A Compact Octave Tunable Switched-Power-Combining PA

Abstract

This paper presents a switched-power-combining RF power amplifier (PA) architecture, using evanescent-mode resonators as input splitters and output combiners. The input resonator also provides proper input matching to the transistor, eliminating the need for an input matching network, which reduces the overall size of the PA. The external couplings into the resonators are switchable to allow for activating one, two, or all three sub-PAs, depending on the power requirement. This results in a higher Output Backoff (OBO) efficiency, compared to a single PA. The presented concepts for the proposed architecture are supported by theoretical analysis and experimental validation. The implemented PA is based on Class-E sub-PAs, operates in the 1.2-2.4 GHz range, provides 36-40 dBm output power, and occupies an area of 41 × 82 mm2. Compared to the state-of-the-art amplifiers operating at this frequency range, this resembles an average of 80% reduction in size.

Keywords

• Power amplifier (PA)
• power-combining
• switched path
• GaN
• tunable amplifier
• wideband