Phase shifter having switchable high pass filter and low pass filter paths and impedance adjustment circuits

Abstract

A phase shifter with a low insertion loss in which impedance mismatch at a point in rear of a high-pass filter or a low-pass filter in the signal flow direction is reduced and difference in insertion loss or phase shifting error across a high-pass filter- low-pass filter is suppressed. A single pole double throw switch, provided on the input side, and another single pole double throw switch, provided on the output side and operatively linked to the single pole double throw switch, are changed over between a low-pass filter and a high-pass filter. An impedance adjustment circuit, provided between an input terminal and the single pole double throw switch, is made up by a capacitor, connected across the input terminal and a single pole side junction of the single pole double throw switch, and an inductor connected across the input terminal and ground.