For mutual inductance the flux change gener ated by the current change induces a voltage in the adjacent conductor circuit Figure 3 1 3 shows the equivalent circuit diagram for coupled coils In an RFID system L would be the transmitter antenna of the reader and L the target antenna uj N 3 1 15 EE Figure 3 1 3 Left magnetically coupled coils right equivalent circuit diagram for magnetically coupled coils 10 The current consumption of the chip is symbolized by the load resistor Rr A time varying flux in the first coil L induces a voltage us in the second coil L due to mutual inductance M A voltage drop across the coil resistance Ra is created due to the flow of current meaning that the voltage ug can be measured across Rz An additional magnetic flux opposing the magnetic flux Y i is generated due to the current flowing through Lz This is summed up in Equation 3 1 16 da diz dig M dt dt dt Since 71 and i2 usually are sinusoidal alternating currents Equation 3 1 16 can be written in the complex notation ug 4 La izR 3 1 16 ug jwM i1 juLa i2 t2R2 3 1 17 If i2 is replaced by Re in equation 3 1 17 then the equation for uz can be solved as seen in Equation 3 1 18 ua jwM a4 oo ug jwM i
26. is calibrated to produce the required magnetic field strength Hin or Hmax at 13 56 MHz on the calibration coil with the reference device in the DUT position R2 is now adjusted to obtain 3V DC across it measured with a high impedance voltmeter The operating field condition is verified by monitoring the voltage on the calibration coil e Oscilloscope The oscilloscope is used to measure the voltage across R2 while the reference device is positioned within the defined operating volume of the DUT For Hmin the voltage shall exceed 3V DC and for Hmas the voltage shall be below 3V DC 8 1 5 Initiator Modulation Index and Waveform This test is used to determine the modulation index of the initiator field as well as the rise and fall times and the overshoot values as described in 6 1 2 within the defined operating volume The test is performed by placing the calibration coil within the operating volume of the initiator e Oscilloscope The oscilloscope is used to measure the overshoots of the modulated signal and to determine the modulation index using the method described in 6 1 2 e Spectrum Analyzer The rise and fall times are determined using the spectrum analyzer with a zero span configuration The markers D1 M1 and D2 are placed to determine the time parameters as described below MKR Marker Marker Delta Position the D1 marker to Hinitiar 100 amplitude value MKR Marker 1 Position the M1 at 90 amplitude of the falling
27. modulation It shows digital data in the form of variation of the phase of a carrier wave For binary phase shift keying BPSK the shift is 180 degrees and for quadrature phase shift keying QPSK the phase shift is 90 degrees Using QPSK over BPSK enables either higher data rates or lower bandwidth requirements depending on the need FSK FSK shows digital data in the form of variation of the frequency of a carrier wave For binary frequency shift keying BFSK a logical 0 is represented by one frequency and a logical 1 is represented by a different frequency 22 Chapter 6 Standardization NFC is already on its way to becoming a part of everyday life and in order to achieve successful consumer adoption of this technology involved companies need to work together closely and applications need to be interoperable NFC is described in the two standards Near Field Communication Interface and Protocol 1 NFCIP 1 ECMA 340 ISO 18092 and 2 NFCIP 2 ECMA 352 1850 21481 NFC is built upon the RFID standard ISO 14443 and became specified in ISO 18092 in 2003 and in ECMA 340 later on Test specifications for the RF interface are found in ECMA 356 ISO 22536 and protocol tests are specified in ECMA 362 ISO 23917 NFC incorporates proximity cards of both type A and type B together with Felica and can therefore show basic interoperability and communicate with al ready existing reader infrastructure NFCIP 2 which is defined in ISO TEC 21481 and
28. of this standard is ISO 18092 6 1 2 ECMA 356 RF Interface Test Methods This test standard specifies a test setup used for NFC devices and compliance tests for the RF interface The ISO variant of this standard is ISO 22536 The test setup used during the thesis is assembled according to this standard Test Setup The test setup consists of a calibration coil a test assembly and two reference devices The test assembly itself consists of two sense coils connected to a compensation board and a field generating antenna as illustrated in Figure 6 1 1 Figure 6 1 1 Test assembly 24 Calibration Coil The ECMA 356 standard describes the layout of a cali bration coil that permits the measurement of magnetic field strengths in the frequency range of 13 56 MHz This way the field strengths and initiator signals are measured and validated before they are applied to the DUT The calibra tion coil can also be used to measure ASK modulation levels in the reader signal During the field strength measurement particular care should be taken to ensure that the calibration coil is only subjected to high ohmic loads by the connected measuring device as every current flow in the calibration coil can falsify the measurement result A high impedance oscilloscope probe e g gt 1 MQ lt 14 pF shall be used to measure the open circuit voltage in the coil The open circuit calibration factor for this coil is 0 32 Vrms per A m This is equivalent t
29. one of the few oscilloscope models that are compatible with the Micropross solution today The oscillo scope is completely controlled by the MP Manager software for the target tests while some manual configurations have to be done for the initiator tests 7 2 5 Software The computer software used is called MP Manager MP Manager is used to control the TCL2 and is a fully integrated development environment The program can be used to e Edit and run script files along with complete test suites e Spy on the communication between the reader and a target and then visualize the log events e Execute electrical tests functions for calibration purposes e Plot graphs that represent how a particular test passes or fails when parameters like frequency or voltage are varied while the test is executed repeatedly 44 The software requires a license together with a USB key to be run If the software is to be run on another computer the license must first be removed and then entered on the new computer along with the USB key Micropross has however confirmed that it will shift this license model to a floating license 45 Chapter 8 Measurement Procedure 8 1 Rohde amp Schwarz AIT Calibration and Configuration Since all the tests where the DUT is in target mode are supposed to be done with linear increasing field strength of up to 7 5 A m the required power levels must be noted beforehand The process of measuring the field strengt
30. passive communication TC 9 2 212kbps NFC F 212 Test Result PASSED Test Log Measures tf Measured 279 2 ns lt OK m Measured 19 15 lt OK tr Measured 624 8 ns lt OK hf Measured 0 001 V lt OK hr Measured 0 003 V lt OK m Measured 19 67 lt OK lt TC 9 2 Initiator 212kbps NFC F 212 Succeeded 6 Test Name Calibration coil Test Type 18092_NFC IP1 normative tests 9 Functional test Initiator TC 9 2 Initiator modulation index and waveform in active and passive communication TC 9 2 424kbps NFC F 424 Test Result PASSED Test Log Measures tf Measured 242 ns lt OK m Measured 17 97 lt OK tr Measured 159 2 ns lt OK hf Measured 0 V lt OK 3 4 12 02 2011 18 03 MP3 11 05 01 DUT B Sony Ericsson hr Measured 0 01 V lt OK m Measured 17 89 lt OK lt TC 9 2 Initiator 424kbps NFC F 424 Succeeded 3 SUMMARY REPORT 3 1 Test Suite Name ISO 22536 RF NFC Device Log Status Number Passed 5 83 33 Failed 1 16 67 Not Applicable 0 0 00 Inconclusive 0 0 00 Error 0 0 00 TOTAL 6 100 Ooo End of Report 000 4 4 A 3 DUT C 86 19 02 2011 16 39 MP3 11 05 01 DUT C Sony Ericsson TEST SUITE REPORT Device Name TCL2 Device Serial Number MP3 11 05 01 Testing Date Report Date Description Operator Manufacture
31. position 70 Initiator Modulation Index and Waveform Due to poor matching triggering on the higher bit rates is not possible and the tests for these bit rates have been omitted For 106 kbps the results are seen in Table 9 22 and 9 23 Time parameter tl t2 t3 t4 Time 2830 ns 1836 ns 350 ns 141 ns Table 9 22 Parameter values for DUT C Overshoots 106 02 Modulation index 97 68 Table 9 23 Parameter values for DUT C The modulation index timings and overshoots are within the defined limits The test passes Summary Test Result Target RF level detection FAIL Target passive communication mode N A Initiator field strength FAIL Initiator modulation index and waveform PASS Table 9 24 Summary of test results for DUT C 71 Chapter 10 Summary and Conclusions NFC has a broad range of uses Public transport payment credit card function ality and setting up other types of wireless connections are only a few examples of the possibilities Since NFC technology is mainly intended for use in mobile phones all the features that NFC brings become available in your pocket The main objective for this thesis was to assemble an NFC measurement sys tem for use at Sony Ericsson Mobile Communications This was not as easy as initially foreseen We had no previous experience with NFC technology and when there we
32. 5 ERR m not between 8 and 30 NOK ERR TC 9 2 Initiator 424kbps NFC F 424 Failed 3 SUMMARY REPORT 3 1 Test Suite Name ISO 22536 RF NFC Device Log Status Number Passed 2 33 33 Failed 4 66 67 Not Applicable 0 0 00 Inconclusive 0 0 00 Error 0 0 00 TOTAL 6 100 Ooo End of Report 000 4 4 Bibliography 10 11 12 13 14 15 16 NFC Forum http www nfc forum org 18 02 2011 S Al Ashraf A Sefedini Prototyper for NFC implementeringar Master s Thesis Malm University 2010 C Balanis Antenna Theory Analysis and Design Wiley third edition 2005 D Dobkin The RF in RFID Newnes 2008 K Breitfu8 E Haselsteiner Security in Near Field Communication NFC 2006 EMVCo EMV Contactless Communication Protocol Specification v2 0 1 July 2009 V Nilsson E Rolf Near Field Communication NFC for Mobile Phones Master s Thesis Lund University August 2006 K Finkenzeller RFID Handbook Wiley second edition 2003 B Glover H Bhatt RFID Essentials O Reilly 2006 L Sundstr m H B rjeson G J nsson Radio Electronics Lund University Faculty of Engineering Department of Electroscience 2004 P Sweeney II RFID for Dummies Wiley 2005 Texas Instruments HF Antenna Design Notes Third edition September 2003 ECMA International ECMA 352 Near Field Communication Interface and Protocol NFCIP 2 Dec
33. Near Field Communication Master s Thesis in Electrical Engineering by Bekir Bilginer Paul Luis Ljunggren Supervisors Masar Sadik and Johan Nilsson Examiner Tomas Jansson Department of Measurement Technology and Industrial Electrical Engineering Lund University Sweden Sony Ericsson Mobile Communications AB Lund Sweden February 2011 LUNDS UNIVERSITET Lunds Tekniska H gskola Sony Ericsson Abstract Near Field Communication NFC is a form of wireless communication technol ogy enabling data transfer by putting two devices close to each other The main idea behind NFC is to integrate wireless payment and tag reading in mobile phones along with peer to peer communication An example of the benefit with NFC peer to peer communication is that it gives the possibility to quickly set up a Bluetooth or a WLAN connection with a simple swipe Wireless payment is made possible through the so called card emulation mode and will be used all over the world in a near future This enables NFC devices to be used not only with the upcoming wireless payment terminals but also to replace contactless plastic cards used in the already established RFID infrastructure The main purpose of this master s thesis is to assemble an RF measurement system for NFC The report covers the basics of NFC together with the involved standards and presents test results from different NFC enabled devices Acknowledgments We would like to thank our sup
34. SS ye os 9237 DUDO ay gee god Din ah Seed ed bb ee A 10 Summary and Conclusions LOW Putur OE s oA olla a ae he ee A SS A Micropross Test Reports Ag Ds IDURD AS A ake BS a Gas ES ti aoe At Ag DULD teclista Ae AS DUT Oop a we hy BAS Ee ee BS Sok er eek etn gd bd ee Bibliography vill 72 73 74 74 81 86 91 Chapter 1 Introduction 1 1 Background Near Field Communication NFC is an upcoming technology based on RFID NFC is expected to be heavily deployed within the next two years and trials are currently ongoing all over the world Examples of applications are public transport payment credit cards electronic tickets and configuration of other wireless technologies The development of NFC is currently driven by the NFC Forum which is an organization of 150 companies working together to promote and develop NFC 1 2 Thesis Objectives Gain overall knowledge of NFC technology Survey different NFC component vendors and define pros and cons Investigate competitors NFC solutions Define constrains and opportunities when designing for NFC Define and build a mock up for NFC Assemble a measurement system for NFC and define test cases limits calibration etc 1 3 Structure The thesis starts by describing the RFID basics since NFC technology is based on RFID This is followed by chapters describing the physical principles and an introduction to NFC It proceeds by describing the communication technology wi
35. WT 8ps 5 355250000 us 1R 397 635 mV Clrw Gat Vid CF 13 56 MHz Date 17 JAN 2011 15 42 17 Figure 9 1 14 Parameter t4 is acquired by reading the time value for D2 The results are summarized in table 9 6 Time parameter tl t2 t3 t4 Time 2 82 us 2 11 ys 458 ns 280 ns Table 9 6 Parameter values for DUT B The overshoots reach 104 1 The modulation index is 98 2 The modulation index timings and overshoots are within the defined limits The test passes Summary Test Result Target RF level detection FAIL Target passive communication mode N A Initiator field strength PASS Initiator modulation index and waveform PASS Table 9 7 Summary of test results for DUT B 62 9 13 DUT C Target RF Level Detection The voltage measured at the calibration coil is 230 mV rms which corresponds to a field strength value of 0 719 A m The DUT fails on this test since the threshold value for RF level detection is 0 1875 A m Target Passive Communication Mode The DUT is currently running Android 2 3 Gingerbread which does not support card emulation mode Initiator Field Strength Parameter Distance mm Voltage V Amin 0 2 45 10 1 06 Hea Any 0 56 Table 9 8 Field strength values for DUT C The test fails due to Hmin n
36. al PCD Man ual CMR Manual and Gerber Files with the necessary design material for assembling the required EMV Reference Equipment Note that to get a hold of the equipment specification an EMVCo subscription of at least Subscriber level is required 6 3 1 EMV Contactless Communication Protocol v2 0 1 This document describes basic theory reference equipment operating volume definition PCD PICC requirements and sequences The specification is mostly based on the ISO RFID standards 14443 1 2 3 and 4 EMV Contactless Level 1 Test Equipment The test equipment consists of three parts e EMV TEST PCD e EMV TEST PICC e EMV TEST CMR 37 Just like the ECMA Test Assembly the EMV TEST PCD is fed from a signal generator and then used for testing DUTs in target mode The EMV Test PICC is used for testing signals sent out by DUTs in initia tor mode and can also send back information through load modulation The responses from a DUT can then be analyzed through the EMV TEST CMR Additional information regarding the reference equipment can be found in EMV Contactless Specifications for Payment Systems Level 1 Test Equipment Specifications PCD PICC and CMR manual respectively RF Power Signal Interface Sequences and Frames The rest of the document covers the technical descriptions requirements and test procedures for each case It follows the same pattern as the ECMA and NFC Forum docu ments by providing
37. ange of Hmin and Amax as described in 6 1 2 The DUT is placed on the test assembly concen tric with the sense coil e K6 Pulse Sequencer A SENS_REQ command sequence is sent to the DUT for the bit rate 106 kbit s to obtain a SENS_RES For the higher bit rates a Polling Request command sequence is sent to the DUT to obtain a Polling Response 47 e Signal Generator The output power is varied between Hmin and Hmaz e Oscilloscope The oscilloscope is set to pulse trigging with a pulse width greater than 2 microseconds for the lower bit rate The pulse width is reduced when the bit rate is increased Exactly two subcarrier cycles of the sampled modulation waveform is Fourier transformed The sidebands are located at f fs 12 7125 and 14 4075 MHz respectively for 106 kbps 8 1 3 Target Active Communication Mode The purpose of this test is to determine the modulation index and the timing of the target s RF field while varying the field strength in the range of Hmin and Hmaw as defined in 6 1 2 The DUT is placed on the test assembly concentric with the sense coil e K6 Pulse Sequencer An ATR_REQ command sequence is sent to the DUT for all bitrates to obtain an ATR_RES e Signal Generator The output power is varied between Hmin and Hmaz e Oscilloscope The oscilloscope is used to read the timing of the RF field generation and measure the different amplitudes of the modulated signal in order to determine the modulation ind
38. any position or angle with respect to the DUT For the testing of Hmin the reference device is tuned to 13 56 MHz The voltage measured across R with a high impedance voltage meter should be 3V DC for a field equal to Hin The reference device is placed within the oper ating volume of the initiator The test passes if the voltage across Ra exceeds 3V DC within the defined operating volume The calibration of the reference devices is described in 8 1 4 Initiator Modulation Index and Waveform The purpose of this test is to investigate the initiator signal to assure that modulation index overshoots rise and fall times are according to specification within the defined operating volume in active and passive communication mode The calibration coil is positioned within the operating volume of the initiator The characteristics of the modulated signal are investigated using an oscillo scope connected to the calibration coil The procedures for measuring the rise and fall times overshoots and modulation index for the bit rates 106 212 and 424 kbps are described in 8 1 5 6 2 NFC Forum The NFC Forum is a group of members who develop NFC specifications en sures interoperability among devices and services promotes the use of NFC technology and educates the market about it as well It was formed in 2004 and has over 150 different members ranging from manufacturers application developers financial services institutions and more The NFC For
39. ate 12 FEB 2011 21 03 19 Figure 9 1 17 Parameter t3 is acquired by reading the time value for D2 amp RBW 3 MHz Att OdB VBW 10 MHz M1 1 10 469054504 mV Ref 10 0 nV SWT 15us 9 194211250 us 4 42 dB 4 080617500 us 21 56 dB 197 492500000 ns VJPOS 9 988 mV CF 13 56 MHZ Date 12 FEB 2011 21 04 11 Figure 9 1 18 Parameter t4 is acquired by reading the time value for D2 The timing results are summarized in table 9 9 65 Time parameter tl t2 t3 t4 Time 2 81 us 1 72 us 299 ns 197 ns Table 9 9 Parameter values for DUT C The overshoots reach 106 32 The modulation index is 97 24 The modulation index timings and overshoots are within the defined limits The test passes Summary Test Result Target RF level detection FAIL Target passive communication mode N A Initiator field strength FAIL Initiator modulation index and waveform PASS Table 9 10 Summary of test results for DUT C 66 9 2 Micropross 9 2 1 DUT A Target RF Level Detection The DUT turns off its RF field when the external RF field has a field strength value of 0 0653 A m The test passes Target Passive Communication Mode The DUT does not support passive communication mode at higher bit rates and the tests have therefore been omi
40. ation 1 0 6 3 EMV CO octane es a BH A ee hy A tyson Gata Nad hl tees ek ule 6 3 1 EMV Contactless Communication Protocol v2 0 1 Measurement Setup 7 1 Rohde amp Schwarz AIT 2 0 ee ee 7 1 1 Signal Generator 7 12 Test Assembly usos er isis amp A FAG RE Amplifier ss y 20k keen a a reer 7 1 4 Spectrum Analyzer o 7 1 5 Digital Oscilloscope MELO Softwaren a 4a ae ge le eee ee at o es C2 MictOprogs dede s daw an a A ee ee ey 7 2 1 Signal Generator 2 2 est Assembly sos 3 a es T29 RE Amplifiers 0 04 24 4 A ee de 7 2 4 Digital Oscilloscope 42 9 IDO WAtE fo ee bP ea EEE ER RE ara a e p Measurement Procedure 8 1 Rohde amp Schwarz AIT o oo 8 1 1 Target RF Level Detection 8 1 2 Target Passive Communication Mode 8 1 3 Target Active Communication Mode 8 1 4 Initiator Field Strength 8 1 5 Initiator Modulation Index and Waveform 8 27 IMICTODIOSS edici n ca ea EE ei a a a Test Results 9 1 Rohde amp Schwarz AIT 2 2 ee o TEE DUTA i amp de es RE bra aal ee EO 4 4 BOA 91 25 PULP ge of ob oh sae e aay en pI a ew YES DUT Gis say gece a E A ee Bae age e ph 932 MicrOpross 2640260 eb 04 Hed ea ee Ee eed we ee 924 DUDA veri dsa gwd eae ee es bolo ee 24 vil 92 20 DUT Be ee BAA A ak A A
41. back Cross sectional area antenna properties etc are factors that all have an effect on how the tag reflects the incoming signal The reflected signal properties can be changed by adding or subtracting a load resistor across the antenna In order to allow transmission and reception of a signal at the same time a directional coupler is often used to allow the received signal to be separated from the transmitted 2 4 2 Capacitive Coupling Capacitive coupling uses capacitive effects to provide the coupling between the tag and the reader It operates best when items like smart cards are inserted into a reader meaning the card is in very close proximity to the reader The AC signal generated by the reader is picked up and rectified within the tag and used to power the devices within the tag Like with backscatter coupling the data is sent to the reader by modulating the load 2 4 3 Inductive Coupling In terms of operation inductive coupling is the transfer of energy from one circuit to another through the mutual inductance between the two circuits When the tag is placed close enough to the reader the field from the reader coil will couple to the tag coil A voltage will be induced in the tag that will be rectified and used to power the tag circuitry To modulate data from the tag to the reader the tag circuitry changes the load on its coil and this can be detected by the reader as a result of the mutual coupling RFID inductive coupling is
42. cal Principles 3 1 Magnetic Field o ete a e de de eek IE ae 3 1 1 Magnetic Field Strength H 3 1 2 Magnetic Flux and Magnetic Flux Density 3 13 Induct nce Livia a e A 3 1 4 Mutual Inductance M o 3 1 5 Coupling Coefficient 3 1 0 Ear dayiS Law aa a oTa a suse ad ay 8 NFC Near Field Communication 4 1 NFC Applications 0020000220005 4 2 NFC Chip Suppliers a 00200 RF and Digital Interface 5 1 RF Signal Interface e 5 1 1 RF Specifications 3 162 Bit Duration 2 sas ga eae cok Ak AO tt 5 1 3 Active Communication Mode 4 5 1 4 Passive Communication Mode 5 2 Digital Signal Interface 2 0 2 0 0 02 000 5 21 Sequences 4k o se ee ed Eki a ba AL vi Oidide PTAMCS eee AA Aol bree a Bw ek 5 3 Modulation 2 gd 2 4 5 a a a e YB 5 3 1 Load Modulation 04 5 3 2 Modulation with Subcarrier 2 5 3 3 Digital modulation methods Standardization 6 1 ISO IEC and ECMA 20004 6 1 1 ECMA 340 NFC Interface and Protocol 6 1 2 ECMA 356 RF Interface Test Methods 62 NEC Eorum s marela a4 oo Dak Be ee ees be ode BO A 6 2 1 NFC RF Analog Technical Specification Draft 0 34 6 2 2 NFC RF Analog Test Specification Draft 0 16 6 2 3 NFC Digital Protocol Technical Specific
43. d Magnetic Flux Density The magnetic flux is a measure of the amount of magnetic field passing through a given surface and is expressed as dm Magnetic flux density is the amount of magnetic flux per unit area of a section perpendicular to the direction of flux The mathematical representation of magnetic flux density can be seen in Equation 3 1 5 _ Pm B A 3 1 5 Here B is magnetic flux density in teslas T m is magnetic flux in webers Wb and A is area in square meters m2 The relationship between flux density B and field strength H is expressed in Equation 3 1 6 B m ur H pu H 3 1 6 Here ug is the magnetic field constant uy 4r 1077 which describes the permeability of a vacuum The variable u is called relative permeability and indicates how much greater than or less than ug the permeability of a material is 3 1 3 Inductance L When a current flows in a conductor of any shape a magnetic field is generated around it The magnetic field will be stronger if the conductor is in the form of a coil A coil consists of N loops of the same area A through which the same current I flows The loops each contribute an equal amount of flux The total flux Y can be expressed as v Y y N N p H A 3 1 7 N The relationship between the magnetic flux and the current is called inductance and is denoted by L Y N N p H A L I I I 3 1 8 Enclosing current Figure 3 1 2 Definition of ind
44. e Inside Contactless ST Microelectronics Texas Instruments Broadcom Polaric etc 13 Chapter 5 RF and Digital Interface 5 1 RF Signal Interface 5 1 1 RF Specifications e The carrier frequency fe shall be 13 56 MHz 7 kHz e A reader shall generate an RF field of at least Hinin 1 5 A m within its defined operating volume e A reader shall not generate an RF field higher than Hig 7 5 A m at any point e If an external RF field with a field strength value equal to or greater than Hinreshola 0 1875 A m is detected the internal RF field must be switched off 5 1 2 Bit Duration The bit duration bp in NFC is dependent on the communication mode and the data rate chosen by the initiator which initializes the communication The bit duration can be calculated by the following equation _ 128 vey where fe is the carrier frequency and the value of the divisor D depends on the bit rate and is given by table 5 1 bp 5 1 1 Communication Mode kbps D active or passive 106 1 active or passive 212 2 active or passive 424 4 Table 5 1 Definition of divisor D the initial bit rate is determined by the initiator 14 5 1 3 Active Communication Mode In active communication mode the specification shall always be the same for both initiator to target and target to initiator communication At the lowest data transfer speed supported by NFC the initial bit rate shall be 106 kbps
45. e test assembly The field strength is then calculated from the measured voltage at the calibration coil where every 0 32 Vrms of measured voltage corresponds to a field strength of 1 A m as shown in equation 8 1 1 Ve alibrationCoi Fieldstrengthpop 2n A m 8 1 1 8 1 1 Target RF Level Detection The purpose of this test is to verify that the DUT detects an external RF field with a field strength in the range of HThreshola UP to Hmag as described in 6 1 2 The DUT is placed concentric with the sense coil and put into initiator mode e Signal Generator The SMU 200A is set to generate an unmodulated RF field at 13 56 MHz The field strength is then increased linearly from 0 up to Hing and the output power level where the phone switches off its RF field is noted This value is then used to measure the corresponding field strength with the calibration coil e Oscilloscope When a DUT set to initiator mode is placed on the test assembly the voltage induced in the closest sense coil will be altered due to the RF field generated by the DUT The signal at the output of the compensation board will therefore be out of balance and not be attenuated by the two counter phased sense coils This makes it easy to detect whether the DUT has its RF field switched on or off 8 1 2 Target Passive Communication Mode The purpose of these tests is to determine the amplitude of the target s load modulation signal while varying the field strength in the r
46. edge This gives a D1 value of 0 91 dB MKR Marker 2 Marker Delta Position the D2 marker at 5 amplitude of the rising edge This gives a D2 value of 25 11 dB 49 The parameter tl can now be acquired by simply checking the time value for D2 The measurements of parameters t2 t3 and t4 are carried out in the same way For parameter t2 set M1 at 5 amplitude of the falling edge to get a D1 value of 26 02 dB Marker D2 should now have a value of 0 dB Parameter t2 can now be read as the time value of D2 For parameter t3 set M1 at 90 amplitude of the rising edge to get a D1 value of 0 91 dB Marker D2 should now have a value of 25 11 dB Parameter t3 can now be read as the time value of D2 For parameter t4 set M1 at 60 amplitude of the rising edge to get a D1 value of 4 43 dB Marker D2 should now have a value of 21 59 dB Parameter t4 can now be read as the time value of D2 8 2 Micropross The calibration and measurement procedures for the Micropross setup are well documented and this report will therefore only have a guideline on which man uals to follow for the different procedures e Universal Test Bench 2010 User Manual Rev E This document describes all the connections in the setup the calibration of the test assembly and a description of all the separate parts used with the test assembly e MP Manager User Manual for Contactless RevC This document describes all the features of MP Manager and how t
47. ember 2003 ECMA International ECMA 340 Near Field Communication Interface and Protocol NFCIP 1 December 2004 ECMA International ECMA 356 NFCIP 1 RF Interface Test Methods June 2004 ECMA International ECMA 362 NFCIP 1 Protocol TestMethods De cember 2005 91 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 ISO IEC ISO 10373 6 Identification cards Test methods Part 6 Proximity cards April 2004 ISO IEC ISO 14448 Identification cards Contactless integrated circuit cards Proximity cards April 2004 ISO IEC ISO 18092 Information technology Telecommunications and information exchange between systems Near Field Communication In terface and Protocol April 2004 H S Kortvedt Securing Near Field Communication Master s Thesis Norwegian University of Science and Technology June 2009 Melexis Near Field Communication protocol MLX 90121 Rev 001 edition January 2005 Microchip microID 13 56 MHz RFID System Design Guide 2004 C Mulliner Attacking NFC Mobile Phones May 2008 NFC Forum NFC Digital Protocol Technical Specification 1 0 December 2010 NFC Forum NFC RF Analogue Technical Specification v 0 34 December 2010 NFC Forum NFC RF Analogue Test Specification v 0 15 January 2011 NXP PN544 C2 Data sheet April 2010 Confidential Austrian Institute of Technology Reference PICC V2
48. er Target Reader Writer and Card Emulator The following properties and requirements for NFC A NFC B and NFC F are explained e Sequence format e Bit level coding e Frame format 36 e Data and payload format e Command sets e Frame delay and guard times Active Communication mode is not described in the current version of this document 63 EMVCo EMVCo is a corporation owned by VISA American Express MasterCard and JCB and was formed in February 1999 EMVCo is responsible for several things such as managing maintaining and enhancing the EMV Integrated Circuit Card Specifications for Payment Systems and also ensuring interoperability and ac ceptance of payment system integrated circuit cards across the world The EMVCo standards are therefore the ones to follow when an NFC Device with Card Emulation mode is to be designed and tested The main focus is laying down the frameworks for wireless payments and making sure they are secure EMVCo has several specifications but only one is targeted for contactless pay ments The report will therefore only cover that specification EMV Contactless The EMV Contactless specification contains itself a few specifications The report will once again not use all of them since some of the specifications are targeted for payment terminals The relevant documents are EMV Contactless Communication Protocol Specification v2 0 1 and Level 1 Test Equipment Specifications The latter contains PICC Manu
49. ervisor Masar Sadik and our manager Mikael Persson for all help and guidance throughout this project We would also like to thank our supervisor Johan Nilsson at the Department of Measurement Technology and Industrial Electrical Engineering Finally we also want to give a special thanks to the following Max Kruse for providing us with all the measurement instruments during the project Murat Gumussoy and Imad Jalaly for all feedback and support List of Abbreviations AIT Austrian Institute of Technology ATR_REQ Attribute Request ATR_RES Attribute Response ASK Amplitude Shift Keying CMR Common Mode Rejection CRC Cyclic Redundancy Check dBm Logarithmic measure of power related to 1 mW HF power DUT Device Under Test ECMA European Computer Manufacturers Association EMVCo Europay MasterCard and Visa Corporation FSK Frequency Shift Keying IEC International Electrotechnical Commission ISO International Organization for Standardization LSB Least significant bit MSB Most significant bit NFCIP Near Field Communication Interface and Protocol NRZ Non Return to Zero Encoding NXP Next eXPerience Semiconductors PCB Printed Circuit Board PCD Proximity Close coupling Device PICC Proximity Integrated Circuit Card PSK Phase Shift Keying RF Radio Frequency RFID Radio Frequency Identification R amp S Rohde amp Schwarz SENS_REQ Sense Request SENS_RES Sense Response iii Nomenclature Initiator Poller Reader Target
50. esponse Set Field to 4 542 A m Test REQA ATQA expected ERR No Response Set Field to 4 551 A m Test REQA ATQA expected ERR No Response Set Field to 7 494 A m Test REQA ATQA expected ERR No Response Set Field to 7 544 A m Test REQA ATQA expected ERR No Response Set Field to 7 552 A m Test REQA ATQA expected ERR No Response ERR TC 8 2 106kbps NFC A Failed 3 Test Name TC 8 2 212kbps NFC F 212 Test Type 18092_NFC IP1 normative tests 8 Functional test Target TC 8 2 Target passive communication mode Test Result FAILED Test Log Set Field to 1 489 A m Test Polling request Polling response expected ERR No Response Set Field to 1 5 A m Test Polling request Polling response expected ERR No Response Set Field to 1 5 A m Test Polling request Polling response expected ERR No Response Set Field to 4 493 A m 3 6 12 02 2011 17 47 MP3 11 05 01 DUT A Sony Ericsson Test Polling request Polling response expected ERR No Response Set Field to 4 549 A m Test Polling request Polling response expected ERR No Response Set Field to 4 549 A m Test Polling request Polling response expected ERR No Response Set Field to 7 501 A m Test Polling request Polling response expected ERR No Response Set Field to 7 544 A m Test Polling request Polling response expected ERR No Response Set Field to 7 548 A m Test Polling request Polling response
51. ex The oscilloscope can also be used to determine that an ATR_RES is acquired 8 1 4 Initiator Field Strength This test measures the field strength produced by an initiator in its operating volume as described in 6 1 2 The reference devices defined in 6 1 2 are used to determine two things First of all that a DUT is able to supply a field strength of at least Hmin to power the target placed anywhere within the defined operating volume and secondly that it does not generate a field higher than the value Hing Once the reference devices have been calibrated the test assembly must not transmit any RF field The generated RF field could otherwise disturb the Hmin and Hmar Measurements e Signal Generator When calibrating the reference devices for Hmin and Himax the SMU 200A is set to produce 1 5 A m and 7 5 A m respectively when measuring with the calibration coil 48 Tuning of resonance frequency The jumper J1 is set to position a on the reference device The calibration coil is driven directly from the SMU 200A set at the required frequency 13 56 MHz for Hmin or 19 0 MHz for Hmaz The calibration coil and the reference device are located as close as possible with the axes of the two coils being congruent The reference device s capacitor C2 is adjusted to the maximum DC voltage at R1 measured with a high impedance voltmeter e Adjustment of R2 The jumper J1 is set to position b on the reference device The test assembly
52. f 128 For this bit rate the initiator shall use 100 ASK modulation of the RF operating field to generate pulses as shown in Figure 5 1 1 The envelope of the field shall decrease monotonically to less than 5 of its initial value Hynrryay and remain less than 5 for a duration of more than t2 see Table 5 2 Overshoots shall remain within 90 and 110 of Hrnrrraz The Target shall detect the End of Pulse after the field exceeds 5 of HiyrrraL and before it exceeds 60 of Hiwrrras as defined by t4 in table 5 2 This definition applies to all modulation envelope timings H Envelope of carrier amplitude 100 90 60 5 gt t 60 90 m ak t2 lt tl t3 Figure 5 1 1 Pulse shape of 100 ASK modulation Pulses length t1 us t2 us t3 us t4 us Condition t1 lt 2 5 t1 gt 2 5 Maximum 3 0 tl 1 5 0 4 Minimum 2 0 0 7 0 5 0 0 0 0 Table 5 2 Definition of time intervals in Figure 5 1 1 The byte encoding shall be LSB first for the bit rate 106 kbps When transfer ring data the following coding is used to represent bits Start of communication at the beginning of the bit duration a Pulse shall occur ONE after a time of half the bit duration a Pulse shall occur ZERO For the full bit duration no modulation shall occur with the following two exceptions If there are two or more contiguous ZEROs
53. from the second ZERO on a Pulse shall occur at the beginning of the bit duration If the first bit after a start of communication is ZERO a Pulse shall occur at the beginning of the bit duration End of Communication ZERO followed by one bit duration without mod ulation No information shall be coded with at least two full bit durations without modulation This method is referred to as Modified Miller coding When communication at a higher bit rate is selected by the initiator another scheme is used The bit rates for the transmission during initialization shall be 212 kbps f 64 or 424 kbps f 32 respectively The modulation scheme used is still ASK but with a modulation index of 8 to 30 of the operating field referred to as 10 ASK The modulation waveform shall comply with Figure 5 1 2 The rising and falling edges of the modulation shall be monotonic The modulation for the transmission during initialization and single device detection shall be the same The peak and the minimum signal amplitude are defined by a and b 16 Envelope of carrier amplitude Figure 5 1 2 Waveform of 10 ASK modulation 212 kbps 424 kbps tr 2 0us max 1 0us max tr 2 0us max 1 0us max y 0 1 a b 0 1 a b hy hy 0 1 a b mazx 0 1 a b mazx Table 5 3 Definition of time intervals in Figure 5 1 2 The byte encoding shall be MSB first and the bit representat
54. h up to Hmaz should be done through the cali bration coil with no DUT on the test assembly Before any measurements are made the test assembly has to be calibrated The first part of the calibration is to make sure that the impedance matching circuit on the field generating antenna PCD is adapted to the SMU 200A out put impedance of 50 Q The command sequences used are sent to the DUT with the K6 Pulse Se quencer Software To start with the NFC project is loaded through the file menu The project contains all necessary plug ins and sequences to perform the RF Interface tests The command to be sent is selected in the sequence library and built into a waveform When the waveform is created the final settings such as frequency and output power for the SMU 200A are set on the transfer tab Note that care should be taken to make sure that the defined output power from the software does not exceed the maximum input power of the amplifier used Triggering the oscilloscope can be quite tricky but since the pulse lengths for the different bit rates are known it makes the procedure easier Pulse triggering is selected with the corresponding pulse width for the different bit rates The appropriate threshold level is adjusted depending on the chosen polarity 46 Reader Field Strength The field strength emitted from the test assembly is determined by a high impedance voltage measurement using the oscilloscope connected to the calibration coil of th
55. ice 1 Test Name TC 8 1 Target RF level detection Test Type 18092_NFC IP1 normative tests 8 Functional test Target Test Result FAILED Test Log HThreshold 0 6987 A m ERR TC 8 1 Target RF level detection Failed 2 Test Name Procedure for Hmax Test Type 18092_NFC IP1 normative tests 9 Functional test Initiator TC 9 1 Initiator Field strength in active and passive communication Test Result PASSED Test Log Results The maximum measured value is 0 52 V lt TC 9 1 Initiator field strength in active and passive communication Hmax Succeeded 3 Test Name Procedure for Hmin Test Type 18092_NFC IP1 normative tests 9 Functional test Initiator TC 9 1 Initiator Field strength in active and passive communication Test Result FAILED Test Log Results The maximum measured value is 2 4 V at 0 mm and 1 2 V at 10 mm ERR TC 9 1 Initiator field strength in active and passive communication Hmin Failed 4 Test Name Calibration coil Test Type 18092_NFC IP1 normative tests 9 Functional test Initiator TC 9 2 Initiator modulation index and waveform in active and passive communication TC 9 2 106kbps NFC A Test Result PASSED Test Log Measures tl Measured 2830 ns lt OK 2 4 19 02 2011 16 39 MP3 11 05 01 DUT C Sony Ericsson t2 Measured 1836 ns lt OK t3 Measured 350 ns lt OK t4 Measured 141 ns lt OK overshoot Measured 106 02 lt
56. ification that can be used as the ba sis for testing and approvals The NFC RF Analog Technical Specification is currently in a draft version and is slated for a September 2011 release NFC Technologies The different NFC technologies defined in the Analog Technical Specification use the same frequency but use different modulation schemes bit level coding and frame formats The protocols and commands may also differ Table 6 1 illustrates the characteristics Technology Direction Modulation scheme Bit coding NFC A Initiator Target 100 ASK Modified Miller Target Initiator On Off Keying Manchester NFC B Initiator Target 10 ASK NRZ L Target Initiator BPSK NRZ L NFC F Both 10 ASK Manchester Table 6 1 Comparison of NFC technologies 30 NFC Forum Reference Devices In order to perform all the various tests stated in the Analog Test Specifications a number of different devices called NFC Forum Reference Polling Devices and NFC Forum Reference Listening Devices are needed Signal generators and power amplifiers are needed to allow the NFC Forum Reference Polling Devices to send commands while the response from an NFC Forum Reference Listening Device can be observed through e g a connected oscilloscope An NFC Forum Reference Polling Device is used when a Listening Device is to be tested and an NFC Forum Reference Listening Device is used when a Polling Device is to be tested
57. ion shall be Manch ester coding with obverse amplitude as shown in Figure 5 1 3 Reverse polarity in the amplitude of the Manchester symbols is permitted The target shall respond with the same load modulating scheme but the bit duration of the Manchester coding must be changed so that it matches the bp related to the actual bit rate The byte encoding shall be MSB in this direction too E 1 bit i ONE Figure 5 1 3 Manchester bit encoding with obverse amplitude 17 5 1 4 Passive Communication Mode In passive communication mode the specifications differ slightly for initiator to target and target to initiator communication Initiator to Target The modulation byte encoding bit representation and coding for the different bitrates from the initiator to the target shall be the same as in active communication mode with the corresponding bit rates Target to Initiator The target shall respond via load modulation generating a subcarrier with frequency fs f 16 The load modulation amplitude has to exceed a minimum value relative to the strength of the present magnetic field Bit representation shall be performed by Manchester coding with obverse amplitude Bytes shall be encoded with LSB first for the bit rate 106 kbps and MSB first for the higher bitrates 5 2 Digital Signal Interface 5 2 1 Sequences An incoming or outgoing signal is called a sequence A receiving device needs information on when to begin a
58. mp S K6 Pulse Sequencer The reason for using this software was that it allowed complex pulses and pulse patterns to be generated and sent to the SMU 200A through any VISA interface The software also supported custom plug ins for additional test cases 41 7 2 Micropross The Micropross measurement setup can be seen in Figure 7 2 1 It consists of a signal generator a test assembly an oscilloscope and an amplifier 42 ANN ih j Figure 7 2 1 Test setup Micropross 43 7 2 1 Signal Generator The Micropross solution uses a proprietary signal generator called TCL2 It does not have a display and is completely controlled by the MP Manager soft ware described in 7 2 5 7 2 2 Test Assembly The test assembly is mainly built according to ECMA 356 and has a few addi tions e Integrated calibration coil beneath the lower sense coil on the test assem bly e A 35 mm TRS connector on the field generating antenna PCD This connector allows the TCL2 to make the choice between the two antenna matchings used for the lower and higher data rates respectively e A connector on the upper sense coil allowing the signal from the DUT to be sent back to the TCL2 7 2 3 RF Amplifier The amplifier is an M2S A121 25 FLT and has a variable RF gain adjustment on the front panel This is needed since the output power cannot be adjusted manually from the TCL2 7 2 4 Digital Oscilloscope The oscilloscope is a Tektronix DPO 4034 and is
59. nd cost half as much it was decided that the assembly should be ordered from AIT AIT only delivered a test assembly with no software or hardware and thus additional hardware was required to perform the measurements Rohde amp Schwarz equipment was cho sen for the AIT test assembly A complete test solution from Micropross was acquired a few weeks before the end of the thesis and we were therefore also able to perform measurements with this system This chapter describes the instruments and tools that are used to perform the necessary tests 7 1 Rohde amp Schwarz AIT The R amp S AIT measurement setup can be seen in Figure 7 1 1 It consists of a signal generator a test assembly an oscilloscope a spectrum analyzer and an amplifier 39 Figure 7 1 1 Test setup R amp S AIT 40 7 1 1 Signal Generator To drive the field generating antenna in the test assembly described in 6 1 2 a signal generator was used The signal generator was a Rohde amp Schwartz SMU 200A with an added software option called K6 This option was needed for communication between the SMU 200A and the R amp S K6 Pulse Sequencer software described in 7 1 6 7 1 2 Test Assembly The assembly was delivered with a 50 2 SMB connector mounted on the PCB with the field generating antenna Since this type of connector was not used at Sony Ericsson and no adapters were acquirable within a reasonable time the SMB connector was replaced with an SMA connector
60. nd stop demodulation and how to recognize a se quence Therefore a sequence always starts and ends with a specific bit pattern The start and end patterns help the receiving device to synchronize with the sender and to identify a valid sequence and therefore allow to extract infor mation included in the sequence The information transported in a sequence is a collection of bits included in a frame 5 2 2 Frames Data transmitted between initiator and target is grouped in frames The format of the frame differs between initialization and data transfer in passive commu nication mode Two types of data frames are used for passive communication at 106 kbps During initialization short frames are used A short frame consists of 7 bits of data together with a start and stop bit See Figure 5 2 1 Pd a 6 al dl Start Command End Figure 5 2 1 Short frame 18 For data exchange at 106 kbps standard frames are used and the structure is shown in Figure 5 2 2 q Transport Data Field Figure 5 2 2 Frame format for 106 kbps The start byte SB shall be set to OxF0 The length byte LEN shall be set to the length of the Transport Data field plus 1 The value of LEN shall be in the range of 3 to 255 CMDO and CMD1 are command bytes El is the CRC for the Frame format of 106 kbps The LSB of each byte shall be transmitted first Each byte shall be followed by an odd parity bit For data frames used in passive communication mode at 212
61. ngth value of 0 0706 A m The DUT passes the test with a good margin since the threshold value for RF level de tection is 0 1875 A m 51 7 50ps 9 203mV s 6 406mv 13 A321us 2 J C kom iam y jT ax am REETA jor Ea j J cm ame 00 Figure 9 1 1 To the left the RF field is turned on to the right the RF field is turned off since an external RF field is detected Target Passive Communication Mode The DUT does not support passive communication mode at higher bit rates and the tests have therefore been omitted For the bit rate 106 kbps a SENS REQ command is sent from the signal generator to obtain a SENS_RES from the DUT In Figure 9 1 2 we see the SENS_REQ sent from the signal generator and the load modulated SENS_RES from the DUT Tek _200mv Pork 1 332V 1 332 1 332 1 332 0 000 E J RMS 409 6mY_409 6m_409 6m_409 6m__0 000 gt gt 165 480us o Figure 9 1 2 A SENS_REQ command is seen to the left and a SENS_RES command to the right ST z0 5 gt The amplitudes of the sidebands are measured as described in 6 1 2 The load modulation amplitude shall be at least Amin 30 H mV The frequency responses for Hmin and Hmax are seen in Figures 9 1 3 and 9 1 4 52 Tek Prevu ca 14 400MH2 O 12 700MH2 29 2 dB A1 7000MH2 A3 60 dB d dt 25 6 dB 2 124dB H2
62. not as automated as the solution from Micropross Another disadvantage is that it does not support testing in active communication mode This was however not an issue during the thesis since there were no available handsets that supported active communication mode 10 1 Future work Micropross currently offers an automated reference PICC and a robotic arm which considerably facilitates testing of the operating volume These items should be considered to complement the existing measurement setup to make testing even more automated Rohde amp Schwarz is currently working on a brand new NFC solution based on NFC Forum specifications Communication with R amp S needs to be main tained to follow the development as they stand at Sony Ericsson s disposal for any possible feature requests Once Google has released an Android version that supports card emulation mode the testing on DUT B and C should be continued to verify the perfor mance in target mode with the NXP PN544 and PN65 chips 73 Appendix A Micropross Test Reports A l DUTA 12 02 2011 17 47 MP3 11 05 01 DUTA Sony Ericsson TEST SUITE REPORT Device Name TCL2 Device Serial Number MP3 11 05 01 Testing Date Report Date Description Operator Manufacturer Reference Reference DUT Device Under Test 12 02 2011 17 47 12 02 2011 17 59 Bekir DUTA 1 RESULT TABLE 1 1 Test Suite Name ISO 22536 RF NFC Device Test Type Tes
63. o 900 mV per A m Field Generating Antenna A precise and reproducible measurement of the load modulation signal at the antenna of a reader is very difficult due to the weak signal The standard therefore defines a compensation board which can be used to compensate the reader s own strong signal The measuring arrangement for this consists of a field generating antenna and two parallel sense coils The field generating antenna shall be tuned to 50 Q by the matching circuit located on the antenna PCB using suitable measurement equipment such as an impedance analyzer or a measurement bridge Sense Coils The two sense coils are located on the front and back of the field generating antenna each at the same distance from it They are connected in phase opposition to one another so that the voltages induced in the coils cancel each other out see Figure 6 1 2 In the unloaded state the output voltage of this circuit arrangement therefore tends towards zero A low residual voltage which is always present between the two sense coils as a result of tolerance related asymmetries can be compensated by the potentiometer on the compensation board 25 ja dis p e dis Active conductors 3 mm air spacing Calibration coil Sense coil a Sense coil b Field generating antenna Figure 6 1 2 Test assembly Reference Devices Reference devices are needed to be able to verify that an initiator generates a field between Hmin and Hmax
64. o use them e User Manual Test suite ISO 22536 RF Rev B This document gives a brief overview on how to use MP Manager for the ISO 22536 test cases MP Manager provides clear instructions often with pictures when a test is executed 50 Chapter 9 Test Results All tests are performed according to the procedures specified in the ISO ECMA NFC standards In Figure 6 2 7 Chapter 6 the operating volume with the defined test positions by the NFC Forum were shown In the ISO ECMA standards no such test positions are defined In our case we positioned the calibration coil at 0 and 10 mm distance from the DUT The calibration coil was moved around at these fixed distances until the maximum voltage was obtained Note that the distance 10 mm is not defined in any standard and is merely used for comparison 9 1 Rohde amp Schwarz AIT This measurement setup is not able to perform any tests in target active com munication mode These tests are therefore not performed 9 1 1 DUTA Target RF Level Detection The DUT has its RF field on and polls continuously as long as no external field is present and switches off as soon as a field is detected This makes it easy to find the threshold value of the DUT see Figure 9 1 1 The DUT detects the external RF field from the test assembly at an output power of 57 2 dBm from the signal generator The voltage measured at the calibration coil is 22 6 mV grms which corresponds to a field stre
65. ocated within the near field of the reader s antenna The transition to the far field occurs at 0 16 A If the data on a chip controls the timing with which the load resistor is switching then this data can be sent from the target to the reader 5 3 2 Modulation with Subcarrier Due to the weak coupling factor between the reader s and the target s antenna the target s response is approximately 80 dB lower than the voltage generated by the reader The detection of such a signal requires complicated receiving circuitry Instead of using direct load modulation as explained in 5 3 1 the target uses a subcarrier frequency fs to modulate data When an additional load resistor in the target is switched on and off at a high frequency fs two modulation sidebands are created at a distance of f from the carrier frequency of the reader fe see Figure 5 3 1 13 56 MHz 0 dB fe N Carrier signal of the reader measured at the antenna coil guns oN Modulation product by DN load modulation with subcarrier 12 7125 MHz 14 4075 MHz 80 dB fs Figure 5 3 1 Modulation products using load modulation with a subcarrier To separate the sidebands from the significantly stronger carrier signal band pass filtering is used The filtered subcarrier signal is then amplified at the reader making it easy to demodulate 20 The procedure for subcarrier load modulation is as follows e The target generates the subcarrier frequency
66. ot reaching 3 V at any position Initiator Modulation Index and Waveform Due to poor matching triggering on the higher bit rates is not possible and the tests for these bit rates have been omitted For 106 kbps the timing results are illustrated in Figures 9 1 15 9 1 18 63 amp RBW 3 MHz Att OdB VBW 10 MHz D2 1 25 07 dB Ref 10 0 nV SWT 154s 2 814226250 us pesa 15 687959149 mV 1Rr 6 182492500 ys Clrw 100 mv 0 91 dB 1 068898750 us Gat Vid 400 uv CF 13 56 MHz Date 12 FEB 2011 20 59 47 Figure 9 1 15 Parameter t1 is acquired by reading the time value for D2 RBW 3 MHz Att 0dB VBW 10 MHz M1 1 870 902668600 LV Ref 10 0 mV SWT 15 1s 7 280773750 us pe 26 02 dB 1Rr 2 167180000 ys Clrw 100 mv 0 04 dBj 1 715945000 us vIPOS 9 988 mV Gat Vid 100 pv CF 13 56 MHz Date 12 FEB 2011 21 02 23 Figure 9 1 16 Parameter t2 is acquired by reading the time value for D2 64 RBW 3 MHz Att OdB VBW 10 MHz M1 1 15 670733556 mV Ref 10 0 mV SWT 15us 9 295461250 us 0 92 dB 4 181867500 us 25 06 dB 298 742500000 ns CF 13 56 MHz D
67. pe 18092_NFC IP1 normative tests 9 Functional test Initiator TC 9 1 Initiator Field strength in active and passive communication Test Result PASSED Test Log Results The maximum value measured is 1 36 V lt TC 9 1 Initiator field strength in active and passive communication Hmax Succeeded 3 Test Name Procedure for Hmin Test Type 18092_NFC IP1 normative tests 9 Functional test Initiator TC 9 1 Initiator Field strength in active and passive communication Test Result PASSED Test Log Results The maximum measured value is 4 17 V at 0 mm and 3 1 V at 10 mm lt TC 9 1 Initiator field strength in active and passive communication Hmin Succeeded 4 Test Name Calibration coil Test Type 18092_NFC IP1 normative tests 9 Functional test Initiator TC 9 2 Initiator modulation index and waveform in active and passive communication TC 9 2 106kbps NFC A Test Result PASSED Test Log Measures tl Measured 2782 4 ns 2 4 12 02 2011 18 03 MP3 11 05 01 DUT B Sony Ericsson lt OK t2 Measured 2244 ns lt OK t3 Measured 386 ns lt OK t4 Measured 266 4 ns lt OK overshoot Measured 104 35 lt OK m Measured 97 73 lt OK lt TC 9 2 Initiator 106kbps NFC A Succeeded 5 Test Name Calibration coil Test Type 18092_NFC IP1 normative tests 9 Functional test Initiator TC 9 2 Initiator modulation index and waveform in active and
68. r Reference Reference DUT Device Under Test 19 02 2011 16 39 19 02 2011 16 47 Bekir DUT C 1 RESULT TABLE 1 1 Test Suite Name ISO 22536 RF NFC Device Test Type Test Name Log Status 18092_NFC IP1 normative tests 8 Functional test Target TC 8 1 Target RF level detection FAILED 18092_NFC IP1 normative tests 9 Functional test Initiator TC 9 1 Initiator Field strength in active and passive communication Procedure for Hmax PASSED 18092_NFC IP1 normative tests 9 Functional test Initiator TC 9 1 Initiator Field strength in active and passive communication Procedure for Hmin FAILED 18092_NFC IP1 normative tests 9 Functional test Initiator TC 9 2 Initiator modulation index and waveform in active and passive communication TC 9 2 106kbps NFC A Calibration coil PASSED 18092_NFC IP1 normative tests 9 Functional test Initiator TC 9 2 Initiator modulation index and waveform in active and passive communication TC 9 2 212kbps NFC F 212 Calibration coil FAILED 18092_NFC IP1 normative tests 9 Functional test Initiator TC 9 2 Initiator modulation index and Calibration coil FAILED 1 4 19 02 2011 16 39 MP3 11 05 01 DUT C Sony Ericsson waveform in active and passive communication TC 9 2 424kbps NFC F 424 2 DETAIL REPORT 2 1 Test Suite Name ISO 22536 RF NFC Dev
69. re questions the available help was limited due to the lack of experience in the area at the company Also the initial order of the test setup had to be done very early due to long delivery times and the general time con straints of the thesis The ISO ECMA standards for NFC are not very clear when the test cases calibration and requirements are explained ECMA 340 and ECMA 356 have not been updated since 2004 but the NFC Forum is fortunately working on rewriting and improving the RF specifications In these new specifications the test assembly used in ECMA 356 is replaced with Reference Devices and EMVCo testing capabilities are added together with RFID Type B The RF specifications are not yet finalized and have been delayed several times The latest update provided is that the Analog Specification will be ready by Septem ber 2011 and the Analog Test Specification by February 2012 The solution from Micropross is very promising although some improvements have to be made for it to be a completely viable solution There are a few limitations in the software e g changing pause timing and the way the soft ware operates with the oscilloscope These issues have been reported directly to Micropross As shown in Chapter 9 our own measurement setup provides virtually the same results as the solution from Micropross The neglectable differences are most likely due to measurement uncertainties 72 A disadvantage with the setup is that it is
70. se is to provide detailed instructions on how each test from the Analog Specification should be executed It is important to note that this specification is under construction and a few chapters are either very short or completely blank It is currently scheduled for a February 2012 release Positioning Conventions and Requirements The specification elaborates on environment requirements naming conventions operating volume and test position definitions There is as of this report no exact definition for how many test positions must be passed for a DUT to pass completely It is still under discussion by the members of the NFC Forum and so far there are only suggestions that are still being evaluated In Figure 6 2 7 the operating volume with the defined test points in blue is shown 34 Z axis r axis Reference Mark Figure 6 2 7 Operating volume Test Bench The test bench needed for the measurements consists of the NFC Reference Devices and external measurement equipment The role requirements and configuration together with uncertainty ranges of each part of the test bench are explained The complete test bench setup is shown in Figure 6 2 8 Generation Test Bench Measurement Measuring Waveform tool NFC Forum Reference Listening Device MAN Field me Strength NFC Forum Reference Polling Device Measuring Field tool Listening Device response generator Polling Device command generator Measuring
71. t TC 8 1 Target RF level detection FAILED 18092_NFC IP1 normative tests 9 Functional test Initiator TC 9 1 Initiator Field strength in active and passive communication Procedure for Hmax PASSED 18092_NFC IP1 normative tests 9 Functional test Initiator TC 9 1 Initiator Field strength in active and passive communication Procedure for Hmin PASSED 18092_NFC IP1 normative tests 9 Functional test Initiator TC 9 2 Initiator modulation index and waveform in active and passive communication TC 9 2 106kbps NFC A Calibration coil PASSED 18092_NFC IP1 normative tests 9 Functional test Initiator TC 9 2 Initiator modulation index and waveform in active and passive communication TC 9 2 212kbps NFC F 212 Calibration coil PASSED 18092_NFC IP1 normative tests 9 Functional test Initiator TC 9 2 Initiator modulation index and Calibration coil PASSED 1 4 12 02 2011 18 03 MP3 11 05 01 DUT B Sony Ericsson waveform in active and passive communication TC 9 2 424kbps NFC F 424 2 DETAIL REPORT 2 1 Test Suite Name ISO 22536 RF NFC Device 1 Test Name TC 8 1 Target RF level detection Test Type 18092_NFC IP1 normative tests 8 Functional test Target Test Result FAILED Test Log HThreshold 0 2272 A m ERR TC 8 1 Target RF level detection Failed 2 Test Name Procedure for Hmax Test Ty
72. t Name Log Status 18092_NFC IP1 normative tests 8 Functional test Target TC 8 1 Target RF level detection PASSED 18092_NFC IP1 normative tests 8 Functional test Target TC 8 2 Target passive communication mode TC 8 2 106kbps NFC A FAILED 18092_NFC IP1 normative tests 8 Functional test Target TC 8 2 Target passive communication mode TC 8 2 212kbps NFC F 212 FAILED 18092_NFC IP1 normative tests 9 Functional test Initiator TC 9 1 Initiator Field strength in active and passive communication Procedure for Hmax PASSED 18092_NFC IP1 normative tests 9 Functional test Initiator TC 9 1 Initiator Field strength in active and passive communication Procedure for Hmin FAILED 18092_NFC IP1 normative tests 9 Functional test Initiator TC 9 2 Initiator modulation index and waveform in active and passive communication TC 9 2 106kbps NFC A Calibration coil PASSED 18092_NFC IP1 normative tests 9 Functional test Initiator TC 9 2 Initiator modulation index and Calibration coil FAILED 1 6 12 02 2011 17 47 MP3 11 05 01 DUT A Sony Ericsson waveform in active and passive communication TC 9 2 212kbps NFC F 212 2 DETAIL REPORT 2 1 Test Suite Name ISO 22536 RF NFC Device 1 Test Name TC 8 1 Target RF level detection Test Type 18092_NFC IP1 normative tests 8 Functional
73. test Target Test Result PASSED Test Log HThreshold 0 0653 A m lt TC 8 1 Target RF level detection Succeeded 2 Test Name TC 8 2 106kbps NFC A Test Type 18092_NFC IP1 normative tests 8 Functional test Target TC 8 2 Target passive communication mode Test Result FAILED Test Log Set Field to 1 486 A m Test REQA ATQA expected lt ATQA 0002 CSV Creation C Documents and Settings 23058 147 Desktop ISO 22536 NFC Device RF EXEC Version 1 1 3180 22536 RF NFC Device Tmp T001_F001_F002_F003_12022011_174724 fourier_points_1 5A m 0 csv Uabs 30 044 mVp Labs 20 914 mVp Vima 18 656 mVp lt OK Set Field to 1 452 A m Test REQA ATQA expected lt ATQA 0002 CSV Creation C Documents and Settings 23058147 Desktop ISO 22536 NFC Device RF EXEC Version 1 1 3 ISO 22536 RF NFC Device Tmp T001_F001_F002_F003_12022011_174724 fourier_points_1 5A m 1 csv Uabs 29 598 mVp Labs 21 128 mVp Vima 19 18 mVp lt OK Set Field to 1 453 A m Test REQA ATQA expected lt ATQA 0002 2 6 12 02 2011 17 47 MP3 11 05 01 DUT A Sony Ericsson CSV Creation C Documents and Settings 23058147 Desktop ISO 22536 NFC Device RF EXEC Version 1 1 3 ISO 22536 RF NFC Device Tmp T001_F001_F002_F003_12022011_174724 fourier_points_1 5A m 2 csv Uabs 31 574 mVp Labs 19 409 mVp Vima 19 159 mVp lt OK Set Field to 4 494 A m Test REQA ATQA expected ERR No R
74. th the RF and digital interface and modulation The main standards are then explained with focus on the ISO ECMA standard By then the reader will have been introduced to all the theoretical background of the technology the following two chapters describe the complete measurement setup and mea surement procedures This is then followed by a chapter containing the test results from all the DUTs used The thesis is summed up with a discussion of the findings a conclusion of the work and suggestions for future proceedings Chapter 2 RFID Basics 2 1 Historical Overview RFID has its origin in military identification systems and was implemented already during World War II in order to identify planes a system known as Identification Friend or Foe IFF The RFID technology was further developed to enable systems to be used for low cost commercial applications The first developments were of electronic surveillance tags They contained two states on and off and if the state had not been switched off when the tag passed the readers the alarm would go off The first tags to exist were passive but with time active tags were also introduced RFID is today a widespread technology used in infrastructures all over the world 2 2 Components of an RFID System An RFID system consists of two components The transponder or tag which is located on the object to be identified and the reader which may be either a read or read write device see Figure 2
75. tive tests 9 Functional test Initiator TC 9 2 Initiator modulation index and waveform in active and passive communication TC 9 2 212kbps NFC F 212 Test Result FAILED Test Log Measures tf Measured 740 ns lt OK m Measured 0 22 ERR m not between 8 and 30 NOK tr Measured 5729 6 ns ERR tr not between 0 ns and 2000 0 ns NOK hf Measured 0 234 V ERR hf not between O V and 0 0002 V NOK hr Measured 0 018 V ERR hr not between 0 V and 0 0002 V NOK m Measured 0 3 ERR m not between 8 and 30 NOK ERR TC 9 2 Initiator 212kbps NFC F 212 Failed 3 SUMMARY REPORT 3 1 Test Suite Name ISO 22536 RF NFC Device Log Status Number Passed 3 42 86 Failed 4 57 14 Not Applicable 0 0 00 Inconclusive 0 0 00 5 6 12 02 2011 17 47 MP3 11 05 01 DUT A Sony Ericsson Error 0 0 00 TOTAL 7 100 Ooo End of Report 000 6 6 A 2 DUT B 81 12 02 2011 18 03 MP3 11 05 01 DUT B Sony Ericsson TEST SUITE REPORT Device Name TCL2 Device Serial Number MP3 11 05 01 Testing Date Report Date Description Operator Manufacturer Reference Reference DUT Device Under Test 12 02 2011 18 03 12 02 2011 18 16 Bekir DUTB 1 RESULT TABLE 1 1 Test Suite Name ISO 22536 RF NFC Device Test Type Test Name Log Status 18092_NFC IP1 normative tests 8 Functional test Targe
76. ts RF field for values equal to or above Hinreshola 0 1875 A m and switches on its RF field for values below Hihreshola the test passes 27 Target Passive Communication Mode The purpose of this test is to de termine the amplitude of the sidebands of the load modulated signal from the passive target This test shall be done for field strength values between Hmin and Hmaz The amplitude shall be at least 30 This means that for a field strength of 1 5 A m Hmin the minimum amplitude 1S 30 1512 18 44 mV and for a field strength of 7 5 A m Hmax the minimum amplitude Amin is 30 7 512 This test shall be performed for the three specified bit rates 106 kbps 212 kbps and 424 kbps Since different bit coding schemes are used for 212 kbps and 424 kbps compared to 106 kbps the test methods are slightly different 2 67 mV In the 106 kbps case a SENS_REQ command shall be sent to the DUT to obtain a SENS_ RES The amplitude of the upper sideband at f fs and the lower sideband f fs the applied fields and modulations shall be measured in this test Exactly two subcarrier cycles of the sampled modulation waveform shall be Fourier transformed If the amplitude of the sidebands is above Amin the test passes For 212 kbps and 424 kbps a polling request is sent to the DUT to obtain a polling response If the amplitude of the sidebands is above Amin the test passes This test shall be repeated with different field strengths
77. ts are seen in Table 9 12 and 9 13 Time parameter tl t2 t3 t4 Time ns 2847 2 2088 8 304 185 6 Table 9 12 Parameter values for DUT A Overshoots 107 48 Modulation index 96 26 Table 9 13 Parameter values for DUT A The modulation index timings and overshoots are within the defined limits The test passes Summary Test Result Target RF level detection PASS Target passive communication mode FAIL Initiator field strength FAIL Initiator modulation index and waveform PASS Table 9 14 Summary of test results for DUT A 68 9 2 2 DUTB Target RF Level Detection The DUT turns off its RF field when the external RF field has a field strength value of 0 2272 A m The test fails Target Passive Communication Mode The DUT is currently running Android 2 3 Gingerbread which does not support card emulation mode Initiator Field Strength Parameter Distance mm Voltage V Amin 0 4 17 10 3 1 Hees Any 1 36 Table 9 15 Field strength values for DUT B The test passes Initiator Modulation Index and Waveform For 106 kbps the results are seen in Table 9 16 and 9 17 Time parameter tl t2 t3 t4 Time ns 2782 4 2244 386 266 4 Table 9 16 Parameter values for DUT B Overshoots 104 35 Modulation index 97 73 Table 9 17 Parameter values for DUT B
78. tted For 106 kbps the DUT passes at 1 5 A m When the test was performed with higher field strength values no answer was received from the DUT This was very odd since the DUT passed the test with the R amp S AIT setup for field strength values up to 7 5 A m After some troubleshooting we noticed that the pause timing on the R amp S signal generator was 2500 ns compared to 2100 ns on the signal generator from Micropross We decided to use Shmoo to study the behaviour of the DUT when the field strength was increased A script containing a SENS_ REQ was loaded and sent with increasing pause timing at different field strengths The pause timing was varied between 0 and 3000 ns with a step size of 50 ns and the field strength was varied between 0 and 7 5 A m with a step size of 5 As seen in Figure 9 2 1 the required pause timing x axis increases with increased field strength y axis Figure 9 2 1 Shmoo data for DUT A 67 Initiator Field Strength Parameter Distance mm Voltage V Hinin 0 1 44 10 0 72 Hnos Any 0 35 Table 9 11 Field strength values for DUT A The test fails due to Hmin not reaching 3 V at any position Initiator Modulation Index and Waveform For 212 kbps the DUT does not provide a stable enough signal to trigger on Since no proper triggering can be done the tests for this bit rate have been omitted The DUT does not support communication at 424 kbps For 106 kbps the resul
79. uctance L The inductance of a conductor loop is dependent on the geometry of the layout and the permeability of the medium that the flux flows through 3 1 4 Mutual Inductance M Mutual inductance describes the coupling of two circuits with a magnetic field and always exists between two electric circuits Its unit and dimension are the same as for inductance Mutual inductance is the physical principle which RFID systems are based upon If a second conductor loop with an area As is located in the vicinity of the first conductor loop with area A through which a current is flowing then this will lead to a portion of the total magnetic flux flowing through A to also flow through Ay The two conductor loops hereby referred to as coils are then connected by this flux The magnitude of the coupling flux V2 depends on the position in relation to each other the magnetic properties of the medium and the dimensions of the coils The ratio of the partial flux Wo enclosed by the second coil to the current J in the first coil is equal to the mutual inductance Mb of the second coil in relation to the first coil as seen in Equation 3 1 9 Voi h Bo t M 21 T ESI dAy 3 1 9 For the mutual inductance M2 the coupling flux Wy in the first coil is deter mined by the current I gt flowing through the second coil The relationship between the mutual inductances is as follows M Mi My 3 1 10 If the magnetic field is
80. um aids all interested parties in creating new consumer driven products and applications through the provided frameworks in the specifications 29 The main goals of the NFC Forum are to e Develop standards based NFC specifications that define architecture and interoperability parameters for NFC devices and protocols e Encourage the development of products using NFC Forum specifications e Work to ensure that products claiming NFC capabilities comply with NFC Forum specifications e Educate consumers and enterprises globally about NFC As of December 2010 the NFC Forum has developed and adopted a total of 15 specifications In this report three specifications will be described The first is the NFC RF Analog Technical Specification followed by NFC RF Analog Test Specification and finally the NFC Digital Protocol Technical Specifications 6 2 1 NFC RF Analog Technical Specification Draft 0 34 This document covers the analog interface of an NFC Forum Device The device shall support Peer Mode Initiator Peer Mode Target Reader Writer Mode and Card Emulation Mode for the three technologies NFC A NFC B and NFC F for the bit rates 106 kbps 212 kbps and 424 kbps The purpose of the specification is to characterize and specify power transmission and receiver requirements as well as time frequency and modulation characteristics for an NFC Forum Device without specifying a design of the antenna In short the document provides a spec
81. values Target Active Communication Mode The purpose of this test is to verify that the generated RF field and modulation of active targets fulfill the specifi cations when the field strength is varied between Hmin and Hmazgz for the three specified bit rates 106 kbps 212 kbps and 424 kbps The modulation levels and pulse shapes generated by the DUT shall be ver ified If the modulation index of the targets RF field the timing of the RF field generation and the command sequence at all data rates are according to specification the test passes a b b minimum signal amplitude respectively with the value of the index expressed as a percentage The modulation index is defined as where a and b are the peak and the 28 RF Interface Initiator Tests This section describes the tests performed on a DUT in initiator mode Initiator Field Strength The purpose of this test is to verify that an ini tiator generates a field between Hmin and Hmax in the entire operating volume in active and passive communication mode The test is carried out with the reference devices described in 6 1 2 For the testing of Hmaz the reference device is tuned to 19 MHz The voltage measured with a high impedance voltage meter should be 3V DC for a field equal to Hing The reference device is placed within the operating volume of the initiator and the test passes if the voltage across the resistor R on the reference device does not exceed 3V DC at
82. vices can be seen in Figures 6 2 4 6 2 6 32 NFC FORUM LISTENER 1 NFC FORUM LISTENER 3 ia UDC OUT SENSE GND SENSE Figure 6 2 5 NFC Forum Reference Listener 3 NFC FORUM LISTENER 6 Cc INNovVvIsion IRT APR 2010 F5010 1162 01 Figure 6 2 6 NFC Forum Reference Listener 6 33 Test Descriptions Each test that has to pass in order to comply with the NFC RF Analog Tech nical Specification is described with a small introduction purpose context and requirements It is important to note that this document does not contain the actual test instructions but rather general requirements of the tests The first tests describe requirements for the unmodulated signals The following tests explain the signal interface requirements between a Reference Polling Device and a Listening Device and a Reference Listening Device and a Polling Device respectively Appendices The first appendix provides all the specific numerical values for operating vol ume RF power and signal interface It also provides setup values and nominal settings as well as calibration procedures for the NFC Forum Reference Devices The second appendix provides all the design information for the NFC Forum Reference Devices including circuit diagrams PCB layouts and mechanical di mensions 6 2 2 NFC RF Analog Test Specification Draft 0 16 This document explains in detail the test cases for the NFC RF Analog Tech nical Specification Its purpo
83. when a loaded target is within the operating volume The initiator shall be capable of supplying a target with sufficient energy in the whole operating volume defined for the initiator These devices are also used to verify that an initiator does not generate a field stronger than Hmaz Both devices use the same antenna coil and can be seen in Figure 6 1 3 26 ISO 10373 6 7 Reference PICC arsenal research ISO 10373 6 7 Reference PICC Figure 6 1 3 Reference devices for measuring Hmin and Hmax RF Interface Target Tests This section describes the tests performed on a DUT in target mode Target RF Level Detection The purpose of this test is to verify that a device detects an outer RF field stronger or equal to Hihreshoia and does not activate its own RF field as long as this field exceeds Hihresnoia The test as sembly described in 6 1 2 is used To determine the generated field strength the calibration coil is connected to an oscilloscope The signal levels generating the corresponding RF fields between 0 and Hmaz are measured without a DUT The DUT is set to initiator mode while the signal generator is set to gener ate an unmodulated signal at the carrier frequency 13 56 MHz The signal should be increased from H 0 to H Hmaz where Haz is the maximum field verified with the calibration coil without the target An oscilloscope is used to measure at which values the DUT switches off its RF field If the DUT switches off i

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