Dual Circularly-Polarized Slot-Array Antenna in Ka-Band fed by Groove Gap Waveguide

A dual circularly-polarized slot-array antenna fed by a Groove Gap Waveguide (GGW) and operating in the Ka-Band is presented in this paper. A simple mechanism is proposed to switch the polarization, from RHCP to LHCP, and viceversa. The lid of the antenna has two pieces: one fixed and one sliding. The fixed piece hosts T-shaped slots, and the sliding block is in charge of adjusting the offset of the perpendicular grooves with respect to the longitudinal slots. Preliminary results show an axial ratio below 1.5 dB for both, RHCP and LHCP, within a bandwidth of 1 GHz centered at 30 GHz.