dual frequency patch antenna design

137 Pages·2007·5.08 MB·English

by  Luyi Chen

DUAL FREQUENCY PATCH ANTENNA DESIGN
FOR GLOBAL NAVIGATION SATELLITE SYSTEM

A thesis presented to
the faculty of
the Russ College of Engineering and Technology of Ohio University

In partial fulfillment
of the requirements for the degree
Master of Science

Luyi Chen
June 2007
This thesis titled
DUAL FREQUENCY PATCH ANTENNA DESIGN
FOR GLOBAL NAVIGATION SATELLITE SYSTEM

by
LUYI CHEN

has been approved for
the School of Electrical Engineering and Computer Science
and the Russ College of Engineering and Technology by

Chris G. Bartone
Associate Professor of Electrical Engineering and Computer Science

Dennis Irwin
Dean, Russ College of Engineering and Technology
Abstract
CHEN, LUYI, M.S., June 2007, Electrical Engineering
DUAL FREQUENCY PATCH ANTENNA DESIGN FOR GLOBAL NAVIGATION
SATELLITE SYSTEM (137 pp.)
Director of Thesis: Chris G. Bartone
The purpose of this research was to design a dual feed, dual frequency (i.e., L1L5)
patch antenna for the Global Navigation Satellite System (GNSS). First, two
commercially available patch antennas were simulated using Ansoft High Frequency
Structure Simulator (HFSSTM) and measured in the Ohio University, School of Electrical
Engineering and Computer Science, Antenna Anechoic Chamber. One was a low-cost
GPS L1 single frequency patch antenna and other was a GPS L1L2 dual frequency patch
antenna. The results from the simulation and measurement for these two antennas are
presented, compared, and used as part of the validation process for the dual frequency
right hand circularly polarized patch antenna designed for GNSS L1L5 operation. This
prototype antenna design was targeted at dual frequency high accuracy civil applications
for future GNSS applications. The antenna was designed based on the simulations from
HFSS, through which the radiation patterns and other antenna parameters were generated.
The predicted performance of this prototype antenna from HFSSTM simulation generally
matches the performance specification for a GNSS dual frequency patch style antenna.

Approved:
Chris G. Bartone
Associate Professor of Electrical Engineering and Computer Science
Acknowledgments
I would like to take this opportunity to thank all who helped me through this
research and my years of study at Ohio University, especially the following.
First and foremost, I sincerely thank my advisor, Dr. Chris Bartone for his
invaluable guidance, inspiration and discussions through all stages of this research. I
appreciate him spending a lot time going through meticulous HFSS simulations,
performing antenna testing, and being extremely patient answering my questions
whenever I go to him. Words alone can not express how important his encouragement
and support were during the whole period, especially in those tough days developing the
simulations. The most important things I learned from him are not only about this project
but far reaching. Thank you so much for all, Chris!
I sincerely thank my committee members: Dr. Michael Braasch, Dr. Frank van
Graas, Dr. Roger Radcliff, and Dr. Steven Grimes for their time and comments on this
work. Also, for the inspiring classes they taught which brought me to this whole new
world of navigation. Dr. Radcliff is also thanked for providing financial support through
the school of EECS. I’d like to thank the Stocker Funds that are available through the
school of EECS.
Ansoft Corporation is thanked for providing student license of HFSSTM which
was used for the simulations of this work.
I would also like to thank Dr. Simbo Odunaiya, and David Quinet for offering the
opportunity to work on interesting ILS projects. It has been a great pleasure working with
them.
The faculty, staff, and fellow students from the Avionics Engineering Center must
be thanked. They are the ones who made the center a wonderful place to gain experience
and an enjoyable place to work. I really enjoyed being part of it.
I am very thankful to my friends, for our friendship! Every moment we spent
together with laughers and tears over the past years, will always be kept in my memory. I
especially thank Yinyin, Zhu Zhen, and Alexey, who are always understanding and
encouraging over the years and over the distance.
Lastly, I thank my family for their most generous love and supporting no matter
how far away I am from home. I specially thank my Dad without whom I would not have
chosen to go this far. As a matter of fact, I would not even choose to be an engineer if it
wasn’t for him. Now I think I enjoy it, most of the time.
6
Table of Contents
Page
Abstract...............................................................................................................................3
Acknowledgments...............................................................................................................4
List of Tables....................................................................................................................10
List of Figures...................................................................................................................11
Definitions of Symbols and Abbreviations.......................................................................14
1 Introduction...............................................................................................................16
1.1 GNSS Overview................................................................................................20

1.1.1 GPS Basics................................................................................................20

1.1.2 GPS Modernization...................................................................................21

1.2 GNSS Signal Characteristics............................................................................22

1.3 GNSS Antenna Basics......................................................................................26

1.3.1 GNSS Antenna Performance Requirements.............................................27

1.3.2 GNSS Antenna Selection Criteria.............................................................31

1.3.3 Available GPS Patch Antenna Design......................................................32

1.4 Thesis Objective................................................................................................33

2 Microstrip Patch Antenna Theory.............................................................................35
2.1 Basic Structure of Patch Antenna.....................................................................35

2.2 Radiation Mechanism of a Patch Antenna........................................................36

2.3 Feeding Techniques for Patch Antennas...........................................................38

2.4 Characteristics of Rectangular Patch Antenna..................................................39
7
2.4.1 Resonant Frequency and Patch Dimension...............................................39

2.4.2 Radiation Pattern.......................................................................................40

2.4.3 Circularly Polarized Rectangular Patch Antenna.....................................41

2.5 Design Tradeoffs of CP Patch Antenna............................................................44

2.5.1 Substrate Material.....................................................................................44

2.5.2 Trade-off in Feed Selection......................................................................45

2.6 Multilayer Patch Antenna.................................................................................45

3 Performance Analysis of a GPS L1 Patch Antenna..................................................47
3.1 Introduction.......................................................................................................47

3.2 Design Configuration and Parameters of Antenna A.......................................47

3.2.1 Nearly Square Circular Polarized Patch Antenna.....................................50

3.2.2 Approximation of Patch Dimension and Substrate Relative Permittivity of
Antenna A.................................................................................................................51

3.3 Simulation Setup of Antenna A in HFSSTM.....................................................52

3.3.1 Introduction to HFSSTM............................................................................52

3.3.2 Initial Simulation Results of Antenna A...................................................54

3.3.3 Simulation Tuning and Simulation Results of Antenna A........................55

3.4 Measurement of Antenna A..............................................................................67

3.4.1 Measurement Setup of Antenna A............................................................67

3.4.2 Measurement Results of Antenna A.........................................................69

3.5 Comparison of Simulation and Measurement Results of Antenna A...............74

4 Dual-frequency GPS L1L2 patch Antenna Simulation and Measurement...............78
4.1 Introduction.......................................................................................................78
8
4.2 Antenna B Structure..........................................................................................78

4.2.1 Configuration of Antenna B......................................................................78

4.2.2 Design Parameters for Antenna B.............................................................79

4.3 Simulation Setup and Tuning in HFSSTM for Antenna B.................................82

4.3.1 3D Model Creation of Antenna B.............................................................82

4.3.2 Solution Setup of Antenna B in HFSSTM..................................................85

4.3.3 Feed Location Analysis of Antenna B......................................................86

4.4 Simulation Results of Antenna B......................................................................91

4.5 Measurement Setup and Results of Antenna B...............................................100

4.5.1 Antenna B Measurement Setup..............................................................100

4.5.2 Measured Elevation Patterns of Antenna B............................................101

4.6 Comparison of Simulation and Measurement Patterns of Antenna B............103

4.7 Investigation of Substrate Property on Performance of Antenna B................105

4.7.1 Effect of Substrate Thickness.................................................................105

4.7.2 Effect of Substrate Dimension................................................................106

4.7.3 Effect of Loss tangent.............................................................................107

5 Dual-frequency GNSS L1L5 Patch Antenna Design and Simulation....................109
5.1 Introduction.....................................................................................................109

5.2 Design Discussions of the Prototype GNSS L1L5 Antenna...........................109

5.2.1 Design Goals and Consideration of the Prototype GNSS L1L5 Antenna....
.................................................................................................................109

5.2.2 Design Configuration of the Prototype GNSS L1L5 Dual Frequency Patch
Antenna .................................................................................................................110

5.2.3 Initial Parameters for the Design............................................................112
9

5.3 Simulations in HFSSTM...................................................................................114

5.3.1 Design Parameters for the Prototype GNSS L1L5 Patch Antenna.........114

5.3.2 Final Design Parameters for the Prototype Dual Frequency GNSS L1L5
Patch Antenna.........................................................................................................121

5.4 Simulation Results of the Prototype GPS L1L5 Patch Antenna.....................121

5.4.1 Simulation Results Analysis for the Prototype GPS L1L5 Antenna......129

6 Conclusions.............................................................................................................132
7 Recommendations...................................................................................................134
References.......................................................................................................................135
10
List of Tables
Page
Table 1.1 Available PRN Codes at GPS L1, L2, L5 Carrier Frequencies........................22

Table 1.2 Characteristics of GNSS Signals on GPS L1, L5 and Galileo E1 E5a.............25

Table 1.3 Performance Goals of Prototype GNSS L1L5 Antenna...................................34

Table 3.1 Listed Parameters of Antenna A.......................................................................49

Table 3.2 S Parameter Comparison..................................................................................75

Table 3.3 Gain Comparison among Simulation, Measurement and Specification...........77

Table 4.1 Preliminary Parameters of Antenna B..............................................................81

Table 4.2 Resonant Frequencies and Associated BW and VSWR...................................86

Table 4.3 Tuned parameters for Antenna B......................................................................91

Table 4.4 Different Substrate Thickness and Corresponding S Parameters...................106

Table 4.5 Substrate Dimensions vs. Patch Antenna S Parameters at Different Thicknesses
.........................................................................................................................................107

Table 4.6 Loss Tangent on Patch performance at Different Thickness..........................108

Table 5.1 Parameters for Scaling Patch Elements..........................................................113

Table 5.2 Different Combination of Substrate Thickness vs. BW.................................114

Table 5.3 Parameters of Prototype GNSS L1L5 Patch Antenna....................................121