Research Overview

The growing importance of high-efficiency RF and microwave power amplifiers and circuits is tied to increased demand for wireless transmission of both data and power, relating to the mass proliferation of wireless devices. While iteration and incremental improvements to conventional architectures provide gradual performance benefits, entirely new approaches are required to address the challenges of emerging systems. In particular, as device technology evolves the design tradeoffs in high-performance power amplifiers (PAs) must be continually re-evaluated.

The primary focus of the RFPAL's research is in novel power amplifier architectures for communications that address the performance tradeoffs (such as linearity vs efficiency) in conventional designs. By manipulating low-power, phase-controlled inputs of multiple nonlinear but efficient PAs whose outputs are combined in a non-isolating network, simultaneous efficiency and wide-range output power control can be achieved. Using this approach, our group was the first develop the RF-input load modulated balanced amplifier (LMBA), and we have demonstrated multiple related techniques in this area including an octave-bandwidth LMBA. This work builds on the PI's pioneering work in RF-input outphasing (RFIO) power amplifiers, which the group has extended and implemented using novel nonlinear analog networks including in MMIC implementation. These and related nonlinear analog network techniques are supported by research in analog control and linearization, and novel integrated RF sensors to monitor operation. Our research extends to various RF applications requiring high performance, such as communications, telemetry, phased-array systems and wireless power transfer.