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Integrated Radio Frequency Isolator University of Calgary PRISM: University of Calgary's Digital Repository Graduate Studies The Vault: Electronic Theses and Dissertations 2014-04-30 Integrated Radio Frequency Isolator Henrikson, Christopher Erik Henrikson, C. E. (2014). Integrated Radio Frequency Isolator (Unpublished master's thesis). University of Calgary, Calgary, AB. doi:10.11575/PRISM/26572 http://hdl.handle.net/11023/1461 master thesis University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission. Downloaded from PRISM: https://prism.ucalgary.ca UNIVERSITY OF CALGARY Integrated Radio Frequency Isolator by Christopher Erik Henrikson A THESIS SUBMITTED TO THE FACULTY OF GRADUATE STUDIES IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE DEPARTMENT OF ELECTRICAL AND COMPUTER ENGINEERING CALGARY, ALBERTA APRIL, 2014 c Christopher Erik Henrikson 2014 Abstract Radio frequency isolators based on ferrite junction circulators have been the domi- nant isolator technology for the past fifty years, yet they have not been integrated practically because ferrites are generally incompatible with semiconductor processes and their size is inversely proportional to their operating frequency. Hall isolators are another approach whose operating frequency is independent of their size, are compat- ible with semiconductor processes and are thus appropriate for integration. Through simulation, this thesis demonstrates that these devices can be on the order of microns in size and have a bandwidth from DC to over a terahertz. Measurements of an un- optimized Hall element demonstrate an operating bandwidth from DC to 1127 MHz. A technique using multi-contact Hall plates is shown to reduce isolator insertion loss to 0.89 dB, which is competitive with ferrite-based devices. Keywords: Isolators, Circulators, Gyrators, Hall effect devices, Ultra wideband technology, Indium antimonide. ii Acknowledgements I am very grateful to my supervisor, Dr. Sebastian Magierowski. His support, di- rection and motivation made it possible for me to complete this challenging project. I would like to express my gratitude to my co-supervisor, Dr. Leo Belostotski, for discussion and guidance. Credit for the original idea of using a MOSFET channel as a Hall plate goes to Dr. Belostotski and Dr. Michal Okoniewski. Thank-you Dr. Ed Nowicki for helping me to begin my graduate school journey. Many thanks go to John Shelley for PCB manufacturing and discussion. Thanks to others in the technical department including Chris Simon, Rob Thompson, Warren Flaman, Angela Morton, Garwin Hancock and Richard Galambos for loaned equip- ment, helpful discussions and fabrication tips. Thank-you to Aaron Beaulieu and Yongsheng Xu of the RFIC lab for discussion and loaned equipment. Special thanks go to Stephen Leikeim (requiescat in pace) of SSEIT and Hugh Pollitt-Smith of CMC for Synopsys Sentaurus software support. Thanks go to K. Louis Law of GMW Associates, for providing samples of Asahi Kasei Hall elements. Grad school would not have been nearly as much fun without the companion- ship and support of the FISH Lab, including Zhixing "Lincoln" Zhao, J-F Bousquet, Shahana Kabir, Ryan Wu, Kevin Dorling, Hazem Gomaa, Khaled Ali, Mike Wasson, Devin Smith, Kassy Rizopolous, Mohammad Gafar and others. A special thank-you goes to Dr. Geoff Messier for sharing lab-space, equipment and lab meetings. My heartfelt thanks go to my friends and family, for tolerating my absences and moodi- ness. Most of all, I must thank my wife, Sarah, whose love and support made all of this possible. iii To my lovely wife, Sarah iv Table of Contents Abstract . ii Acknowledgements . iii Dedication . iv Table of Contents . v List of Tables . viii List of Figures . ix List of Symbols and Abbreviations . xi 1 Introduction . 1 1.1 Motivation: Why integrate an isolator? . 2 1.2 Project History . 3 1.3 Applications . 4 1.3.1 Hall Isolator . 4 1.3.2 Hall Circulator . 5 1.3.3 Hall Gyrator . 7 1.3.4 Areas of application . 7 1.4 Contributions . 8 1.5 Thesis Structure . 8 2 Background and Theory of Hall Isolators . 9 2.1 What is an isolator? . 9 2.2 Non-Reciprocal Devices . 11 2.2.1 Circulators . 12 2.2.2 Gyrators . 14 2.3 What is a Hall Isolator? . 15 2.4 History of Hall Isolators (Literature Review) . 16 2.5 Unilateralization of Hall Devices . 18 2.6 Figure of Merit: Mason's U . 19 2.7 Hall Gyrator . 20 2.7.1 Gyrator-Mode Isolator . 22 2.8 Hall Circulator . 24 2.8.1 Circulator-Mode Isolator . 25 2.9 Summary . 26 3 Simulation and Fabrication . 28 3.1 Simulation Method . 28 3.2 Properties of Hall Plates . 31 3.2.1 Performance and Magnetic Field . 32 3.2.2 Mobility, Doping and Materials . 35 3.3 Geometry . 39 3.3.1 Thickness . 40 3.3.2 Contact Size and Hall Plate Shape . 41 3.3.3 Top-Contacted Hall Plates . 43 3.3.4 Skewed Electrodes . 44 3.4 Load Resistance Value . 46 v 3.5 Temperature Stability . 47 3.6 Frequency Response . 48 3.7 Other Considerations . 53 3.7.1 Power Handling and Thermal Effects . 53 3.7.2 Linearity . 54 3.7.3 Noise . 54 3.8 Enhancement - Grutzmann's Method . 55 3.9 Device Fabrication . 56 3.9.1 Thin Film Fabrication . 57 3.9.2 Magnetic Bias design . 64 4 Measurement of a Hall Element . 68 4.1 Hall Elements . 68 4.2 Measurement Technique . 69 4.2.1 Equipment . 70 4.2.2 Magnetometer design . 71 4.2.3 Printed Circuit Board Design . 72 4.2.4 Spacers / Flux Concentrator Design . 73 4.2.5 Measurement Procedure . 73 4.2.6 Sources of error . 75 4.3 Mobility and Thickness Estimation . 76 4.3.1 Discussion . 76 4.4 Microwave Measurement Results . 77 4.4.1 Four-Port Circulator . 78 4.4.2 Gyrator-Isolator . 80 4.4.3 Circulator-Isolator . 82 4.5 Comparison . 83 4.6 Summary . 85 5 Conclusion and Future Work . 87 5.1 Contributions . 87 5.2 Future Work . 88 5.3 Final Words . 89 Bibliography . 90 A Operation of the Ferrite Junction Circulator . 105 B Galvanomagnetic Phenomena . 108 B.1 Lorentz Force . 108 B.1.1 Lorentz Force in a Vacuum . 108 B.1.2 Lorentz Force in a Solid . 109 B.2 Hall Effect . 111 B.3 Current Deflection Effect . 114 B.4 Magnetoresistance Effect . 116 C Useful Properties of Network Parameters . 117 C.1 Network Parameters . 117 C.2 Properties of Network Parameters . 118 C.2.1 Immittance Parameters . 118 C.2.2 Hybrid Parameters . 120 vi C.2.3 Cascade Parameters . 120 C.2.4 Scattering Parameters . 121 C.3 Definitions of Immittance Parameters . 125 C.4 Conversions of Network Parameters . 125 C.5 Port Collapsing . 127 C.5.1 Input and Output Impedance . 128 C.6 Mixed-Mode S-Parameters . 129 D Derivations . 131 D.1 Double Transformer Impedance Transform . 131 D.2 Analysis of the 4-Terminal Hall Gyrator . 132 D.2.1 Lossy Unilateralization of a Hall Gyrator . 135 D.3 4-port Differential to 2-port Single-Ended Y-Parameter Conversion . 136 D.3.1 Lossless Unilateralization of a Hall Gyrator . 137 D.4 Analysis of the 3-Terminal Hall Circulator . 139 D.4.1 Hall Circulator as an Isolator . 140 D.4.2 Lossless Unilateralization of a Hall Circulator . 141 D.5 Single Transformer Impedance Transform . ..
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