Patent Number: 6,297,696

Title: Optimized power amplifier

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.

Inventors: Abdollahian; Mehdy (Westford, MA), Griffiths; James R. (Londonderry, NH), Tewksbury; Theodore L. (Boston, MA)

Assignee: International Business Machines Corporation

International Classification: H03F 3/60 (20060101); H03F 003/28 ()

Expiration Date: 10/02/2018