Active antenna in the rear window of a motor vehicle
First Claim
1. An active antenna arranged in an electrically heated rear window of a motor vehicle to receive long-, medium-, short-, and ultra-short wave broadcasts, said rear window having a boundary conductor and a set of heating elements connected via bus bars to direct current power connections, said antenna comprisingan elongated, flat antenna element arranged in the window on a free area between said set of heating elements and said boundary conductor to receive long-, medium-, and short wave signals;
- an antenna amplifier including a linear amplifying stage having a capacitive input connected to said flat antenna element for processing long-, medium- and short-wave signals, a branch circuit for processing ultra-short wave signals having an input coupled to said set of heating elements in said window acting as an antenna element for the reception of said ultra-short wave signals, and a common ground terminal connected to said boundary conductor; and
a frequency separating circuit having two inputs connected respectively to outputs of said amplifying stage and of said branch circuit to separate said long-, medium- and short-wave signals from said ultra-short wave signals and an output connected to a connector for an antenna cable.
3 Assignments
0 Petitions
Accused Products
Abstract
An active antenna for the reception of long-, medium-, short-and ultra-short wave broadcasts is arranged in a rear window of a motor vehicle equipped with a boundary conductor enclosing an array of heating elements. The reception of long-, medium- and short-wave signals is made by means of an elongated flat antenna element which is arranged in the window on a free area above or below the heating elements, and the reception of the ultra-short wave signals is effected by the array of heating elements. An antenna amplifier includes a linear amplifying stage connected to the flat antenna element, an amplifying branch circuit connected to the array of heating elements and a common ground terminal connected to the boundary conductor. A frequency separator has two inputs connected, respectively, to the output of the amplifying stage and of the branch circuit, and an output connected via an antenna cable to a conventional radio receiver.
53 Citations
26 Claims
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1. An active antenna arranged in an electrically heated rear window of a motor vehicle to receive long-, medium-, short-, and ultra-short wave broadcasts, said rear window having a boundary conductor and a set of heating elements connected via bus bars to direct current power connections, said antenna comprising
an elongated, flat antenna element arranged in the window on a free area between said set of heating elements and said boundary conductor to receive long-, medium-, and short wave signals; -
an antenna amplifier including a linear amplifying stage having a capacitive input connected to said flat antenna element for processing long-, medium- and short-wave signals, a branch circuit for processing ultra-short wave signals having an input coupled to said set of heating elements in said window acting as an antenna element for the reception of said ultra-short wave signals, and a common ground terminal connected to said boundary conductor; and a frequency separating circuit having two inputs connected respectively to outputs of said amplifying stage and of said branch circuit to separate said long-, medium- and short-wave signals from said ultra-short wave signals and an output connected to a connector for an antenna cable. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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17. An active antenna as defined in claim 1, wherein said set of heating elements is arranged between the upper and lower sides of the window and said elongated flat antenna element being situated in a free area between the upper side of the window and said set of heating elements.
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18. An active antenna as defined in claim 1, wherein the elongated flat antenna element is formed of a grid-like conductive structure.
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19. An active antenna as defined in claim 1, wherein the elongated flat antenna element is assembled of a plurality of parallel elongated conductors interconnected at the ends thereof which are connected to the amplifier stage while the opposite ends of the parallel conductors are disconnected.
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20. An active antenna as defined in claim 19, wherein the parallel conductors are applied on the window by a screen-printing process.
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21. An active antenna as defined in claim 1, wherein said branch circuit for processing ultra-short wave signals has an input which is capacitively coupled to said elongated flat antenna element, said capacitive coupling having a relatively small capacity with respect to the input capacity Cv of the amplifier so as to avoid any impairment of reception in the L-M-S wave range due to excessive capacitive loads.
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22. An active antenna as defined in claim 1, wherein said branch circuit for processing ultra-short wave signals has an input which is inductively coupled to said elongated flat antenna element via a transformer.
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23. An active antenna as defined in claim 1, wherein said signal amplifying stage for the long-medium and short wave signal has its input connected to one of the narrow sides of said elongated flat antenna elements.
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24. An active antenna as defined in claim 1, wherein a connection point of said elongated flat antenna element to an input of said signal amplifying stage for the long-medium-short wave signals and a connection of said antenna element for the ultra-short wave signals are arranged in close proximity to each other and to said boundary conductor.
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25. An active antenna as defined in claim 1, further including a bifilar choke having a impedence for long-medium-short wave range and being connected to the direct current power connections, and a distance ah between the set of heating elements and the opposite side said of elongated flat antenna element being smaller than a distance ak between said boundary conductor and the facing long side of the flat antenna element so as to maximize the long-medium-short wave signal.
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26. An antenna as defined in claim 1 wherein said elongated, flat antenna element has a transverse dimension b whose value is adjusted empirically so as to obtain an optimum signal.
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Specification