Wideband Beam-Scanning Circularly Polarized Inclined Slots Using Ridge Gap Waveguide

A wideband circularly polarized (CP) frequency-dependent slot antenna array is designed for beam scanning using the ridge gap waveguide (RGW) technology. The merge between both the printed and the RGW technologies for providing a wideband CP antenna array is newly implemented here. The designed CP antenna has been fabricated, and measurement results are provided and compared to the full-wave analysis. A measured antenna axial ratio (AR) and impedance bandwidths of ~ 21% are achieved from 12.5 to 15.5 GHz. The proposed antenna preserves its CP characteristics of AR below 3 dB while achieving continuous frequency beam scanning from backward to forward directions including broadside radiation that covers +15° to -15° with an average gain of 12.5 dBi.