novel multifunctional filtering power dividers made on circular patch resonators

117 Pages·2013·2.55 MB·English

NOVEL MULTIFUNCTIONAL FILTERING POWER
DIVIDERS MADE ON CIRCULAR PATCH
RESONATORS

KHOR Y CHUN

MASTER OF ENGINEERING SCIENCE

Faculty of Engineering and Science
Universiti Tunku Abdul Rahman
FEBUARY 2013
ABSTRACT

Microwave power dividers and filters are among the key passive components in
any microwave circuits and subsystems. The former has been broadly employed for
dividing or combining microwave signals; whereas, the later is to be used for selecting
the wanted and unwanted signals. Both components are found necessary in circuitries
such as power amplifiers, phase shifters, antenna arrays and so on. In practice, a power
divider is usually cascaded with a bandpass filter in order to eliminate noise
contributed by the surrounding subsystems or components. However, it results in a
bulkier circuit size and higher loss, suffering by microwave signals along the signal
paths.

The latest trend of miniaturizing a wireless communication system is to merge
various components into a single RF module and, also sometimes, with the use of
reconfigurable designs. In this thesis, for the first time, several types of
multifunctional microstrip bandpassing power dividers are presented. This project is
composed by two parts. Part 1 will be describing the double-layered dual-mode
microstrip bandpassing power dividers; while a reconfigurable one will be presented
in Part 2. Both of them will be elaborated in the subsequent paragraphs.

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ACKNOWLEDGEMENT

I would like to thank Dr. Lim Eng Hock and Prof. Chung Boon Kuan for their
directions, ideas and guidance. Throughout the completion of this research project,
invaluable recommendations and suggestions have been shared. In addition, they were
always available whenever I faced doubt.

I also wish to thank Mr. Ho, who guided me on fabrication process. With his
experience, I am able to fabricate my design precisely. Besides that, I also like to
extend my gratitude to all the seniors and friends during problem solving.

Special thanks should be given to UTAR for supporting all the equipments,
facilities, and materials. Furthermore, the online database such as IEEE Xplore and
ProQuest are very handy where most of the related information is available.

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APPROVAL SHEET

This thesis entitled ‘NOVEL MULTIFUNCTIONAL FILTERING POWER
DIVIDERS MADE ON CIRCULAR PATCH RESONATORS’ was prepared by
KHOR Y CHUN and submitted as partial fulfillment of the requirement for the degree
of Master of Engineering Science at Universiti Tunku Abdul Rahman.

Approved by,

_________________________
(Dr. Lim Eng Hock) Date: _________________
Supervisor
Department of Electrical and Electronic Engineering
Faculty of Engineering Science
Universiti Tunku Abdul Rahman

_________________________
(Prof. Dr. Chung Boon Kuan) Date: _________________
Professor/Co-supervisor
Department of Electrical and Electronic Engineering
Faculty of Engineering Science
Universiti Tunku Abdul Rahman
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Yours truly,

________________________________________
(KHOR Y CHUN)
v
DECLARATION

I hereby declare that the thesis is based on my original work except for citations and
quotations which have been duly acknowledged. I also declare that it has not been
previously and concurrently submitted for any other degree or award at UTAR or
other institutions.

Name : KHOR Y CHUN

Date : 22th Feb 2013

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NOVEL MULTIFUNCTIONAL FILTERING POWER
DIVIDERS MADE ON CIRCULAR PATCH
RESONATORS

In Part 1, two bandpassing power dividers, for both the two and three outputs,
are investigated. To demonstrate the design ideas, two prototypes are designed to work
at 6 GHz with the use of a circular patch resonator. The filter synthesis method is
employed to generate coupling matrix for each of the bandpassing power dividers.
Here, it will be showcased that the design freedom can be made higher by having
more outputs while keeping the design ideology. Another distinct advantage of the
proposed bandpassing power divider is that a pair of transmission zeroes can be
clearly identified at finite frequencies. This is due to tight coupling between the
resonator and the output patches of the double-layered structure.

Now, another new idea for multifunctional power dividers is proposed. As for
Part 2, the idea of integrating an PIN diode as a switching element is presented. The
proposed reconfigurable bandpassing power divider consists of a 2.4 GHz circular
patch resonator and an embedded PIN diode at each output port. The design principle
of this part is to individually optimize both the in-phase and out-of-phase
performances. Later, both of them are combined into one resonator. It was found that
the prototype has very good performances. Also, the idea of reconfiguration can be
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easily achieved by incorporating the PIN diodes, either by turning anyone of them ON
or OFF.

Finally, a comprehensive parametric analysis is carried out for each project in
order to completely understand each of the parameters and their limitations. All the
simulations were done by using Ansoft HFSS software and prototypes were fabricated.
Measurements were then carried out to verify the simulated results.
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TABLE OF CONTENTS

ABSTRACT ii
ACKNOWLEDGEMENT iii
APPROVAL SHEET iv
SUBMISSION SHEET v
DECLARATION vi
TABLE OF CONTENTS ix
LIST OF TABLES xii
LIST OF FIGURES xiii

CHAPTER
1 Introduction 1
1.1 Background 1
1.2 Research Objectives and Motivations 7
1.3 Thesis Organization 8
2 Literature Review 10
2.1 Microstrip Lines 10
2.1.1 Effective Dielectric Constant and Characteristic
Impedance 12
2.1.2 Wavelength λ and physical length l 14
g
2.1.3 Microstrip losses 14
2.2 Circular Patch Resonator 15
2.3 Transfer Function for Filters 21
2.4 Filter Synthesis 25
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3 Double-layered Bandpassing Power Dividers 29
3.1 Introduction 29
3.2 3 dB Double-layered Bandpass Power Divider (BPD-A) 30
3.2.1 Configuration 30
3.2.2 Synthesis Analysis 33
3.2.3 Simulation and Experiment Results 35
3.2.4 Theoretical and Parametric Studies 38
3.3 4.8 dB Double-layered Bandpass Power Divider (BPD-B) 50
3.3.1 Configuration 50
3.3.2 Synthesis Analysis 52
3.3.3 Simulation and Experiment Results 53
3.3.4 Parametric Analysis 57
3.4 Conclusion 63
4 Reconfigurable Bandpassing Power Divider 64
4.1 Introduction 64
4.2 In-phase Bandpassing Power Divider (BPD-1) 65
4.2.1 Configuration 65
4.2.2 Simulation and Experimental Results 67
4.2.3 Theoretical and Parametric Studies 69
4.3 Out-of-phase Bandpassing Power Divider (BPD-2) 73
4.3.1 Configuration 73
4.3.2 Simulation and Experiment Results 74
4.3.3 Theoretical and Parametric Studies 76
4.4 Reconfigurable Bandpassing Power Divider (BPD-3) 81
4.4.1 Configuration 81
4.4.2 Biasing Circuitry for RF PIN Diode 83
4.4.3 Simulation and Experimental Results 84
4.5 Conclusion 88
5 Summary and Future Work 89
5.1 Summary 89
5.2 Future Works 92
x