Cross-polarization reduction in a directive ultra-wideband antenna using electromagnetic polarization filter

Abstract

An electromagnetic polarization filter (EMPF) is designed to reduce the cross-polarization of a directive ultra-wideband (UWB) antenna. The filter is a rectangular cap with solid metal sheets on two sides and printed metal strips on the top and other sides. This cap increases the height of the whole structure by 5 mm while reducing the maximum cross-polarization level by 7 dB over the frequency band 8 GHz to 11 GHz. The resulting antenna has a maximum cross-polarization level of -20 dB over the frequency band.