INPUT MATCHING CIRCUIT AND METHOD FOR ADJUSTING THE SAME

摘要

An input matching network in an input circuit of an amplifier comprises a basic input matching circuit including a serial inductance, a strip line of an approximately quarter wavelength connected in series to the basic matching circuit, and a parallel capacitance including an open stub connected between the strip line and the basic input matching circuit. An electrical length of the open stub is selected such that a phase angle of a signal source reflection coefficient as viewed from the amplifier is larger than a mean value of manufacturing variations of a phase angle of an optimum signal source power reflection coefficient of the amplifier. By shortening the electrical length of the open stub by cutting it by a laser, a matching point can be adjusted to comply to substantially entire distribution of the manufacturing variations of the optimum signal source power reflection coefficient of the amplifier.