Amplitude modulator, selector switch, high frequency transmitting/receiving apparatus including the same, and radar apparatus, and radar apparatus-mounting vehicle and radar apparatus-mounting small ship

摘要

An amplitude modulator in which modulator characteristics can be tuned is provided. In an amplitude modulator, between two high frequency transmission lines for transmitting high frequency signals, is provided a PIN diode which is a high frequency modulating element that modulates a high frequency signal input from one of the high frequency transmission lines and outputs the high frequency signal to an output terminal of the other of the high frequency transmission lines. A bias supply circuit includes a trimmable chip resistor which is a variable resistor for adjusting a bias current flowing through the PIN diode. By adjusting a resistance value, the bias current flowing through the PIN diode is controlled, so that it is possible to tune the modulator characteristics.