Double reflector configuration for optimal exposure of wideband focal plane arrays with optical beamforming

An optimized double-reflector antenna concept for a wideband focal plane array (FPA) configuration is presented for Ka-band applications with a limited scan range, e.g., ground terminals for satellite communication. The proposed reflector configuration allows maximizing the number of active array elements and minimizing the actual array size during scanning. In addition, the FPA configuration has been optimized for wideband optical true-time-delay beamforming, resulting in wideband operation from 20 to 40 GHz. Based on a minimum required 80% aperture efficiency at 30 GHz, the double-reflector concept allows expanding the illuminated region of the array by a factor of 60 compared to traditional prime-focus configurations. The proposed configuration also decreases the magnification factor M by a factor of 2.5 compared to the double-parabolic configuration for a ±1.5° scan range.