Independently fed AM/FM heated window antenna
First Claim
1. An antenna and feed circuit for coupling an electromagnetic signal to a radio apparatus and comprising:
- a) an antenna mounted to a window formed in an aperture through a conductive sheet connected to a ground, the antenna also being a resistive heating element and having first and second terminals for connection to an electrical source of heating current;
b) an RF transformer capable of passing and inductively coupling RF signals, the transformer having a primary winding connected between said first antenna terminal and said ground and having a secondary winding connected between said ground and said radio apparatus for feeding lower frequency signals; and
c) a transmission line connected through a capacitor between said antenna and said radio apparatus for feeding higher frequency signals.
1 Assignment
0 Petitions
Accused Products
Abstract
A radio antenna formed in a vehicle window is coupled with a radio apparatus using an RF transformer having a primary winding connected between the antenna/heating element and the vehicle body and a secondary winding connected between the vehicle body and the radio apparatus. Preferably, the transformer also has a third winding which connects to a second antenna/heating element terminal for completing the electrical supply current circuit through the heating element. The primary winding and third winding are wound with identical turns and connected so the electrical heating current flowing through each winding generates a flux equal in magnitude and opposite in direction to the other to cancel the flux resulting from the heating current and thus prevent saturation of the transformer. Shunting capacitors cause RF currents through the primary winding and third winding to be equal in magnitude and in phase.
28 Citations
9 Claims
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1. An antenna and feed circuit for coupling an electromagnetic signal to a radio apparatus and comprising:
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a) an antenna mounted to a window formed in an aperture through a conductive sheet connected to a ground, the antenna also being a resistive heating element and having first and second terminals for connection to an electrical source of heating current; b) an RF transformer capable of passing and inductively coupling RF signals, the transformer having a primary winding connected between said first antenna terminal and said ground and having a secondary winding connected between said ground and said radio apparatus for feeding lower frequency signals; and c) a transmission line connected through a capacitor between said antenna and said radio apparatus for feeding higher frequency signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification