https://www.dolphmw.com/products/double-ridged-waveguide-horn-antennas/
As one of professional horn antenna manufacturers, Dolph Microwave manufactures a high-quality line of double ridged horn typically used for EMI testing, surveillance equipment, antenna gain and pattern measurement, which available in WRD1800, WRD750, WRD700, WRD650, WRD580, WRD475, WRD200, WRD180 etc. Also, wide band double ridged waveguide horn antenna are still can be offered from 0.2GHz to 40GHz. The most common Gain values available are 4-20dB. Taking wide band double ridged guide horn antenna as example below.