The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 21, 1992
Filed:
Jul. 13, 1989
Toshihiko Saitou, Ebina, JP;
Takashi Yamashita, Sagamihara, JP;
Kenichi Ishii, Aichi, JP;
Masanobu Ogawa, Kanagawa, JP;
Shinya Shibata, Kanagawa, JP;
Kenji Oda, Yokohama, JP;
Masaharu Kume, Yokohama, JP;
Asahi Glass Company Ltd., Tokyo, JP;
Abstract
An antenna device for an automobile comprises an electric heating type defogger having heating strips and a bus bar for feeding a current to the heating strips and an antenna conductor having antenna strips arranged to form a pattern, which are fitted on the rear window glass fitted to a rear window opening formed in an automobile, wherein the defogger and the antenna conductor are spaced apart from each other with a predetermined small space in a capacitive coupling relation so a reactance circuit is connected to the defogger to effect anti-resonance between the defogger and the rear window opening of the body of the automobile at the central frequency in terms of logarithmic scale of a broadcast frequency band region; a quality factor value is determined by the inductance of a choke coil in the reactance circuit and the stray capacitance between the defogger and the rear window opening of the body of the automobile so that the ratio of an input impedance to a receiver to the impedance of the antenna conductor viewed from the side of a power feeding terminal becomes 1; and a matching circuit is inserted between the power feeding terminal of the antenna conductor and the receiver so that the sum of the impedance of the antenna conductor viewed from the side of the input terminal of the receiver and the functional part as an antenna in the rear window glass exhibits a little capacitive reactance in a broadcast frequency band region.