DESIGN OF MULTI-BAND BANDPASS FILTER FOR NEXT

GENERATION WIRELESS SYSTEM

LEE KAH WENG

This report submitted in partial fulfillment of the requirements for the award of

Bachelor of Electronic Engineering (Telecommunications Electronics) With

Honours

Faculty of Electronics and Computer Engineering

Universiti Teknikal Malaysia Melaka

June 2015

UNIVERSITI TEKNIKAL MALAYSIA MELAKA

UNIVERSTI TEKNlKAL MALAYSIA MELAKA FAKULTI KEJURUTERAAN ELEKTRONIK DAN KEJURUTERAAN

KOMPUTER

BORANGPENGESAHANSTATUSLAPORAN PROJEK SARJANA MUDA II

Tajuk Projek DESIGN OF MULTI-BAND BANDPASS FILTER FOR NEXT GENERATION WIRELESS SYSTEM

Sesi Pengajian 4

Saya LEE KAH WENG

I 5

(HURUF BESAR) mengaku membenarkan Laporan Projek Saijana Muda ini disimpan di Perpustakaan dengan syarat­syarat kegunaan seperti berikut:

I. Laporan adalah hakmilik Universiti Teknikal Malaysia Melaka.

2. Perpustakaan dibenarkan membuat salinan untuk tujuan pengajian sahaja.

3. Perpustakaan dibenarkan membuat salinan laporan ini sebagai bahan pertukaran antara

institusi pengajian tinggi.

4. Sila tandakan ( -V ) :

D SULIT ..

D TERHADH

0 TIDAK TERHAD

*(Mengandungi maklumat yang berdarjah keselamatan atau kepentingan Malaysia seperti yang termaktub di dalam AKT A RAHSlARASML 1972)

**(Mengandungi maklumat terhad yang telah ditentukan oleh organisasi/badan di mana penyelidikan dijalankan)

Disahkan oleh:

(fANDAe PENULIS)

. II I b / .2.01'? Tankh: ........ .. . . .. .. .. .. .. .... .

DR. ZAHRILADHA BIN ZAKARIA Profesor Madyo

Fikul1l Kejunrtm;n Elektronlk oan Ke)uruteraan lCo;npi.~}f. Unlversltl Teknlkal Malaysia ivlelaka {U1eM

Hang Tuah Jaya 76100 Durian Tungr,al, M~I~~~

Tarikh: ... ..... . .. 1 .1./.~ !.i..0. '.5

DECLARATION

I declared that this thesis entitled "DESIGN Of MULTI-BAND BANDPASS

f!LTER fOR NEXT GENERATION WIRELESS SYSTEM" is the result of my

own research except as cited in the reference.

Signature

Author

Date

: LEE KAH WENG

II (fo( 'U)I~

Ill

lV

APPROVAL

l hereby declare that I have read this thesis and in my opinion this thesis is su±licient

in term of the scope and quality for the award of Bachelor of Electronic Engineering

(Telecommunication Electronics) With Honors.

Signature

Supervisor's Name

Date

-~~~ : PM. DR. ZAI-I:ill:!A BIN ZAK.ARIA

11/1o/ UJ/5

v

DEDICATION

Special dedication to my beloved parents,

Lee Wing Fook & Kong Lai Peng

My supporting siblings:

Lee Poh Yoke

Lee Kah Meng

To my supervisor

PM Dr Zahriladha Bin Zakaria

My friends and my fellow lecturers

Thank you for all your care, support and believe in me

vi

ACKNOWLEDGMENT

This acknowledgement was written as I completed the Final Year Project

program in University Technical Malaysia Melaka. First of all, I would like to take

this opportunity to extend my deepest gratitude to my supervisor, PM. Dr. Zahriladha

Bin Zakaria for his inestimable and invaluable guidance. The supervision and

support gave truly help on the progression and the smoothness of the project during

Final Year Project program. Your kindness, your leadership and your word of

wisdom will keep close to my heart at all times. The co-operation is much indeed

appreciated. Next, I would like to extend my deepest gratitude to our Final Year

Project program course coordinator, Dr. Kok Swee Leong for his inestimable and

invaluable guidance. As I know, he is a very good instructor. Thanks so much for

taking time from your busy schedule to give an introduction about this training

program and provided the sources of the modules or courses. Furthermore, I would

also like to convey my gratefulness and appreciations to PhD research student, Sam

Weng Yik who volunteers to teach and assist me in this Final Year Project program

with the understanding. My grateful thanks goes to technicians, Mr. Imran Bin

Mohamed Ali and Mr. Mohd Sufian Bin Abu Talib. A big contribution from them

involved during this Final Year Project program.

vii

ABSTRACT

This project presents the design of multi-band bandpass filter using

microstrip with Defected Microstrip Structure (DMS) to produce bandpass and band

reject characteristics simultaneously. This class of filter is designed based upon

λ_g0/4 short-circuited stubs structure of 7th degree. The integrated multi-band BPF

and DMS produce 3 wideband bandpass and 2 band reject response simultaneously

in order to remove any undesired signals in the passband of the bandpass response

with S11, better than -20dB and insertion loss, S21, of around -1dB respectively. The

DMS exhibits two band-reject responses better than -20dB and forms first band

2.3GHz-2.7GHz, second band 3.1GHz-4.8GHz and third band 5.15GHz-5.85GHz.

This design is simulated on a Roger Duroid RO4350 with a dielectric constant, ε_r of

3.48 and a thickness of 0.508 mm while the loss tangent is 0.0019. The theoretical,

simulated and measured results were obtained and demonstrated in this thesis. This

type of filter is useful in any RF/ microwave communication systems such as

Worldwide Interoperability for Microwave Access (WiMAX) and wireless UWB

tracking system.

viii

ABSTRAK

Projek ini membentangkan reka bentuk penapis jalur laluan yang

pelbagai jalur menggunakan penapis laluanlulus menggunakan kecacatan struktur

mikro-strip untuk menghasilkan laluan jalur dan jalur menolak yang bercirikan

serentak didalam respon penapis. Kelas penapis direka berdasarkan λ_g0 / 4 struktur

pendek litar pintas dengan 7 perintah. penapis jalur laluan yang pelbagai jalur

bersepadu dengan kecacatan struktur mikro-strip menghasilkan 3 jalur lebar laluan

jalur dan 2 respon jalur menolak pada masa yang sama untuk mengeluarkan apa-apa

isyarat yang tidak diingini dalam kehilangan pulangan S11, lebih baik daripada -

20dB dan kehilangan masukkan S21, kira-kira -1dB masing-masing. DMS

mempamerkan dua respon jalur menolak yang lebih baik daripada -20dB dan

membentuk jalur pertama 2.3GHz-2.7GHz, jalur kedua 3.1GHz-4.8GHz dan jalur

ketiga 5.15GHz-5.85GHz. Reka bentuk ini adalah disimulasikan menggunakan

Roger Duroid RO4350 dengan pemalar dielektrik, ε_r 3.48 dan ketebalan 0.508mm

manakala kehilangan tangen adalah 0,0019. Teori, simulasi dan keputusan diukur

diperolehi telah ditunjukkan di dalam tesis ini. Jenis penapis ini adalah berguna

dalam mana-mana sistem komunikasi gelombang mikro seperti Akses Gelombang

Mikro (WiMAX) dan wayarles sistem pengesanan UWB.

ix

TABLE OF CONTENTS

CHAPTER CONTENTS PAGES

TITLE i

DECLARATION iii

APPROVAL iv

DEDICATION v

ACKNOWLEDGMENT vi

ABSTRACT vii

ABSTRAK viii

TABLE OF CONTENTS ix

LIST OF FIGURES xii

LIST OF TABLES xv

I. INTRODUCTION

1.1 Introduction 1

1.2 Problem statement 2

1.3 Objective 2

1.4 Scope of project 3

1.5 Chapter review 3

II. LITERATURE REVIEW

2.1 Band pass filter 5

2.2 Planar microstrip band pass filter 6

2.3 Multi-band band pass filter 7

2.4 Notched responses 7

x

2.5 Related research 8

III. METHODOLOGY

3.1 Methodology 15

3.2 Designing multi-band band pass filter 17

3.2.1 Filter specification and parameter 18

3.2.2 Design technique, equation and calculation 19

3.2.3 Ideal transmission line 23

3.2.4 Microstrip line 24

3.2.5 Layout structure 26

3.3 Defected microstrip structure (DMS) 26

3.3.1 Parametric study 26

3.4 Bandpass filter integrated with DMS 27

3.5 Fabrication and measurement 28

IV. RESULT & DISCUSSION

4.1 Multi-band bandpass filter ideal transmission line

structure 30

4.2 Microstrip line structure 33

4.2.1 Microstrip line structure with T-junction 34

4.2.2 Symmetric width and length of bandpass

filter 39

4.3 Parametric study on defected microstrip structure

(DMS) 41

4.4 Bandpass filter integrated with DMS 46

4.5 Physical structure and comparison result of

multi-band bandpass filter 49

xi

V. CONCLUSION

5.1 Conclusion 52

5.2 Future works 53

REFERENCES 54

APPENDICES

Appendix A Gantt chart 57

Appendix B Poster INOTEK 2015 58

Appendix C INOTEK 2015 certificate 59

Appendix D INOTEK 2015 award 60

xii

LIST OF FIGURES

FIGURE TITLE PAGES

2.1 Frequency response of band pass filter 6

2.2 Example of planar microstrip band pass filter 6

2.3 Notched responses introduced to remove unwanted

frequency range 7

2.4 DMS structure on the microstrip 8

3.1 Flow chart of designing multi-band band pass filter 16

3.2 Process to design multi-band band pass filter 17

3.3 Topology of quarter-wavelength short-circuited stubs

filter 19

3.4 The table of element values of Cheyshev low pass prototype

filter 20

3.5 Schematic of ideal transmission line of band pass filter. 23

3.6 Setting of “LineCalc” 24

3.7 Schematic of microstrip line structure based on the

value of table 3.4 25

3.8 Layout structure of bandpass filter 26

3.9 Different shape of DMS designed (hashtag, U, C) 26

3.10 Bandpass filter without defaced 27

3.11 Bandpass filter has been defaced 28

3.12 Layout in CorelDraw software 28

3.13 DUT (device under test) by using VNA 29

4.1 Ideal transmission line of band pass filter 30

4.2 Simulation result of ideal transmission line 31

4.3 Tuning process of transmission line 31

xiii

4.4 Schematic of ideal transmission line after tuning 32

4.5 Simulation result of transmission line after tuning 32

4.6 Schematic of microstrip line structure. (without MTEE) 33

4.7 Simulation result of microstrip line structure. (without

MTEE) 33

4.8 Layout of bandpass filter structure 34

4.9 Setting of via ground 34

4.10 Schematic of microstrip line structure. (with MTEE) 35

4.11 Simulation result of microstrip line structure. (with

MTEE) 35

4.12 Microstrip line structure (with MTEE) of bandpass filter

after tuning 37

4.13 Simulation of microstrip line structure (with MTEE) of

bandpass filter after tuning 37

4.14 Layout structure of bandpass filter after tuning 38

4.15 Simulation of layout structure (with MTEE) of bandpass

filter after tuning 38

4.16 Schematic of bandpass filter 39

4.17 Layout structure of symmetric bandpass filter 40

4.18 Simulation result from the layout structure 41

4.19 Dimension of DMS 42

4.20 EM simulation result by adjusting ‘a’ 42

4.21 EM simulation result by adjusting ‘d’ 43

4.22 EM simulation result by adjusting ‘b’ 44

4.23 EM simulation result by adjusting ‘c’ 44

4.24 EM simulation result by adjusting ‘e’ 45

4.25 Layout structure of bandpass filter integrated with

first U-shape DMS 46

4.26 Simulation result of bandpass filter integrated with

first U-shape DMS 46

4.27 Layout structure of bandpass filter integrated with second

U-shape DMS 47

xiv

4.28 Simulation result of bandpass filter integrated with second

U-shape DMS 47

4.29 Layout structure of multi-band bandpass filter integrated

with two U-shape DMS 48

4.30 Simulation result of multi-band bandpass filter integrated

with two U-shape DMS 48

4.31 Current flow visualization of multi-band bandpass filter

integrated with DMS 48

4.32 Current flow visualization of multi-band bandpass filter

integrated with DMS 49

4.33 Physical structure of multi-band bandpass filter 50

4.34 Measurement result of multi-band filter by using

Vector Network Analyzer (VNA) 50

4.35 Comparison between simulation result and measurement

result of multi-band bandpass filter 51

xv

LIST OF TABLES

TABLE TITLE PAGES

2.1 The information of related research papers 8

3.1 Specification and parameter of band pass filter 18

3.2 Specification of Roger 4350B substrate 18

3.3 Value of admittances and impedances after

calculating the equation given 22

3.4 Value of width and length used to construct

microstrip line schematic 25

3.5 Specification of defected microstrip structure 27

4.1 The values of microstrip line structure (with

MTEE) before tuning and after tuning 36

4.2 The symmetric width and length of short

stub line and connecting line for bandpass filter 39

1

CHAPTER I

INTRODUCTION

1.1 Introduction

Wireless communication has been rapidly developing in recent years. The

evolution has started with Global System for Mobile Communications (GSM) and

has proceeded to Wireless Local Area Network (WLAN), Worldwide

Interoperability for Microwave Access (WiMAX), Code Division Multiple Access

(CDMA), and the latest, Long Term Evolution (LTE) and Fifth Generation (5G).

Microwave filters are required in microwave systems to separate wanted and

unwanted signals. Recently, multi-band microwave filters developed by various

researchers to satisfy the current demands of wireless communication systems.

Before, single-band filters can only operate in single-frequency bands are used. After

researching and demanding, dual-band and tri-band or multi-band microwave which

can be supported in a single device are needed. A single device has the ability to

work in multiple frequencies and support various wireless communications such as

GSM, WLAN, WiMAX and LTE is one of the requirements for global devices [1].

Defected Microstrip Structure (DMS) is made by etching a little slot over the

microstrip, generating a stop band as a function of the slot length. With DMS, there

is no etching in the ground plane as avoiding any increment of leakage through the

ground plane. In the case of the DMS structure, there was no frequency shift for

different microstrip lengths. As a result, the design of a specific DMS structure is

2

independent of the microstrip length which can be very useful in the design of

microstrip filters, among other different applications. In this proposed project, a new

design of triple-band band pass filter integrated with DMS [2].

1.2 Problem statement

Development in wireless communication has created more potential in IEEE

802 family local area networks and metropolitan area networks. They able to support

high speed wireless broadband applications with rather long reach, mobility, and

roaming. The most latest wireless communication network LTE or Long Term

Evolution UMTS networks have made strong inroads into the commercial arena

worldwide. So, a single microwave filter which can support multiple wireless

applications is strongly demanded. The challenges to circuit designers designing a

multi-band band pass filter are to achieve compact size and low insertion loss

simultaneously. The previous works are usually too many components inside and

cause large circuit size. Besides of the ability to support various wireless

communication applications, also need to satisfy the specifications of band pass filter

which are size reduction, high stability, high selectivity simultaneously [3].

1.3 Objective

The objectives of this project is to design and develop a multi-band band pass

filter for wireless communication system at frequency 2.3-2.7GHz, 3.1-4.8GHz,

5.15-5.85GHz by using the planar microstrip line. In order to introduce a multi -

band, design the Defected Microstrip Structure (DMS) to remove the unwanted

frequency band. The capabilities of DMS to introduce notched responses have been

investigated. Lastly, fabricate and validate the design of multi-band band pass filter

through experimental works in laboratory and compare the results with the

simulation result in software.

3

1.4 Scope of project

The design of this proposed project is multi-band band pass filter. The

topology of the band pass filter is quarter wavelength short-circuited stubs with

Defected Microstrip Structure (DMS). The pass band bandwidth of the filter is 2.3-

2.7GHz, 3.1-4.8GHz and 5.15-5.85GHz at -3dB. The pass band return loss is better

than -20dB whereas the pass band insertion loss is between 0dB till -1dB. Besides,

the stop band insertion loss is better than 40dB. Before fabrication, design and

simulate the filter and DMS in Advanced Designed System (ADS) software. The

material used to fabricate this filter is Roger 4350B with dielectric constant of 3.48

and loss tangent of 0.0019. This filter is done with equation of short circuited stubs

and the introduced notched responses. The DMS technology is carried out using a

parametric study to provide the shape and better performance in term of selectivity.

1.5 Chapter review

Chapter I mainly describes the general overview of this project. Chapter 1

explains the introduction, problem statement, objective and scope of this project.

Besides, this chapter also reviews all chapters of this project.

Chapter II mainly describes findings on a literature review of the project. It

covers related research from band pass filter, dual-band band pass filter, tri-band

band pass filter, multi-band band pass filter and DMS. The chapter starts with the

basic theory and fundamental of the filter. The basic understanding of the parameters

and the basics of microwave filter must be clearly made before continuing on

understanding the project. The most important part of this chapter is emphasizing

literature on different technique designing band-pass filter.

Chapter III will explain in detail the implementation of the project. Design

multi-band band pass filter and DMS will be illustrated in detail. Besides, process for

designing this project will be constructed. To design multi-band band pass filter,

there are a few important processes must undergo such as calculation, simulation,

fabrication and measurement.

4

Chapter IV will illustrate, explain, discuss and present the simulation result

and measurement result of multi-band bandpass filter. For the implementation of this

project, design start from ideal transmission line structure, then microstrip line

structure, next momentum layout structure and last physical structure of multi-band

bandpass filter.

Chapter V will discuss about the conclusion, sustainable development,

commercialization and the future work for this project.

5

CHAPTER II

LITERATURE REVIEW

In this chapter, it describes findings on a literature review of the project.

Overall, it covers related research from band pass filter, dual-band band pass filter,

tri-band band pass filter, multi-band band pass filter and DMS. The chapter starts

with the basic theory and fundamental of the filter. The basic understanding of the

parameters and the basics of microwave filter must be clearly made before

continuing on understanding the project. The most important part of this chapter is

emphasizing literature on different technique designing band-pass filter.

2.1 Band pass filter

Band pass filters play a significant role in wireless communication systems.

Transmitted and received signals have to be filtered at a certain center frequency

with a specific bandwidth. Figure 2.1 illustrates the basic bandpass filter frequency

response. A band pass filter is an important component must be found in the

transmitter and receiver. Band pass filter is a passive component which is able to

select signals inside a specific bandwidth at a certain center frequency and reject

signals in another frequency region, especially in frequency regions, which have the

potential to interfere the information signals [4].

6

Figure 2.1: Frequency response of band pass filter.

2.2 Planar microstrip band pass filter

Microstrip line is one of the most popular types of planar transmission lines

primarily because it can be fabricated by photolithography processes and is easily

miniaturized and integrated with both passive and active microwave devices. Figure

2.2 shows the example of planar microstrip band pass filter. The planar transmission

line is a transmission line with conducting metal strips that lie entirely in parallel

planes. The most common structure has one or more parallel metal strips placed on a

dielectric substrate over a conducting ground plane. All the active devices and all the

interconnecting lines, impedance-matching elements, capacitors, inductors and

resistors are fabricated on the planes [5].

Figure 2.2: Example of planar microstrip band pass filter.

7

2.3 Multi-band band pass filter

Multi-band band pass filter is the filter which has three desired frequency

bands by introducing notched responses as illustrated in Figure 2.3. The notched

responses will remove the unwanted frequency bands and introduce the desired

frequency bands for multiple wireless communication applications.

Figure 2.3: Notched responses introduced to remove unwanted frequency range.

2.4 Notched responses

Design Defected Microstrip Structure (DMS) is one of the ways to introduce

notched responses. DMS structure is made by etching a little slot over the microstrip

as shown in Figure 2.4. It is based on the changed in impedance (inductance and

capacitance) in microstrip with slotted planes. DMS will produce a narrow

bandwidth and sharp rejection at a specific frequency. It can also be represented by

the single parallel RLC [2].

8

Figure 2.4: DMS structure on the microstrip.

2.5 Related research

In order to implement this project, findings and researches about the bandpass

filter have been done and tabulated as shown in Table 2.1.

Table 2.1: The information on related research papers.

[No] Filter

/Year

Researcher(s) Freq

(GH

z)

Insertio

n loss,

S21(dB)

Return

loss,

S11(dB)

Substra

te/diele

ctric

constan

t

Method

[6] Dual

band/

2011

J. Lee and Y.

Lim

2.4,

5.2

1.4, 1.3 14.1,

22.3

Taconic

RF-

35A/3.

5

Interdigital

capacitor loop

step

impedance

resonator and

short circuit

stub loaded

resonator

[7] Dual

band/

2010

H.W. Liu,

Z.C. Zhang,

S.Wang,

1.57,

2.4

1.55-

1.63

>15 -/4.5 F-shaped

spurline

embedded

9

L.Zhu,X.H.G

uan,J.S.Lim

and D. Ahn

into uniform

impedance

resonator

[8] Dual

band/

2012

M.T. Doan,

W.Q. Che

and W.J.

Feng

2.4,

5.2

Minim

um

0.85

>20 -/4.4 Short-stub

loaded half

wavelength

resonator

[9] Tri

band/

2012

A.M.

Elelimy,

A.M. El-

Tager, A.G.

Sobih and

M.H. Abdel-

Azeem

0.9,

2.45,

3.5

0.85,

1.12,

1.16

10.8,

18.14,

16.25

Roger

RT/Dur

oid

6010

Teflon/

10.5

Cross coupled

resonators to

produce tri-

section step

impedance

resonator

[10] Tripl

e

band/

2011

C.Y.Lin,

W.T.Li,

C.P.Liang

and

S.J.Chung

2.4,

3.5,

5.2

- >10 - Cascade

grounded

active

inductor

circuit

topology

[11] Tri-

band/

2011

Z.B.Wang,

F.Nasri,

C.W.Park

6.42,

10.7,

14.9

8

15.7,

31.7,

30.1

- Duroid

5880/2.

2

Interdigital

hairpin finger

structure

[12] Tripl

e

band/

2014

J.P.Wang,

J.D.Zhao,

J.L. Li

5.2,

5.8,

8.0

>15 <15 Duroid

5880/3.

38

Parallel U-

shaped

defected

microstrip

structure

[13] Tripl

e-

band/

2012

M.M.Prabhak

ar and

M.G.Madhan

0.92

5,

1.57

5,

3.88,

3.78,

4.8

6.79,

7.19,

6.49

FR4/4.

4

Trisection

SIR