Patent ID: 8022342

Claim:
A microwave source system comprising: a resistor attached to one of a plurality of amplifiers such that the resistor is in direct contact with a surface section of an outer packaging body of one of the plurality of amplifiers to thereby receive heat generated by one of the plurality of amplifiers to thereby generate thermal noise power; a filter means which receives an input of the thermal noise power generated by the resistor and extracts thermal noise power in a predetermined microwave frequency band from the thermal noise power; the plurality of amplifiers including: a first amplifier which has a controllable gain and amplifies microwave power, which is the thermal noise power extracted by the filter means; and a second amplifier which amplifies the microwave power output from the first amplifier at a predetermined gain and outputs the amplified microwave power as microwave power to be supplied to the outside, and a control means which detects the intensity of the microwave power output from the first amplifier and controls the gain of the first amplifier in such a way as to maintain the microwave power output from the first amplifier at a predetermined constant intensity according to the detected intensity.