High-Efficiency Circularly Polarized Slots Pair Element for K-Band Radial-Line Slot Array Antennas

This paper presents a novel Circularly Polarized (CP) slot pair element designed for Radial-Line Slot Array (RLSA) antennas. By employing an all-metal parallel plate waveguide (PPW) integrated with metallic pins, the design effectively mitigates dielectric loss, resulting in enhanced radiation efficiency. Simulation results demonstrate a favorable axial ratio and radiation pattern at 19.5 GHz, with a 1-dB axial ratio bandwidth from 18.7 GHz to 20.3 GHz. The metallic pins' height optimization prevents grating lobes while maintaining wide bandwidth. The proposed design, with varying slot lengths, ensures uniform antenna performance, achieving a peak gain of 8.35 dBi and a minimum axial ratio of 0.1 dB. This high-gain, low-profile, wideband solution promises practical applications in K-band RLSA antennas.