Abstract: The invention relates to a digitally controlled variable power amplifier for radio frequency signals. The power amplifier has application to power amplifiers for driving the individual elements of a phased array radar system in which accurate tapering of the power supplied to individual antenna elements is desired for sidelobe control in the face of jamming and other circumstances. In this application, each power amplifier must maintain a stable phase transfer response and should remain at a high power transfer efficiency at each reduced power setting. This performance is achieved by the use of a power transistor of a segmented dual gate design. The segments of the second gate electrode are of digitally scaled widths and are individually energized to activate digitally scaled regions of the transistor. These regions are operated in a saturated class "A" mode in all power settings to achieve the desired stable phase transfer response and high power added efficiency.