Communications: radio wave antennas – Antennas – Wave guide type
Reexamination Certificate
1999-08-30
2001-11-13
Wong, Don (Department: 2821)
Communications: radio wave antennas
Antennas
Wave guide type
C343S712000, C343S756000, C343S757000
Reexamination Certificate
active
06317096
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to an antenna system for motor vehicles, in particular for the reception of television and radio broadcasts and for the data transfer via geo-stationary satellites in the frequency range greater than 10 Ghz.
2. The Prior Art
For antennas for receiving transmissions from geo-stationary satellites, the elevation angle in central Europe lies at 30 degrees. Known and customarily employed satellite receiving antennas are the parabolic mirror antennas and, to a lesser extent, the planar antennas. Now, if one wanted to arrange somewhere on the body of a motor vehicle a parabolic mirror antenna with the geometry and size required for adequate gain, this would not be accepted according to current design ideas and for aerodynamic reasons.
Planar antennas are more compact; however, they are just as little suitable with their radiation lobes disposed orthogonally relative to the aperture as well. If one were to integrate a planar antenna, for example in a horizontal position in the roof of a vehicle, the direction of radiation would be wrong. If one would position it with the correct elevation, one would have the same problems as with the parabolic mirror antennas.
In addition, an antenna with directional characteristic arranged in or on the vehicle is also required to continually react to changes in the direction of radiation in accordance with the constant changes in direction occurring when the vehicle is in operation.
Antennas with directional characteristic are known from the field of radar technology where an omnidirectional radiation effect is achieved by cintinuously rotating the emitter or reflector. Such antennas combine the high, or at least adequate gain achievable with the directional effect, with an azimuth scanning of 360 degrees. The antenna, in most cases a parabolic mirror antenna, is rotated with mechanical means with a constant speed and direction.
However, said principle is not suitable for motor vehicles, in particular not for passenger cars because of the form in which the antenna is constructed. Furthermore, one needs to think of the relatively high rotational speeds at which the system would have to rotate for satellite reception, as well as of the expenditure connected therewith.
In central Europe, the reception of signals from geostationary satellites by the motor vehicle has been possible heretofore only by parking the vehicle and then extending or setting up a satellite antenna of the described type and then aligning it like a stationary antenna by hand or automatically depending on the degree of comfort offered by the equipment. This is customarily done, for example in connection with recreational motor vehicles (RV's).
SUMMARY OF THE INVENTION
The purpose of the present invention is to permit the mobile reception of television and radio broadcasts and of data of geostationary satellites independently of the operating condition of the vehicle. The invention is based on the problem of realizing for motor vehicles an antenna arrangement for the frequency range of greater than 10 Ghz with quasi-omni-radiation in the horizontal radiation diagram at an azimuth scanning of 360 degrees. The antenna arrangement is to be integrated in the structure of the vehicle in such a way that it is not visually noticeable.
Said problem is solved with the features specified in the main claim. The dependent claims contain preferred design variations and details.
By bundling a multitude of individual emitters with high packing density on a surface, the invention provides an overall compact structure. The individual emitters all have the same elevation angle, which is equal to the elevation of the overall arrangement. The required receive output is assured by a defined number of individual emitters depending on the density of the power flux, with the apertures of said emitters being added up.
With mechanical rotational motion of the arrangement, for example if all individual emitters are mounted with the same direction of radiation on a base plate intermittently moving about an axis, the number of emitters actually directed at the signal source can be equal to the total number of emitters.
With electronic rotation, groups have to be formed from the total number of emitters which, in case of reception, each supply the required gain on their own, and whose directional characteristics add up to the full circle, with a certain overlap in each case.
The basis of the direction-selective reception with intermittent change of the direction of radiation as defined by the invention are the diversity principle as well as the combined urilization of a gyromagnetic sensor and the global positioning system (GPS), by which means it is possible to detect and compensate changes in the direction of travel of the vehicle and thus the azimuth angle for the antennas with respect to a selected satellite. With the gyromagnetic sensor and with the support of the GPS-unit, a control signal for a change of the receive parameters is generated when the driving direction is changed. The diversity circuit, when the actual receive quality is reduced, additionally scans the environment of the direction of radiation and the group of emitters switched to reception, and, when the reception is falling short of a threshold value, reverses to a more favorable group of emitters. This applies to the variation of electronic rotation. With mechanical rotation, a control signal is generated for the motor of the base plate, and the system swings into the new receive direction by mechanical rotation.
The advantages of the invention are obvious: Most of all, a possibility was found for assuring a stable reception of transmissions from geostationary satellites in the moving vehicle also under conditions of low geographic elevation, for example in central Europe. The spatial dimensions of the antenna arrangement as defined by the invention are still within acceptable limits even under unfavorable conditions, i.e. low gain of the individual emitter along the edge of the supplied region and thus a high number of required emitters, and can be realized also on the average types of passenger motor vehicles. This applies even under the precondition that the system has to assure at least 30 dBi antenna gain.
A further advantage consists in that the total or overall arrangement can be divided into sectors or segments with emitter groups which are integrated in different structural parts of the body and connected via a central management. This provides for high variability of association and integration of the antenna units.
The principle as defined by the invention is shown in the present claims and exemplified embodiments in variations and details, by which the function and the advantages have already been tested and demonstrated. However, this does not mean that the idea of the invention does not also comprise further designs and variations. Conceivable is mainly also the integration in vertical elements of the body such as the side parts or, for example in a bus, the vertical arrangement behind the large-sized windowpanes inclusing the front and the rear windowpanes, where antenna systems such as the flat planar antennas switched or connected together as defined by the invention are conceivable as well. Planar antennas, which are rectangular in most cases, failed to gain successful acceptance for home use; however, they may be found to be advantageous for certain motor vehicles because of their simple construction and possible low mass.
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patent: 0 810 685 (19
Aminzadeh Mehran
Bucksch Georg
Daginnus Michael
Denn Walter
Schafmeister Meinolf
Collard & Roe P.C.
FUBA Automotive GmbH
Tran Thuy Vinh
Wong Don
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