Design of Low-Profile CTS Antenna for Wideband Communication System

다국어 초록 (Multilingual Abstract)

This thesis proposes a lightweight, low-cost Continuous Transverse Stub (CTS) antenna and a passive beam-steering system for broadband K/Ka-band communication platforms. The CTS antenna is implemented on a multilayer PCB, and this PCB-based approach realizes a non-resonant radiation mechanism, enabling wideband operation, while significantly reducing weight and fabrication cost compared to conventional metallic waveguide-based high-gain antennas. To realize beam steering without active components, a phase-gradient metasurface (PGM) was designed using a 3D-printed dielectric structure, and a configuration that mechanically rotates two PGM layers was introduced to achieve multiple beam-steering angles. The CTS antenna maintains stable boresight directivity over the entire operating band, and clear beam-steering behavior is observed when combined with the PGM lenses. These results confirm that the proposed system can achieve wideband, highly directive, and stable passive beam-steering performance while maintaining a lightweight and low-power architecture, which makes it suitable for next-generation mobile communication platforms such as UAVs, compact vehicles, and satellite terminals.

국문 초록 (Abstract)

본 논문에서는 이동체 기반 K/Ka 대역 광대역 통신 시스템을 위해 경량, 저비용 Continuous Transverse Stub (CTS) 안테나와 수동형 빔 조향 시스템을 제안하고, 설계, 제작, 측정을 수행하였다. 제안된 CTS 안테나는 다층 PCB 구조로 구현되었으며, 비공진형 방사 메커니즘을 통해 넓은 대역폭을 확보하였다. 또한 기존 금속 도파관 기반 고이득 안테나 대비 중량, 부피, 비용을 효과적으로 절감하였다. 능동 소자 없이 빔 조향을 구현하기 위해 위상 구배 메타표면(PGM)을 3D 프린팅 기반 유전체 구조로 설계하였으며, 두 개의 PGM을 기계적으로 회전시켜 다양한 빔 조향 각도를 구현하는 구조를 제안하였다. CTS 안테나는 전체 대역에서 안정적인 보어사이트 지향성을 유지하였고, 렌즈 결합 시 명확한 빔 조향이 확인되었다. 이를 통해 제안된 시스템이 광대역 고지향성과 안정적인 수동 빔 조향 성능을 달성할 수 있음을 검증하였다. 본 연구 결과는 무게와 전력 제한이 큰 차세대 이동체 통신 플랫폼에서 유용한 해결책이 될 것으로 평가된다.

목차 (Table of Contents)

• Abstract i
• Table of Contents ii
• List of Tables v
• List of Figures vii
• Chapter 1. Introduction １
• Chapter 2. Theoretical Background ４
• 2.1 Transmission Line ４
• 2.1.1 Transmission Line Waves ４
• 2.1.2 Rectangular Waveguide ８
• 2.1.3 Substrate Integrated Waveguide １１
• 2.1.4 Parallel Plate Waveguide １４
• 2.1.5 Grounded Co-Planar Waveguide １６
• 2.1.6 GCPW to SIW Transition １８
• 2.2 Antenna Theory ２０
• 2.2.1 Radiation Mechanism· ２０
• 2.2.2 Antenna Parameter ２３
• 2.2.3 Horn Antenna ２５
• 2.2.4 Parabolic Antenna ２７
• 2.2.5 Aperture Radiation ２９
• 2.3 Phase Gradient Metasurface ３１
• 2.3.1 Concept of Metasurface ３１
• 2.3.2 Generalized Snell’s Law ３２
• 2.3.3 Phase Control Mechanism ３３
• Chapter 3. Antenna Design and Configuration ３４
• 3.1 Overall System Design ３４
• 3.2 Linear Source Generator ３５
• 3.2.1 GCPW to SIW Transition ３５
• 3.2.2 Via-Based Parabolic Reflector ３７
• 3.3 Parallel-fed Distribution Network ４１
• 3.3.1 Divider Unit ４２
• 3.3.2 Divider Network ４７
• 3.4 Radiation Stub ４９
• 3.4.1 Radiation Stub Unit ４９
• 3.4.2 Integration of Divider Network and Radiation Stub ５１
• 3.5 Antenna Full Structure Integration ５３
• 3.6 Phase Gradient Metasurface ５７
• 3.6.1 Unit cell ５７
• 3.6.2 Supercell ５９
• 3.6.3 Antenna with PGM ６４
• Chapter 4. Fabrication and Measurement ７４
• 4.1 Prototype Overview ７４
• 4.2 Measurement Setup ７８
• 4.3 Antenna-Only Measurement ８０
• 4.4 Measurement of Antenna with PGM Lenses ８４
• Chapter 5. Conclusion ９３
• Reference ９６
• 국문 초록 ９９
• Acknowledgements １００