University of Bath PHD A suspended-membrane balanced frequency doubler to 200 GHz Chance, Gregory Ian Award date: 2005 Awarding institution: University of Bath Link to publication Alternative formats If you require this document in an alternative format, please contact: [email protected] General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Download date: 09. Oct. 2021 A Suspended-Membrane Balanced Frequency Doubler to 200 GHz Gregory Ian Chance A thesis submitted for the degree of Doctor of Philosophy University of Bath Department of Physics June 2005 CO PY R IG H T Attention is drawn to the fact that copyright of this thesis rests with its author. This copy of the thesis has been supplied on condition that anyone who consults it is understood to recognise that its copyright rests with the author and that no quotation from the thesis and no information derived from it may be published without the prior consent of the author. This thesis may be made available for consultation within the University Library and may be photocopied or lent to other libraries for the purpose of consultation. 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Box 1346 Ann Arbor, Ml 48106-1346 — C DtC fKp CHAPTER INDEX Chapter 1 9 Introduction 1.1 Heterodyne Receiver ........................................................................................... 9 1.2 Elements of the Receiver .................................................................................... 10 1.2.1 Mixer .................................................................................................... 10 1.2.1.1 Superconductor Insulator Superconductor (SIS) Mixer 10 1.2.1.2 GaAs Schottky Diode Mixer ................................................. 10 1.2.2 LO power source .................................................................................. 11 1.2.2.1 Gunn Diodes ......................................................................... 11 1.2.2.2 Transistors and Other Devices .............................................. 13 1.3 Applications ......................................................................................................... 14 1.3.1 Radio Astronomy ................................................................................. 15 1.3.2 Atmospheric Remote Sensing .............................................................. 16 1.3.3 Chemical and Biological Warfare Agent Detection ............................ 17 1.3.4 Communication Systems ...................................................................... 18 1.3.5 Plasma Diagnostics .............................................................................. 19 1.3.6 Explosives and Weapon Detection ...................................................... 19 1.4 Summary............................................................................................................. 21 1.4.1 Harmonic Generation ........................................................................... 21 1.4.2 Project Originality ................................................................................ 21 References - Chapter 1............................................................................................. 22 Chapter 2 25 Multiplier Theory 2.1 Multiplier Theory ................................................................................................ 25 2.2 Circuit Considerations ......................................................................................... 27 2.3 Filter Theory & Design ....................................................................................... 30 2.3.1 Filter Theory ........................................................................................ 31 2.3.2 Filter Design ......................................................................................... 35 2.3.3 Filter Simulation .................................................................................. 36 2.3.4 Scale Model Filter ................................................................................ 37 2.4 High Frequency Backshorts .................................................... 39 2.5 Bandwidth & Loss .............................................................................................. 43 2.6 Limits of Varactor and Varistor Multipliers ....................................................... 44 2.7 Burckhardt Approach .......................................................................................... 45 References - Chapter 2 ............................................................................................. 48 Chapter 3 49 Literature Review 3.1 Literature Review..................................................................................................... 49 3.2 Summary................................................................................................................... 71 References - Chapter 3 ........................................................... 73 2 Chapter 4 76 Diode Theory & Modelling 4.1 Diode Theory ....................................................................................................... 76 4.2 Diode Current Considerations ............................................................................. 82 4.2.1 Barrier Current Transport Mechanisms .............................................. 82 4.2.1.1 Thermionic Emission ............................................................ 82 4.2.1.2 Barrier Tunnelling ................................................................. 83 4.2.1.3 General I/V Characteristics and Ideality.............................. 84 4.2.2 Ohmic Contacts .................................................................................... 85 4.2.3 Current Saturation ................................................................................ 87 4.3 Impedance Considerations ................................................................................. 89 4.3.1 Undepleted Epilayer Impedance .......................................................... 89 4.3.2 Resistance Through n+ layer................................................................ 93 4.3.3 Other Parasitic Losses .......................................................................... 95 4.4 Diode Optimising................................................................................................ 98 References - Chapter 4 ............................................................................................. 101 Chapter 5 104 Structure Simulation 5.1 Multiplier Design ................................................................................................ 104 5.2 Input Circuit Optimising .................................................................................... 108 5.2.1 Computer Modelling ............................................................................ 109 5.2.2 Scale Modelling ................................................................................... 113 5.3 Output Circuit Optimising .................................................................................. 115 5.3.1 Output Backshort ................................................................................. 116 5.3.2 RF Filter................................................................................. 119 5.3.3 Parasitic Modes .................................................................................... 120 5.4 Multiplier Embedding Impedance ...................................................................... 123 5.4.1 Diode Anti-Series Circuit Considerations ........................................... 124 5.4.2 Determining Embedding Impedance .................................................. 126 5.4.3 Embedding Impedance Consistency .................................................... 128 5.4.3.1 Gap Source Impedance Zg..................................................... 128 5.4.3.2 Gap Source Height hg............................................................ 129 5.4.3.3 Lateral Gap Source Position lg............................................. 130 5.4.3.4 Gap Source Area Ag.............................................................. 131 5.4.3.5 Height of Membrane, hmi in Waveguide .............................