Window glass antenna system for automobile.

摘要

An antenna system for an automobile comprises an integrated circuit consisting of T-shaped FM and AM matching circuits (64,66) each connected to a common cable (5). The T-shaped FM matching circuit (64) comprises as least two varactor diodes (17,23) each supplied with a channel selection voltage to match the FM antenna impedance with that of the FM receiver including that of the transmission cable (5). The channel selection voltage is supplied through the cable (5) to the FM matching circuit (64) and to the AM matching circuit (66). The FM matching circuit (64) has a high selectivity so that interference from a pair of FM signals received during AM reception is highly attenuated. The T-shaped FM matching circuit (64) comprises a main matching circuit (13,15,17) that matches the antenna, and an auxiliary matching circuit (21,23,25) that matches the load at the input end (28) of the cable (5). <IMAGE>