Patent ID: 7019700

Claim:
A glass antenna system for a vehicle, comprising: a rear window glass sheet; a defogger formed on a lower part of the glass sheet, the defogger having horizontal heater strips and positive and negative bus bars for feeding an electric current to the heater strips; and an antenna formed on an upper part of the glass sheet, the antenna comprising: (a) a feed point located at a position that is adjacent to a top or side member of a metal rear window frame of the vehicle, when the rear window glass sheet is fixed to the rear window frame; (b) a first horizontal strip connected to the feed point, the first horizontal strip being adjacent to the top member of the rear window frame, when the rear window glass sheet is fixed to the rear window frame, to achieve a capacitive coupling with the rear window frame, the first horizontal strip extending across a vertical center line of the glass sheet to an end point such that a length defined from the feed point to the end point of the first horizontal strip is equal to “αλ/2” where λ represents a wavelength of a received frequency and α represents a wavelength shortening coefficient of 0.4 to 0.6; (c) a first vertical strip vertically extending from the end point of the first horizontal strip toward the heater strips; (d) a first return strip horizontally extending from a lower end of the first vertical strip toward a side of the feed point, the first return strip being away from the heater strips such that a distance between the first return strip and a top of the heater strips is equal to one-third or more of a distance between the top of the heater strips and the top member of the rear window frame when the rear window glass sheet is fixed to the rear window frame; and (e) a second return strip horizontally extending from a middle point of the first vertical strip toward the side of the feed point, wherein a total length of the first vertical strip and the first return strip is equal to “βλ/4” where λ is defined as above and β represents a wavelength shortening coefficient of about 0.7.