Patents by Inventor Theodore L. Tewksbury

Theodore L. Tewksbury 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: 6297696
    Abstract: Apparatus and method for reducing reflected power in a radio frequency amplifier. A first directional coupler divides the radio frequency signal to first and second quadrature signals. First and second amplifiers amplify each of the quadrature signals. A second directional coupler combines signals from the amplifiers to produce a combined signal. A third directional coupler samples a portion of the reflected power received on the second directional coupler output. A control signal is derived from sampling the reflected power. A variable load impedance connected to the remaining output port of the second directional coupler has an impedance value which changes with respect to a control signal and the impedance is varied so as to substantially match the impedance received by the first output port.
    Type: Grant
    Filed: June 15, 2000
    Date of Patent: October 2, 2001
    Assignee: International Business Machines Corporation
    Inventors: Mehdy Abdollahian, James R. Griffiths, Theodore L. Tewksbury