A One-Dimensional Focusing Antenna Based on the Cassegrain Principle

This paper proposes a one-dimensional focusing antenna operating in the D-band, based on the Cassegrain principle. By modifying the structure of traditional Cassegrain antennas, a low-profile, high-gain antenna unit is designed. Compared to conventional Cassegrain antennas, the proposed design achieves electromagnetic wave focusing in the H-plane to compress the radiation pattern while retaining the wide coverage characteristics of a flared aperture in the E-plane. The energy transmission path is optimized to mitigate the adverse effects of sub-reflector blockage. Additionally, a tapered radiation port is introduced to enhance antenna gain. Simulation and experimental results demonstrate that the antenna achieves a gain of 21.46 dBi while meeting miniaturization requirements, making it suitable for 5G millimeter-wave communication systems.