DESIGN AND FABRICATION OF POWER DIVIDER AT 2.4 GHZ USING NORMAL MATERIAL BOARD AND

FABRIC MATERIAL

SYALWANI BINTI KAMARUDIN

UNIVERSITI TEKNOLOGI MALAYSIA

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DESIGN AND FABRICATION OF POWER DIVIDER AT 2.4 GHZ USING NORMAL MATERIAL BOARD AND

FABRIC MATERIAL

SYALWANI BINTI KAMARUDIN

A project report submitted in partial fulfilment of the requirements for the award of the degree of

Master of Engineering (Electrical - Electronics & Telecommunications)

Faculty of Electrical Engineering Universiti Teknologi Malaysia

JUNE 2012

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To my beloved family and friends

for their endless and unconditional support

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ACKNOWLEDGEMENT

Alhamdulillah, thanks to Allah. This final year project was successfully

completed in partial fulfillment of the requirement for the degree of Master of

Engineering (Electrical - Electronics & Telecommunications), University

Technology Malaysia (UTM). I sincerely thank my supervisor, Associate Professor

Dr. Mohamad Kamal A. Rahim for guiding me throughout the past two semesters

with his patience, creativity, and profound wisdom. His instruction was not only

limited to teaching me knowledge and technology, more importantly, he trained me

to correctly analyze problems and discover the mechanisms behind experimental

data, which benefited my entire studies.

I would also like to truly thank to all research students of Microwave

Technology Lab for their invaluable advice and taught me practical knowledge in

significant ways, to overcome countless difficulties throughout some of my

designing problems. This work would not have been possible without their insightful

guidance. Also gratitude thanks to all of my colleagues and the lab’s technician; Mr.

Fairus bin Foat, for their great help until my final year project are successful.

I wish to express my deep appreciation for my parents and family, not

forgetting all my friends, for their continuous support and encouragement through all

the years and for being behind me throughout all my endeavors.

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ABSTRACT

This project describes the design, fabrication and testing of curve, taper and

90° bend power divider at 2.4GHz operating frequency. The divider network is

designed using Advance Design Simulation (ADS) software by applying basic

Wilkinson power divider design. The schematic is converted into layout before

going to fabrication process on FR4 board and fabric materials. Each types of power

divider is integrated to 1x2 array antenna that operated at same frequency as power

divider for implementation stage. The project that had developed can improve

electrical flow and surface current at the sharp end of array antenna’s feeding line.

For various function of material, fabric material is used for flexibility and wearable

application. Curve power divider has better performance compared to taper and bend.

Fabric material has high performance compared to FR4 board and it is able to use for

wearable application.

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ABSTRAK

Projek ini menerangkan reka bentuk, fabrikasi dan ujian untuk lengkung, tirus

dan selekoh 90° pada pembahagi kuasa dalam operasi frekuensi 2.4GHz. Rangkaian

pembahagi telah direkabentuk menggunakan perisian Advance Design Simulation

(ADS) dengan menggunakan asas rekabentuk pembahagi kuasa Wilkinson.

Skematik telah ditukar kepada susun atur sebelum pergi kepada proses fabrikasi

menggunakan papan FR4 dan kain jeans. Setiap jenis pembahagi kuasa

disambungkan kepada 1x2 antena susunan yang beroperasi pada frekuensi yang sama

sebagai pembahagi kuasa untuk peringkat pelaksanaan. Projek yang telah

dibangunkan boleh meningkatkan aliran elektrik dan arus permukaan pada laluan

suapan bagi antenna susunan. Untuk pelbagai fungsi lain, bahan fabrik digunakan

untuk tujuan fleksibiliti dan mudah pakai. Pembahagi kuasa lengkung mempunyai

prestasi yang lebih baik berbanding tirus dan selekoh 90°. Kain jeans pula

berprestasi tinggi berbanding papan FR4 lembaga dan ia boleh digunakan untuk

mudahpakai.

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TABLE OF CONTENT

CHAPTER TITLE PAGE

DECLARATION ii

DEDICATION iii

ACKNOWLEDGEMENT iv

ABSTRACT v

ABSTRAK vi

TABLE OF CONTENTS vii

LIST OF TABLES x

LIST OF FIGURES xi

LIST OF ABBREVIATIONS xiii

1 INTRODUCTION 1

1.1 Introductions 1

1.2 Project Background 3

1.3 Problem Statement 4

1.4 Objective 4

1.5 Scope and Limitation of the Project 5

1.6 Thesis Organization 6

2 LITERATURE REVIEW 7

2.1 Introductions 7

2.2 Wilkinson Power Divider Properties 8

2.2.1 Return Loss 8

2.2.2 Matching Property 8

2.2.3 Reciprocal Property 9

2.2.4 Lossless Property 9

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2.3 Even-Mode Analysis 10

2.4 T Junction 11

2.5 Bending of Power Divider 12

2.6 Fabric materials 13

2.7 Related Research 14

2.8 Summary 25

3 MEHODOLOGY 26

3.1 Introductions 26

3.2 Project Methodology and Flow Chart of

Power Divider 26

3.3 Software Simulation 28

3.3.1 Microstrip Design Equations 30

3.4 Layout 33

3.5 Hardware Development 34

3.5.1 FR4 Board Material 34

3.5.2 Jeans Fabric Material 38

3.6 Fabricated Power Divider 39

3.7 Measurement Process 41

3.7.1 Calibration Process 41

3.8 Isolation Resistor 42

3.9 Connector 43

4.0 Summary 43

4 RESULT ANALYSIS AND DISCUSSION 44

4.1 Introductions 44

4.2 Simulation and Measurement Result 45

4.2.1 Power Divider on FR4 Board 45

4.2.2 Power Divider on Fabric Material 47

4.2.3 Power Divider with Array Antenna

Integration 50

4.3 Comparison of FR4 Board and Fabric

Material Performance 51

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4.4 Power Divider on Different Size of Fabric Material 53

4.5 Overall Discussion 57

5 CONCLUSION 58

5.1 Overall Conclusion 58

5.2 Key Contribution 59

5.3 Future Research 59

REFERENCES 60-61

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LIST OF TABLES

TABLE NO. TITLE PAGE

2.1 Previous Related Research 22

3.1 Design Specifications of FR4 Board and Fabric 28

3.2 Layout and Actual Hardware 33

3.3 Legend for the specific layers 35

4.1 FR4 Result Summary 45

4.2 Fabric Result Summary 48

4.3 Power Divider and Integrated Antenna

on FR4 Board 50

4.4 Power Divider and Integrated Antenna

on Fabric Material 50

4.5 Different Conditions for Fabric Analysis 54

4.6 S-parameters Reading for Different Conditions

of Fabric Analysis 56

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LIST OF FIGURES

FIGURE NO. TITLE PAGE

1.1 Real Time Tracking System with 8 output ports 2

2.1 Schematic Block diagram of n+1 ports power divider 7

2.2 Even-mode analysis of Wilkinson network 10

2.3 Garg and Bahl T-junction theory 12

2.4 (a) Layout of 4-way Wilkinson power divider for

design 1. (b) Layout of 4-way Wilkinson power

divider for design 2. 14

2.5 Tapered-line power divider designs. 16

2.6 Top view of the geometry of the proposed transition 17

2.7 Whole Configuration of the Power divider 18

2.8 (a) The structure of the proposed tri-band Wilkinson

power divider. (b) Replacement of the conventional

quarter wavelength transformer with a pair of two

section transmission lines and a coupled line in

between. 19

2.9 Re-entrant mode and proposed coupler structure.

(a) Re-entrant mode coupler. (b) Proposed coupler. 21

3.1 Process Flow of the Power Divider Design 27

3.2 Curve Design 29

3.3 Taper Design 29

3.4 Bend Design 30

3.5 LineCalc in ADS 32

3.6 Fabrication Process Flow 34

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3.7 Photo Board Cross Section 35

3.8 Film Processing 35

3.9 Vacuum Exposure Unit 36

3.10 Developer Process 36

3.11 Etching Process 37

3.12 Photoresist Stripper Tank 37

3.13 Process Flow of Jeans Fabrication 38

3.14 Curve Power Divider 39

3.15 Taper Power Divider 39

3.16 Bend Power Divider 40

3.17 1x2 Array Antenna 40

3.18 E5071C ENA Network Analyzer 41

3.19 Agilent 3.5mm Calibration Kits 42

3.20 Calibration Kits with SMA connector 42

3.21 Male SMA Connector 43

4.1 Simulation Result of FR4 Board 46

4.2 Measurement Result of FR4 Board 47

4.3 Simulation Result of Fabric Material 49

4.4 Measurement Result of Fabric Material 49

4.5 S11 Simulation Result of FR4 and Fabric Material 51

4.6 S11 Measurement Result of FR4 and Fabric Material 52

4.7 S23 Simulation Result of FR4 and Fabric Material 52

4.8 S23 Measurement Result of FR4 and Fabric Material 53

4.9 S11, S21, S31 and S23 Measurement Result for

Different Conditions of Fabric Analysis 57

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LIST OF ABBREVIATIONS

ADS – Advance Design Simulation

CST – Computer Simulation Technology

ENA – Enhanced Network Analyzer

RF – Radio Frequency

IMT - International Mobile Telecommunication

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CHAPTER 1

INTRODUCTION

1.1 Introductions

Power divider is a passive microwave component used for power division. In

microwave system it is often needed to distribute Radio Frequency (RF) power to

various paths for different application. The easiest way to perform this operation is

by employing power divider circuits. There are few types of power divider which

are:

i. T-model power divider

ii. Resistive power divider

iii. Ultra wideband power divider

iv. Wilkinson power divider

In an ideal power divider, the power given in Port 1 is equally split between

N-ways output for power division and vice versa for power combining as shown in

Figure 1.1. However, the most familiar power divider is three sections of Wilkinson

divider which has high isolation between output ports. This type of divider is

simplest compares to others [1].

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Figure 1.1: Real Time Tracking System with 8 output ports [1]

This thesis proposes the designs and development of 3 different types of

Wilkinson power divider operating at 2.4GHz. The designs covered are curve, taper

and bend. Fabrication materials used are positive dip coated FR4 board and fabric. A

resistor has been applied to the divider to improve isolation performance. This work

involves the design, fabrication and hardware measurement of the dividers for future

long range communication with higher gain and sharper beam.

This thesis describes the divider’s design and development including the

literature review on the 3 different types of power divider, the simulation design

using Advance Digital Simulation (ADS) and CST Microwave Studio software, ends

up with fabrication and hardware measurement. At the final stage, the dividers are

integrated to 1X2 array antenna to see the output performance.

In this first chapter, the brief background of the project is discussed,

providing problem statements, objectives, methodology, and scope of work in

conducting the research including the project’s possible outcome and contributions

and also the thesis organization.

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1.2 Project Background

Power divider is a passive microwave component used for power division.

Input signal is divided into N-way output signal. In the field of microwave

engineering and circuit design, the Wilkinson Power Divider is a specific class of

power divider circuit that can achieve isolation between the output ports while

maintaining a matched condition on all ports. The Wilkinson design can also be used

as a power combiner because it is made up of passive components and hence

reciprocal. First published by Ernest J. Wilkinson in 1960 [1], this circuit finds wide

use in radio frequency communication systems utilizing multiple channels since the

high degree of isolation between the output ports prevents crosstalk between the

individual channels.

Output power divided at each port can be equal or unequal, depends on

requirement needed. For this project, three types of power divider are designed based

on certain specification:

i. Curve power divider

ii. Tapered power divider

iii. Bend power divider

An ideal power divider design supposed to achieve 3 requirements, which are:

i. Reciprocal

ii. Matching

iii. Lossless network / High isolation

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1.3 Problem Statement

Most of the array antenna’s feed line built uses rectangular structure that

comes with pointy edges which is strongly influences the surface current and

electrical flow. Through a 2D and 3D microwave simulation, these frequency

dependent electric and current values are found accumulating at the sharp end of any

conventional array antenna design. A novel power divider is proposed which

focusing on a better curve structure intending on enhancing smoother power

transition. By using basic Wilkinson Power Divider theory, various types of the

power divider design are simulated. Advances in communication and electronic

technologies have enabled the development of compact and intelligent devices that

can be placed on the human body or implanted inside it, thus facilitating the

introduction of BANs (Body Area Networks). Huge processing and complex BANs

will be needed in the future to provide the powerful computational functionalities

required for advanced applications. These requirements have led to increasing

research and development activities in this area for many purposes with the main

interest being in health care. For various function of material, fabric material is used

for flexibility and wearable application.

1.4 Objectives

This project has 4 main objectives which are:

� To design, simulate and fabricate 3-ways of curve, taper and bend of

equal power divider in microstrip technology. The divider is designed

to serve working frequency at 2.4GHz of bandwidth. The output ports

will be arranged in array configuration of 4.

� The result will be analyzed based on S-parameter reading.

� The performances of every design shape and fabrication materials

used are compare

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1.5 Scope and Limitation of the Project

The main scopes of this project are:

i. Literature review and previous research study on power divider design.

ii. Design, simulate and analyze the schematic design of power divider

using Advance Digital Simulation (ADS) software. CST Microwave

Studio software is used for existing 1x2 array antenna simulation.

iii. Fabricate and measure each type of power divider and array antenna.

The fabrication part includes isolation resistors soldering.

iv. Analyze and compare the result between simulation and measurement.

The result is also compared between FR4 board and fabric material.

v. Thesis documentation.

The limitations of this project are:

i. The range frequency is limited to 2.4GHz due to the availability of

existing antenna design.

ii. The E5071C ENA Network Analyzer has only two ports. Since this

project is 3-ways ports with 1-port and 2-ports inputs and outputs

respectively, the terminator is used for S-parameters measurement.

iii. Dielectric constant of fabric material used is taken from previous

project.

iv. The antenna measurement is only taken for S11 reading, since there’s

no availability of anechoic chamber to do radiation pattern

measurement.

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1.6 Thesis Organization

This thesis is organized in 5 chapters that describe total work flow for this

project. The first chapter consist of introduction, project background, problem

statement, objectives of the project, scope of study and project limitation. Literature

review that explains research study of different types of power divider was presented

in chapter 2. Different designs are presented with different design specification of

bending at the corner side. The design process of Power Divider is presented in

Chapter 3.

The simulated and measured results of the various types of power divider are

presented in Chapter 4. The simulated result such as return loss, isolation is clearly

presented. Then, the measurement process is done to validate the simulated results

and both results have been compared to each other in terms of different materials

used. A discussion of the results is presented clearly with full analysis. Lastly, the

conclusion of the project is presented in Chapter 5. This chapter concludes the

findings of the project, some key contribution and provides recommendations for

futurework.

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REFERENCES

1. E. Wilkinson, “An N-way hybrid power divider,” IRE Trans. Microw. Theory Tech., vol. MTT-8, no. 1, pp. 116–118, Jan. 1960.

2. D. Pozar, Microwave Engineering, 3rd ed. New York: Wiley, 2005.

3. Cascade Microtech Application Group, Layout Rules for GHz Probing http://www.cascademicrotech.com/pubs/Layout19.pdf.

4. Design, Fabricate and Testing of Feed Network for 2X2 Array Antenna by M.S.R Mohd Shah, Maisarah Abu, M.Z.A Abdul Aziz,2007.

5. Novel N - way Power Divider and Array Configuration for RFID Readers operating at 5.8 GHz, Sushim Mukul Roy, Isaac Balbin and Nemai Chandra Karmakar, Sr. Member, IEEE.

6. Ultra Wideband Power Divider Using Tapered Line by C.-T. Chiang, B.K. Chung.

7. P. Salonen, L. Sydaheimo, M. Keskilammi, M. Kivikoski, A small planar inverted-f antenna for wearable applications, The Third International Symposium on Wearable Computers, 1999, pp. 95-100.

8. P. Salonen, H. Hurme, Modeling of a fabric GPS antenna for smart clothing, in: Proc. IASTED International Conference Modeling and Simulation, Palm Springs, CA, USA, 2003, pp. 18-23.

9. M. Tanaka, J.H. Jang, Wearable microstrip antenna, 2003 IEEE AP-S

International Symposium on Antennas and Propagation and URSI North American Radio Science Meeting, Columbus, OH, USA, 2003.

10. M.A.R.Osman and M.K.Rahim, “Wearable Textile Antenna: Fabrics

Investigation”, University Technology Malaysia, Malaysia.

11. "New public safety applications and broadband internet access among uses envisioned by FCC authorization of ultra-wideband technology",- FCC news release (February 14, 2002).

12. E. Wilkinson, “An N-way hybrid power divider,” IRE Trans. Microw. Theory Tech., vol. MTT-8, no. 1, pp. 116–118, Jan. 1960.

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13. D. Maurin and K.Wu, “A compact 1.7–2.1 GHz three-way power combiner using microstrip technology with better than 93.8% combining efficiency,” IEEE Microw. Guid. Wave Lett., vol. 6, no. 2, pp. 106–108, Feb.1996.

14. J. Chiu, J. Lin, and Y.Wang, “A novel planar three-way power divider,”IEEE Microw. Wireless Compon. Lett., vol. 16, no. 8, pp. 449–451, Aug. 2006.

15. [15] C.T. Chiang and B.K. Chung “Ultra Wideband Power Divider Using Tapered Line” Progress in Electromagnetic Research, Vol. 106, 61-73, 2010.

16. C.H. Ho, L. Fan and K. Chang, "Slot-coupled double-sided microstrip interconnects and couplers", Microwave Symposium Digest, MTT-S International, vol. 3, pp. 1321-1324, 1993.

17. N.Seman, M.E. Bialkowski and C.K Wee, “Ultra Wideband Vias and Power Dividers in Microstrip-Slot Technology”, Asia-Pacific Microw. Conf,2007.

18. A.M. Abbosh, “A compact UWB Three-Way Power Divider”, IEEE Microw. Wireless Comp., vol. 17, no. 8, Aug.2007.

19. S.M. Roy, I Balbin and N.C. Karmakar “Novel N - way Power Divider and Array Configuration for RFID Readers operating at 5.8 GHz”, IEEE Int. Conf. on RFID, 2008.

20. Q.Bai and R.J.Langley “Bent and Crumpled Textile Antenna”, University of Sheffield, United Kingdom.

21. S.Sankaralingam and B.Gupta, Senior Member of IEEE “Determination of Dielectric Constant of Fabric Materials and Their Use as Substrates for Design and Development of Antennas for Wearable Applications”.

22. D.W. Chun and C.C. Shin “Design Of A Directional Coupler Using Three Layer Microstrip Structure, Ajou University, Korea.