wherein a reflecting surface acts also as a polarisation filter or a polarising device

Full Title

Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic > using reflecting surfaces > having two or more spaced reflecting surfaces (H01Q19/20 takes precedence) > comprising one main concave reflecting surface associated with an auxiliary reflecting surface > wherein a reflecting surface acts also as a polarisation filter or a polarising device