MICROSTRIP LEAKY WAVE ANTENNA DESIGN FOR WLAN
APPLICATION
NURLIYANA BT ABD MALIK
This report is submitted in partial fulfillment of requirements for the award of Bachelor of Electronic Engineering (Telecommunication Electronics) With Honours
Faculty of Electronic Engineering and Computer Engineering Universiti Teknikal Malaysia Melaka
UNIVERSTI TEKNIKAL MALAYSIA MELAKA
FAKULTI KEJURUTERAAN ELEKTRONIK DAN KEJURUTERAAN KOMPUTER
BORANG PENGESAHAN STATUS LAPORAN
PROJEK SARJANA MUDA II
Tajuk Projek : MICROSTRIP LEAKY WAVE ANTENNA DESIGN FOR WLAN APPLICATION
Sesi
Pengajian : 2008/2009
Saya NURLIYANA BT ABD MALIK
mengaku membenarkan Laporan Projek 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)
“I hereby declare that this report is the result of my own work except for quotes as cited in the references.”
Signature : ………
Author : ………
Date : ………
NURLIYANA BT ABD MALIK
“I hereby declare that I have read this report and in my opinion this report is sufficient in terms of the scope and quality for the award of Bachelor of Electronic Engineering
(Telecommunication Electronics) With Honours.”
Signature : ………...
Supervisor’s Name : ………..
Date : ………...
MOHAMAD ZOINOL ABIDIN BIN ABD AZIZ
DEDICATION
To
M y Beloved Parents,
En Abd M alik Hj M ahfudz & Pn Sabariah I smail,
M y Brother and Sister,
M y kind hearted supervisor,
M r M ohamad Zoinol Abidin Abd Aziz
ACKNOWLEDGEMENT
First of all, I would like to thank to Allah the Almighty who always beside me guiding and giving me blessing to finish my Project Sarjana Muda II successfully.
My sincere appreciation and gratitude are dedicated to my honorable supervisor, En Mohamad Zoinol Abidin Bin Abd Aziz for his encouragement, guidance and critics. Without his continued support and interest, this thesis would not have been the same as presentd here.
I would like to extend my sincere appreciation to all my dearest friends especially Shela, Hajar, Kak Iwan and Wani for their friendship, encouragement and always being beside me in every condition. Not to forget, all students under the same supervisor thank you for sharing the similar knowledge.
ABSTRACT
ABSTRAK
CONTENTS
CHAP TITLE PAGES
PROJECT TITLE i
STATUS REPORT FORM ii
STUDENT DECLARATION iii
LIST OF ABBREVIATIONS xviii
LIST OF APPENDICES xx
I INTRODUCTION
1.1 Project Introduction 1
1.2 Objective of Project 1
1.3 Problem Statement 2
1.4 Scope of Project 2
II LITERATURE REVIEW
2.1 Introduction 4
2.2 Basic Antenna Parameter 4
2.2.1 Radiation Pattern 5
2.4 Microstrip Antenna 16
2.5 Rectangular Patch and Transmission Line 19
2.5.1 Single Patch Antenna Design 19
III MICROSTRIP LEAKY WAVE ANTENNA DESIGN
3.1 Introduction 29
3.2 Design Methodology 29
3.3 Design Specification 32
3.4 CST Microwave Studio 33
3.5 Single Patch Antenna Design and Simulation 37 3.6 Design of 12 elements with different value of β 40 3.7 Design for different number of elements N with fixed value
of β
42
3.8 Design of 6 elements with variation arrangement ofβ 42
3.9 Array Factor of MLWA 44
3.10 Fabrication Process 44
3.11 Measurement 48
3.11.1 Return Loss Measurement 48
3.11.2 Radiation Pattern Measurement 48
IV RESULT ANALYSIS AND DISCUSSION
4.1 Result Analysis for Single Patch Antenna 50 4.2 Design Analysis of 12 Elements with Different Value of β 51 4.3 Design Analysis for Different Number of Elements, N with 53 Fixed Value of β = 45˚
4.4 Design Analysis of 6 Elements with Variation of β 57
4.5 Analysis for Design I and II 59
4.6 Analysis for Design III and Design IV 62
4.7 Array Factor Plot of 6 Elements with Different Value of β 64 4.8 Array Factor Plot for β = 45º with different number of
elements, N
66
V CONCLUSION AND RECOMMENDATION
5.1 Conclusion 73
5.2 Recommendation 74
REFERENCES 75
LIST OF TABLES
NO TITLE PAGES
2.1 Advantages and Disadvantages of Microstrip Antenna 18
3.1 MLWA Design Specifications 32
3.2 Parameter Setup in CST 34
3.3 Calculated Dimensions for Single Patch 37
3.4 Calculated Dimensions for Transmission Line 38 3.5 Calculated and Optimized dimension for single patch 39
3.6 Value of d with respect to β 40
3.7 Value of β for each design 43
4.1 Difference of Original and Normalized Patch in terms of Return Loss
50
4.2 Variation of Phase Difference (β°) for 12 element patches 52
4.3 Variation Number of Elements, N 54
4.4 Beam Angle for Different Number of Elements 56 4.5 Variation of Phase Difference (β˚) for 6 Elements Patches 57
4.6 Beam Angle for Different value of β 59
4.7 Simulation Result for Design I and Design II 60 4.8 Simulation Result for Design III and Design IV 62 4.9 Comparison of Beam Angles between Simulation and array
Factor for Variation of β
67
for different number of elements, N
4.11 Comparison of simulation and measured return loss for Design 1 69 4.12 Comparison of simulation and measured return loss for Design I
and II
70
LIST OF FIGURES
NO TITLE PAGES
2.1 Antenna Radiation Pattern 5
2.2 Radiation pattern for isotropic antenna and omni directional antenna
6
2.3 Radiation Pattern of an omni directional antenna 7
2.4 Antenna Directivity 9
2.5 Equivalent circuit of transmitting antenna 11
2.6 Vertical and circular polarization in 3-D 13
2.7 Common antenna polarizations 14
2.8 Definition of antenna bandwidth in respect to return loss measurement
15
2.9 Types of Antennas 16
2.10 Microstrip Antenna 17
2.11 Microstrip Antenna Radiation 18
2.12 Structure of a Microstrip Patch Antenna 19
2.13 Microstrip Transmission Line 20
2.14 Types of Array Feed Network 23
2.15 Types of Leaky Wave Antenna 24
2.16 Reduced equivalent circuit for slit-coupled MLWA 25
2.17 Single-conductor strip structure 26
2.18 Flat Slotted Waveguide (FSW) 27
3.1 Design Process 30
3.2 Project Methodology 31
3.3 Design Environment 33
3.4 Workspace Window 34
3.5 Brick parameter Window 35
3.6 Steps and Parameter Setup 35
3.7 Single Patch Antenna 37
3.8 Structure and Simulation for Single Patch Antenna (a) 2-D View, (b) 3-D View
38
3.9 Response of return loss for single element 39 3.10 Structure for MLWA with 12 Elements in 2-D View 40 3.11 Figure 3.11 Simulation of MLWA for (a) 12 Elements, (b) 6
Elements
41
3.12 Simulation of MLWA for 3 elements 42
3.13 Design II (a) Structure, (b) Simulation 44
3.14 Example of Layout (a) CST Microwave Studio, (b) CorelDraw Suite 12
45
3.15 Flow Chart for Fabrication Process 46
3.16 UV Exposure Unit 47
3.17 Return Loss Measurement Setup 48
3.18 Radiation Pattern Measurement Setup 49
4.1 Return Loss for Original and Optimized Single Patch 51
4.11 2-D plot of radiation pattern for increasing Design I and II 61
4.12 Structure for Design III 62
4.13 Response of S11 for Design III and Design IV 63 4.14 2-D plot of radiation pattern for Design III and Design IV 63 4.15 Array Factor Plot versus Simulation Plot with β = 60º 64 4.16 Array Factor Plot versus Simulation Plot for 9 Elements 66
4.17 Fabricated MLWA 68
4.18 Radiation pattern for simulation and measurement result for Design 1
71
4.19 Radiation pattern for simulation and measurement result for Design I
71
4.20 Radiation pattern for simulation and measurement result for Design II
72
4.21 Radiation pattern for simulation and measurement result for Design III
LIST OF ABBREVIATIONS
LWA - Leaky-Wave Antenna
FPC - Fabry Perot Cavities
FSS - Frequency Selective Surface FSW - Flat Slotted Waveguide
MLWA - Microstrip Leaky-Wave Antenna MOS - Microwave Office Sotware PRS - Partially Reflective Surface
RL - Return Loss
VSWR - Voltage Standing Wave Ration WLAN - Wireless Local Area Network
P - Total Power Radiated
S - Power Density
Ui - Radiation intensity for isotropic antenna HPBW - Half power beam-width
FNBW - First Null Beamwidth
D - Directivity of Antenna
Zin - Antenna impedance at the terminals
Rin - Antenna resistance at the terminals
Xin - Antenna reactance at the terminals
RL - Return Loss
L - Length of Patch
W - Width of Patch
w - Width of Transmission Line
ΔL - Length extension
h - Height of Substrate
β - Phase different between two radiating elements
N - Number of elements
d - Distance between elements
θ - Polar Angle
AF - Array Factor
φ - Phase Shift
dB - Decibel
dBi - Isotropic Decibel
C - Speed of light in vacuum
LIST OF APPENDICES
APPENDIX TITLE PAGES
A Types of Antenna Review 77
B MLWA Design 81
C Simulation Result 83
D SigmaPlot Result 86
CHAPTER I
INTRODUCTION
1.1 Project Introduction
In recent years, the microstrip leaky-wave antenna (MLWA) has got more and more attention for its simple feeding construction, easily coupling and frequency scanning. MLWA works in the first high mode TE10. These antennas are intrinsically non-resonant and so are capable of wide band performance and, in addition, the main beam can be scanned by changing frequency. For these reasons, of late, they have attracted a lot of attention, especially for airborne applications. A microstrip leaky wave antenna with first higher-order mode excitation radiates power in the narrow frequency regime before cutoff. The radiation main-beam depends on the operating frequency. Therefore it can be used as a frequency-scanning antenna.
1.2 Objective of Project
designed antenna should have return loss of ≤ -10 dB and maximum value of directivity and gain.
1.3 Problem Statement
Wireless local area network and wireless information network requires low-cost, low profiles and efficiency smart antenna. Besides that, the demand of antenna which has the ability to frequency-scan leads to the development of new design of microstrip antenna. Since that conventional design of microstrip antenna doesn’t have the frequency-scanning ability, Microstrip Leaky-Wave Antenna (MLWA) can be the best candidate for its simple construction, low profiles, easy to match and frequency-scanning ability.
1.4 Scope of Project
This project will focus on 4 areas and the main focus is to design Microstrip Leaky-Wave Antenna operates at frequency of 2.4 GHz. Then, CST Microwave Studio was used to simulate the return loss, radiation pattern, directivity, gain, HPBW and FNBW of the design. Next, the design of leaky wave antenna was fabricated on FR4 board using the chemical etching technique. Finally, the return loss, directivity, gain, HPBW, FNBW and radiation pattern of the leaky wave antenna were measured.
1.5 Report Organization
CHAPTER II
LITERATURE REVIEW
2.1 Introduction
Antennas are metallic structures designed for radiating and receiving electromagnetic energy. An antenna acts as a transitional structure between the guiding device (e.g. waveguide, transmission line) and the free space. The official IEEE definition of an antenna as given by Stutzman and Thiele follows the concept: “That part of a transmitting or receiving system that is designed to radiate or receive electromagnetic waves”. The performance of an antenna can be gauged from a number of parameters [1].
2.2 Basic Antenna Parameter
