Radiotelephone system for motor vehicles with a group antenna

Details Radiotelephone system for motor vehicles with a group antenna Radiotelephone system for motor vehicles with a group antenna

2000-04-12

2003-06-03

Vo, Nguyen T. (Department: 2682)

Telecommunications

Receiver or analog modulated signal frequency converter

With wave collector

C455S272000, C455S275000, C342S359000, C342S383000, C343S711000, C343S704000

Reexamination Certificate

active

06574460

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a radiotelephone system for motor vehicles with a group antenna installation having a plurality of antenna elements coupled to a mobile radiotelephone with a high-frequency input
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2. The Prior Art
Motor vehicle antennas for mobile radiotelephony (e.g. GSM) in the form of group antenna system are known from German Patent DE 44 08 744.6 and have been designed heretofore exclusively as antennas with omnidirectional characteristics. This provides a preferred dimensioning for a time-invariant radiation characteristic for a permanent connection between the base station and the mobile subscriber in a moving motor vehicle. Antenna elements are typically employed for this purpose that are secured on the rear window as glued on-glass antennas and/or mounted on the roof of the vehicle. The electrically short antenna elements are necessarily associated with strong coupling to the electrically conductive body of the motor vehicle, so that the antenna properties have to be specifically selected so that the effect of the radiation properties of the antenna is taken into account.
A time-invariant radiation characteristic has a drawback in that due to the omnidirectional characteristic of the radiation required for mobile radiotelephony, no gain can be obtained through radiation focusing based on the given prevailing direction of incidence of the electromagnetic waves from the direction of the fixed station. Therefore, an antenna gain can be achieved only with the help of a focusing group antenna whose main direction of reception can be adjusted to the actual direction leading to the fixed station, and which is continually reset during driving. It has been found that even with pronounced focusing of the radiation diagram, fading occurs during reception due to multi-way propagation. Such fading has an interference effect with respect to the quality of the received signal. With digitally modulated signals, such fading and the reception interference connected therewith lead to increased bit error rates.
SUMMARY OF THE INVENTION
Therefore, the invention provides a group antenna for a moving vehicle at low cost, with improved reception quality through increased focusing in the radiation diagram, and avoids the reception interference that is associated with fading.


REFERENCES:
patent: 5619214 (1997-04-01), Lindenmeier et al.
patent: 5764185 (1998-06-01), Fukushima et al.
patent: 5848361 (1998-12-01), Edwards
patent: 6061553 (2000-05-01), Matsuoka et al.
patent: 6377213 (2002-04-01), Odachi et al.
patent: 6400318 (2002-06-01), Kasami et al.
patent: 2001/0016478 (2001-08-01), Lindenmeier et al.
patent: 2002/0025793 (2002-02-01), Meijer et al.
patent: 44 08 744 (1995-09-01), None

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