Beamformers and Phased Arrays

A fully planar circular beam-switching antenna module with 360° coverage is proposed for drone collision avoidance radar. It comprises a dual-mode single-pole-multi-throw switch (developed in collaboration with Professor Kun-You Lin's Lab (MICSLab)), a circular beamforming network (CBFN), one-bit phase shifters, and quasi-Yagi antennas. The switch enables redirection of input power to either a single output port (single-ON mode) or two adjacent ports (dual-ON mode), effectively doubling the total number of beams. The CBFN arranges modified sub-matrices in a circular configuration, sharing edge components by employing three-way power dividers. A 5.8 GHz 12-beam prototype demonstrated excellent agreement between simulated and measured results, achieving consistent 30° beamwidths with sidelobe levels below -13 dB and gain variation within 1 dB. 

Researcher: Sheng-Wei Wu (吳聖偉)

The proposed phased array antenna for Low Earth Orbit (LEO) satellite communication (SATCOM) offers significant improvements in data transmission rates through its wide axial-ratio bandwidth, which expands usable bandwidth while minimizing polarization mismatches. This array leverages an innovative single-feed triple-mode antenna design that reduces the number of required beamforming integrated circuits by half, thereby enhancing heat management. Moreover, its RF/digital beamforming networks are meticulously designed to minimize coupling, ensuring the integrity of both RF and digital signals. The phased array will incorporate sophisticated beamforming and beam-tracking algorithms for efficient and real-time communication. 

Researcher: Yun-Ting Tsai (蔡昀廷)

In LEO satellite communications, satellites travel at high velocities, necessitating precise beam-tracking techniques to ensure stable connectivity. Our research focuses on phased array beam-tracking algorithms to enhance reliability, reduce latency, and optimize overall performance. We emphasize antenna-on-the-move (AOTM) scenarios, where dynamic tracking is crucial for moving platforms such as unmanned aerial vehicles (UAVs). Unlike fixed ground stations, AOTM demands continuous adaptive beam adjustments to compensate for platform motion, presenting a significant challenge in achieving precise tracking despite the predictable nature of LEO trajectories. 

Researcher: Wan-Ting Chang (張琬婷) and Yun-Ting Tsai (蔡昀廷)