radiation pattern reconfigurable antenna for...
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RADIATION PATTERN RECONFIGURABLE ANTENNA FOR LTEAPPLICATIONS
GORANTLA DILEEP KUMAR
UNIVERSITI TEKNOLOGI MALAYSIA
RADIATION PATTERN RECONFIGURABLE ANTENNA FOR LTEAPPLICATIONS
GORANTLA DILEEP KUMAR
A project report submitted in partial fulfilment of the requirements for the award of the degree of
Master of Engineering (Electronics and Telecommunication)
Faculty of Electrical Engineering Universiti Teknologi Malaysia
JANUARY 2018
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To my parents, for their endless love and support
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ACKNOWLEDGEMENT
First, I have to thank my parents for their love and support throughout my life. Thank you for giving me strength to reach my dreams. I would like to sincerely thank my supervisor, DR.MOHAMAD RIJAL BIN HAMID, for his guidance and support throughout this study, and especially for his confidence in me. Finally, to all my friends, thank you for your understanding and encouragement in my studies.
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ABSTRACT
This project proposes a radiation pattern reconfigurable antenna for LTE applications. Long Term Evolution (LTE) is an advanced system in the wireless telecommunication development. Compared to previous standards, LTE offers improved performance. The main advantage of this project is to steer the radiation pattern to a particular direction. The radiation pattern steering is achieved by applying progressive phase shifting. The transmission line model is used to obtain design parameters of the antenna. By using the progressive phase shift concept, three different configurations of patch array antennas are designed at 2.6GHz operating frequency. The three different directions had been formed at -15°, 0°, 15°. FR4 substrate is used for designing the reconfigurable antenna with thickness of 1.6mm. Measured and simulated results are well matched, but with some minor deviations. The gain of the antenna is 4.4dB with broadside direction and the gain is 4.6dB when the beam steers to either ±15°.
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ABSTRAK
Projek ini mencadangkan antenna dengan corak radiasi beralih secara elektronik untuk aplikasi Evolusi Jangka Panjang (LTE). Evolusi Jangka Panjang (LTE) adalah sistem yang maju dalam pembangunan telekomunikasi. Berbanding dengan standard terdahulu, LTE menawarkan prestasi yang lebih baik. Kelebihan utama projek ini adalah untuk memandu corak radiasi ke arah yang ditentukan. Pemanduan corak radiasi dicapai dengan mengaplikasikan perubahan sudut secara progresif. Model talian penghantaran digunakan untuk menentukan parameter- parameter untuk antenna. Dengan menggunakan konsep perubahan sudut secara progresif, tiga konfigurasi yang berbeza untuk antenna patch array direka pada frekuensi operasi 2.6 GHz. Tiga arah berbeza dibentuk pada -15°, 0°, 15°. FR4 substrate digunakan untuk merekabentuk antenna yang boleh dikonfigurasi dengan ketebalan 1.6mm. keputusan pengukuran dan simulasi adalah berpadanan, tetapi dengan sedikit perbezaan. Gandaan antenna adalah 4.4dB dengan arah lebarsisi dan gandaan 4.6dB apabila pasak dipandu ke sudut ±15°.
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CHAPTER TITLE PAGE
DECLARATION iiDEDICATION iiiACKNOWLEDGEMENT ivABSTRACT vABSTRAK viTABLE OF CONTENTS viiLIST OF TABLES xiLIST OF FIGURES xiiLIST OF ABBREVIATIONS xviLIST OF SYMBOLS xviiLIST OF APPENDICES xviii
1 INTRODUCTION 11.1 Problem Background 11.2 Problem Statement 21.3 Objective 31.4 Scope of the work 31.5 Summary 3
2 LITERATURE REVIEW 42.1 Introduction 42.2 A review on Wireless Communications 42.3 Overview of LTE 52.4 Overview on Antenna 7
2.4.1 Wire antennas 7
TABLE OF CONTENTS
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2.4.2 Aperture antennas 82.4.3 Reflector antennas 92.4.4 Microstrip antennas 10Overview on microstrip antenna 112.5.1 Substrate 122.5.2 Feeding techniques 122.5.3 Antenna Arrays 152.5.4 Two Element Array 162.5.5 N-Element Array 182.5.6 Broadside Array 192.5.7 End Fire Array 192.5.8 Phased (Scanning) or Beam Steering
Array 20Overview on radiation pattern 212.6.1 Drawbacks of directional radiation pat-
tern 22Review on switching 222.7.1 Pattern Reconfigurable Patch Array for
2.4 GHz WLAN Systems 222.7.2 Novel Radiation Pattern Reconfigurable
Antenna with Six Beam Choices 242.7.3 A Planar Electronically Reconfigurable
Wi-Fi Band Antenna Based on a ParasiticMicrostrip Structure 26
2.7.4 Electronically Reconfigurable BeamSteering Antenna Using Embedded RFPIN Based Parasitic Arrays (ERPPA) 27
2.7.5 Reconfigurable Beam Steering Using aMicrostrip Patch Antenna With a U-Slotfor Wearable Fabric Applications 29
2.7.6 Electronically Switched Beam Disk -Loaded Monopole Array Antenna 30
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2.7.7 Beam Steering Patch Antenna UsingReactive Loading and Yagi - Antenna Concept 31
2.7.8 A Twelve-Beam Steering Low-ProfilePatch Antenna With Shorting Vias for Vehicular Applications 33
2.7.9 Broadside Beam-Steerable Planar Parasitic Pixel Patch Antenna 34
2.7.10 A Beam-Steering Broadband MicrostripAntenna for Noncontact Vital Sign Detection 36
2.8 Summary 38
3 RESEARCH METHODOLOGY 393.1 Introduction 393.2 Design flow 393.3 Microstrip patch antenna 403.4 Design of array antenna 443.5 Antenna simulation software 453.6 Fabrication and Measurement process 46
3.6.1 Fabrication process 463.6.2 Measurements Process 49
3.6.2.1 Measuring Gain 493.6.2.2 Measuring E-field 503.6.2.3 Measuring H-field 51
3.7 Summary 52
4 RESULTS AND DISCUSSION 534.1 Introduction 534.2 Results of Single patch antenna without phase
shifting and with phase shifting 534.3 Simulation and Measurement Results 56
4.3.1 Simulated Antenna Configurations 56
4.3.2 Fabricated Antenna Configurations 574.3.3 Simulated Reflection coefficient 574.3.4 Measured Reflection coefficient 584.3.5 Simulated Gain 604.3.6 Measured Gain 614.3.7 Simulated E-plane 614.3.8 Measured E-plane 634.3.9 Simulated H-plane 644.3.10 Measured H-plane 65
4.4 Summary 65
5 CONCLUSION AND FUTURE W ORK 665.1 Conclusion 665.2 Future work 66
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REFERENCESAppendix A
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LIST OF TABLES
TABLE N° . TITLE PAGE
2.1 Comparisons of all generations of mobile technologies 52.2 LTE band numbers with frequency allocation 62.3 LTE frequency band allocation for mobile services in
Malaysia 62.4 Advantages and disadvantages of microstrip antennas 122.5 Different types of feeding techniques of advantages and
disadvantages 132.6 Comparison of different feeding techniques 153.1 Design specifications and parameters of single element 443.2 Design specifications and parameters for 2x 1 antenna 44
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FIGURE NO. TITLE PAGE
2.1 Wire antennas 72.2 Aperture antennas 82.3 Reflector antennas 92.4 Types of the microstrip antennas 102.5 Advantages and disadvantages of microstrip antennas 112.6 Two infinitesimal horizontal dipoles 162.7 Fairfield observations 172.8 Figure 2.4: N-element array liner array. 182.9 (a) coordination system for antenna analysis (b) Radiation
lobes and beam widths of an antenna amplitude pattern inpolar form 21
2.10 Fabricated antenna 232.11 (a) Reflection coefficient (b) Radiation Pattern when SP3
connects the middle line (c) Radiation Pattern when SP3 switch select the left branch line (d) Radiation Pattern whenSP3 switch select the right branch line 24
2.12 Photos of the fabricated antenna 252.13 Radiation patterns at 5.2 GHz 252.14 Photograph of the prototype of the parasitic antenna 26
LIST OF FIGURES
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2.15
2.16
2.17
2.182.19
2.20 2.21 2.22
2.23
2.242.25
2.262.27
2.28
(a) Normalized radiation patterns in correspondence with the fully deactivated configuration (b) Normalized radiation patterns in correspondence with the three-sectors suppressing structure (c)normalized radiation patterns in correspondence with the six-sectors suppressing structure (d) normalized radiation patterns in correspondence with the nine-sectors suppressing structure 27The physical structure of the antenna used in simulation during the preliminary investigation (a) Front view (b) Back view 28(a) reflection coefficient (b) radiation pattern for three different modes of operations 28
29(a) Measured return losses in free space (b) Measured radiation patterns and overall HPBW 30Integrated disk-loaded CPW antenna made for 2.45 GHz. 30Measured normalized E-plane antenna radiation patterns 31Top: scheme of the proposed antenna and bottom: photo of one prototype 32(a) Measured reflection coefficient at different varactor bias voltages (b) Measured gain at different varactor bias voltages 32Top and side views of the proposed antenna. 33(a) Measured and simulated reflection coefficient (b) Demonstration of beam steering with tilted beams using single feed configuration and dual feed configuration 34Plan and elevation view of the proposed antenna 35Measured and simulated results (a) Reflection coefficients (b)Radiation patterns 35Proposed antenna (a) bottom layer with diodes that connectthe stubs and the partial ground plane (b) top layer 36
2.29 Comparison of measured radiation patterns of the proposed
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antenna and reference antenna, and simulated radiation patterns of the proposed antenna along Theta = 900plane. Radiation patterns at frequencies of (a) 3, (b) 3.5, (c) 4, and (d) 4.5 GHz are plotted. 37
3.1 Methodology flow chart 403.2 Basic antenna structure 443.3 2x1 array antenna 453.4 CST software user interface 463.5 Anennas layout printed on transperant sheet 473.6 Fabrication process by steps 483.7 Chemical etching machine 483.8 Radiation pattern measurement setup 493.9 Anechoic chamber 503.10 Antenna postions for measuring the h-field 514.1 Single patch antenna simulation results (a) design (b)
reflection coefficient (c) 3D radiation pattern 544.2 Single patch antenna with phase simulation results (a) design
(b) reflection coefficient (c) 3D radiation pattern 554.3 Antenna simulated three configurations (a) Broadside (b) Left
(c) Right 564.4 Antenna fabricated three configurations (a) Broadside (b) Left
(c) Right 574.5 simulated Reflection coefficients 584.6 Measured Reflection coefficients results 594.7 Simulated vs Measured Reflection coefficients result 594.8 Simulated results with different Dielectric constant values 604.9 Simulated Gain results 604.10 Measured Gain results 614.11 2D E-plane Radiation pattern for three configurations 624.12 Measured E-plane radiation pattern for three configurations 634.13 Measured E-plane results with Cartesian graph 644.14 2D H-plane Radiation pattern for three configurations 644.15 Measured H-plane radiation pattern for three configurations 65
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A.1 Broadside Direction 73A.2 Steering Left 74A.3 Steering Right 74
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1G - First Generation2G - Second Generation3G - Third Generation4G - Fourth generationLTE - Long Term EvolutionCST - Computer Simulation TechnologyMTS - Mobile Telephone SystemsAMTS - Advanced Mobile Telephone SystemsPTT - Push To TalkIMTS - Improved Mobile Telephone ServiceGPRS - General Packet Radio ServiceWLAN - Wireless Local Access NetworkFDMA - Frequency Division Multiple AccessCDMA - Code Division Multiple AccessGSM - Global System for Mobile CommunicationEDGE - Enhanced Data Rates for GSM EvolutionUMTS - Universal Mobile Telecommunication SystemsHSDPA - High-Speed Downlink Packet Access3GPP - 3rd Generation Partnership ProjectMIMO - Multiple Input Multiple OutputOFDM - Orthogonal Frequency Digital MultiplexingMBWA - Mobile Broadband Wireless AccessWiMAX - Worldwide Interoperability for Microwave Access
LIST OF ABBREVIATIONS
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Z0 - Characteristics ImpedanceZin - Input impedanceI - CurrentV - VoltageA - AmpereW - WidthL - LengthEffective lengthLeff - Effective lengthAL - Change in lengthC - Speed of lightM - MicrondB - DecibeldBi - Decibel reference to isotropic antennaA - wavelengthA0 - Free space wavelengthAef f - Effective wavelengthA - conductivityer - relative permitivityeeff - effective permitivityQ - Ohm
LIST OF SYMBOLS
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APPENDIX
A
LIST OF APPENDICES
TITLE p a g e
Simulation 3D Radiation Patterns 73
CHAPTER 1
INTRODUCTION
1.1 Problem Background
In wireless communications, four generations have been implemented until now. The 1st generation (1G), or analog, 2nd generation (2G), or digital, 3rd generation (3G), or broadband, 4th generation (4G), or digital broadband. Long Term Evolution (LTE) is the technology of 4G [1]. LTE is the advanced system in telecommunication and it offers improved performance.
There are different types of antennas, wire antenna, aperture antenna, reflector antenna and microstrip antenna. Microstrip antenna is easy and low cost to fabricate, low-profile, ease of installation, high-performance, less in size, light weight, and its exit in different shapes such as rectangular, square, circle and triangle are the most common shapes. However, the main drawback of microstrip antenna is that, it has narrow bandwidth [2].
The drawback of fixed radiation pattern is less coverage area, and to overcome this problem, pattern reconfigurable antennas are implemented. Pattern reconfigurable antennas, switch the radiation pattern towards a particular direction and provide more coverage area.
For some applications, single element antennas are unable to meet the gain or radiation pattern requirements. Combining several single antenna elements in an array can be a possible solution. Antenna arrays have the advantages of providing the capability of a steerable beam (radiation direction change) [3].
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This chapter starts with an introduction, problem statement, objectives, and scope of the project.
1.2 Problem Statement
Microstrip patch antennas built on printed circuit board (PCB) substrate, are attractive due to their various features like light weight, low cost, easy to fabricate. Obviously, the microstrip element suffers from the inherent limitation of narrow impedance bandwidth and high substrate losses and low radiation efficiency. To relax the precision problem of conventional microstrip antenna, it is proposed to fabricate the antenna using lossless low permittivity substrates.
In general, an antenna design with very directive characteristics (very high gains) to meet the demands of long distance communication. Usually the radiation pattern of a single element microstrip radiator is relatively wide and each element provides the low value of directivity (gain). Enlarging the dimensions of the single elements offer high directivity, but this is not a practical solution. Another simple way is to form an assembly of radiating elements in an electrical and geometrical configuration. This multiple element is referred to as antenna array.
A conventional array antenna is capable of producing a single directional beam pattern, therefore it limited to a fixed direction of the main beam. This limitation can be overcome by using a beam reconfigurable antenna, which is upgrading the single antenna into a multifunctional antenna. Therefore, Beam reconfigurable, which capable to steer the main beam at three different places in the single antenna design was proposed in the present research. There only one beam can be steered at one time within the proposed design. Practically user's position is not stable, to maintain the connection, the antenna maximum radiation must always be pointing towards the base station. This requires a beam steerable antenna array.
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1.3 Objective
The main objectives of this project as follows:
1. To model and design a microstrip antenna for LTE applications.2. To steer the radiation pattern towards a particular direction.3. To fabricate and measure the proposed antenna design.
1.4 Scope of the work
The scopes of this project starts with understanding the concept of radiation pattern and micro strip patch array antenna. The two element micro strip patch antenna operating at 2.6 GHz has been chosen and simulated by using a CST microwave studio. The measured return loss of the proposed antenna obtained below -10 dB and the gain of the antenna is almost similar, when steering the radiation pattern. Finally, the proposed antenna design has been fabricated and the simulated and measured results are compared.
1.5 Summary
This chapter presents the introduction of the project and an overview of the antennas, radiation pattern and array elements. The chapter also covers the problem statement, the objectives, scope of the work.
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