AUTOMATIC GAIN CONTROLLER FOR MICROWAVE

PROBLEM TO BE SOLVED: To attain an automatic microwave gain controller prevented from being influenced by the characteristic dispersion and packaging position dispersion of microwave detecting diodes. SOLUTION: The controller is composed of a signal amplifier 1, a directional coupler 2 connected to one terminal side of the amplifier 1, a microwave detecting diode 3 connected to one end of the coupler 2, a bias supplying circuit 6 capable of supplying DC bias voltage to the diode 3 and adjusting bias voltage, a DC amplifier 7 for amplifying voltage obtained by adding microwave detecting output voltage from the diode 13 and bias voltage from the circuit 6, and a variable attenuator connected to the other terminal side of the amplifier 1. The variable amplifier controls the attenuation quantity of a signal outputted from the other terminal side of the signal amplifier based on the output voltage of the amplifier 7.