Instrument panel radio antenna

Claim 1

In an automotive vehicle, the combination comprising: an instrument panel assembly having a top edge extending approximately horizontally across the interior width of the vehicle body; a conductive body structure forming a shield by which radio waves are normally prevented from entering the vehicle, the body structure including a windshield opening having a lower edge extending approximately horizontally across the exterior width of the vehicle body generally parallel to and spaced forward of the top edge of the instrument panel assembly and having an upper edge extending approximately horizontally across the exterior width of the vehicle body generally parallel to and spaced rearward of the lower edge of the windshield opening so that radio waves directed downward through the windshield opening from outside of the vehicle body pass through an irradiated space defined between the lower edge of the windshield opening and the top edge of the instrument panel assembly; a radio receiver mounted within the instrument panel assembly; a top portion of the instrument panel assembly extending within the irradiated space and including a nonconductive rigid inner layer, a nonconductive pliable outer layer, a nonconductive resilient intermediate layer interposed between the inner and outer layers, and a conductor physically disposed within the intermediate layer between the inner and outer layers for inductively collecting passing radio waves to provide an antenna which is protected from potentially damaging forces outside of the vehicle and which does not detract from the aesthetic appearance of the vehicle; and a transmission line for coupling the radio receiver to a point on the antenna conductor at which the output impedance of the antenna conductor is approximately matched to the input impedance of the radio receiver thereby to maximize the electrical efficiency with which radio waves are transferred from the antenna conductor to the radio receiver and wherein the close proximity of the antenna conductor to the radio receiver minimizes the length of the transmission line such that the amount of signal antennuation and impedance mismatch produced by the relatively small impedance of the transmission line is negligible.