A Novel Circularly-Polarized T-shaped Slot Array Antenna in Ka-band

A T-shaped slot-array antenna fed through a Groove Gap Waveguide (GGW) is presented in this paper. The array antenna operates at 30 GHz. The way the slots are excited, along with the T-shape on its lid allows a compact single-layer architecture. A uniform linear array of 12 elements is designed to demonstrate the viability of this concept for high-efficient singlelayer slot-array antennas. Preliminary results show a frequency bandwidth of 1 GHz with input reflection coefficient better than –12 dB. In addition, being a full-metal antenna, the expected efficiency is high. It is worth stressing the good polarization purity achieved, being below 1.5 dB within the band of interest.