Communications: radio wave antennas – Antennas – With vehicle
Reexamination Certificate
1999-11-10
2001-05-15
Phan, Tho G. (Department: 2821)
Communications: radio wave antennas
Antennas
With vehicle
C343S704000
Reexamination Certificate
active
06232926
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to antenna systems. More specifically, the present invention relates to antenna systems mounted on glass windshields of vehicles.
2. Description of the Related Art
Antennas are required for virtually every wireless communication application including radio, cellular, and global positioning system (GPS) applications. Many such applications involve the use of transmitters and/or receivers mounted in vehicles. For these applications, glass mounted antennas are often used. Typically, the antenna is electrically connected to a coupling mechanism which is secured to an outside surface of the windshield of the vehicle. On the opposite side of the windshield, a second coupling device couples radio frequency energy from the antenna to the transmitter or receiver via a cable.
Unfortunately, a coupling loss is typically experienced with conventional glass mount antenna arrangements. At 800 MHz, the coupling loss may be as much as 3 decibels. At higher frequencies, the coupling loss increases substantially. Consequently, for certain high frequency applications, such as satellite radio (at 2.4 GHz), the coupling loss is expected to be unacceptably high (2-4 dB).
As these losses would make reception difficult, a need exists in the art for a system or technique for reducing the losses associated with glass mounted vehicle antennas for high frequency wireless communication applications, particularly satellite radio applications.
SUMMARY OF THE INVENTION
The need in the art is addressed by the dual coupled vehicle glass mount antenna system and method of the present invention. The inventive system is adapted for operation through any suitable partition, such as an automobile windshield, and comprises an antenna mounted on a first side of the partition for receiving a signal and a first circuit connected to the antenna. The antenna and the first circuit are mounted on a first side of the partition. In accordance with the present teachings, an arrangement is provided for supplying power to the first circuit. The output of the first circuit is coupled through the partition to a second circuit mounted on a second side thereof by a first coupling arrangement.
In the illustrative embodiment, the antenna is a radio frequency antenna, the partition is a vehicle windshield, the first circuit is an amplifier, and the arrangement for supplying power includes a second coupling arrangement. In the illustrative embodiment, the first and second coupling arrangements are coils and power is supplied to the second coupling arrangement from a direct current source by a cable. In alternative embodiments, power is supplied to the first circuit by a battery or solar cell arrangement. In the illustrative embodiment, the second circuit includes an impedance matching circuit and a transmitter or receiver depending upon the application.
The location of the amplifier on the antenna side of the windshield reduces the noise figure of the system and provides improved gained.
REFERENCES:
patent: 4835541 (1989-05-01), Johnson et al.
patent: 5289197 (1994-02-01), Lindenmeier et al.
patent: 5477232 (1995-12-01), Yamamoto
patent: 5805113 (1998-09-01), Ogino et al.
patent: 5977919 (1999-11-01), Kudo et al.
patent: 6069588 (2000-05-01), O'Neill
U.S. application No. 08/654321, Crosby, filed Jul. 1999.
Chatzipetros Argyrios A.
Ma Hien Duc
Nguyen Anh
Benman William J.
Phan Tho G.
XM Satellite Radio Inc.
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