Antennas, Waves, and Circuits in Radio Frequency Identi(cid:12)cation David M. Hall A thesis submitted for the degree of Doctor of Philosophy in Electrical and Electronic Engineering The University of Adelaide September 2011 “Alltruthsareeasytounderstandoncetheyarediscovered –thepointistodiscoverthem.” GalileoGalilei(1564-1642). Contents Abstract viii Statement of Originality ix Acknowledgments x Conventions xi Publications of the Author xii Abbreviations xiv List of Figures xvii List of Tables xxii Chapter 1. Introduction 1 1.1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.2 Outlineofthethesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.3 Originalcontributionsoftheauthor . . . . . . . . . . . . . . . . . . 4 Chapter 2. UHF Planar Tags 6 2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.2 Readrange . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.3 RFIDantennaimpedance . . . . . . . . . . . . . . . . . . . . . . . . 7 2.4 Calibratingthesimulator . . . . . . . . . . . . . . . . . . . . . . . . . 11 2.4.1 TheBalanisdipoleanalysis . . . . . . . . . . . . . . . . . . . 11 2.4.2 Losscalculationofahalf-wavedipole . . . . . . . . . . . . . 13 2.5 Shorteningtheantenna . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2.6 Dipolewithaloop . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 2.6.1 Modellingabook . . . . . . . . . . . . . . . . . . . . . . . . . 21 2.7 Close-coupledtags . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 2.8 Atwo-porttag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 2.9 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 iii Contents iv Chapter 3. A Two-Part UHF Antenna 35 3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 3.2 Partsofthetag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 3.2.1 Theprimaryantenna . . . . . . . . . . . . . . . . . . . . . . . 37 3.2.2 Thesecondaryantenna . . . . . . . . . . . . . . . . . . . . . 38 3.2.3 Thecompletedtag . . . . . . . . . . . . . . . . . . . . . . . . 39 3.3 Tagtesting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 3.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 Chapter 4. A Combined UHF and HF Antenna 47 4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 4.2 Animproveddesign . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 4.3 UHFlayer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 4.4 HFlayer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 4.5 CombinedUHFandHFlayers . . . . . . . . . . . . . . . . . . . . . 50 4.6 RFIDloop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 4.7 Thecompletetag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 4.8 RFIDoperationoftheHFfeature . . . . . . . . . . . . . . . . . . . . 54 4.9 RFIDloopontheUHFlayer . . . . . . . . . . . . . . . . . . . . . . . 54 4.10 RFIDloopontheHFlayer . . . . . . . . . . . . . . . . . . . . . . . . 54 4.11 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 Chapter 5. DVD or CD Tag 57 5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 5.2 Thedisctagantenna . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 5.3 Testingthetag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 5.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 Chapter 6. Integrated Antenna Matching Network 67 6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 6.2 AsmallUHFloop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 6.3 Testingtheintegratedmatchingnetwork . . . . . . . . . . . . . . . 72 6.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 Contents v Chapter 7. Increasing the UHF Field Near Metal 74 7.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 7.2 Electromagneticabsorbermaterial . . . . . . . . . . . . . . . . . . . 75 7.3 Designingatagforametalsurface . . . . . . . . . . . . . . . . . . . 77 7.4 Fabricatingatagforametalsurface . . . . . . . . . . . . . . . . . . 78 7.5 Measurementsontheabsorbermaterial . . . . . . . . . . . . . . . . 82 7.6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 Chapter 8. A Drill String Identi(cid:12)cation Tag 85 8.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 8.2 Constructionofthetestwell . . . . . . . . . . . . . . . . . . . . . . . 86 8.3 Constructionofadrillstringmodel . . . . . . . . . . . . . . . . . . . 88 8.4 Constructionoftestcoils . . . . . . . . . . . . . . . . . . . . . . . . . 89 8.4.1 Impedanceinsidethewell . . . . . . . . . . . . . . . . . . . . 89 8.4.2 Calculationofsourcevoltagefromcoils . . . . . . . . . . . . 89 8.4.3 Powerfromcoilinamagneticfield . . . . . . . . . . . . . . . 92 8.5 Availablesourcepower . . . . . . . . . . . . . . . . . . . . . . . . . . 92 8.6 On-sitenoisemeasurements . . . . . . . . . . . . . . . . . . . . . . . 95 8.6.1 Equipmentused . . . . . . . . . . . . . . . . . . . . . . . . . 95 8.6.2 Platformmeasurements . . . . . . . . . . . . . . . . . . . . . 96 8.7 Availablesourcepowerinoctagonantennafield . . . . . . . . . . . 98 8.8 Reduceddepthofthewell . . . . . . . . . . . . . . . . . . . . . . . . 100 8.9 Empiricalresults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 8.9.1 Amountofdetuning . . . . . . . . . . . . . . . . . . . . . . . 103 8.9.2 Changeofavailablesourcepower . . . . . . . . . . . . . . . 104 8.10 Designofatag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 8.11 Constructionofatag . . . . . . . . . . . . . . . . . . . . . . . . . . . 105 8.12 Numericalanalysisofataginametalwell . . . . . . . . . . . . . . 109 8.13 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 Chapter 9. Current Reference 114 9.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115 9.2 MOSFEToperationinweakinversion . . . . . . . . . . . . . . . . . 115 9.3 Circuitstability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115 9.4 Start-upcircuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117 9.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121 Contents vi Chapter 10.Random-Number Oscillator 122 10.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123 10.2 Designinganunstableoscillator . . . . . . . . . . . . . . . . . . . . . 125 10.3 Clockextractionfromthecarrier . . . . . . . . . . . . . . . . . . . . 127 10.4 Anunstableoscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . 129 10.5 Animprovedunstableoscillator . . . . . . . . . . . . . . . . . . . . 135 10.5.1 Long-termasynchronousoscillatorstability . . . . . . . . . . 135 10.6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139 Chapter 11.HF Recti(cid:12)ers 140 11.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141 11.2 Pointstoconsiderforrectifierdesign . . . . . . . . . . . . . . . . . . 141 11.3 TheP-switchN-dioderectifier . . . . . . . . . . . . . . . . . . . . . . 142 11.3.1 Thebasicrectifierconfiguration . . . . . . . . . . . . . . . . 142 11.3.2 TheCMOSrealisation . . . . . . . . . . . . . . . . . . . . . . 143 11.3.3 Circuitoperation . . . . . . . . . . . . . . . . . . . . . . . . . 145 11.3.4 ReducingthegainoftheparasiticverticalPNP . . . . . . . . 146 11.3.5 Explanationofguardrings . . . . . . . . . . . . . . . . . . . 147 11.3.6 Placementoftheelements . . . . . . . . . . . . . . . . . . . . 147 11.4 TheN-diodeN-dioderectifier . . . . . . . . . . . . . . . . . . . . . . 149 11.4.1 Layoutconsiderations . . . . . . . . . . . . . . . . . . . . . . 152 11.5 Electrostaticdischargeprotection . . . . . . . . . . . . . . . . . . . . 153 11.5.1 Protectingtheantennaterminals . . . . . . . . . . . . . . . . 153 11.6 TheN-diodeN-switchrectifier . . . . . . . . . . . . . . . . . . . . . 156 11.7 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157 Chapter 12.Passive Shunt Regulators 158 12.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159 12.2 Modulationdetectors . . . . . . . . . . . . . . . . . . . . . . . . . . . 159 12.2.1 TheAMdetector . . . . . . . . . . . . . . . . . . . . . . . . . 159 12.2.2 Thevoltagecomparator . . . . . . . . . . . . . . . . . . . . . 160 12.2.3 Choosingthenominalcurrent . . . . . . . . . . . . . . . . . 160 12.2.4 Alow-passfilter . . . . . . . . . . . . . . . . . . . . . . . . . 161 Contents vii 12.2.5 Avoltage-pulse-detectcircuit . . . . . . . . . . . . . . . . . . 162 12.3 Theregulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162 12.4 Regulatordesign . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166 12.4.1 Maximum-stressmeasurements . . . . . . . . . . . . . . . . 167 12.4.2 Thebasicshuntregulator . . . . . . . . . . . . . . . . . . . . 168 12.4.3 Alaggingregulatorwithacapacitor . . . . . . . . . . . . . . 171 12.4.4 Step-inputstability . . . . . . . . . . . . . . . . . . . . . . . . 172 12.4.5 Alaggingregulatorwithoutacapacitor . . . . . . . . . . . . 173 12.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175 Chapter 13.A Zero-Power On-Wafer Detector 176 13.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177 13.2 Circuitoperation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178 13.3 Specificimplementation . . . . . . . . . . . . . . . . . . . . . . . . . 179 13.4 Verificationofthecircuit . . . . . . . . . . . . . . . . . . . . . . . . . 180 13.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183 Chapter 14.Conclusion 184 14.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185 14.2 Antennas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185 14.3 Waves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188 14.4 Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189 14.5 Validation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192 14.6 Possiblefurtherwork . . . . . . . . . . . . . . . . . . . . . . . . . . . 192 Bibliography 193 Abstract High-performance electronic labelling systems require the separate components to be designed in an optimum way and with a consideration of their interactions with other components in the system. As with many system designs many as- pects of the electrical and electronic discipline must be pursued with skill for a successfuldesigntoemerge. Inadditiontodealingwiththesematters,theauthor considers low cost and long range along with manufacturability as key criteria for a high-performance labelling system and thus has kept these aspects in mind throughoutthecomponentdesignprocess. Thefirstpartoftheworkdescribesthedesignofbothnear-fieldandfar-fieldUHF antennas including a UHF antenna which is combined with an HF antenna. In a second part of the work are investigations of techniques for reading UHF tags on a metal surface and HF tags inside a hole formed in metal. Finally, the designs oflow-powerandlow-costmicroelectroniccircuitsforpassivetagsarediscussed. Each system element designed by the author has been fabricated for successful empiricalevaluation. viii Statement of Originality Name: Program: This work contains no material which has been accepted for the award of any other degree or diploma in any university or other tertiary institution to David M. Hall and, to the best of my knowledge and belief, contains no material previously published or written by another person, except where due reference hasbeenmadeinthetext. Igiveconsenttothiscopyofmythesis,whendepositedintheUniversityLibrary, being made available for loan and photocopying, subject to the provisions of the CopyrightAct1968. I also give permission for the digital version of my thesis to be made available ontheweb,viatheUniversity’sdigitalresearchrepository,theLibrarycatalogue, the Australasian Digital Theses Program (ADTP) and also through web search engines, unless permission has been granted by the University to restrict access foraperiodoftime. Signature: Date: ix Acknowledgments The author would like to thank his supervisor Professor Peter H. Cole for his tireless support in the study for and writing of this thesis. Professor Cole has provided the author with insights into RFID unequalled in this field of study. He hasalsoprovidedfundsforfabricationsandsustenanceduringmanyalongnight inthelaboratory. The author would also like to thank the following persons in no order of impor- tance. GordonAllisonforhisskillsinthemachineshop. SaidAlsarawiforhelpwithlayouttools,OpAmps,LaTex,andUNIX. AndrewBeaumont-SmithforhelpwithlayouttoolsandSPICEextraction. GarethFinchforluggagetagmeasurements. BennoFleckerforbookandfashiontagmeasurements. AlfGrassoforVLSIfabrication. StephenGuestforgeneraluseoffacilities. NathanHuforhelpwithLaTex. BenJamaliforhelpwithUNIX. KinSeongLeongforhelparoundthelaboratory. IanLinkeforaccesstotheworkshop. PhilippeMartinforchipassembly. AlastairMcArthurforhelpwithpatents. AliMoiniforhelpwithVLSItapeout. MunLengNgforhelparoundthelaboratoryandwithLaTex. DamithRanasingheforhelpwithMATLAB. x