Patent ID: 7336143

Claim:
A variable delay line comprising: a hybrid coupler having an input terminal for receiving an input signal, first and second output terminals for outputting first and second output signals, respectively, which are 90° out of phase with each other, and an isolation terminal for outputting a reflected signal based on said first and second output signals as a third output signal; and first and second reactance parts connected respectively to said first and second output terminals, said first and second reactance parts having substantially the same reactance, said first and second reactance parts comprising first and second variable-reactance devices and first and second resonant circuits, respectively, said first and second variable-reactance devices comprising respective first and second series-connected circuits of first and second capacitors having substantially the same capacitance, and first and second variable-capacitance devices, each of said resonant circuits being connected between said respective variable-reactance device and a common ground, and said variable-reactance devices having substantially the same reactance.