Fujitsu Corporation

Fuminori Sakai

Hidetake Suzuki

A phase inverter includes first, second, third and fourth terminals, a first coupling circuit coupled between the first and second terminals, a second coupling circuit coupled between the second and third terminals, a third coupling circuit coupled between the third and fourth terminals, and a fourth coupling circuit coupled between the first and fourth terminals. The first to fourth terminals and the first to fourth coupling circuits are arranged into a ring. The first coupling circuit is of a type different from a type of the fourth coupling circuit. The second and third coupling circuits are identical in type. Two output signals having a phase difference of 180.degree. are drawn from the second and fourth terminal when an input terminal is applied to the first terminal, and an output signal is drawn from the first terminal when two input signals having a phase difference of 180.degree. are applied to the second and fourth terminals. A push-pull amplifier using two phase inverter each having the above-mentioned configuration is also provided.

Phase inverter and push-pull amplifier using the same

A microwave power amplifier includes first and second circuits each having first, second, third and fourth terminals. Each of the first and second circuits has functions of distributing an input signal to the second and third terminals and generating first and second output signals 180.degree. out of phase with each other through the second and third terminals, respectively, adding a first pair of 180.degree. out-of-phase input signals to the second and third terminals and outputting a first resultant signal through the first terminal, and adding a second pair of in-phase input signals to the second and third terminals and outputting a second resultant signal through the fourth terminal. The microwave power amplifier further includes a first amplifier circuit connected between the second terminal of the first circuit and the third terminal of the second circuit, a second amplifier circuit connected between the third terminal of the first circuit and the second terminal of the second circuit, and a feedback circuit connected between the fourth terminal of the first circuit and the first terminal of the second circuit. The first terminal of the first circuit serves as an input terminal of the microwave power amplifier, and the fourth terminal of the second circuit serves as an output terminal of the microwave power amplifier.

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Yokohama, Japan

Fuminori Sakai