US 4,789,866 AGranted

Automobile antenna system

AssigneeToyota Jidosha Kabushiki Kaisha

InventorsJunzo Ohe, Hiroshi Kondo

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Abstract

The present invention provides an automobile antenna system including a high-frequency pick-up device for receiving broadcast waves and which includes a loop antenna or detection electrode element disposed parallel and in close proximity to the marginal edge of the vehicle body and spaced from the marginal edge of the vehicle body within a range represented by 12.times.10.sup.-3 .lambda.(m) where .lambda. is the wavelength of a given broadcast wave measured metric units, to detect surface high-frequency currents on the marginal portion of the vehicle body. The high-frequency pick-up device is connected with a varactor diode to adjust the resonance frequency of the antenna system. The tuned frequency of a receiver is used to vary a voltage applied to the cathode of the varactor diode such that the frequency of the antenna system will coincide with the tuned frequency of the receiver.

Claims8

Dependent claims

An automobile antenna system which operates in conjunction with a built-in receiver in the vehicle body, said antenna system comprising:

high-frequency pick-up means for detecting surface high-frequency currents induced on the vehicle body by broadcast waves which flow concentratedly on a marginal portion of the vehicle body, said high-frequency pick-up means being disposed along and spaced apart from an outer marginal edge of the vehicle body at substantial (12.times.10.sup.-3).lambda.(m), where .lambda. is the wavelength of a broadcase wave to be received measured in metric units;
circuit means for processing a signal detected by said high-frequency pick-up means;
a casing housing said high-frequency pick-up means and said circuit means;
and
varactor diode means connected between said high-frequency pick-up means and said circuit means and being controlled by the built-in receiver for setting the resonance frequency of said antenna system to coincide with a tuned frequency selected by the built-in receiver.

2 more elements

Dependencies are inferred from the claim text.