i
COMPACT BUTLER MATRIX DESIGN
NORJANNAH BINTI NORDIN
This report is submitted in partial fulfillment of requirements for the award of Bachelor of Electronic Engineering (Telecommunication Electronics Engineering) With Honours.
Faculty of Electronic and Computer Engineering Universiti Teknikal Malaysia Melaka
COMPACT BUTLER MATRIX DESIGN
NORJANNAH BINTI NORDIN
UNIVERSTI TEKNIKAL MALAYSIA MELAKA
FAKULTI KEJURUTERAAN ELEKTRONIK DAN KEJURUTERAAN KOMPUTER
BORANG PENGESAHAN STATUS LAPORAN PROJEK SARJANA MUDA II
Tajuk Projek : COMPACT BUTLER MATRIX DESIGN Sesi
Pengajian : 2007/2008
Saya NORJANNAH BINTI NORDIN
mengaku membenarkan laporan Sarjana Muda ini disimpan di Perpustakaan dengan syarat-syarat kegunaan seperti berikut:
1. 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 ( ) :
SULIT*
(Mengandungi maklumat yang berdarjah keselamatan atau kepentingan Malaysia seperti yang termaktub di dalam AKTA RAHSIA RASMI 1972)
TERHAD* (Mengandungi maklumat terhad yang telah ditentukan oleh organisasi/badan di mana penyelidikan dijalankan)
TIDAK TERHAD
Disahkan oleh:
__________________________ ___________________________________
(TANDATANGAN PENULIS) (COP DAN TANDATANGAN PENYELIA)
Alamat Tetap: PBA/2 KG PENGKALAN BERANGAN, 21040 MARANG TERENGGANU
iii
“I hereby declare that this report is the result of my own work except for quotes as cited in the references.”
iv
“I hereby declare that I have read this report and in my opinion this report is sufficient in terms of scope and quality for the award of Bachelor of Electronic Engineering
(Telecommunication Electronics) With Honours.”
Signature : ……… Supervisor’s Name : MR. MOHAMAD ZOINOL ABIDIN BIN
v
vi
ACKNOWLEDGEMENT
In the name of Allah, the Most Beneficent and Most Merciful.
First and foremost, I would like to extend my highest gratitude and thanks to my supervisor, Mr. Mohamad Zoinol Abidin Bin Abdul Aziz for his generous support, comments, advice and guidance throughout the duration of my project. Without his continuous support and interest, this thesis would not have been the same as presented here.
The thanks also go to all my friends for their constant kind help and moral support despite the hectic semester that we had to undergo. Special thanks to Muhammad Rafie’, Faiz, Ahmad, Suzyliana, Hidayah and others who have provided assistance at various occasions.., thanks for being such a wonderful companion.
vii
ABSTRACT
viii
ABSTRAK
ix
TABLE OF CONTENT
CHAPTER TITLE PAGE
PROJECT TITLE i
PROJECT APPROVAL ii
DECLARATION iii
SUPERVISOR APPROVAL iv
DEDICATION v
ACKNOWLEDGEMENT vi
ABSTRACT vii
ABSTRAK viii
TABLE OF CONTENT ix
LIST OF TABLES xiii
LIST OF FIGURES xv
LIST OF ABBREVIATION xviii
LIST OF APPENDICES xx
I INTRODUCTION
1.1 Project Background 1
1.2 Objective 3
1.3 Scopes of Project 3
1.4 Problem Statement 3
x
II LITERATURE REVIEW
2.1 Chapter Overview 5
2.2 Smart Antenna Technology 5
2.3 The Evolution of Smart Antenna 6
2.3.1 Omni-Directional Antenna 7
2.3.2 Directional Antenna 8
2.4 The Revolution of Smart Antenna 8
2.4.1 Smart Antenna 9
2.4.2 Switched Beam Antenna System 9 2.4.3 Adaptive Array Antenna System 11
2.5 Beamforming Network 13
2.6 Beamforming Matrices 14
2.6.1 Butler Matrix 14
2.6.2 Blass Matrix 19
2.6.3 Nolen Matrix 20
2.7 Beamforming Lenses 21
2.7.1 Bootlace Lens 21
2.7.1 Rotman Lens 22
2.8 Power Divider Beamforming Network 22
2.9 Multiple Input Multiple Output 23
2.10 Beamforming Network for a 4 Beam Antenna 24
2.11 Microstrip Design 25
2.12 Others 4 x 4 Butler Matrix Designs 27
2.13 Chapter Summary 28
III DESIGN of COMPACT 4 x 4 BEAMFORMING NETWORK
3.1 Chapter Overview 29
xi
3.3 Design Methodology 30
3.4 Microwave Office (MWO) 2006 Software 31
3.5 CorelDRAW 12 Software 35
3.6 Fabrication Process 38
3.7 Measurement Process 40
3.8 Chapter Summary 41
IV DESIGN AND ANALYSIS
4.1 Chapter Overview 42
4.2 Design Specification and General Parameter 42
4.2.1 General Hybrid Coupler 43
4.2.2 General Crossover 46
4.2.3 Phase Shifter (Straight Line) 49
4.2.4 Butler Matrix 52
4.3 Design 1 53
4.3.1 Hybrid Coupler 53
4.3.2 Crossover 54
4.3.3 4 x 4 Butler Matrix 55
4.4 Design 2 59
4.4.1 Hybrid Coupler 60
4.4.2 Crossover 60
4.4.3 4 x 4 Butler Matrix 61
4.5 Simulation Result Analysis 68
4.6 Chapter Summary 69
V MEASUREMENT RESULTS AND ANALYSIS
xii
5.2 Measurement Results 70
5.2.1 Measurement Results for Design 1 71 5.2.2 Measurement Results for Design 2 72 5.3 Comparison of Fabrication and Simulation Results 73
5.3.1 Design 1 75
5.3.2 Design 2 77
5.3.3 The Comparison of Output Phase 79
5.4 The Comparison of Size 80
5.5 Chapter Summary 81
VI CONCLUSION AND SUGGESTIONS
6.1 Chapter Overview 82
6.2 Conclusion 82
6.3 Suggestions for Future Work 83
REFERENCES 84
APPENDIX A 87
APPENDIX B 91
APPENDIX C 93
xiii
LIST OF TABLES
NO DESCRIPTION PAGE
2.1 Specification of microstrip design 25
4.1 Summary of simulation result hybrid coupler 46
4.2 Summary of simulation result crossover 49
4.3 Design specifications (phase) of the Butler Matrix 52
4.4 Hybrid coupler simulation results for Design 1 54
4.5 Crossover simulation results for Design 1 55
4.6 Summary of magnitude results for Butler matrix of Design 1 58
4.7 Summary of phase results for Butler matrix of Design 1 59
4.8 Hybrid coupler simulation results for Design 2 60
4.9 Crossover simulation results for Design 2 61
4.10 Summary of magnitude results for Butler matrix of Design 2 64
4.11 Summary of phase results for Butler matrix of Design 2 65
4.12 Comparison of return loss, isolation and coupling for hybrid coupler designs 66
4.13 Comparison of return loss, isolation and coupling for crossover designs 66
4.14 Comparison of return loss and isolation for Butler matrix designs 67
4.15 Comparison of coupling for Butler matrix designs 67
4.16 Comparison of coupling in phase difference ( ) for Butler matrix designs 67
xiv 5.2 Summary of phase results for Butler matrix of Design 1 71 5.3 Summary of magnitude results for Butler matrix of Design 2 72 5.4 Summary of phase results for Butler matrix of Design 2 72
5.5 Summary of magnitude for both designs 74
xv
LIST OF FIGURES
NO TITLE PAGE
2.1 Radiation patterns of an omni-directional antenna 7
2.2 Radiation pattern of a directional antenna 8
2.3 Transmit strategy of a switched beam antenna system 11 2.4 Transmit strategy of an adaptive array antenna system 12 2.5 a) Transmission part
b) Reception part of a smart antenna system 13 2.6 A schematic diagram of a 4 x 4 Butler matrix and antenna array 15 2.7 4 orthogonal beams formed by a 4x4 Butler matrix 15
2.8 Layout of hybrids coupler 17
2.9 Layout of crossover 18
2.10 Layout of Lange Coupler used as crossover 18
2.11 Types of bends 19
2.12 Blass Matrix BFN 20
2.13 Nolen Matrix BFN 21
2.14 Diagram of Bootlace lens 22
2.15 Diagram of Rotman lens 22
2.16 An analog beamforming network 23
2.17 Microstrip structure 25
2.18 4 x 4 Butler matrix 27
3.1 Project flow chart 30
xvi
3.3 MWO design environment 32
3.4 Creating a new Schematic 33
3.5 Selecting microstrip components from elements 33
3.6 The steps of using Microwave Office 34
3.7 CorelDRAW12 35
3.8 Open File dxf 36
3.9 Choose scaling 36
3.10 The layout imported from Microwave Office 37
3.11 Layout ready to be printed 37
3.12 Ultra Violet exposed 39
3.13 Developer chemical 39
3.14 Etching process 39
3.15 Flow chart of the fabrication process 40
3.16 Network Analyzer 41
4.1(a) Circuit schematic of a hybrid coupler 43
4.1(b) General layout of a hybrid coupler 44
4.1(c) S-Parameter simulation on Port 1 in dB 44
4.1(d) S-Parameter simulation on Port 1 in Phase 45
4.2(a) Circuit schematic of a crossover 47
4.2(b) General layout of the crossover 47
4.2(c) S-Parameter simulation on Port 1 in dB 48
4.2(d) S-Parameter simulation on Port 1 in phase 48
4.3(a) Circuit schematic of the phase shifters 50
4.3(b) Layout of the phase shifters 51
4.3(c) S-Parameter simulation on Port 1 in decibel (dB) 51 4.3(d) S-Parameter simulation on Port 1 in phase 52
4.4 Layout of the hybrid coupler for Design 1 53
4.5 Layout of crossover for Design 1 54
4.6(a) Circuit schematic of Butler matrix layout for Design 1 56
xvii 4.6(c) Return Loss and Isolation for Butler matrix Design 1 57 4.6(d) Couplings for Butler matrix of Design 1 57
4.6(e) Output phases from Input at Port 1 for Butler matrix
of Design 1 58
4.7 Layout of the hybrid coupler for Design 2 60
4.8 Layout of crossover for Design 2 61
4.9(a) Circuit schematic for Design 2 62
4.9(b) Butler matrix layout for Design 2 62
4.9(c) Return Loss and Isolations for Butler matrix of Design 2 63
4.9(d) Couplings for Butler matrix of Design 2 63
4.9(e) Output phases from Input at Port 1 for Butler matrix of Design 2 64
5.1 S-parameter based on S11 in dB (return loss) 75
5.2 S-parameter based on S21 in dB (isolation) 76 5.3 S-parameter based on S51 in dB (Transmission Line) 76 5.4 S-parameter based on S11 in dB (return loss) 77 5.5 S-parameter based on S21 in dB (isolation) 78 5.6 S-parameter based on S51 indB (Transmission Line) 78 5.7(a) The phase difference at output port in simulation result
for Design 1 79
5.7(b) The phase difference at output port in measurement result
for Design 1 79
5.8(a) The phase difference at output port in simulation result
for Design 2 80 5.8(b) The phase difference at output port in measurement result
for Design 2 80
5.9 Circuit Design 1 80
xviii
LIST OF ABBREVIATIONS
BFN - Beamforming Network
BER - Bit Error Rate
d - Substrate Thickness FR4 - Flame Retardant 4 GHz - Giga Hertz
IEEE - Institute of electrical and Electronic Engineering MIMO - Multiple Input Multiple Output
mm - Millimeter
MWO - Microwave Office 2006
h - Conductor Thickness Tan d - Tangent Loss
- Average output phase
W - Width
LAN - Local Area Network
WLAN - Wireless Local Area Network Z - Impedance
Zo - Characteristic Impedance
r - Relative Permitivity
eff - Effective Permitivity - Length
- Phi
- Wavelength
xix
cm - centimeter
PCB - Printed Circuit Board
RF - Radio Frequency
RSSI - Received Signal Strength Indicator SNR - Signal to Noise Ratio
SNIR - Signal to Noise and Interference Ratio
xx
LIST OF APPENDICES
NO TITLE PAGE
A Calculation of Hybrid Couplers 87
B Calculation of Crossover 91
C 4 x 4 Butler matrix Simulation Results 93
CHAPTER I
INTRODUCTION
1.1 Project Background
As demand for wireless communications continues to grow, wireless operators face increasing network capacity challenges. As the number of users increase, the channel interference fading also increases. This may reduces the transmission quality in wireless systems and limits their performance. Several studies have proposed that by using smart antenna to reject interference and will enhanced capacity.
2 A smart antenna system for WLAN applications based on switched beam system, it can produce narrow multi-beams in different directions instead of omni-directional patterns. However this method has its drawbacks. Among them are low channel capacity, low signal to interference ratio and the small area by the antenna. Switched beam architectures are being proposed as a means to either increase coverage area or decrease the necessary input power for effective communication through wireless channel. The beam scanning can be obtained by different feedings with the phase increment provided by Butler Matrix.
Beamforming networks were originated in the late 1950s by Jesse Butler. The term beamforming relates to the function performed by a device in which energy is radiated by an aperture antenna is focused along a specified direction in space. This objective is either to preferentially receive a signal from that direction or to preferentially transmit a signal in that direction. The Butler matrix was first discussed by Butler in 1960. The conventional Butler Matrix is a multiple beamed antenna system. It consists of a linear antenna array and many output ports. Usually, the number of output ports equals the number of input antennas, which is often a binary number (or 2n where
n is an integer) [4].
3
1.2 Objective
The objective of this project are to design, simulate and fabricate a compact beamforming network by using 4 x 4 Butler Matrix base on microstrip technology operating at frequency 2.4 GHz.
1.3 Scopes of Project
Scope of this project is to study the theory of beamforming network and Butler Matrix technique. In order to understand all the basic theories and concepts of the related topic of this project, some literature review had been made in beamforming network using 4 x 4 Butler Matrix techniques and exploring the function of Microwave Office 2006. The materials that related to the beamforming, Butler Matrix and others such as in books, journals and articles have been collected. The design parameters for transmission line such as width and length had been calculated. Then, the 4 x 4 beamforming network circuits have been simulated by using Microwave Office 2006. The transmission coefficient, isolation and phase difference for each port have been simulated. Then, the designs have been fabricated by using chemical etching technique. The measurement has been measured by using Network Analyzer. The circuits have been measured and the results are compared with the simulation result.
1.4 Problem Statement
