UNIVERSITI PUTRA MALAYSIA

COMPACT MICROSTRIP BANDPASS FILTERS USING COUPLED

SPIRAL RESONATOR AT 2.3 GHz

ADAM REDA HASAN ALHAWARI

FK 2009 15

COMPACT MICROSTRIP BANDPASS FILTERS USING COUPLED SPIRAL RESONATOR AT 2.3 GHz

By

ADAM REDA HASAN ALHAWARI

Thesis Submitted to the School Graduate Studies, Universiti Putra Malaysia, in Fulfilment of the Requirements for the Degree of Master of Science

August 2009

ii

DEDICATION

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To my ever-loving parents…

To my beloved wife…

To my dearest siblings…

To my caring parents in laws…

To every kind pious person who loves universal peace and prosperity…

To those who are patient towards tyranny and oppression…

To those who love knowledge and are pursuing it for world positive change…

iii

Abstract of thesis presented to the Senate of Universiti Putra Malaysia in fulfilment of the requirement for the degree of Master of Science

COMPACT MICROSTRIP BANDPASS FILTERS USING COUPLED SPIRAL RESONATOR AT 2.3 GHz

By

ADAM REDA HASAN ALHAWARI

August 2009

Chairman: Dr. Alyani Binti Ismail, PhD

Faculty: Engineering

Microstrip filters are essential components utilized in the RF/Microwave

applications because of their low loss and simple structure. Moreover, it can be

fabricated using simple printed circuit technology and characterize main advantages

in RF/Microwave filters like high performance, light weight and low cost which the

fast track of continuous evolution in wireless communication systems highly

demands.

This thesis presents design and development of three different microstrip bandpass

filters (BPFs) for high selectivity applications. A fourth order microstrip BPF was

designed using Chebychev lowpass prototype with passband ripple of 0.05 dB and

bandwidth of 120 MHz, which operates at center frequency of 2.3 GHz. This filter is

designed by using coupled spiral resonator, where these types of resonator structures

simplify the design method for microstrip BPF and yet more efficient. This filter

iv

design is then rearranged and modified by using square spiral resonator structures

and embedded-resonator topology with the same fundamental frequency to make it

more compact; furthermore, it has high quality performance in terms of the

frequency responses.

All the microstrip BPF designs were developed and analyzed by a 3-D

electromagnetic simulator. To confirm the simulation results, the three proposed

filters are fabricated on R/T Duroid 5880 with dielectric constant of 2.2. The

Experimental measurements are carried out using an Agilent N5230A network

analyzer. The simulated and measured results are presented, compared and

discussed. The analysis indicates a fairly good agreement between simulation and

measurment. Finally, compact microstrip BPFs which could demonstrate high

quality performance are thoroughly investigated.

In this design, the minimum measured insertion loss is 2.65 dB, and the measured

return loss is greater than 11 dB in the passband operating at 2.3 GHz, with a

fractional bandwidth of 5.2% with two transmission zeros on both sides of the

passband. The total size of this layout is 24.74 x 21.2 mm2. This new filter provides

a significant size reduction of more than 30% and 18%, with respect to the

conventional microstrip BPFs and the recently reported bandpass filter by Wang and

others in 2008, respectively, at the same center frequency.

Later, multilayer technology is used to reduce more than 25% of the filter size;

which is much smaller compared to the microstrip filters using single layer structure.

The new filter structure consists of four spiral resonators placed on two stacked

v

layers where the metallic ground plane is deposited onto bottom surface of the

dielectric. The measured minimum passband insertion loss is 5.2 dB with measured

return loss is no more than -17 dB in the passband. The overall filter size is 380

mm2, which is approximately 10% smaller compared to the multilayer filter reported

by Denidni and Djaiz in 2005. It is also reduced more than 25% and 41% compared

to our proposed single layer microstrip filter and bandpass filter reported by Wang

and others in 2008, respectively, at the same center frequency.

It is a promising product to attract usage in modern wireless communication system

applications which demand compact size bandpass filters at very low insertion loss

but high selectivity, and good out-of-band rejection.

vi

Abstrak tesis yang dikemukakan kepada Senat Universiti Putra Malaysia sebagai memenuhi keperluan untuk ijazah Master Sains

PENURAS LOLOS LALUAN JALUR MIKRO PADAT MENGGUNAKAN PENYALUN PILIN BERPASANGAN PADA 2.3 GHz

Oleh

ADAM REDA HASAN ALHAWARI

Ogos 2009

Pengerusi: Dr. Alyani Binti Ismail, PhD

Fakulti: Kejuruteraan

Penuras jalur mikro adalah komponen yang sangat penting kepada aplikasi

Frekuensi Radio/Gelombang Mikro kerana faktor natijah kehilangan kuasa yang

rendah dan strukturnya yang ringkas. Malahan, ia boleh difabrikasi menggunakan

teknologi litar bercetak yang menyumbang ciri – ciri kelebihan utama kepada

penuras Frekuensi Radio/Gelombang Mikro seperti berprestasi tinggi, ringan, dan

kos yang rendah untuk membuatnya yang menjadikannya dambaan arus deras aliran

evolusi sistem komunikasi tanpa wayar.

Tesis ini membentangkan rekabentuk dan penghasilan tiga (3) penuras lolos laluan

jalur mikro BPF yang berbeza untuk aplikasi pilihan tinggi. Satu penuras jalur mikro

dengan empat (4) penyalun direka menggunakan prototaip laluan rendah Chebychev

dengan riak lolos laluan 0.05 dB dan lebar lolos jalur 120 MHz, yang beroperasi

vii

pada pusat frekuansi 2.3 GHz. Penuras ini direka menggunakan penyalun pilin

berpasangan; struktur penyalun jenis ini meringkaskan kaedah menghasilkan rekaan

penuras jalur mikro BPF tetapi ianya amat efisien. Rekaan penuras ini kemudiannya

disusun atur semula dan diubahsuai menggunakan struktur penyalun pilin empat segi

dan topologi penyalun terbenam dengan asas frekuensi yang sama untuk

menjadikannya lebih padat. Jika dibandingkan dengan penuras jalur mikro BPF

konvensional, penuras yang dicadangkan berupaya mengurangkan 30% daripada

saiz keseluruhan struktur.

Kesemua rekaan jalur mikro dicipta dan dianalisa dengan bantuan simulasi

elektromagnetik 3-dimensi. Untuk mengesahkan keputusan simulasi, ketiga – tiga

penuras yang dicadangkan itu difabrikasi di atas substratum R/T Duroid 5880

dengan kemalaran dieletrik pada 2.2. Keputusan ujikaji diperolehi dengan

menggunakan sebuah mesin penganalisa rangkaian jaringan Agilent N5230A.

Natijah simulasi dan keputusan ujikaji dibentangkan, dibandingkan dan

dibincangkan. Analisa menunjukkan keserasian yang agak bagus di antara simulasi

dan natijah ujikaji. Hasilnya, penuras jalur mikro BPF yang mampu menonjolkan

prestasi berkualiti tinggi telah dikaji dengan jayanya.

Dalam rekaan ini, kiraan minimum kehilangan insersi ialah 2.65 dB, dan nilai

kehilangan kembali adalah 11 dB lebih besar berbanding jalur lolos yang beroperasi

pada 2.3 GHz dengan nilai lebar 5.2% jalur fraksional dengan 2 transmisi sifar pada

kedua-dua belah jalur lolos. Saiz keseluruhan tata letak ini ialah 24.74 x 21.2 mm2.

Penuras baru ini menjanjikan pengurangan saiz yang amat ketara sehingga lebih

daripada 30% pada penuras jalur mikro konvensyenal dan 18% pada penuras jalur

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lolos yang dilaporkan baru-baru ini oleh Wang dan lain-lain pada tahun 2008,

masing-masing pada pusat frekuensi yang sama.

Kemudian, teknologi pelbagai lapis digunakan bagi mengurangkan 25% lagi

daripada saiz penuras agar lebih kecil daripada penuras jalur mikro yang

menggunakan teknologi selapis. Struktur penuras baru ini terdiri daripada empat (4)

penyalun pilin yang diletakkan pada dua lapisan berperekat di mana satah dasar

metalik dilekatkan di bahagian bawah permukaan dielektrik. Kiraan minimum

kehilangan insersi jalur lolos ialah 5.2 dB dengan kehilangan kembali tidak lebih

daripada -17 dB pada jalur lolos. Saiz keseluruhan ialah 380 mm2, iaitu lebih kurang

10% lebih kecil berbanding penuras pelbagai lapis yang dilaporkan oleh Denidni

dan Djaiz pada tahun 2005. Ia juga berkurangan lebih daripada 25% dan 41%

berbanding penuras mikro selapis kami dan penuras jalur lolos yang dilaporkan oleh

Wang dan lain-lain pada tahun 2008, masing-masing pada pusat frequensi yang

sama.

Ia adalah satu prospek produk yang menarik untuk digunakan dalam aplikasi sistem

komunikasi tanpa wayar moden yang membutuhkan saiz jalur lolos yang kompak

pada kehilangan insersi yang lebih rendah tetapi berselektiviti tinggi dan rejeksi luar

jalur yang baik.

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ACKNOWLEDGMENTS

First and foremost, my greatest gratitude goes to the Most Merciful Allah S.W.T.

who Granted me the opportunity to pursue my second degree study in Malaysia.

I am also so grateful to have a very supportive, helpful, encouraging and patient

family members; which helps a lot to accomplish this completion of the assigned

thesis. My special thanks are due to my beloved wife for being understanding and

cooperative.

Last but not least, my due appreciation to my generous supervisor: Dr. Alyani binti

Ismail for her objective guidance and firm support; which I am at lost without it. I

am in a way indebted to my best friends and lab-mates for their kind assistance

especially in sharing information, skills and experience.

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I certify that an Examination Committee met on 14th August 2009 to conduct the final examination of Adam Reda Hasan Alhawari on his thesis entitled “Compact Microstrip Bandpass Filters Using Coupled Spiral Resonator at 2.3 GHz” in accordance with the Universities and University Colleges Act 1971 and the Constitution of the Universiti Putra Malaysia [P.U.(A) 106] 15 March 1998. The Committee recommends that the student be awarded the Master of Science. Members of the Examination Committee were as follows: Sabira Khatun, PhD Associate Professor Faculty of Engineering Universiti Putra Malaysia (Chairman) Ahmad Fauzi Abas, PhD Senior Lecturer Faculty of Engineering Universiti Putra Malaysia (Internal Examiner) Mohd Nizar Hamidon, PhD Senior Lecturer Faculty of Engineering Universiti Putra Malaysia (Internal Examiner) Mohamad Kamal A. Rahim, PhD Associate Professor Faculty of Electrical Engineering Universiti Teknologi Malaysia (External Examiner) BUJANG KIM HUAT, PhD

Professor and Deputy Dean School of Graduate Studies Universiti Putra Malaysia

Date:

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This thesis was submitted to the Senate of Universiti Putra Malaysia and has been accepted as fulfilment of the requirement for the degree of Master of Science. The members of the Supervisory Committee were as follows: Alyani Binti Ismail, PhD Senior Lecturer Department of Computer and Communication System Engineering Faculty of Engineering Universiti Putra Malaysia (Chairman) Raja Syamsul Azmir Bin Raja Abdullah, PhD Senior Lecturer Department of Computer and Communication System Engineering Faculty of Engineering Universiti Putra Malaysia (Member) Mohd. Fadlee Bin A. Rasid, PhD Senior Lecturer Department of Computer and Communication System Engineering Faculty of Engineering Universiti Putra Malaysia (Member)

HASANAH MOHD. GHAZALI, PhD Professor and Dean School of Graduate Studies Universiti Putra Malaysia

Date: 16 November 2009

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DECLARATION

I declare that the thesis is my original work except for quotations and citations which have been duly acknowledged. I also declare that it has not been previously, and is not concurrently, submitted for any other degree at Universiti Putra Malaysia or at any other institution.

ADAM REDA HASAN ALHAWARI Date: 08 September 2009

xiii

TABLE OF CONTENTS Page DEDICATION ii ABSTRACT iii ABSTRAK vi ACKNOWLEDGMENTS ix APPROVAL x DECLARATION xii LIST OF TABLES xv LIST OF FIGURES xvi LIST OF ABBREVIATIONS xix CHAPTER

1 INTRODUCTION 1 1.1 Background 1 1.2 Statement of Problem and Motivation 2 1.3 Research Objectives 5 1.4 Scope of Research 6 1.5 Organization of the Thesis 7

2 LITERATURE REVIEW 9 2.1 Introduction 9 2.2 Evolution of Filter Size 9 2.3 Microwave Frequencies 10 2.4 Scattering Parameter Measurements 11 2.5 Applications of Microwave Filters 13 2.6 Bandpass Filtering Functions 14 2.6.1 Ideal Filter 14 2.6.2 Chebychev Filtering Response 15 2.6.3 Elliptic Function Response 16 2.7 Chebychev Lowpass Prototype Filters 17 2.8 Use of Lowpass to Bandpass Mappings 18 2.9 Microstrip Transmission Lines 20 2.9.1 Microstrip Structure 20 2.9.2 Electric and Magnetic Field Lines in Microstrip 21

2.9.3 Effective Dielectric Constant and Characteristic Impedance 22 2.9.4 Guided Wavelength, Propagation Constant, Phase Velocity, and Physical Line Length

Formulas 23 2.9.5 Losses in Microstrip 24 2.10 Review of Various Microstrip Bandpass Filters Using

Coupled Resonators 25 2.11 Review of Various Microstrip Bandpass Filters Using

Multilayer Technology 30

xiv

3 RESEARCH METHODOLOGY 35 3.1 Introduction 35 3.2 Coupled Resonator Bandpass Filters Design 35 3.3 Bandpass Filter Design Using Coupling Coefficients 39 3.4 Extracting the External Quality Factors Using 3-D EM

Simulator 40 3.5 Extracting the Coupling Coefficients between the Resonators Using 3-D EM Simulator 42

3.6 Measurement Setup 44

4 RESULTS AND DISCUSSION 46 4.1 Introduction 46 4.2 Microstrip BPF Design Using Coupled Spiral Resonator 47 4.2.1 Design and Layout 47

4.2.2 Extraction of External Quality Factor and Coupling Coefficients 50

4.2.3 Filter Implementation and Results 51 4.3 Microstrip BPF Design Using Dissimilar Coupled Resonators with Embedded-Resonators Topology 53

4.3.1 Design Approach 53 4.3.2 Simulated and Measured Results 56 4.4 Microstrip BPF Design Using Multilayer Technology 58 4.4.1 Novel Filter Design 58 4.4.2 Extraction of Coupling Coefficients 60 4.4.3 Experimental Results 61 4.5 Comparative Study on Filters Performance 64

5 CONCLUSIONS 66 5.1 Conclusion 66 5.2 Thesis Contributions 67 5.3 Recommendations for Future Research 68 REFERENCES 69 APPENDICES 74 BIODATA OF STUDENT 87 LIST OF PUBLICATIONS 88

xv

LIST OF TABLES Table

Page

1.1 Typical specifications of designed BPF 7

2.1 Summary of the performance comparison among the reviewed filters

33

4.1 Specifications of the designed BPF

48

4.2 Dimensions of the proposed coupled resonator BPF

51

4.3 Dimensions of the proposed embedded-resonator BPF

56

4.4 Material specifications of multilayer filter

60

4.5 Dimensions of the proposed multilayer BPF

61

4.6 Measured filter characteristics 64

xvi

LIST OF FIGURES

Figure

Page

1.1 Scope of Research 6

2.1 Evolution of Spiral Resonator Filters 10

2.2 The Electromagnetic Spectrum

11

2.3 Two-Port Network and Its S-Parameters

12

2.4 Ideal Lowpass Filter and Its Frequency Response

14

2.5 Chebychev Lowpass Response

15

2.6 Elliptic Function Lowpass Response

16

2.7 Lowpass Prototype Filter (a) Ladder Network Structure (b) Its Dual

17

2.8 Chebychev Bandpass Filter Response

19

2.9 Bandpass Filter Lumped Elements

20

2.10 General Microstrip Structure

21

2.11 Microstrip Electric and Magnetic Field Lines (Cross Section)

22

2.12 Four-Pole Microstrip Bandpass Filter (Wang et al., 2008) 29

2.13 Typical Cross-Section Multilayer Structure

31

3.1 Method-Flow of Microstrip Bandpass Filter Design

36

3.2 General Structure of Parallel-Coupled Microstrip Bandpass filter

37

3.3 Half-Wavelength Square Open-Loop Resonator

38

3.4 (a) Layout of Spiral Resonators and (b) Its Lumped-Element Equivalent Model

39

3.5 Design Parameters of a Coupled Resonator Bandpass Filter

40

3.6 Extracting exQ from 3-D EM Simulator

41

3.7 21S Typical Simulated Response for exQ

41

xvii

3.8 Extracting ijM from 3-D EM Simulator

42

3.9 21S Typical Simulated Response for ijM 43

3.10 Measurement Setup (a) Block Diagram (b) Photograph 45

4.1 Layout of Proposed Microstrip BPF

47

4.2 Coupling Topology of Four Coupled Resonator

47

4.3 Ideal Simulation and Coupling Matrix of the Proposed BPF

49

4.4 External Quality Factor as a Function of t

50

4.5 Coupling Coefficient between Resonators as a Function of S

51

4.6 Simulated Frequency Response of the Proposed Coupled Spiral Resonator BPF

52

4.7 Photograph of the Fabricated Coupled Spiral Resonator BPF

53

4.8 Configuration of the Proposed Microstrip BPF with Embedded-Resonator Topology

54

4.9 Geometrics of Three Resonator Types: (a) Uniform Impedance

Resonator (UIR) (b) Normal Square Open-Loop Resonator (c) Square Spiral Resonator (SSR)

54

4.10 Coupling Scheme of Four Coupled Resonators with Input/Output Coupling

54

4.11 Coupling Coefficients for Coupled Resonators: Electric Coupling for Resonators 1 and 4, Magnetic Coupling for Resonators 2 and 3, and Mixed Coupling for Resonators 1 and 2, and 3 and 4

55

4.12 Photograph of the Fabricated BPF with Embedded-Resonators

56

4.13 Simulated and Measured Frequency Responses of the Proposed BPF with Embedded-Resonators Topology (a) Insertion loss (S21) and (b) Return loss (S11)

57

4.14 Structure of the Proposed Filter in a Multilayer Configuration (a) Top View (b) Perspective View

59

4.15 Typical coupling coefficients between Resonators 1 and 2 and Resonators 3 and 4

60

4.16 Mixed Coupling with Resonators on Different Layers

61

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4.17 Simulated and Measured Frequency Responses of the Proposed Multilayer BPF (a) Insertion loss (S21) and (b) Return loss (S11)

62

4.18 Photograph of the Fabricated Multilayer BPF

63

4.19 Photographs of the Fabricated Filters

64

xix

LIST OF ABBREVIATIONS

BPF Bandpass Filter

CSR Coupled Spiral Resonators

dB Decibels

DUT Device Under Test

EM Electromagnetic Spectrum

FBW Fractional Bandwidth

GHz Gigahertz

GSM Global System for Mobile Communications

HTS High-Temperature Superconductivity

MEMS Micro-Machining or Microelectromechanical Systems

MHz Megahertz

mm Millimetre

MMICs Monolithic Microwave Integrated Circuits

PCB Printed Circuit Board

RF Radio Frequency

SIR Stepped Impedance Resonator

S-parameters Scattering parameters

SSR Square Spiral Resonator

TEM Transverse Electromagnetic Mode

UIR Uniform Impedance Resonator

VNA Vector Network Analyzer

WiMAX Worldwide Interoperability for Microwave Access

WLAN Wireless Local Area Network

CHAPTER 1

INTRODUCTION

1.1 Background

Current fast track technological advancement has turned gregarious human to rely

on various microwave or RF devices and gadgets in daily communications. Devices

like microwave filters, antenna, amplifiers, switches, etc. have become civil and

military utter telecommunication necessity of contemporary lifestyle.

Recent progress witnesses strong demand from communications industry for

creative innovation of more compact microwave devices which are capable to

outperform previous technology. Among the most demanded in the microwave

devices list is microwave filter which is used most in wireless communication

technology to provide a more highly sought after telecommunication efficiency

beyond typical imagination.

In wireless communication systems, microwave filters are vital components and

play important roles in many RF/Microwave applications. Bandpass filters are

essential components utilized in the RF/Microwave and wireless communication

systems, which are usually found in both transmitters and receivers to discriminate

between intended and unintended signal frequencies. In other words, they are used

to select or reject RF/Microwave signals within assigned spectral limits. Evidently,

the quality of bandpass filters is extremely important to acquire precise desired

frequency.

2

As far filter technology went throughout history since its advent before the burst of

world War II, it had produced various typical technologies like lumped-element LC

filters, planar filters, coaxial filters, cavity filters, dielectric filters, and high-

temperature superconductivity (HTS) filters. Among them, the planar technology is

the most immensely used in improving the compactness of the filter size and has a

more promising future ahead mainly because it is the easiest to fabricate especially

ones using printed circuit technology at minimum cost production compared to other

technologies mentioned but still could compromise quality performance.

There are many types of planar filter designs had been created like parallel-couple

line topology proposed by Cohn, which is the most commonly used filter (Cohn,

1958). Several configurations were then introduced to make the filters more compact

like hairpin resonator filters and open-loop resonator filters, and are widely used in

many wireless communication applications due to their smaller size compared to the

conventional coupled-line resonator filters.

1.2 Statement of Problem and Motivation

Modern microwave communication systems demand low cost, high performance

narrowband bandpass filters which characterize low insertion loss, high selectivity

and out-of-band rejection together with optimized size reduction especially in

wireless communication system applications such as worldwide interoperability for

microwave access (WiMAX), wireless local area network (WLAN) and global

system for mobile communications (GSM). Recent advancement in materials and

technologies such as high-temperature superconductors (HTS), micro-machining or

microelectromechanical systems (MEMS) and hybrid or monolithic microwave

3

integrated circuits (MMICs) has stimulated the development of new compact

microstrip filters (Hong and Lancaster, 2001).

Miniaturization of microwave filters is one of the fundamental requirements in

communication systems. Therefore, small-size and high performance filters are

always necessary to reduce cost and enhance system performance. To meet these

demands, intensive research efforts have been focused on achieving compact low

loss bandpass filters for wireless system applications using parallel coupled-line

resonator filters (Fok et al., 2005; Lin et al., 2005; Chen and Wang, 2009), hairpin

resonator filters (Kuo et al., 2004; Denidni and Djaiz, 2005; Hasan and Nadeem,

2008; Liu and Li, 2008), open-loop resonator filters (Hong and Lancaster, 1999 and

2000; Romani et al., 2007; Zhang et al., 2007), and coplanar waveguide (CPW) filter

(Ismail et al., 2008). However, the size of planar filters with parallel coupled-line

resonators, hairpin resonators, open-loop resonators or coplanar waveguide (CPW)

filters design is obviously still too large to adapt the demand of modern systems,

moreover, would add complexity to some designs and therefore, very difficult to be

tuned into the right operating frequency (Clavet et al., 2007; Militaru et al., 2007).

In addition to compact size, less weight, high selectivity, and low losses, other

desirable features of microstrip bandpass filters are low cost and narrowband. So, in

this thesis, the inspired design is to utilize the microstrip spiral resonators instead of

its frequent usage in HTS technology; due to its cost and fabrication problems

(Huang, 2001; Huang and Xiong, 2003; Zhang et al., 2005a and 2005b; Ono et al.,

2007; Abu-Hudrouss et al., 2008).

4

Thus, the need for size reduction and lower fabrication cost are critical issues in

RF/Microwave filters development. Consequently, more creative researches are

needed to find effective designs to achieve the above mentioned demanded

characteristics of modern filters and to get precise measurement as closest as

possible to the ideal accuracy in the whole design process.

These ideals were found in one of the literature review referred (Wang et al., 2008),

which had ignited interest to investigate similar design specifications e.g. four-pole

bandpass filter design using embedded–resonator topology which is more compact

than other designs existed. Motivated by their creative design, this study reaches out

for a wider exploration on various design possibilities in order to achieve better

modifications especially in terms of frequency responses, losses and selectivity

performance. Their filter topology with Chebychev response could not respond at

par with elliptic response, since in comparison it does not produce skirts as sharp as

the elliptic one.

Most of the present wireless communication system applications screened are below

3 GHz (Bahl, 2003). In this spectrum, achieving narrowband bandpass filters (BPFs)

that yield high quality performance at smaller size and lower cost is a challenging

task. Hence, this research specifically aims to design a lower loss microstrip four-

pole BPFs which is capable to meet the required specifications of wireless

communication systems. Compact novel microstrip BPFs designs using coupled

spiral resonator principle with Chebychev and elliptic responses are developed to

achieve a prospect practical solution for pre-select filters in a base station of wireless

communication systems with sharp rejection and adequate fractional bandwidth.

5

1.3 Research Objectives

The aim of this research is to study and develop new filter designs that could avoid

size and precision problems but tackling them to perform well at a very low cost

which is useful prospect for wireless communication system applications. Research

objective is to produce and develop four-pole microstrip BPFs using coupled spiral

resonator structures for high selectivity applications.

The thesis is built around three main objectives:

1. To design a novel compact microstrip BPFs using single layer structure at

center frequency of 2.3 GHz.

2. To design a novel compact microstrip BPF using multilayer technology at

center frequency of 2.3 GHz.

3. To simulate, fabricate and measure the filters responses.

Finally, the synthesis and design of new compact microstrip BPFs is conducted. The

resulting BPFs should be easier to design with excellent performance.