Antenna arrangement
First Claim
1. A matching circuit having a signal input and a signal output, the matching circuit being operative to receive on its signal input an MF or LF signal output of a screen antenna (70) and for feeding a signal though its signal output via a capacitive feeder (14) to a radio receiver (10), the matching circuit comprising components which operate in conjunction with capacitance in components connected to the signal input and the signal output characterised in that the matching circuit and capacitances in components connected to the signal input and the signal output form an internally-loaded band-pass filter network having a pass-band which covers a range of frequencies to be received by the receiver (10), and present a predominantly capacitive output to the receiver over the pass band.
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Accused Products
Abstract
A matching circuit for a screen antenna receives on its signal input an MF or LF signal output of a screen antenna and feeds a signal though its signal output via a capacitive feeder to a radio receiver. The matching circuit includes components which operate in conjunction with capacitances in components connected to the signal input and the signal output to form an internally-terminated band-pass filter network having a pass-band which covers a range of frequencies to be received by the receiver.
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Citations
14 Claims
- 1. A matching circuit having a signal input and a signal output, the matching circuit being operative to receive on its signal input an MF or LF signal output of a screen antenna (70) and for feeding a signal though its signal output via a capacitive feeder (14) to a radio receiver (10), the matching circuit comprising components which operate in conjunction with capacitance in components connected to the signal input and the signal output characterised in that the matching circuit and capacitances in components connected to the signal input and the signal output form an internally-loaded band-pass filter network having a pass-band which covers a range of frequencies to be received by the receiver (10), and present a predominantly capacitive output to the receiver over the pass band.
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13. A method of optimising a matching circuit for use between an output of a screen antenna and a coaxial feeder (14) connected to a radio receiver (10) for reception of signals over a defined band in the LF and MR range the method characterised by the steps of:
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(a) devising a first circuit (FIG.
3) having optimal voltage transfer from a voltage source in series with an impedance to an open circuit over the defined band;
(b) deriving the dual (FIG.
4) of the base circuit being a bandpass filter circuit arranged such that optimal current flows in a short circuit, its signal output being derived across an output capacitor of value substantially equal to or greater than the capacitance of the feeder, the capacitor being the last element in the bandpass filter circuit;
(c) constructing a circuit (72) omitting the output capacitor, the feeder (14) being connected in substitution for the output capacitor whereby an output of the circuit is derived across the capacitance of the feeder (14). - View Dependent Claims (14)
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Specification