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Metasurface Polarization Converters for Enhanced Antenna Performance : Design and Applications

초록/요약

In this dissertation, innovative metasurface-based antenna designs are explored to address the growing demands of modern wireless communication systems, particularly focusing on compact sizes, high efficiency, broad bandwidths, and multi-band operation. Circular polarization (CP) offers significant advantages over linear polarization (LP), including improved resilience to multipath distortion, reduced polarization mismatch losses, and enhanced resistance to Faraday rotation effects caused by the ionosphere. These benefits make CP antennas ideal for applications such as satellite communication, and mobile communication. Key contributions of this work include the development of a novel circularly polarized bowtie slot antenna, utilizing a metasurface with corner-truncated patches to achieve wide impedance and axial ratio (AR) bandwidths, specifically tailored for C-band satellite communication. For bidirectional applications, a metasurface composed of back-to-back arrays of truncated corner square patches with a slot in the ground plane is proposed, enabling same-sense circular polarization. This design is particularly well-suited for environments like tunnels and industrial spaces. Additionally, an end-fire dipole array antenna integrated with a non-uniform metasurface enhances radiation characteristics making it highly suitable for 5G communication systems. The dissertation further introduces an ultra-thin, ultra-wideband linear-to-circular (LTC) polarization converter based on a crossed-dipole-shaped metasurface, offering high transmittance and low insertion loss for advanced communication systems. Moreover, a single-layer dual-wideband LTC polarization converter is developed, covering two distinct frequency bands, crucial for managing multiple communication channels in satellite and advanced wireless networks. Finally, a high gain wideband CP antenna is achieved by integrating a metasurface polarization converter with a modified dipole antenna and a cavity reflector. Overall, the findings and metasurface-based designs presented in this work offer practical solutions for the challenges faced in modern wireless communication, contributing to the development of high-performance antenna systems that are crucial for next-generation technologies.

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목차

Chapter 1. Introduction 1
1.1 Metasurface Overview 1
1.2 Metasurface Polarization Converters 2
1.3 Circularly Polarized Metasurface Based Antennas 6
1.4 Motivations of the Dissertation 6
1.5 Problem statement 8
1.6 Contributions of the Dissertation 9
1.7 Dissertation Organization 11
1.8 References 13
Chapter 2. Circularly Polarized Unidirectional Metasurface-Based Antenna 16
2.1 Introduction 16
2.2 Antenna Geometry and Design 19
2.3 Parametric Study 25
2.4 Experimental Results 30
2.5 Conclusion 35
2.6 References 35
Chapter 3. Bidirectional Metasurface-Based Antenna 40
3.1 Introduction 41
3.2 Antenna Geometry 43
3.3 Antenna characteristics 45
3.4 Experimental Results 49
3.5 Conclusion 51
3.6 References 52
Chapter 4. Circularly polarized end-fire radiation metasurface-based antenna 56
4.1 Introduction 57
4.2 Antenna Geometry and Design 60
4.3 Operation Mechanism 63
4.4 Antenna characteristics 66
4.5 Experimental Results 79
4.6 Conclusion 83
4.7 References 83
Chapter 5. Ultra-thin ultra-wideband transmissive linear-to-circular polarization converter 88
5.1 Introduction 89
5.2 Metasurface Design and Operation Mechanism 93
5.3 Equivalent circuit model 100
5.4 Numerical Analysis and Parametric Study 102
5.5 Measurement Results 110
5.6 Comparison 112
5.7 Conclusion 115
5.8 References 115
Chapter 6. Single-layer dual-wideband linear-to-circular polarization converter with integrated parasitic elements 119
6.1 Introduction 120
6.2 Numerical Analysis 124
6.3 Metasurface Design 126
6.4 Unit Cell Design Evolution 128
6.5 Current Distribution on Unit Cell 133
6.6 Parametric Study 137
6.7 Experimental Results 145
6.8 Comparison 148
6.9 Conclusion 153
6.10 References 154
Chapter 7. Dipole Antenna Incorporated with Metasurface and Cavity Reflector for Wideband Circular Polarization and High Gain 158
7.1 Introduction 159
7.2 Antenna Geometry and Design 163
7.3 Antenna Design Evolution 169
7.4 Antenna Parametric Study 174
7.5 Experimental Results 181
7.6 Performance Comparison 185
7.7 Conclusion 189
7.8 References 190
Chapter 8. Conclusion and Future works 194
8.1 Summary and Key contributions 194
8.2 Future works 195

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