A Wide-band Circularly-Polarized Metal Cavity Antenna Array

this paper, a novel circularly polarized metal cavity antenna is proposed. The radiating element is composed of a tilted slot cut in the narrow walls of a ridge waveguide and a bending slot in the bottom of the L-shaped wall. The inclined part of the bending slot is orthogonal to the slot on the narrow walls. Two polarized fields form a 90°phase difference, which is offered by the quarter of the wave length depth of the ridge. At the center frequency of 10 GHz, impedance bandwidth of S11 less than -10 dB is about 16% (8.8GHz-10.4GHz) and the axial bandwidth of antenna less than 3dB is 25% (8.5GHz-11.0GHz). The proposed antenna obtains high efficiency, excellent circular polarization purity, wide-band characteristics and simple structure.