Large area W-band quasi-optical faraday rotators for imaging applications

We have developed W-band large area Quasi-Optical Faraday Rotators (QOFRs) for millimetre wave imagers, where they are used to achieve compact folded optics or for receiver local oscillator suppression. Devices of 600mm square (for 80-100GHz) and 265mm circular diameter (for 92-96GHz) achieved insertion losses of 1dB and isolations of 30 to 40dB using a novel construction technique which helps overcome the linear birefringence of plastoferrite.