A High Efficiency 835 MHz Linear Power Amplifier for Digital Cellular Telephony

In a next-generation digital cellular telephone transmitter, employing quadrature amplitude modulation, it is required that the post modulator amplifiers be amplitude linear so as to preserve the varying envelope component of the modulation. A conventional "class AB" linear power amplifier exhibits substantially lower average dc-to-rf conversion efficiency (typically 25%) than its "class C", constant-envelope, counterpart now special concern in portable equipment since most of the battery energy is consumed by the rf power amplifier.