| 摘要 |
PROBLEM TO BE SOLVED: To suppress a reflective power to a prestage amplifier in a microwave receiver having a plurality of amplifiers, while destruction and deterioration of a poststage amplifier thereof is prevented via a small protection circuit when a microwave signal of large power is inputted. SOLUTION: The protection circuit is inserted and connected between an output end of the prestage amplifier and an input end of the poststage amplifier in the microwave receiver according to the present invention. The protection circuit includes a transmission line, a first resistor, a diode, a second resistor, and a third resistor. The transmission line is of about 1/4 wavelength at its operating frequency from its input terminal to its output terminal. One end of the first resistor is connected to the input terminal. A cathode terminal is connected to the other end of the first resistor, and an anode terminal of the diode is grounded. The second resistor is connected between a bias terminal and the cathode terminal of the diode, The third resistor is connected between the cathode terminal of the diode and a gate bias circuit. COPYRIGHT: (C)2011,JPO&INPIT
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