Abstract: A phase shifter, which can switch between a phase delay circuit and a phase leading circuit consisting of inductors and capacitors, is constituted by disposing FETs having inductors or capacitors arranged in parallel with the source and drain electrodes of each FET connected and controlling a bias voltage to be applied to the gate electrodes of the FETs to switch between the on and off conditions of the FETs. Thus, a phase shifter obtained has a small frequency characteristic.

Abstract: There is provided a small size phase shifter which can shift a phase by 180 degrees wherein the accuracy of preset phase is less dependent on frequency. The phase shifter comprises first to fourth switches provided between a first line pair and a second line pair. By turning the first and second switches ON and the third and fourth switches OFF, a signal inputted to the first line pair is outputted from the second line pair in phase. By turning the first and second switches OFF and the third and fourth switches ON, a signal inputted to the first line pair is outputted from the second line pair out of phase. A small-size phase shifter which has the accuracy of preset phase less dependent on frequency can then be obtained.