A Broadband Circularly-Polarized Waveguide Slot Cavity Array

This paper presents a new broadband circularly-polarized antenna array. The principle of circularly-polarized radiation is realized by orthogonal waveguide slots with a 90° spatial phase delay based on the special structure of the L-shaped waveguide. The simulation results show that it achieves a relative impedance bandwidth (VSWR 2) of 27.1 %, covering a frequency range from 18.9 GHz to 24.8 GHz, a relative circularly-polarized bandwidth (axial ratio ≤ 3 dB) of 17.3 %, and an aperture efficiency of 79.7 ~ 90.9%. At the same time, its full-metal structure and two-dimensional scanning capability of ±15° are very suitable for harsh space environment applications.