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.