investigations on broadband planar dipol antennas

239 Pages·2013·5.03 MB·English

by  Supriyo Dey

INVESTIGATIONS ON BROADBAND
PLANAR DIPOLE ANTENNAS
A THESIS SUBMITTED BY
SUPRIYO DEY
IN PARTIAL FULFILMENT OF THE REQUIREMENTS
FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY
DEPARTMENT OF ELECTRONICS
FACULTY OF TECHNOLOGY
COCHIN UNIVERSITY OF SCIENCE AND TECHNOLOGY
KOCHI 682 O22
INDIA
DECEMBER 1993
tgafiwafion :21 a/2/my/oedaive
0/om, aw/n @120/la/nee’
Will Durant
CERTIFICATE
This is to certify that the thesis entitled "Investigations on Broadband
Planar Dipole Antennas" is a bona fide record of the research work carried out by
Mr. Supriyo Dey under my supervision. in the Department of Electronics, Cochin
University of Science and Technology. The results embodied in this thesis or part
of it have not been presented for any other degree.
(or. K. G. NAIR)
(Supervising Teacher)
KOCHI 682 022 Dept. of ElecPtrorfeossonr &i Hcesad
28"‘ December 1993 Cochin University of Sci. & Tech.
DECLARATION
I hereby declare that the work presented in the thesis entitled "Investigations
0
on Broadband Planar Dipole Antennas" is based on the original work done by me
under the supervision of Dr. K. G. Nair, in the Department of Electronics, Cochin
University of Science and Technology, and that no part thereof has been presented
for the award of any other degree.
KOCI-II 682 O22 (SUPRIYO DEY)
28"‘ December 1993
ACKNOWLEDGEMENTS
First and foremost I would like to express my profound gratitude to my research
guide Dr. K. G. Nair, Professor and Head, Department of Electronics, Cochin
University of Science and Technology, for his invaluable help in the course of this
study. This thesis is the outcome of education, able guidance, encouragement and
inspiration I received from him.
Sincere thanks are due to Dr. C. S. Sridhar, Dr. K. G. Balakrishnan,
Professors of Department of Electronics, for their valuable suggestions and
encouragements during the tenure of this work.
I am particularly indebted to Dr. P. Mohanan, Reader of this department, for
his inestimable suggestions and invaluable help during the course of this work.
Special thanks are due to Dr. K. Vasudevan and Dr. K. T. Mathew, Readers of this
department for the keen interest they have shown in my work.
My acknowledgement would be incomplete if a mention is not made of the
kind cooperation and valuable suggestions I received from Dr. C. K. Aanandan,
Lecturer, Department of Electronics.
I owe special debt to Dr. K. A. Jose, Research Associate, PennState
University, USA, Dr. K. K. Narayanan, Research Associate, Department of
Electronics and Mr. V. Ajaikumar, USA, for their help and encouragement in
various ways.
I take this opportunity to express my sincere thanks to all the members of
1»-:
faculty, laboratory and non~teaching staffs and research scholars of the department,
who served as beacon and made my stay in Kochi a memorable one. While
expressing my greatfulness to all of them, I would also like to place on record the
splendid cooperation I received from my enjoyable colleagues Mr. J . Jagannath Bhat,
Mr. U. Ravindranath, Mr. T. K. Mathew, Mr. S. Stephen, Mr. J. George and
Mr. P. V. John, research scholars and Mrs. B. Aanandan, Librarian of this
department, who sustained me with their encouragement and their affection during
the period of my research work.
Thanks are also due to Dr. S. Rodrigues and Mr. W. Gomez, Lectures, St.
Paul’s College, Kochi, Dr. P. M. Joseph, Lecturer, Karunya Institute of Technology,
Coimbatore, Mr. P. P. Thomson, Project associate, New South Wails University,
Australia, Mr. Sreemoolanathan, Research scholar, Regional Research Laboratory,
Trivandrum, Dr. P. V. Hunagund, Reader, Department of Applied Electronics,
Gulberga University, Gulberga and Dr. P. Vanugopal, Scientist-C, NPOL, Kochi.
In the course of my research work I was enjoying UGC research fellowship.
This financial support provided by UGC is greatfully acknowledged.
I am indebted to one and all, who have enlightened me, in this short, but
crucial period of life.
INVESTIGATIONS ON BROADBAND
PLANAR DIPOLE ANTENNAS
Contents
-a
Chapter 1 Introduction
1.1 Waveguide antennas
1.1.1 Slot element design and development
1.1.2 Waveguide arrays
1.1.3 Dielectric waveguide arrays
1.2 Triplate antennas
1.2.1 Design of slot element
1.2.2 Triplate slotted arrays
1.3 Cavity backed printed antennas
1.3.1 Printed dipole elements
1.3.2 Cavity backed printed arrays
1.4 Microstrip antennas
1.4.1 Microstrip dipole antenna
1.5 Motivation for the present work
1.6
Brief sketch of the present work
Chapter 2 Review of past work in the field
2.1 Printed dipole antenna
2.1 Microstrip dipole antenna
Chapter 3 Methodology
3.1 Design and fabrication of antennas
3.1.1 Printed dipole
3.1.2 Microstrip dipole
3.2 Antenna feeding
3.3 Facilities utilised
3.3.1 Anechoic chamber
3.3.2 Network Analyser
3.3.3 Antenna positioner and controller
3.4 Method of measurements
3.4.1 Impedance
3.4.2 Radiation pattern
3.4.3 Gain
Chapter 4 Experimental results I: Printed dipoles
4. 1 Flared printed dipole
4.1.1 Flaring angle
4.1.2 Arms overlapping
4.1.3 Arm width at feed point
4.1.4 Main arm to ground arm ratio
4.1.5 Design details
4.2 Triangular end~loaded printed dipole
4.2.1 Triangle dimensions
4.2.2 Arm width at feed point
4.2.3 Main arm to ground arm ratio
4.2.4 Flaring angle
4.2.5 Cavity backed triangular end-loaded printed dipole
4.2.6 Design details
4.3 Parallelogram end-loaded printed dipole
4.3.1 Cavity backed parallelogram end-loaded printed dipole
4.3.2 Design details
Chapter 5 Experimental results II: Microstrip dipoles 131
5.1 Triangular end-loaded microstrip dipole 132
5.1.1 Main arm length 134
5.1.2 Height of triangle 137
5.1.3 Apex angle 139
5.1.4 Design details 144
5.2 Triangular microstrip dipole 146
5.2.1 Balun length 148
5.2.2 Feed point location 148
5.2.3 Arms separation 151
5.2.4 Flaring angle 153
Chapter 6 Theoretical analysis 159
6.1 Rectangular microstrip patch 160
6.1.1 Derivation of the Green's function 160
6.1.2 Calculation of complex power 163
6.1.3 Space wave radiation 164
6.2 Rectangular printed dipole 165
6.3 Flared printed dipole 170
6.4 Triangular end-loaded printed dipole 172
6.4.1 Q of the triangle 173
6.4.2 Q of the remaining dipole 173
6.4.3 Q of the complete structure 175
Chapter 7 Conclusions 177
7.1 inferences from the experimental studies 177
7.1.1 Printed dipole 178
7.1.2 Microstrip dipole 181
7.2 Conclusions from the theoretical analysis 183
7.3 Some practical applications of the present antennas 183
7.4 Scope of further work in the field 184
Appendix A Development of an input impedance tunable
circular patch antenna 186
A. 1 Introduction 186