Patent ID: 6084486
Filing Date: 2000-07-04
Classification: H03H

Abstract:
A filter comprising:an inductor;a first variable capacitance diode;a second variable capacitance diode having nearly identical characteristics as said first variable capacitance diode, said second variable capacitance diode is connected in series to said first variable capacitance diode with polarities thereof reversed;a control terminal for applying voltage to said first variable capacitance diode and said second variable capacitance diode;an input terminal;an output terminal; anda signal line between said input terminal and said output terminal;said first variable capacitance diode and said second variable capacitance diode are coupled between said signal line and ground, said inductor is coupled between a point of connection of each ends of said first variable capacitance diode and said second variable capacitance diode and said signal line, and a second inductor is coupled between a point of connection of each ends of said first variable capacitance diode and said second variable capacitance diode and ground;wherein a cutoff frequency of said filter is controllable by changing the voltage applied to said control terminal.