Circularly Polarized T-Shaped Slot Waveguide Array Antenna for Satellite Communications

A novel circularly polarized waveguide slot array for satellite communications is proposed. The antenna features a unique feeding network and a unit cell that consists of a pair of simple T-shaped waveguide slots. The proposed configuration not only eliminates grating lobes, which are often seen in conventional waveguide slot arrays, but also simplifies the fabrication process without any sacrifice in the performance, while also allowing scalability. A prototype 6 × 8 array antenna is designed at 29.5 GHz, and fabricated by dip brazing. A high gain of 21.9 dBi and a -10 dB impedance bandwidth of 1 GHz are achieved with an axial ratio (AR) of 1.3 dB without any grating lobes. The measured results are in very good agreement with the simulated results.