CA2374784A1 - Variable phase-shifting rf power amplifiers - Google Patents

Abstract

Variable phase-shifting rf power amplifiers shift rf outputs at any angle up to 90, 180, or 270 degrees, respectively, while maintaining an rf output substantially constant. The variable phase-shifting rf power amplifiers include two to four field-effect transistors that are interposed between phase splitters and combiners, and that are connected in series between a source voltage and a lower voltage. Phase shifting is achieved by selectively and variably controlling amplification of the field-effect transistors. Selective and variable control of amplification is achieved by separately and variably controlling gate voltages of the field-effect transistors, whereby a difference between the source voltage and the lower voltage is used selectively by one of the field-effect transistors and selectively proportioned between two of the field-effect transistors. Phase controls generate separate and variable phase-shifting voltages, or gate voltages, in response to a variable phase-shifting voltage.