Patent ID: 6888508

Claim:
An active broad-band reception antenna having a passive antenna part ( 1 ), with first and second output connectors ( 18 , 1 â€²) with a frequency dependent effective length le for use on a vehicle wherein the internal amplification of its active antenna is reduced when a predetermined reception signal level is exceeded, comprising; a high-impedance, high frequency control connector ( 15 ) connected to the first connector ( 18 ) of the passive antenna part ( 1 ); at least one amplifier circuit ( 21 ) having at least one three-pole amplification element ( 2 ), with its input coupled to said control connector ( 15 ); at least one transformation network ( 31 ) disposed within said amplification circuit ( 21 ) and comprising an adjustable transformation member ( 34 ) having at least one adjustable electronic element ( 32 ) coupled to the output ( 24 ) of said at least one three pole amplification element ( 2 ) for adjustable lowering of the reception signal level; and at least one low loss filter ( 3 ) having its input ( 6 ) coupled to said adjustable transformation member ( 34 ), and an output connected to said network ( 31 ), said transformation network ( 31 ), having an input admittance ( 7 , 7 â€²) at its input ( 24 ) designed for receiving low intensity, high-frequency reception signals ( 8 ), and loaded with a continuing circuit at its output ( 4 ); a control circuit ( 33 ) coupled to the output ( 4 ) of said amplification circuit ( 21 ) and producing a control signal ( 42 ) that is fed back to said adjustable transformation member ( 34 ) in said transformation network ( 31 ) for producing a counter-coupling and linearizing effect in the high-frequency connection between said amplification element output ( 24 ) and the second connector ( 1 â€²) of the passive antenna part ( 1 ), so that said input admittance ( 7 â€²) of said transformation network ( 31 ) is reduced when there is a reduction of the level of the high-frequency reception signal ( 8 ).