Double ridged horn antenna designs for wideband applications

In this paper, different double ridged horn antenna (DRHA) designs are investigated for wideband applications. A classic design of 1-18 GHz DRHA with exponential ridges is modelled and the antenna pattern deficiencies are detected at frequencies above 12 GHz. The antenna pattern is optimized by modification of the antenna structure. However, the impedance matching is affected and the VSWR is increased at the frequencies below 2 GHz. The matching problem can be resolved by adding lossy materials to the back cavity of antenna. We have shown reduction of the antenna efficiency by 15% over the whole frequency range, except at the lower frequencies.