Patents by Inventor Hiroji Shoyama

Hiroji Shoyama has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 4219779
    Abstract: 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.
    Type: Grant
    Filed: April 17, 1978
    Date of Patent: August 26, 1980
    Assignee: Hitachi, Ltd.
    Inventors: Keiro Shinkawa, Hiroji Shoyama, Chuichi Sodeyama, Mitsuhisa Shinagawa
  • Patent number: 4211977
    Abstract: 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.
    Type: Grant
    Filed: February 15, 1977
    Date of Patent: July 8, 1980
    Assignee: Hitachi, Ltd.
    Inventors: Keiro Shinkawa, Hiroji Shoyama, Chuichi Sodeyama
  • Patent number: 4187476
    Abstract: 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.
    Type: Grant
    Filed: January 30, 1978
    Date of Patent: February 5, 1980
    Assignee: Hitachi, Ltd.
    Inventors: Keiro Shinkawa, Hiroji Shoyama, Chuichi Sodeyama