UNIVERSITI TEKNIKAL MALAYSIA MELAKA

Transcription

1 UNIVERSJTI TEKNIKAL MALAYSIA MELAKA UNIVERSITI TEKNIKAL MALAYSIA MELAKA MINKOWSKI FRACTAL PATCH ANTENNA FOR Wi-Fi APPLICATION This report submitted in accordance with the requirement of the Universiti Teknikal Malaysia Melaka (UTeM) for the Bachelor's Degree in Electronics Engineering Technology (Telecommunications) with Honours by AMIRA ELEZA BINTI AZEMI B FACULTY OF ENGINEERING TECHNOLOGY 2015

2 UNIVERSITI TEKNIKAL MALAYSIA MELAKA BORANG PENGESAHAN STATUS LAPORAN PROJEK SARJANA MUDA TAJ UK: Minkowski Fractal Patch Antenna for Wi-Fi Application SESI PENGAJIAN: 2014/15Semester1 Saya Amira Eleza Binti Azemi mengaku membenarkan Laporan PSM ini disimpan di Perpustakaan Universiti Teknikal Malaysia Melaka (UTeM) dengan syarat-syarat kegunaan seperti berikut: 1. Laporan PSM adalah hak milik Universiti Teknikal Malaysia Melaka dan penulis. 2. Perpustakaan Universiti Teknikal Malaysia Melaka dibenarkan membuat salinan untuk tujuan pengajian sahaja dengan izin penulis. 3. Perpustakaan dibenarkan membuat salinan laporan PSM ini sebagai bahan pertukaran antara institusi pengajian tinggi. 4. **Sila tandakan (../) D D D SULIT (Mengandungi maklumat yang berdarjah keselamatan atau kepentingan Malaysia sebagaimana yang termaktub dalam AKTA RAHSIA RASMI 1972) TERHAD (Mengandungi maklumat TERHAD yang telah ditentukan oleh organisasi/badan di mana penyelidikan dijalankan) TIDAK TERHAD Di;{ Cop Rasmi: Kubang Paya Pauh, Arau, NlrRlJ AL M Bi HASS:r. Perl is. Tarikh: :l.6, 0 I '2 G 15 do,t<>r: fg ~ '1 0 1 ogi ~ 'd dll' Plltro,1'-l ", tn~ ~ <.i ulr ~el(rtol{)g ~.e pjr ter,foo ~~.-,. i fcr.i.. U M <o1j~,1 <1 \:~ J ** Jika Laporan PSM ini SULIT atau TERHAD, sila lampirkan surat daripada pihak berkuasa/ organisasi berkenaan dengan menyatakan sekali sebab dan tempoh laporan PSM ini perlu dikelaskan sebagai SULIT atau TERHAD.

3 DECLARATION I hereby, declared this report entitled "Minkowski Fractal Patch Antenna For Wi-Fi Application" is the results of my own research except as cited in references. Signature ~ Author's Name Date Amira Eleza Binti Azemi io\s

4 APPROVAL This report is submitted to the Faculty of Engineering Technology of UTeM as a partial fulfillment of the requirements for the degree of Bachelor of Electronic Engineering Technology (Telecommunication) with Honours. The member of the supervisory is as follow: onjl... t).~~ (NURULHALIM BIN HASSIM) ii

5 ABSTRACT This report elaborated on the theories and techniques in the process of shrinking the size of an antenna through the usage of fractals. The Minkowski fractal patch antenna was investigated. The Minkowski fractal patch antenna was introduced in order to reduce the size of antenna using miniaturization technique. This project presented the design of fractal patch antenna based on the basic structure of square antenna operating at 2.45GHz for Wi-Fi application. The fractal design was introduced into the basic structure for the purpose of reducing the size of the elements. Thus, an expectation would be set on the miniaturization to be achieved. Simulations wave performed on several sets of the structures design using Computer Simulation Technology Software. The simulation result showed that the fractal iteration and the iteration factor had different effects on the reduction of the patch antenna. From the experiment, the result showed that the 1st and znd iteration Minkowski fractal patch antenna managed to reduce the antenna size, while maintained the same resonant frequency as that of the normal square patch antenna. Fractal antennas can obtain radiation pattern and input impedance_ similar to a longer antenna, yet take less special area due to the many contours of the shape. Fractal antenna is a fairly new research area and more likely to have a promising future when used and designed into whole other applications. iii

6 ABSTRAK Laporan ini mengulas mengenai teori dan teknik dalam proses mengecilkan saiz antena menggunakan pembahagian atau pecahan kepada bahagian-bahagian kecil melalui fraktal. Di dalam laporan ini, antena Minkowski akan dikaji. Antena Minkowski diperkenalkan bagi mengurangkan saiz dengan mengunakan teknik pengecilan. Projek ini menunjukkan corak lakaran atau rekaan antena yang mengandungi pembahagian kecil yang asalnya adalah antena segiempat sama yang beroperasi pada frekuensi 2.45 GHz untuk aplikasi Wi-Fi. Corak pada fraktal ini diperkenalkan kepada struktur asas untuk mengurangkan saiz pada elemen-elemen tersebut. Oleh itu, pengecilan saiz antena akan dicapai. Lakaran struktur antena dapat dilihat dengan menggunakan perisian CST (Computer Simulation Technology). Keputusan simulasi menunjukkan pecahan kepada bahagian-bahagian kecil dan faktor pembahagian memberi kesan yang berlainan kepada pengecilan saiz antena. Daripada eksperimen yang telah dijalankan, keputusan menunjukkan pecahan kepada bahagian kecil bagi peringkat pertama dan kedua akan mengurangkan saiz antena disamping mengekalkan frekuensi resonan seperti anten~ segiempat sama. Fraktal antena ini berjaya mendapatkan corak radiasi dan penentangan litaran elektrik terhadap pengaliran kuasa elektrik yang sama dengan antena asal tetapi mengambil kawasan yang kurang dengan bentuk kontur. Fraktal antena adalah penyelidikan yang agak baru dan dijangka akan memberi masa depan yang cerah untuk pelbagai aplikasi. iv

7 DEDICATION To my dearest mother, father and my family for their continuous encouragement and support. "You are my inspiration to strive for excellence" v

8 ACKNOWLEDGEMENT Let me start by giving my gratitude to the one and only AJlah the Almighty who with His insight and blessing has been a beacon to guide me on my journey in finishing this report. My sincerest appreciation and heartfelt recognition towards my honorable supervisor, Mr. Nurulhalim Bin Hassim for assisting me in understanding the fundamental of antenna that inspired me to make this work a success, as well for his valuable and priceless experiences and wisdom. I greatly appreciate his assistance and support during the completion of this report. I would also like to extend my gratitude to my co-supervisor Mr Abdul Halim Bin Dahalan for all the inputs and aids in developing my practical skills as well as providing the overall concept for the thesis. I would like to show my gratefulness to the wannth and encouragement that I was at pleasure of receiving from my beloved father, En. Azemi Bin Zakaria, my beloved mother, Pn. Chik Binti Isa and also all my family members throughout the duration of my project. Without their love and patience, I would not be able to go through the tough times experience in the process of making this report. A special mention also for my wonderful acquaintance, Hafiz Aizat Bin Hazli for his neverending supports and the internal and external motivation that has been provided, as well as his earnest efforts in ensuring this project to come to fruition. Finally, my gratitude is directed towards my mentor Mr. Nornikman Bin Hassan for his contribution of ideas that had been provided regarding the theories behind the antenna and also for the meetings and sessions that were conducted. I simply would not be able to proceed if not for his kind and compassionate tutoring. Last but not least, I would also like to give my thanks to whoever has assisted me in the process of completing this report. vi

9 TABLE OF CONTENT CHAPTER ITEM PAGE PROJECT TITLE ABSTRACT ABSTRAK DEDICATION ACKNOWLEDGEMENT TABLE OF CONTENT LIST OF TABLES LIST OF FIGURES LIST OF ABBREVIATION LIST OF SYMBOLS iii iv v vi vii xiii xiv xvii xviii 1 INTRODUCTION 1.1 Brief Technical Overview Wi-Fi Introduction 1.2 Objective Problem Statement Introduction Solution Overview Work Scopes Project Methodology Work Flow Description Report Structure 7 vii

10 2 LITERATURE REVIEW 2.1 Introduction to Wi-Fi Wi-Fi standards Frequency Range Benefits ofwi-fi l Wireless Ethernet Extended Reach Cost Reduction Mobility Flexibility Applications For Wi-Fi Internet Sharing Devices Wireless Printers or Scanners Video Streaming Introduction of Antenna Antenna Theory Types of Antennas Antenna Characteristic Parameters of Antenna l Radiation Pattern Return Loss Voltage Standing Wave Ratio Bandwidth Gain Directivity 21 viii

11 Efficiency Beamwidth Polarization Fractal Antenna Introduction Fractal Geometry Fractal Advantages Microstrip Antennas Introduction ofmicrostrip Antennas Basic of Microstrip Antennas Advantages and disadvantages of Microstrip Antennas 2.7 Feeding Technique Microstrip Line Feed Coaxial Feed Aperture Couple Feed Proximity Coupled Feed Comparison of Feeding Methods 2.8 The Minkowski Fractal Introduction Design Consideration for Minkowski Fractal Patch Antenna l Substrate Selection Element Width and Length Design Consideration for Minkowski Patch Geometry 42 ix

12 3 PROJECT METHODOLOGY 3.1 Project Methodology Theoretical Development Performance Requirements Fractal Antenna Patterns Implementation Considerations Design the Minkowski Fractal Patch antenna Substrate Selection Design the Minkowski Fractal Patch Antenna Calculation on Square Patch Antenna Calculation on 1st Iteration Minkowski Fractal Patch Antenna Calculation on znd Iteration Minkowski Fractal Patch Antenna Design the Minkowski Fractal Patch Geometry Design a rnicrostrip patch antenna with the following parameters Design Equations Theoretical Formula Square Patch Minkowski Fractal Antenna (Calculation) st Iteration Minkowski Fractal Antenna (Calculation) 50 x

13 znd Iteration Minkowski Fractal Antenna (Calculation) Optimization l Square Patch Minkowski Fractal Antenna (Optimized) st Iteration Minkowski Fractal Antenna Antenna (Optimized) znd Iteration Minkowski Fractal Antenna Antenna (Optimized) Experimental Setup l Simulation Process Fabrication Method Measurement Process Experimental Testing Antenna Resonance Testing Gantt Chart 60 4 RES UL TS AND DISCUSSION 4.1 Simulation Result l Square Microstrip Patch Antenna (Optimized) st Iteration Minkowski Fractal Antenna (Optimized) 64 xi

14 nd Iteration Minkowski Fractal Antenna (Optimized) Measurement Result Square Microstrip Patch Antenna st Iteration Minkowski Fractal Antenna d Iteration Minkowski Fractal Antenna Discussion 71 5 CONCLUSION AND FUTURE WORKS 5.1 Conclusion Future Works 76 REFERENCES 77 APPENDIX A APPENDIXB APPENDIXC APPENDIXD xii

15 LIST OF TABLES NO TITLE PAGE Table 2.1 Summary of the various Wi-Fi offerings 11 Table 2.2 Table 2.3 Table 2.4 Advantages and disadvantages of microstrip antenna 28 Comparison of feeding methods 36 Material properties 40 Table 3.1 Table 3.2 Table 3.3 Table 3.4 Calculation valu~ and optimization value 55 Parametric study of width and length of the antenna 56 Project planning for psm 1 60 Project planning for psm 2 60 Table 4.1 Comparison between simulation and measurements result 69 Table 4.2 Comparison of gain and return loss between simulation and measurements result 69 xiii

16 LIST OF FIGURES NO TITLE PAGE Figure 1.1 Methodology Flow Chart 6 Figure 2.1 Logo of Hardware devices certified by the Wi-Fi Alliance 9 Figure 2.2 Radiation lobes and beam widths of antenna pattern 17 Figure 2.3 Linear plots of power pattern and its associated lobes and beam width 17 Figure 2.4 Antenna bandwidth in respect to return loss measurement 20 Figure 2.5 Beamwidth pattern of an antenna 22 Figure 2.6 Shapes of microstrip patch antenna 26 Figure 2.7 Basic Structure of microstrip 27 Figure 2.8 Microstrip feed (line feed) 32 Figure 2.9 Probe fed Rectangular Microstrip Patch Antenna (Coaxial Feed) 33 Figure 2.10 Aperture coupled feed 34 Figure 2.11 Proximity-coupled Feed 35 Figure 2.12 Zero, 1st and znd iteration Minkowski fractal microstrip antennas 38 Figure 2.13 The Antennas Structures 42 xiv

17 Figure 3.1 Figure 3.2 Figure 3.3 Figure 3.4 Figure 3.5 Figure 3.6 Figure 3.7 Figure 3.8 Figure 3.9 Figure 3.10 Figure 3.11 Figure 3.12 Square Patch Antenna (Calculation) 1st Iteration Minkowski Fractal Antenna (Calculation) znd Iteration Minkowski Fractal Antenna (Calculation) Square Patch Antenna (Optimized) 1st Iteration Minkowski Fractal Antenna (Optimized) znd Iteration Minkowski Fractal Antenna (Optimized) The flow of fabrication process Machine for fabrication process Return Loss Measurement Setup Gain Measurement Setup Radiation Pattern Measurement Setup Experimental setup for antenna return loss measurements Figure 4.1 Figure 4.2 Figure 4.3 Figure 4.4 Figure 4.5 Figure 4.6 Figure 4.7 Figure 4.8 Figure 4.9 Return loss of the square microstrip patch antenna Bandwidth for square microstrip patch antenna The S-Parameter Smith Chart of the square microstrip patch antenna 3D Radiation Pattern of the square microstrip patch 2D Radiation Pattern of the square microstrip patch antenna Return loss of the first Iteration Minkowski Fractal Antenna (Optimized) Bandwidth for first iteration Minkowski fractal patch antenna 3 D Radiation Pattern of the first Iteration Minkowski Fractal Antenna (Optimized) 2D Radiation Pattern of the first Iteration Minkowski Fractal Antenna (Optimized) xv

18 Figure 4.10 Figure 4.11 Return loss of the second Iteration Minkowski Fractal Antenna (Optimized) 66 Bandwidth for second iteration Minkowski fractal patch antenna 66 Figure 4.12 Figure D Radiation Pattern of the second Iteration Mink:owski Fractal Antenna(Optimized) 67 2D Radiation Pattern of the second Iteration Minkowski Fractal Antenna (Optimized) 67 Figure 4.14 Return loss of the square microstrip patch antenna 68 Figure 4.15 Radiation Pattern of the square microstrip patch antenna 68 Figure 4.16 Return loss of the 1 strteration microstrip patch antenna 69 Figure 4.17 Radiation Pattern of the 1st Iteration microstrip patch antenna 69 Figure 4.18 Return loss of the zndlteration microstrip patch antenna 70 Figure 4.19 Radiation Pattern of the znd Iteration microstrip patch antenna 70 Figure 4.20 Construction of Minkowski Fractal Patch Antenna 71 Figure 4.21 Simulation and measurement return loss of Minkowski fractal patch antenna 73 Figure 4.22 Radiation pattern for the second iteration minkowski patch antenna in 3D 74 xvi

19 LIST OF ABBREVIATION ABBREVIATION CST IEEE FR4 SMA VSWR BW HPBW OFDM HT MIMO FEC RL RF WLAN Wi-Fi DESCRIPTION Computer Simulation Technology Institute of Electrical and Electronics Engineers Flame Retardant 4 SubMiniature version A Voltage Standing Wave Ratio Bandwidth Half Power Beam width Orthogonal frequency-division multiplexing High Throughput Multiple input/multiple output Forward error correction Return Loss Radio Frequency 2 Dimensional 3 Dimensional Wireless Local Area Network Wireless Fidelity xvii

20 LIST OF SYMBOLS SYMBOL f fr G DESCRIPTION Frequency Frequency resonant Antenna Gain Total radiated power Total input power Characteristics impedance Load impedance Input impedance Upper frequency Lower frequency Center Frequency Directivity Substrate height Dielectric constant f.eff e r w L Effective dielectric constant Antenna efficiency Reflection coefficient Width Length Reflected voltage Incident voltage Thickness xviii

21 p D.i Le WP Lp Iteration factor Patch Length Extension Effective Patch Length Patch Width Patch Length xix

22 CHAPTER I INTRODUCTION 1.1 Brief Technical Overview The goal of this project is to design a Minkowski fractal patch antenna for Wi-Fi application. The antenna will have properties that benefit the modern wireless communication. A new development of fractal antenna engineering research is driven due to significant improvement of speed in computing, which is required for the design. Several attributes of fractal antenna deemed as advantages over conservative antenna types include how it radiate electromagnetic energy. This can be used to improve the functionality of latest wireless communication receivers Wi-Fi Introduction "Wi-Fi" is a type of wireless networking protocol that allows devices to communicate without cords or cables. Wi-Fi is technically an industry term that represents a type of wireless local area network (LAN) protocol based on the IEEE network standard (Chen, 2009). It is the most popular means of communicating data wirelessly, within a fixed location, today. 1

23 The IEEE established b in 1999 is to improve the data rate of the original standard. IEEE b wireless Ethernet also operates on the 2.4GHz band (Chou, 2010). There are many good reasons to use IEEE b wireless Ethernet. One of which is due to reduced cost in fabrication because of the FR 4 and exceptional signal range. ln order to satisfy the demand for precision and reliability, a high performance Wi-Fi antenna must be able to operate at 2.45GHz frequency. 1.2 Objectives a) To design a miniaturized antenna using Minkowski fractal. b) To investigate the behavior of the Minkowski fractal patch antenna properties. c) To make a comparison between the hardware measurement and simulation. 1.3 Problem Statements Introduction Common designs are sensitive to only a narrow range of frequencies and thus, cause it to be less efficient. One of the ways to improve antenna performance is to use array antenna but this technique requires larger antenna size and increased weight. Fractal antenna designs can overcome some of these problems. Another common design problem is antenna sensitivity to the narrow range of frequencies whith creates inefficiency. It is a known problem for small and portable antennas. Experiments have shown that antennas built with only a small number of iterations of a fractal process can exhibit sensitivity at frequency. 2

24 1.3.2 Solution Overview Fractals can be used to enhance antenna designs. The method is in the design of miniaturized antenna elements. These can lead to antenna elements which are more discrete for the end user. Minkowski fractal patch antenna is proposed since it can reduce the size with miniaturization technique The Minkowski fractal design is introduced into the basic structure intended to reduce the frequency of operation. Hence, miniaturization can be achieved. Since using fractals as an approach to antenna design is a relatively new development in the field of antenna research, the Minkowski microstrip antenna is selected for this project. This antenna is simple to design and its radiation properties are far better documented in research literature than other types of antennas. Fractals have been used in computer graphics and coding, non-linear chaotic circuits and more. Generally, by using fractals in antennas, the following properties can be achieved. a) Reduction of physical radiator size, degree of reduction depends on type of fractal used b) Multiband behavior is result of self-similarity c) Radiation patterns in frequency also is self-similar d) Non-integral ratio of following resonant frequencies e) Opportunity of realization in planar technique 3