Communications: radio wave antennas – Antennas – With vehicle
Patent
1996-09-30
1998-12-15
Le, Hoanganh T.
Communications: radio wave antennas
Antennas
With vehicle
343767, 343848, H01Q 132, H01Q 1310
Patent
active
058501983
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to an antenna of the type specified in the introductory part of claim 1. An antenna of said type can be very advantageously used in the radio operation on motor vehicles for mobile radio services. Especially in the GHz-frequency range, it has the advantage of combining a low overall height with the desired directional diagram.
2. Prior Art
The invention is based on antennas of said type, as they are known from D-AS 2153 827 and D-AS 2633 757, as well as from the European patent applications EP 0176311, EP 0177362, and EP 0163454. The antennas described therein are substantially designed with an L-shaped, flat part above a conductive base surface, or as U-shaped flat antennas.
The operating principle of said antennas consists in that the have a resonance at the operating frequency, whereby the resonance is characterized by an equalized blind power balance between the magnetic blind power and the capacitive blind power, so that a substantially real or not excessively reactive impedance prevails at the intended antenna connection point. Said resonance effect is described in the substitute circuit diagram, FIG. 4 of EP 0177362 for an L-shaped antenna. With resonance of the L-structure, the blind powers of the magnetic fields forming the strong currents on and within the proximity of bridge 38 in FIG. 3 are equalized with the capacitive blind power forming the electrical fields between the surface 36 and the base plate 39.
SUMMARY OF THE INVENTION
All antennas of said type are, according to the present state of the art, monofrequent antennas, i.e., they are operated at their basic resonance frequency, which physically is a precondition for the fact that the directional diagram substantially has a round characteristic in connection with a structure above a conductive surface. However, particularly when used as a mobile radio antenna on board of motor vehicles, antennas are desired that can be used at the same time in a number of frequency ranges. An important example is the use of a mobile radio antenna both in the D-mobile radio network and in the frequency range of the E-mobile radio network at about twice the frequency (1.8 GHz). In addition, the simultaneous use of an antenna in the frequency-adjacent GPS-navigation radio service is often desired.
Therefore, the problem of the invention is to make available in connection with an antenna according to the introductory part of claim 1 the function of several frequency ranges with the help of measures that can be implemented in a simple way. Such measures are to permit a manufacture at costs as favorable as possible.
According to the invention, said problem is solved by an antenna with the features in the characterizing part of claim 1.
Exemplified embodiments of the subject matter of the invention are described in the following by reference to the drawings, in which:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows an L-shaped antenna with an almost rectangular first conductive surface above a conductive counterweight, with operating zones in a further higher-frequent frequency range shown shaded: 11=marginal zones with small current; 13=inner zone active for resonance formation; 3=current path between coupling point 3 and conductive bridge 4.
FIG. 2 shows the same antenna as the one in FIG. 1, however, with a nearly circular first conductive area and a circle segment missing.
FIG. 3 shown an antenna with a trapezoidal first conductive area above a conductive counterweight and exemplified design of the slots 10, with high input impedance at their open ends for suppressing edge currents in another higher frequency range, and with additional slots as capacitive load at the open ends, whereby the slots are inductively loaded by rectangular cutouts, so that at the open slot end on the margin of the area, a high-impedance blind resistance is adjusted in the other higher frequency range. Dashed: minimum quantity of the second conductive area.
FIG. 3a shows a highly simplified substitute
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patent: 5627550 (1997-05-01), Sanad
Hopf Jochen
Lindenmeier Heinz
Reiter Leopold
FUBA Automotive GmbH
Ho Tan
Le Hoanganh T.
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