Abstract: A radar detector adapted to be carried by a motor vehicle, includes a housing enclosing a compact horn antenna having a tapering wall portion which defines a cavity extending from an aligned aperture within the housing. A plano-convex dielectric lens extends across the aperture and cavity and introduces a microwave phase delay decreasing from the center of the cavity towards the tapered wall portion of the horn antenna to compensate for the deficiencies in the compromised design of the antenna and for significantly increasing the sensitivity and gain of the detector. The dielectric lens may project outwardly from the housing or inwardly into the antenna cavity and may be molded as an integral part of the front wall of the detector housing. In one embodiment, the lens is also adapted to be conveniently attached to an existing radar detector.

Abstract: A compact radar detector incorporates an elongated dielectric antenna, one end of which is coupled to an aligned cylindrical resonant waveguide. The dielectric antenna has cylindrical and tapered portions which cooperate with the waveguide to provide a narrower beam width, high gain and more directivity in comparison to prior art radar detectors. The antenna projects forwardly from a relatively thin rectangular housing which encloses the waveguide and other components in a manner providing for convenient and efficient assembly.