A Doppler radar transceiver in a traffic monitoring system includes a pyramidal horn antenna having a rectangular aperture and a dielectric lens mounted at the rectangular aperture. Preferably the pyramidal horn antenna is corrugated and the rectangular aperture has a breadth at least twice its width...http://www.google.de/patents/US20020060640?utm_source=gb-gplus-sharePatent US20020060640 - Doppler-shift radar transceiver for traffic monitoring system
