Design and development of high gain wideband microstrip antenna and DGS filters using numerical experimentation approach [Elektronische Ressource] / von Adel Bedair Abdel-Mooty Abdel-Rahman

Informations

• Publié par: otto-von-guericke-universitat_magdeburg
• Publié le: 01 janvier 2005
• Nombre de lectures: 21
• Langue: English
• Poids de l'ouvrage: 5 Mo

Extrait

Design and Development of
High Gain Wideband Microstrip Antenna
and
DGS Filters Using Numerical
Experimentation Approach

Dissertation
zur Erlangung des akademischen Grades
Doktoringenieur
(Dr.-Ing.)
von MSc. Adel Bedair Abdel-Mooty Abdel-Rahman
geb. am 05.08.1968 in Aswan
genehmigt durch die Fakultät Elektrotechnik und Informationstechnik der Otto-von-
Guericke-Universität Magdeburg
Gutachter: Prof. Dr. A. S. Omar
Prof. Dr. B Michaelis
Doc. Ing. J. Machac, DrSc.
Promotionskolloquium am 01.06.2005

ACKNOWLEDGEMENTS
All gratitude is due to “ ALLAH ” who guides me to bring forth to light this thesis.

Pursuing Ph.D in Microstrip antennas and DGS compact Microstrip filters is one
of the most valuable and exciting experiences in my education. The knowledge I learned
and confidence I gained during the study years will be beneficial to my whole life.
I am greatly indebted to my supervisor, Prof. Dr.-Ing. A. S. Omar, who takes so
much effort and patience in mentoring me to become a qualified researcher. From leading
me at the beginning into the Maxwell domain and then step by step to its actual
application in Antennas and Filters, to revise my poorly written papers and edited
presentations. Prof. Omar gave me direction in every step of my thesis work, while never
forgetting trivial details. It is his insight and wide knowledge that guided me to the
completion of this thesis work. Due to his broad research interests, he gave me the
opportunity to explore many interesting antennas, low-pass and band-pass filters.
I am also grateful to Prof. Dr.-Ing. Habil. Bernd Michaelis, University of
Magdeburg, and Prof. Doc., Ing., DrSc. Jan Machac, Czech Technical University, for
kindly agreeing to be referees for this thesis in spite of their hectic schedules.
I also want to thank Prof. A. K. Verma who is with the Department of Electronic
Science, University of Delhi, New Delhi, India for his interest in Microstrip antennas and
filters and helpful discussion even face to face or by e-mail.
Great of thanks and very deep appreciation to Assist Prof. G. Kirov for his guide and
deeply discussion in antennas.
Deep thanks to Prof. G. Nadim, Cairo University, Cairo, Egypt for his help and support.
I would like to thank Dr. H. Holub, Dr. H. Bresch, Dr. A. Jöstingmeyer and Dr. T. Meyer
for their continuous help.
I also appreciate the support I received from all engineers and technicians in the
workshop, in particular, Mr. H. Rodiek and Mr. D. Salbert.
i
I always feel lucky to be with so many excellent researchers in Prof. Omar’s group. I
sincerely thank A. Boutejdar for being a good partner in the filter part work and earnest
colleague with whom I had so many intensive discussions. Many thanks go to Nick,
whose enormous contributions to the measurement lab greatly facilitated the progress of
my work.
Finally, I would like to thank my family and friends. I am very grateful to my
father and my mother who encourage and support me during their life time. I owe all my
achievement to my wife and children, who share all my joy and bitterness every day and
night. Again, thanks to all my friends: Omar Ali, Ehab Hamad, A. Bandyopadhyay, M.
Anis, A. Teggatz, F. Abu-Jarad, Ali Aassie, A. Slavova and A. R. Ali for their support.




















ii

Abstract


This work covers two aspects of microwave communication technology. The first is the
analysis and design of new wideband high gain microstrip antennas and the second aspect
is the design of compact high performance low-pass and band-pass filters. We have
introduced the resonating coupling slot in the aperture coupled microstrip antenna to
increase its bandwidth. A new method is reported for impedance matching of the antenna
structure with 50-Ohm microstrip feed line. Also we have developed the concept of the
short surface mounted horn to increase the gain without adversely affecting its
bandwidth. By inserting the horn into the substrate, the gain of the patch antenna has been
increased by more than 6 dB. The surface mounted horn has been applied around the four
and eight element arrays. An increase of 3.5 dB in gain has been obtained with the horn
frame around the array elements. For the compact microstrip based filter design we have
adopted the defected ground structure (DGS). We have shown that proper selection of the
shape and position of DGS slot is important for the improved performance of the low-
pass filter in the stop and transition bands. We have also introduced the band-pass
structure in the DGS configuration and used it to design a new compact band-pass filter.





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Table of Contents
1. Introduction 1
1.1 Antennas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.2 Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
1.3 Organization of the Thesis . . . . . . . . . . . . . . . . . . . . . . 15
2. Single Element Aperture Coupled Microstrip Antenna 17
2.1 17 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.2 Microstrip Antenna Feeds . . . . . . . . . . . . . . . . . . . . . . . 18
2.3 Aperture Coupled Microstrip Antennas . . . . . . . . . . . . . . . . . . . . 21
2.3.1 Linearly Polarized Microstrip Antenna . . . . . . . . . . . . 22
2.3.1.1 Antenna Design . . . . . . . . . . . . . . . . . . . 23
2.3.2 Analysis and Simulation . . . . . . . . . . . . . . . . . . . . 41
2.3.2.1 Matching Characteristics . . . . . . . . . . . . . . . 41
2.3.2.2 Far-Field . . . . . . . . . . . . . . . 42
2.3.3 Practical Implementation 43
2.3.4 Experimental Results . . . . . . . . . . . . . . . . . . . . . . 46
2.3.4.1 Measured Matching Characteristics . . . . . . . . . 46
2.3.4.2 Measured Radiation Characteristics. . . . . . . . . . 48
2.4 Impedance Matching Improvement for a Class of Wideband Antennas 50
2.4.1 Description of The Proposed Solution . . . . . . . . . . . . . 50
54 2.4.1 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3. Defected Ground Structure Low-pass and Band-pass Filters 57
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
3.2 Filter Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
vi
3.2.1 Illustration Example . . . . . . . . . . . . . . . . . . . . . . 60
3.3 Defected Ground Structure Filters . . . . . . . . . . . . . . . . . . . . . . . 62
62 3.3.1 Frequency Characteristics of DGS Unit Section . . . . . . . .
3.3.2 Modeling and Parameter Extraction . . . . . . . . . . . . . . 63
3.4 Study of Different DGS Slots Configuration . . . . . . . . . . . . . . . . . 66
3.4.1 Rectangular Slot . . . . . . . . . . . . . . . . . . . . . . . . 68
3.4.2 Dumb-bell Slot. . . . . . . . . . . . . . . . . . . . . . . . . 70
3.4.3 Square Head Slot . . . . . . . . . . . . . . . . . . . . . . . 74
3.4.4 Arrow Head Slot . . . . . . . . . . . . . . . . . . . . . . . . 78
3.5 Stepped-Impedance Low-Pass Filter . . . . . . . . . . . . . . . . . . . . . 86
3.6 Stepped Impedance Low-Pass Filter Using DGS Slots . . . . . . . . . . 88
3.6.1 Study of DGS Slot Position on 3-Pole Hi-Lo LPF . . . . . . . 88
3.6.2 Fabrication and Measurement of 3-Pole Hi-Lo LPF . . . . . 91
3.7 Frequency Characteristics of DGS Unit Section with Cutting Gap in
95 the 50 Ω Line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.7.1 Modeling of DGS Based Band- Reject and Band- Accept
96 (Band-Pass) Components . . . . . . . . . . . . . . . . . . .
3.7.2 The 3-Pole Band-Pass Filter . . . . . . . . . . . . . . . . . . 98
3.7.3 Fabrication and Experimental Results . . . . . . . . . . . . . 99
4. Microstrip Antenna Gain Enhancement Technique Using Quasi-Planar
103Surface Mounted Horn
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
4.2 Aperture Coupled Microstrip Antenna with Quasi-Planar Surface
Mounted Horn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
4.2.1 Numerical Experimentation . . . . . . . . . . . . . . . . . . . . . . 105
vii
4.2.2 Fabrication and Measurement . . . . . . . . . .