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(UHF) Radio Frequency Identification (RFID) Antenna Design, May 2012

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(UHF) Radio Frequency Identification (RFID) Antenna Design, May 2012 LONG RANGE ULTRA-HIGH FREQUENCY (UHF) RADIO FREQUENCY IDENTIFICATION (RFID) ANTENNA DESIGN A Thesis Submitted to the Faculty of Purdue University by Nathan D. Reynolds In Partial Fulfillment of the Requirements for the Degree of Master of Science in Engineering May 2012 Purdue University Fort Wayne, Indiana ii For my loving family and wife, who have always supported me. iii ACKNOWLEDGMENTS First, I thank Dr. Abdullah Eroglu who advised me. I am very thankful for all his input, expertise, and guidance. I also thank Dr. Eroglu for helping me keep on track and stay focused throughout this research process. Next, I would like to extend thanks to the rest of my examining committee: Dr. Carlos Pomalaza-Ráez and Dr. Chao Chen. I am very appreciative of Dr. Chen's willingness to replace a committee member so late in the semester. I would also like to sincerely thank Dr. Ráez for guiding the graduate program and providing resources for my research. I am very grateful for the research stipend and other funding provided by the National Science Foundation. In addition, I would like to thank the three other students in the NSF graduate program for peer support: Josh Thorn, Glenn Harden, and David Clendenen. I would like to thank Barbara Lloyd for all the thesis formatting information she gave me and for being available for consultation. Last, I would like to give a special thanks to my wife, Katie, for all the countless hours she helped with editing and organizing this thesis and for all her love and support during this process. iv TABLE OF CONTENTS Page LIST OF TABLES ............................................................................................................. vi LIST OF FIGURES ......................................................................................................... viii LIST OF ABBREVIATIONS ............................................................................................ xi LIST OF SYMBOLS ........................................................................................................ xii ABSTRACT ..................................................................................................................... xiv 1. INTRODUCTION ......................................................................................................... 1 1.1 Objective of Research ..........................................................................................1 1.2 UHF RFID ............................................................................................................1 1.3 Microstrip Patch Antennas ...................................................................................2 2. PATCH ANTENNA DESIGN ....................................................................................... 4 2.1 Overview of Patch Antenna Design .....................................................................4 2.2 Rectangular Patch Antenna Design ......................................................................5 2.3 Square Patch Antenna Design ..............................................................................6 3. MATCHING TECHNIQUES FOR PATCH ANTENNA DESIGN ............................. 9 3.1 Matching Techniques ...........................................................................................9 3.2 Transmission Line Model ..................................................................................11 3.3 Cavity Model .....................................................................................................12 3.4 Matching By Adjusting the Location of the Feed .............................................13 3.5 Matching With a Quarter-wave Transformer ....................................................14 3.6 Characteristic Impedance of Feeding Transmission Lines ................................14 v Page 4. COMPARISON OF THEORETICAL MODELS ....................................................... 17 4.1 First Set of Simulations ......................................................................................17 4.2 Second Set of Simulations .................................................................................22 4.3 Simulating Slight Changes in the Feeding Transmission Line ..........................26 4.4 A Different Method to Obtain the Edge Zin .......................................................28 4.5 Utilizing the Results From the De-embedding Simulations ..............................33 4.6 Overall Conclusions for Matching a Patch Antenna ..........................................37 5. ELECTROMAGNETIC BAND GAP (EBG) STRUCTURES ................................... 39 5.1 Introducing EBG Structures ...............................................................................39 5.2 Mushroom-like EBG Structures .........................................................................40 5.3 Parametric Study of Mushroom-like EBG Structures .......................................54 6. ANTENNA DESIGNS WITH EBG STRUCTURES ................................................. 57 6.1 EBG Distance From Patch .................................................................................57 6.2 Final Working Design ........................................................................................62 6.3 Similar Research ................................................................................................74 7. CONCLUSIONS.......................................................................................................... 76 BIBLIOGRAPHY ............................................................................................................. 78 APPENDICES A. OBTAINING WIDTH AND LENGTH OF A SQUARE PATCH ............................ 80 B. OBTAINING THE WIDTH AND GAP OF AN EBG STRUCTURE ....................... 81 vi LIST OF TABLES Table Page 1.1 Advantages and Disadvantages of Patch Antennas [4] ................................................ 3 4.1 Probe-fed Patch Antennas With Constants h = 1.5mm and fr = 915MHz ................. 18 4.2 Probe-fed Patch Antennas With Constants εr = 9.8 and fr = 915MHz ....................... 18 4.3 Probe-fed Patch Antennas With Constants h = 1.5mm and εr = 9.8 .......................... 19 4.4 Inset-fed Patch Antennas With Constants h = 1.5mm and fr = 915MHz ................... 19 4.5 Inset-fed Patch Antennas With Constants εr = 9.8 and fr = 915MHz ......................... 20 4.6 Inset-fed Patch Antennas With Constants h = 1.5mm and εr = 9.8 ........................... 20 4.7 Probe-fed Patch Antennas With Constants εr = 9.8 and h = 1.5mm .......................... 24 4.8 Probe-fed Patch Antennas With Constants εr = 6.5 and fr = 915MHz ....................... 24 4.9 Quarter-wave Transformer to Inset-fed Patch Antennas With Constant fr = 915MHz ......................................................................................................... 25 4.10 Comparing Transmission Line Model With and Without Mutual Effects Using Inset-fed Patch Antennas With Constant fr = 915MHz .............................. 25 4.11 Changing Width of Feed on an Inset-fed Patch Antenna With Constants εr = 9.8, fr = 915MHz, and h = 1.5mm ................................................................. 27 4.12 De-embedding Simulations With Constants h = 1.5mm and εr = 9.8 ...................... 31 4.13 De-embedding Simulations With Constants h = 1.5mm and fr = 915MHz ............. 32 4.14 De-embedding Simulations With Constants εr = 9.8 and fr = 915MHz ................... 32 vii Table Page 4.15 Probe-fed Patch Antennas Using De-embedding Results With Constants h = 1.5mm and fr = 915MHz ................................................................................. 34 4.16 Probe-fed Patch Antennas Using De-embedding Results With Constants εr = 9.8 and fr = 915MHz ....................................................................................... 34 4.17 Probe-fed Patch Antennas Using De-embedding Results With Constants h = 1.5mm and εr = 9.8 .......................................................................................... 35 4.18 Inset-fed Patch Antennas Using De-embedding Results With Constants h = 1.5mm and fr = 915MHz ................................................................................. 35 4.19 Inset-fed Patch Antennas Using De-embedding Results With Constants εr = 9.8 and fr = 915MHz ....................................................................................... 36 4.20 Inset-fed Patch Antennas Using De-embedding Results With Constants h = 1.5mm and εr = 9.8 .......................................................................................... 36 5.1 Calculated Bandwidth of the Frequency Band Gap ................................................... 43 5.2 Comparison of EBG Simulation Methods ................................................................. 53 5.3 EBG Simulation Times .............................................................................................. 53 6.1 Review of Patch Antenna Design Components ......................................................... 62 6.2 Final Working Design Parameters ............................................................................. 63 6.3 Overall Results of Final Working Design .................................................................. 67 6.4 Dispersion Diagram Results for EBG Verification ................................................... 69 6.5 Increasing Ground Plane of Patch Antenna With EBG Structure ............................. 70 6.6 Increasing Ground Plane of Patch Antenna Without
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