PATTERN AND FREQUENCY RECONFIGURABLE ANTENNA FOR WIRELESS APPLICATIONS DELPHINE ABIJURU. requirements for the award of the degree of

Transcription

1 PATTERN AND FREQUENCY RECONFIGURABLE ANTENNA FOR WIRELESS APPLICATIONS DELPHINE ABIJURU A project report submitted in partial fulfilment of the requirements for the award of the degree of Master of Engineering (Electrical-Electronics and Telecommunications) Faculty of Electrical Engineering Universiti Teknologi Malaysia JUNE 2014

2 iv To God Almighty for his favor, my family and my country Rwanda for their endless support and encouragement.

3 v ACKNOWLEDGEMENT First of all, I would like to thank God for his unconditional love upon my life; more especially during my studies in UTM, he strengthened me with special encouragement which pushed me until the completion. With a sincere heart, my profound gratitude goes to my supervisor Dr Mohamad Rijal bin Hamid for his patience, kindness and for his limitless advice during this project work. He indeed guided me and helped me to build a strong background in antenna design. It was an honor to be under his supervision. I wish to thank also Husna Idris for her kindness and help during the antenna fabrication process in the laboratory. I also appreciate Igbafe Orikumhi, Ali Obadiah whose encouragement, ideas and help where vital in making this project a success. I would like to appreciate all my friends and classmates, especially Ning, Ayu, Rossi and Skudai Joy Chapel members who stood by me during my masters degree programme. Finally my special thanks be conveyed to my beloved mum, siblings my uncle, his wife and Richard Ikuesan Adeyemi for their love, counsel, support through my master s degree programme, though it was difficult but they never fade up to carry this heavy weighted burden. Thanks be to the government of Rwanda, UTM and department of electrical and electronics engineering. May God bless you all.

4 vi ABSTRACT In general, equal gain in all direction is needed as the system moves in wireless applications such as body area network. Reconfigurable radiation pattern antennas have contributed a lot in solving this problem due to the potential features offered by these types of antennas. In addition wideband operation to narrow band operation reconfigurable antenna is also needed to provide high antenna efficiency in communication systems. The aim of this project is to design an antenna which quantifies the potential gain of the pattern and frequency control in order to suit the requirement of wireless applications such as body are networks. Therefore a new concept of a pattern and frequency reconfigurable antenna is proposed. The proposed antenna uses two types of feedings (CPW and slotlines) for controlling the radiation pattern and the same time, ring resonators were integrated in order to switch from a wideband operation to a narrow band operation while maintaining the same polarization. The antenna ranges from 3 to 6 GHz for wideband operation and operates at 3.5GHz for a narrowband operation with good radiation pattern reconfigurability. The proposed antenna was designed and simulated in CST microwave studio and printed on a Taconic board and the analysis yielded a well behaved radiation pattern and a good agreement of return loss between measured and simulated results. Hence the proposed antenna is suitable for use in pattern and frequency reconfigurable for wireless applications such as body area network

5 vii ABSTRAK Secara amnya gandaan sama rata pada semua arah adalah diperlukan bagi sistem bergerak tanpa wayar seperti rangkaian ruang badan. Antena bolehubah polaradiasi telah banyak membantu dalam menyelesaikan masalah ini kerana ciri-ciri yang berpotensi yang ditawarkan oleh antena jenis ini. Selain itu, antena boleh ubah frekuensi jalur lebar ke frekuensi jalur sempit juga diperlukan bagi menyediakan kecekapan antena yang tinggi di dalam sistem komunikasi. Tujuan projek ini adalah untuk mereka sebuah antena yang mempunyai kawalan radiasipola dan frekuensi supaya dapat memenuhi keperluan aplikasi tanpa wayar seperti rangkaian kawasan badan. Oleh itu, satu konsep antena bolehubah semula radiasipola dan frekuensi yang baru adalah dicadangkan. Antena yang dicadangkan menggunakan dua jenis suapan talian (CPW dan baris slot) bagi mengawal polaradiasi dan pada masa yang sama, gelang resonator telah diintegrasikan supaya dapat mengubah operati jalur lebar ke operasi jalur sempit sambil mengekalkan pengutuban yang sama. Julat antena antara 3 ke 6 GHz untuk operasi jalur lebar dan 3.5 GHz untuk operasi jalur sempit dengan polaradiasi bolehubah yang baik. Antena yang dicadangkan direka dan disimulasi menggunakan perisian CST Microwave Studio dan dicetak di atas papan Taconic dan analisa menghasilkan keputusan polaradiasi dan kehilangan balik yang baik antara pengukuran dan simulasi. Oleh itu, antena yang dicadangkan sesuai digunakan di dalam konfigurasi semula pola dan frekuensi untuk aplikasi tanpa wayar seperti rangkaian ruang badan.

6 viii TABLE OF CONTENTS CHAPTER TITLE PAGE TITLE DECLARATION DEDICATION ACKNOWLEGMENT ABSTRACT ABSTRAK TABLE OF CONTENTS LIST OF TABLES LIST OF FIGURES LIST OF SYMBOLS LIST OF ABBREVIATIONS i iii iv v vi vii viii xii xiv xvii xvii 1 INTRODUCTION Introduction Problem statement Project objectives Scope of Project Thesis outline Summary 5

7 ix 2 MAJOR CONCEPT OF ANTENNA Introduction Antenna Properties Radiation pattern Polarization Gain Return loss Bandwidth Voltage Standing wave Ratio (VSWR) Half power Beam Width (HPBW) Efficiency Reconfigurable Antenna Varieties of feeding techniques Aperture coupled planar feed Coaxial feed Proximity coupled feed Microstrip Line feed Coplanar w waveguide feed Polarization categories Linear polarization Circular polarization Summary 27 3 PROJECT METHODOLOGY Introduction Design specifications Design Procedure and equations used Wideband reconfigurable antenna in CST environment Ideal switch case Integration of ideal switches in terms of pattern configurability Outcome of ring resonators and integrated ideal switches on the reconfigurable antenna 38

8 x 3.8 Real switch case Procedure to the antenna fabrication printing on transparent film Cleaning substrate portion Laminator scanner Exposition to ultra violet Developing Etching process Soldering Conducted measurement and testing Return Loss and Gain Measurement Radiation Pattern Measurement Summary 46 4 SIMULATION&MEASUREMENT ANALYSIS FOR IDEAL SWITCHES Introduction Antenna structure view Simulation results with ideal switches Ideal wideband case Ideal narrowband case Measured Result with ideal switches Measured Wideband Return loss Measured Narrowband Return Loss Comparison of Measured vs Simulated results Compared wideband return loss results Compared narrowband return loss results Radiation Pattern Analysis Gain Summary 62

9 xi 5 ANALYSIS & DISCUSSION OF RESULTS WITH REAL SWITCHES Introduction Antenna Design with Pin diode and Bias Network Biasing Procedure Measured Results Mode Mode Mode Mode Mode 5 and Mode Comparison of return loss between ideal switches and real switches Compared WB ideal and real switched results Compared NB ideal and real switched results Summary 76 6 CONCLUSION Conclusion Future Works Summary 78 REFERENCES 79

10 xii LIST OF TABLES TABLE NO. TITLE PAGE 2.1 Different types of switches used in the design of 13 electrically and optically reconfigurable antenna 3.1 Antenna design specification Effective width at the operating frequencies Calculated effective dielectric constant at 1.6mm of 33 substrate height 3.4 Effective length at operating frequencies Extended length at different frequencies Real length at desired frequencies Ideal switch configuration Real switch configuration 67

11 xiii LIST OF FIGURES FIGURE NO. TITLE PAGE 2.1 Radiation pattern of a generic directional antenna Different types of polarization Various techniques adopted to achieve reconfigurable 13 antennas 2.4 Schematic view of the reconfigurable patch antenna Patches of aperture coupled array antenna Coaxial feed Proximity coupled feed Microstrip line feed Coplanar waveguide feed of the microstrip patch antenna Linear polarized EM waves Circular polarized EM waves 26

12 xiv 3.1 Flowchart of the project methodology Simulated wideband return loss Three different states used for controlling frequency Simulated radiation pattern at 3.5 GHz Simulated narrowband with center frequency at 3.5 GHz Fabricated antenna with implementation of pin diodes Proposed antenna Simulated S11 parameter with ideal switches S11 parameter of the implemented ring resonators Measured S11 wideband antenna Measured narrowband return loss Measured vs Simulated wideband return loss CPW feeding Measured vs Simulated wideband return loss left slot feeding 4.8 Measured vs Simulated wideband return loss right slot feeding 4.9 Measured vs Simulated narrowband return loss CPW feeding 4.10 Measured vs Simulated narrowband return loss left slot feeding

13 xv 4.11 Measured vs Simulated narrowband return loss right 57 slot feeding 4.12(a) Radiation pattern for XZ plane at the resonant frequency 59 of 3.5GHz 4.12 Radiation pattern for YZ plane at the resonant frequency 60 (b) of 3.5GHz 4.13 Measured gain vs Measured return loss for wideband 61 (a) antenna 4.13 Measured gain vs Measured return loss for narrowband 62 (b) antenna 5.1 Antenna designed in CST with real switches (a) Fabricated Antenna with pin diodes (b) Equivalent circuit model of pin diode and dc blocks Measure return loss for wideband fed by CPW Measured S11 parameter for the wideband fed by left slot Measure return loss for the wideband antenna in the 70 right direction 5.6 Measure return loss for narrowband up direction ( a) Measured S11 parameter for NB left (b) Measured S11 parameter for NB right (a) Measured return loss comparing WB up ideal vs real case (b) Measured return loss comparing WB left ideal vs real case (c) Measured return loss comparing WB right ideal vs real case 75

14 xvi 5.9 (a) Measured return loss comparing NB up ideal vs real case (b) Measured return loss comparing NB left ideal vs real case (c) Measured return loss comparing NB Right ideal vs real case 77

15 xvii LIST OF SYMBOLS BW - Bandwidth c - Velocity of light db - decibel fc - Center Frequency fl - Lower Frequency Band fh - Upper Frequency Band p - Maximum directivity Hz - Hertz tan δ - Loss Tangent W - Width of the slot line λo - Free space Wavelength η - Efficiency E - Electric Field H - Magnetic Field ε - Permittivity εr - Relative Permittivity εeff - Effective Relative Permittivity ηr - Radiation Efficiency ηt - Total Efficiency λ - Wavelength Z - Impedance T - Actual thickness of substrate Γ - Reflection Coefficient υph - Phase Velocity

16 xviii S11 - Return Loss D - Directivity

17 19 LIST OF ABBREVIATIONS MEMS - Micro Electro Mechanical system UV - Ultra Violet 4G - Fourth Generation EIRP - Effective Isotropic Radiated Power VSWR - Voltage Standing Wave Ratio HPBW - Half Power Beam width RHCP - Right Hand Circular Polarization LHCP - Left Hand Circular Polarization CPW - Coplanar Waveguide RL - Return Loss RF - Radio Frequency EBG - Electromagnetic Band Gap MMICs - Microwave Monolithic Integrated Circuits EM - Electromagnetic

18 20 CHAPTER I INTRODUCTION 1.1 Introduction Although wireless communication systems are designed to perform optimally, this isn t really the case. As it rarely maximizes the obstacles it encounters along its part. The propagating signals are degraded by reflection and scattering in a multipath environment. As a result diffraction from buildings, land forms and also nearby objects occurs hence this cause the fluctuations in the signal strength. One of the techniques which have been proposed for the purpose of solving the multipath effect is by applying diversity technique. The diversity technique includes spatial diversity, pattern diversity as well as polarization diversity which aim at improving the signal to noise ratio and hence improves the overall performance. This can be achieved by the use of an antenna with reconfigurability ability. This means that the antenna is able to alternate using switches between several predetermined states for diversity purpose.

19 21 A reconfigurable antenna can be referred to as an antenna with the ability of achieving diversity in wireless system; this diversity may be in terms of spatial, temporal, pattern as well as polarization depending on the goal of the design as well as the application. There are three major categories of reconfigurable antenna; these can be frequency, polarization or pattern reconfigurable which play a major role in integrated system with a purpose of using a single multifunctional antenna for different services [1]. For the frequency reconfigurable antenna, only the frequency is reconfigurable while o the radiation pattern of this antenna remains principally unchanged as the operating frequency switches. For the pattern reconfigurable antenna over the frequency band of interest, concentrate its energy in a particular direction hence minimizing the gain in further directions exclusive of affecting the impedance bandwidth of the antenna [2]. The reconfigurable antenna in terms of its polarization is designed in order to switch the antenna polarization states either in linear polarization or right hand circular (RHCP) and left hand circular polarization (LHCP). Various studies have been carried on some pattern and frequency reconfigurable antenna structure by applying switching PIN diodes and dc bias network on the antenna topology [3]-[4]. Therefore, this project is aimed at designing a pattern and frequency reconfigurable antenna fed by a coplanar wave guide (CPW) of a wideband (3 to 6 GHz) and narrowband (3.5GHz) antenna with the capability of controlling the radiation pattern but in the same time with ability of handling frequency reconfigurable where switches are used to obtain polarization in different direction. It could be also applied in order to switch the wideband to the narrowband for wireless applications.

20 Problem statement Most of the projects nowadays are focused on wideband reconfigurable antenna for WLAN/WIMAX applications due to broadband demands. A general realistic indication has shown that the wireless link quality varies hastily in some wireless applications such as body area networks, hence this raised a permanent transmit power results in either misused energy (when the link is decent) or low consistency (when the link is corrupted). Therefore, this project seeks to quantify the potential gain of pattern and frequency control in order to maintain an upright external radiating antenna gain through most of the system (body) to avoid problems with an outstanding gain over a certain direction as the system (wearer) moves or turns. 1.3 Project Objective To design and fabricate pattern and frequency reconfigurable antenna by means of switches. To switch wideband (3-6 GHz) operation to narrowband (3.5 GHz) operation. 0 To control beam direction from -180 to 0 0 and

21 Scope of work The project involves the design and simulation of a wide band frequency (3 6GHz) and a narrowband (3.5 GHz) antenna. Fabrication of the reconfigurable antenna implementing ideal and real switches. Testing, measurement and analyzing the performance of both the simulated and measured results. 1.5 Thesis Outlines This thesis is divided into six chapters. Each chapter will discuss on different issues of the project. Following are the outlines of the project for each chapter. Chapter 1 begins with the introduction and overview of the project, problem statements, objective, scope of project, and methodology of project to carry out the work. The second chapter describes the theory behind reconfigurable antenna, antenna properties, Feeding methods, polarization types. It also includes the literature review to assist the project. The third explains in detail about the design process and methodology of this

22 24 Project. Additionally, the fabrication process and measurement process are also presented. The fourth provides the simulated and measured results. Discussions for these results are also being attached. Comparisons are being made between the simulated results and measured results for the fabricated antennas. The fifth provides the results obtained by Implementing real switches and the comparison made between ideal switches and real switches in terms of return loss. The sixth concludes this thesis with the work carried out for this project and the future work that can be further study. 1.6 Summary This chapter provides introduction of the project, followed by a brief explanation about the chosen type of antenna. This chapter also covers the objective of the project, as well as scope of work that involved.

23 99 REFERENCES 1 Sung-Jung Wu, Tzyh-Ghuang, Ma, A., Wideband Slotted Bow-Tie Antenna with Reconfigurable CPW-to-Slot line Transition for Pattern Diversity. Antennas and Propagation, IEEE Transactions, Vol. 56, NO. 2, February Tamer Aboufoul, Clive Parini, Xiaodong Chen, Akram Alomainy., Pattern Reconfigurable Planar Circular Ultra-Wideband Monopole Antenna and Propagation, IEEE Antennas Transactions, Vol. 61, NO. 10, October Symeon Nikolaou, Ramanan Bairavasubramanian,, Cesar Lugo, Jr., Student,Ileana Carrasquillo, Dane C. Thompson,, George E. Ponchak,,,John Papapolymerou,Manos M. Tentzeris.,Pattern and Frequency Reconfigurable Annular Slot Antenna Using PIN Diodes, Antenna and Propagation, IEEE Antenna Transactions,Feb G. H. Huff, J. Feng, S. Zhang, J. T. Bernhard., A Novel Radiation Pattern and Frequency Reconfigurable single turn square spiral microstrip antenna,ieee Microwave and Wireless Components Letters, Vol. 13, NO. 2, February Dr. Nor hisham Bin haji Khamis Teaching Module, Antenna Design and propagation. UTM, Garg, R., Bhartia, P., Bahl, I., Ittipiboon, A., Microstrip Antenna Design Handbook, Artech House, Inc, 2001

24 100 7 N. J: John Wiley, Sons. Antenna Theory, Analysis and design. 2 nd ed. Hoboken Balanis, C. A Mohd. Kamal bin A. Rahim. Teaching Module, RF / Microwave and Antenna Design. UTM., David M. Pozar, Microwave Engineering, John Wiley& Sons, Fourth Edition, Christos G. Christodoulou, Youssef Tawk, Steven A. Lane, Scott R. Erwin Reconfigurable Antennas for Wireless and Space Applications., IEE Communication magazine, April Zhang Jiajie, Wang Anguo, Wang Peng, A Survey on Reconfigurable Antennas. ICMMT Proceedings. 2008, 12, Se mi Lee, Ki Joon Kim, Young Joong Yoon, Frequency and Pattern Reconfigurable Antenna with Chip inductors and Parasitic elements Proceedings of ISAP, Nagoya, Japan Tamer Aboufoul, Khalida Ali, Akram Alomainy, Cilve Parini, Combined Pattern& Frequency Reconfiguration of single element ultra-wideband monopole antenna for cognitive radio device. Antenna and Propagation, 7 th European Conference, M. R. Hamid, Peter Gardner, Peter S. Hall, F. Ghanem, Vivaldi Antenna With Integrated Switchable Band Pass Resonator, Antennas and Propagation, IEEE transactions vol. 59, no. 11, November 2011

25 Ros Marie C Cleetus, T. Sudha, Design and Analysis of frequency and Pattern Reconfigurable microstrip patch antenna for wireless applications, International Conference on Control Communication and Computing [ICCC], M. F. Jamlos1, T. A. Rahman2, M. R. Kamarudin2, M. T. Ali2, M. N. Md Tan2, P. Saad3 Reconfigurable Aperture Coupled Planar Antenna Array at 2.3GH. Progress Electromagnetics Research Symposium Proceedings, Xi'an, China, March 22{26, [17].Frank B. Gross. Frontiers in Antenna, next generation design and engineering, MC-Graw hill, [18] Clarke, R. W. Lecture notes and lab scripts. University of Bradford, 2011