Recap Antenna Synthesis and Optimization Using Backpropagation and Radial-Basis Function ...

161 Pages·2015·9.34 MB·English

by  Diego Langoni

Florida State University Libraries
Electronic Theses, Treatises and Dissertations The Graduate School
2014
Recap Antenna Synthesis and Optimization
Using Backpropagation and Radial-Basis
Function Artificial Neural Networks
Diego Langoni
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FLORIDA STATE UNIVERSITY

FAMU-FSU COLLEGE OF ENGINEERING

RECAP ANTENNA SYNTHESIS AND OPTIMIZATION USING
BACKPROPAGATION AND RADIAL-BASIS FUNCTION ARTIFICIAL
NEURAL NETWORKS

By

DIEGO LANGONI

A Dissertation submitted to the
Department of Electrical and Computer Engineering
in partial fulfillment of the
requirements for the degree of
Doctor of Philosophy

Degree Awarded:
Spring Semester, 2014
Diego Langoni defended this dissertation on April 11, 2014.
The members of the supervisory committee were:

Mark H. Weatherspoon
Professor Directing Dissertation

Anke Meyer-Baese
University Representative

Simon Y. Foo
Committee Member

Petru Andrei
Committee Member

The Graduate School has verified and approved the above-named committee members, and
certifies that the dissertation has been approved in accordance with university requirements.

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To Silvia (my beautiful wife), my parents, and all my friends.
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ACKNOWLEDGEMENTS

I have to, once again, thank Dr. Weatherspoon, for all of his assistance throughout my
graduate career. It took some time, but we made it there. I would also like to extend my
gratitude to the other members of my supervisory committee, Dr. Simon Foo, Dr. Anke Meyer-
Baese, and Dr. Petru Andrei. I know you didn’t have to be a part of it, so I am glad that you
decided to get on board.

I would also like to thank my parents for their unconditional support, both spiritually and
financially, whenever times were tough. To the Electrical and Computer Engineering
department, for appointing me as a TA for many semesters, allowing me to stay in school until
the work was done. To my lab mates, Richard Aarons and Ruben Nelson, for any assistance they
have provided over the years. To any of my friends that one way or another helped me pull
through.

Last, but certainly not least, I would like to thank my wife, Silvia. For being my pillar of
strength whenever the pressure got intense, for keeping me focused on the task at hand, and for
the unconditional love and support I receive every day. I am the luckiest man in the world.

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TABLE OF CONTENTS

List of Tables ................................................................................................ viii
List of Figures ................................................................................................ x
List of Abbreviations & Symbols ........................................................................ xiv
Abstract ................................................................................................ xv

1. INTRODUCTION ......................................................................................... 1

1.1 Introduction .......................................................................................... 1
1.2 Motivation for Work ............................................................................. 2
1.3 Summary of Objectives ........................................................................ 4
1.4 Organization of Work ........................................................................... 6

2. ANTENNA THEORY ................................................................................... 7

2.1 Introduction .......................................................................................... 7
2.2 Microstrip Antennas ............................................................................. 7
2.3 Square-Patch Antennas ........................................................................ 9
2.4 Patch Antenna Analysis ....................................................................... 10
2.4.1 Transmission-Line Model ........................................................... 10
2.4.2 Cavity Model .............................................................................. 14
2.4.3 Directivity ................................................................................... 24
2.5 Antenna Array Configurations ............................................................. 26
2.5.1 Two-Element Array .................................................................... 27
2.5.2 Linear Array ................................................................................ 29
2.5.3 Planar Array ................................................................................ 30
2.5.4 Other Array Configurations ........................................................ 32
2.6 Summary ............................................................................................... 33

3. MICROWAVE CIRCUIT THEORY ............................................................ 34

3.1 Introduction .......................................................................................... 34
3.2 Antenna Feed ........................................................................................ 35
3.2.1 Coaxial Line ................................................................................ 35
3.2.2 Microstrip .................................................................................... 36
3.3 Maximum Power Transfer Considerations .......................................... 40
3.3.1 Quarter-Wave Transformer ......................................................... 40
3.3.2 T-Junctions .................................................................................. 43
3.3.3 Mitering ....................................................................................... 45
3.4 Summary ............................................................................................... 46

4. NEURAL NETWORKS THEORY ................................................................ 47

4.1 Introduction .......................................................................................... 47
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4.2 Backpropagation Networks ................................................................... 51
4.2.1 BP Training .................................................................................. 53
4.2.2 BP Simulation .............................................................................. 57
4.3 Radial-Basis Function Networks ......................................................... 58
4.3.1 RBF Training .............................................................................. 59
4.3.2 RBF Simulation .......................................................................... 59
4.4 Summary .............................................................................................. 60

5. RECAP ANTENNA DESIGN & SIMULATION ......................................... 61

5.1 Introduction .......................................................................................... 61
5.2 Antenna Characteristics ....................................................................... 61
5.3 FEM Simulation & Data Extraction .................................................... 64
5.4 Summary ............................................................................................... 68

6. RECAP ANTENNA SYNTHESIS & OPTIMIZATION ............................... 69

6.1 Introduction .......................................................................................... 69
6.2 Input-Output Mapping .......................................................................... 69
6.3 Synthesis Architectures ......................................................................... 72
6.3.1 BP ................................................................................................ 72
6.3.1.1 Competition Setup .......................................................... 75
6.3.2 RBF ............................................................................................. 77
6.3.3 Performance Factors ................................................................... 77
6.4 Optimization Architectures .................................................................. 79
6.4.1 BP ................................................................................................ 79
6.4.2 RBF .............................................................................................. 80
6.5 Summary .............................................................................................. 80

7. SYNTHESIS & OPTIMIZATION RESULTS ............................................... 81

7.1 Introduction .......................................................................................... 81
7.2 Synthesis Results ................................................................................. 81
7.2.1 BP Synthesis ................................................................................ 83
7.2.2 RBF Synthesis ............................................................................. 100
7.2.3 Synthesis Generalization Test: BP & RBF ................................ 101
7.3 Optimization Results ............................................................................ 102
7.3.1 BP Optimization........................................................................... 103
7.3.2 RBF Optimization ....................................................................... 107
7.3.3 Optimization Generalization Test: BP & RBF ........................... 112
7.4 Summary .............................................................................................. 112

8. CONCLUSIONS ............................................................................................ 113

8.1 Introduction .......................................................................................... 113
8.2 Work Summary ..................................................................................... 113
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8.3 Specific Technical Contributions ......................................................... 114
8.4 Future Work ......................................................................................... 115

APPENDICES ................................................................................................ 116

A. SINGLE-PATCH RESULTS ............................................................... 116

A.1 COMSOL Simulations .................................................................. 116
A.2 MATLAB Calculations ................................................................. 120
A.3 Calculations vs. Simulations ......................................................... 123

B. SYNTHESIS PRE-TRAINING OUTPUT SCALING ........................ 125

C. BP NETWORK SYNTHESIS COMPETITION .................................. 127

C.1 Phase I Results .............................................................................. 129
C.2 Phase II Results ............................................................................. 131

D. OPTIMIZATION ERROR TABLES .................................................. 132

REFERENCES ................................................................................................ 141

BIOGRAPHICAL SKETCH .............................................................................. 144

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LIST OF TABLES

5.1 Microstrip Patch Antenna Element Parameters ......................................... 62

5.2 Microstrip Corporate Feedline Parameters ................................................. 63

7.1 RECAP Antenna Synthesis Results for BP ANNs .................................... 84

7.2 RECAP Antenna Synthesis Results for RBF ANNs .................................. 100

7.3 RECAP Antenna Synthesis Test Results for BP ANNs ............................ 101

7.4 RECAP Antenna Synthesis Test Results for RBF ANNs .......................... 102

7.5 BP ANN Optimization Results for Different Network Sizes .................... 103

7.6 RBF ANN Optimization Results for Different Spread Constants ............. 108

A.1 Calculated and Simulated Directivity Results for Single Patch ................. 124

B.1 RECAP Antenna Response Parameter Characteristics .............................. 125

B.2 BP ANN Synthesis Pre-Training Scaling Matrix ...................................... 125

C.1 Single Output Network Synthesis Results .................................................. 127

C.2 Two-Output Network Synthesis Results .................................................... 127

C.3 Three-Output Network Synthesis Results .................................................. 128

C.4 Four-Output Network Synthesis Results ................................................... 128

C.5 1-Output/4-Output Network Competition .................................................. 129

C.6 2-Output/3-Output Network Competition .................................................. 129

C.7 1-Output/2-Output/2-Output Network Competition .................................. 129

C.8 1-Output/1-Output/3-Output Network Competition .................................. 130

C.9 1-Output/1-Output/1-Output/2-Output Network Competition .................. 130

C.10 2-Network Competition Results ................................................................ 131

C.11 3-Network Competition Results ................................................................ 131
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D.1 Optimization Errors for 2 Hidden Layers, 100 Neurons/Layer BP ANN .. 132

D.2 Optimization Errors for 0.001 Spread Constant RBF ANN ....................... 139
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