plasma and dielectric barrier discharge actuator radar cross section

259 Pages·2012·6.05 MB·English

PLASMA AND DIELECTRIC BARRIER DISCHARGE ACTUATOR
RADAR CROSS SECTION
by
Farid Mirhosseini
Bachelor of Science in Telecommunications (Tehran Polytechnic, 1998)
Master of Science in Telecommunications Systems (Tehran Polytechnic, 2001)

A Dissertation Submitted in Partial Fulfillment
of the Requirements for the Degree of

Doctor of Philosophy
in the Graduate Academic Unit of Electrical and Computer Engineering

Supervisor: Bruce G. Colpitts, PhD, Electrical and Computer Engineering
Examining Board: Brent R. Petersen, PhD, Electrical and Computer Engineering
Richard J. Tervo, PhD, Electrical and Computer Engineering
Abdelhaq M. Hamza, PhD, Physics, Chair

External Examiner: Lotfollah Shafai, PhD, Electrical and Computer Engineering,
University of Manitoba

This dissertation is accepted by the
Dean of Graduate Studies

THE UNIVERSITY OF NEW BRUNSWICK
June, 2016
©Farid Mirhosseini, 2016
Abstract
Plasma actuators for aerodynamic applications are receiving significant research
attention and it is necessary to know the effects of this plasma on the vehicle radar cross
section (RCS). This study identifies the critical parameters affecting the RCS of plasma
along with experimental techniques and numerical techniques for determining the effects
of plasma on RCS.
A review of plasma physics is presented along with the background of cavity design,
cavity-waveguide coupling, choke design and the microwave perturbation technique. A
cylindrical dielectric barrier discharge (DBD) plasma under five different pressures is
generated in an evacuated glass tube. The microwave perturbation method is used to
measure permittivity and loss factor of the plasma and then the plasma frequency,
electron-neutral collision rate and electron density are determined for these five
pressures. Simulations by a commercial microwave simulator are comparable to the
experimental results which show little effect at sea level and increasing effects with
increased elevation.
Plasma has a capability that its refractive index can be controlled by changing
parameters such as the electron density profile, plasma frequency or collision rate so the
RCS becomes controllable. However controlling the aforementioned parameters
practically in order to decrease RCS is not as simple as the theoretical simulations. From
the various methods of plasma generation, our focus is on the DBD because this method
has shown benefits like aerodynamic drag reduction noticed in the last decade. The effect
of a plasma slab on the RCS of a conductive sheet is investigated. The RCS is simulated
and measured to verify the validity of the model used for simulations. Moreover, we
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show the DBD actuator generates extra scattering because of Bragg diffraction a
phenomenon not previously reported in the DBD literature.
A comprehensive study on dispersive media RCS using Finite-Difference Time-
Domain (FDTD) method is done. The method used to generate the plane wave is the
discrete plane wave (DPW) method. However, by plane wave we mean a wave packet
which can behave like a plane wave not a real plane wave. A 12-layer split-field perfectly
matched layer (PML) is used for the Absorbing Boundary Conditions (ABC). The
dispersive media is modelled by shift-operator FDTD. Near-to-Far Field transformation
(NTFT) is applied to calculate RCS in the far-field. This NTFT method is based on the
surface equivalence theorem (Huygens’s principle). Finally the Fast Fourier Transform
(FFT) is used to transform time domain signals to the frequency domain. Moreover, the
simulation was extended for anisotropic dispersive media for two general profiles of
exponential and polynomial. The results show that by choosing the right profile the RCS
can be reduced to a large extent; however, achieving such a profile practically is very
challenging.
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Dedication

This dissertation is lovingly dedicated:
To my wife,
Naeeme Bidgol,
who has sacrificed so much for me.
To my mother and my father,
Farzaneh Daneshvar and Jalal Mirhosseini,
who have been role models to me all of my life.
To my sister and brother,
Elham and Farshid,
who have provided the extra motivation to finish my Ph.D.
To my daughter
Ariana Parvin
Who shined my life.
And finally to all my teachers,
who sparked a passion that has not died.
Their support, encouragement, and constant love have sustained me throughout my life.

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ACKNOWLEDGEMENTS
Firstly, I would like to express my sincere gratitude to my supervisor Prof. Bruce
Colpitts for the continuous support of my Ph.D study and related research, for his
patience, motivation, and immense knowledge. His guidance has helped me in the
research and writing of this thesis. I could not have imagined having a better advisor and
mentor for my Ph.D studies.

Also I thank Defence Research and Development Canada (DRDC)-Valcartier plasma
actuator team members Dr. Rogerio Pimentel, Mr. Yves DeVillers for supporting me and
timing of the project and the discussions we had together. In particular, I am grateful to
Dr. Rogerio Pimentel for enlightening me the first glance of research.

Besides my supervisor, I would like to thank the rest of my thesis committee: Prof.
Maryhelen Stevenson, Prof. Brent R. Petersen, Prof. Richard J. Tervo and Prof. Abdelhaq
M. Hamza, for their insightful comments and encouragement, but also for the hard
question which incented me to widen my research from various perspectives.

My sincere thanks also goes to Prof. Yevgen Biletskiy, who gave me helpful ideas. I
also thank Mr. Joey Bernard for helping me in distributed computing system (ACENet).
Without their valuable support it would not be possible to conduct this research.

I thank Mr. Kevin Hanscom, Mr. Ryan Jennings for helping me during the fabrication
process and experimental tests. I also thank Shelley Cormier.
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I thank my fellow lab mates in for the helpful and stimulating discussions, for the
time we were working together before deadlines, and for all the fun we have had in the
last four years.

Last but not the least, I would like to thank my family: my wife, my parents and to my
brother and sister for supporting me spiritually throughout the PhD study, writing this
thesis and my life in general.
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Table of Contents
ABSTRACT………………………………………………………………………………ii
DEDICATION……………………………………………………………………………iv
ACKNOWLEDGEMENT………………………………………………………………..v
Table of Contents……………………………………………………………………...…vii
List of Tables……………………………………………………………………………..xi
List of Figures……………………………………………………………………………xii
List of Symbols, Nomenclature or Abbreviations…………………………………...…xvii
Chapter 1- Introduction ……………………………………………………………..…..1
1.1 Overview ………………………………………………………………………...1
1.2 Contributions …………………………………………………………………....3
1.3 Thesis Organization…………………………………………………………...…4
1.4 References……………………………………………..…………………………7
Chapter 2- Plasma Physics………………………………………………..……………..9
2.1 Introduction…………………………………………………………………...…9
2.2 Plasma Parameters………………………………………..…………………….10
2.2.1 Debye Shielding………………………………………………………...…10
2.2.2 Plasma Parameter………………………………………………………….12
2.2.3 Plasma Frequency…………………………………………………………13
2.2.4 Collisions………………………………………………………………….15
2.3 Plasma Kinetic Theory (Klimontovich Equation)…………………………..…23
2.3.1 Introduction……………………………………………………………….23
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2.3.2 Klimontovich Equation……………………………………………………24
2.3.3 Plasma Kinetic Equaion……………………………………………..…….28
2.4 Fluid Equations…………………………………………………………..…...…..31
2.4.1 Introduction………………………………………………………………..31
2.4.2 The Derivation of the Fluid Equation from the Vlasov Equation…………33
2.5 The Effect of AC Electric Fields…………………………………………………35
2.5.1 A Drude-Lorentz Dispersive Model………………………………...…….50
2.5.2 Dielectric Constant of a Colisional Plasma……………………………….51
2.6 Perturbation Theory of Resonant Cavities………………………………...…..….54
2.6.1 Introduction………………………………………………………………..54
2.6.2 Derivation of The Perturbation Formula……………………………….….55
2.7 Perturbation Theory and Its Applications……...…………………………………63
2.7.1 The Perturbation Formulae……………………...………………………..64
2.7.2 The Evaluation of 𝐄 , 𝐇 , 𝐃 , 𝐁 ……...…………………………………68
1 1 1 1
2.7.3 Frequency Shift of a Cavity due to a Small Solid Specimen……………..70
2.7.4 Dielectric Loss in a Simple Waveguide…………………………………..74
2.8 Cavity Design and the Coupling………………………………………………..77
2.8.1 Aperture in a Transverse Wall…………………………………………….80
2.8.2 Aperture-Coupled Cavity………………………………………………….84
2.8.3 Loop-Coupled Cavity……………………………………………………...93
2.8.4 Large Apertures Coupling at Microwave Frequencies……………………95
2.8.4.1 The High-Frequency Response of a Large Aperture………………...97
2.8.4.2 The Resonant Frequency of an Aperture…………………………….98
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2.8.4.3 The Resonant Q of an Iris………………………………………..…100
2.8.4.4 Effect of Wall Thickness………………………………………...…100
2.9 Choke Design………………………………………………………………….102
2.10 References……………………………………………………………………104
Chapter 3- Simulations and Experimental Results of Electron Density Measurement
using Microwave Perturbation Method………..………………...…..………..110
3.1 Simulations…………………………………………………………………....113
3.2 Experimental Results………………………………………………………….119
3.3 References……………………………………………………………………..125
Chapter 4- The Effect of Dielectric Barrier Discharge (DBD) Plasma Actuators on
Electromagnetics………………………………..……………………………..128
4.1 Introduction…………………………………………………………….……...128
4.2 RCS Measurements and Simulations from Conductive Flat Plate and DBD
Actuators………………………………………..……………...….. ……........129
4.2.1 Validation of Modelling……………………………………...…………..130
4.2.2 DBD Actuators……………………………………………………..…….133
4.2.3 Bragg Diffraction from DBD Plasma Actuator……………………...…..136
4.3 Conclusion………………………………………….………………………….138
4.4 References……………………………………………………….………….…140
Chapter 5- Comprehensive RCS Simulation of Dispersive Media using SO-FDTD-
DPW Method…………………………………………...…………………..…143
5.1 Introduction……………………………………………………………..……..143
5.2 Background……………………………………………………………..……..143
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5.3 Formulation…………………………………………………………………....146
5.3.1 Split-Field PML………………………………………………………….146
5.3.2 Discrete Plane Wave……………………………………………………..148
5.3.3 Shift-Operator FDTD…………………………………………………….151
5.3.4 Near-to-Far Field Transformation (NTFT)………………………………152
5.4 Simulation Results…………………………………………………………….153
5.5 Conclusion………………………………………………………………….…163
5.6 References……………………………………………………………………..164
Chapter 6- Contributions, Conclusion, and Future Work…………………….………168
6.1 Contributions………………………………………………………………….168
6.1.1 Cavity and Choke Design..……………………………………………....168
6.1.2 Cold Plasma Parameters………………………………………………....168
6.1.3 Interaction of Electromagnetic Wave with DBD Actuator………….…..169
6.1.4 Comprehensive RCS Simulation of Dispersive Media Using using SO-
FDTD-DPW Method……………………………………………….……169
6.2 Conclusion……………………………..………………………….…………..170
6.3 Future Work……………………………………………………….…………..171
6.3.1 High Quality Factor Cavity………………………………………..…….171
6.3.2 High Performance Computing……………………………………….…..171
6.3.3 Modified Numerical Method…………………………………………….172
Appedices……………….………………………………………………………………173
A VBScript Code for VNA Automation……………………………………………….173
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