Microwave integrated circuit.

摘要

In a microwave integrated circuit, a series circuit of an inductive element (6) and a variable capacitance element (7) is inserted between a source of a field effect transistor (5) of an initial stage circuit and ground. The capacitance of the variable capacitance element (7) is controlled by an input signal applied to an external terminal (10) so that an input impedance of the initial stage circuit is properly changed by the input signal applied to the external terminal (10). Thus, it is possible to set a system to an input matching characteristic which has both a noise matching characteristic and a gain matching characteristic which fit to a system specification.