A ribbon type of polarization grating for the 4/6 GHz frequency bands

This paper reports the results of polarization isolation measurements on a polarization grating at 6 GHz. The grating was designed for a four-foot diameter circular reflector antenna. Between 5.9 and 6.4 GHz the grating alone exhibited a worst case cross-polarization isolation of 29.4 dB within the 3 dB beamwidth of the antenna. In combination with the inherent isolation of the antenna this isolation was increased to better than 45 dB.