Hitachi, Ltd.

Hiroji Shoyama

Keiro Shinkawa

Chuichi Sodeyama

Mitsuhisa Shinagawa

A self-oscillating mixer circuit to operate mainly at SHF band comprises a single-gate FET and a micro strip line. The gate or source terminal of the FET is connected to a radio frequency signal input line. A feedback path is provided between the drain terminal and the gate or source terminal. An intermediate frequency output line is connected to the drain electrode of the FET. A dielectric resonator is coupled to the radio frequency signal input line to improve the stability of an oscillator frequency and to suppress leakage of a local oscillator signal.

Self-oscillating mixer circuit

A mixer circuit employing a distributed constant circuit using a strip line includes a strip line for applying a high frequency signal and a local oscillation signal to a diode. The strip line is provided with a filter for exclusively blocking the local oscillation signal and a filter for exclusively blocking the high frequency signal. The strip line further includes a line which acts as a shortcircuit for an intermediate frequency signal and as an open impedance for the high frequency signal and the local oscillation signal.

Mixer circuit arrangement

An SHF band oscillation circuit using a field effect transistor (FET) having a feedback path between gate and drain or source and a resonator connected to the gate. Impedances connected to the respective terminals of the FET comprise microstrip lines. A gate bias circuit includes a temperature-sensitive semiconductor device so that a gate bias is changed with the change in ambient temperature. In this manner, the change of oscillation frequency which would otherwise occur by the change of the ambient temperature is compensated. The resonator connected to the gate comprises a dielectric resonator to further stabilize the oscillation frequency.

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Yokohama, Japan

Hiroji Shoyama