Patent ID: 8736336

Claim:
A phase shifter that gives a phase to an input signal in a range from 0 degrees to 90 degrees, comprising: a 90-degree divider that divides an input signal into a signal to which a 90-degree phase is given and a signal to which no phase is given, and outputs the divided signals; a first gain-variable amplifier that outputs a signal whose amplitude is changed according to a phase control amount of the phase shifter, the first gain-variable amplifier being connected to a 0-degree side output port of the 90-degree divider; a second gain-variable amplifier that outputs a signal whose amplitude is changed according to the phase control amount, the second gain-variable amplifier being connected to a 90-degree side output port of the 90-degree divider; and a combiner that combines an output signal of the first gain-variable amplifier and an output signal of the second gain-variable amplifier, wherein an impedance of an isolation port of the 90-degree divider is variable, and the 90-degree divider is connected to a transistor through the isolation port, and an impedance between a source and a drain of the transistor can be changed according to the phase control amount.