ANNULAR SLOT WINDSHIELD ANTENNA

An automotive AM/FM hidden antenna using the slot between the body of the automobile and a metal solar heat-reduction film in the front wind shield is described. Such solar heat-reduction metal films are becomin g common and thus represent an opportunity to incorporate an antenna a t only marginal cost. The radio frequency (RF) input impedance and gai n patterns will be described, and techniques for impedance matching wi ll be shown. Theoretical and experimental antenna patterns will be com pared. A test range measurement system and experimental results will b e described. A mobile on-road system to characterize the antenna in ur ban and suburban environments will be shown. The application of this m obile system to the measurement of calibrated gain patterns will be de monstrated.