WIDEBAND CONTINUOUS MODE POWER AMPLIFIERS FOR OUTPHASING WIRELESS TRANSMITTERS

Abstract

This thesis aims to demonstrate the bandwidth and efficiency enhancement techniques for radio frequency (RF) power amplifiers (PAs) at the peak as well as at saturated output power to handle the complex modulated signals complying the modern standards efficiently. In this context, the thesis focuses on two main directions. The first is the bandwidth enhancement technique for waveform engineered PA modes such as class F. In this, the design space of broadband and multi-octave continuous class F PAs are investigated using a nonlinear embedding model to provide feasible load impedances over a wide frequency range of operation. This analysis is beneficial from the PA designer's point of view as it solves the major problem related to the realization of a feasible matching network over wide bandwidth. The second work of this thesis focuses on the bandwidth and efficiency enhancement technique at backoff power levels for high peak to average power ratio (PAPR) signals. For backoff efficiency enhancement, the reconfigurable Chireix combiner design technique for multiband outphasing transmitters is presented. The proposed scheme enables high backoff efficiency over multiple frequency bands to make the outphasing transmitter useful for multi-band/multi-standard software defined radio (SDR) applications.