A Compact Wideband GaN Fully Distributed Efficient Power Amplifier

This paper presents the design of a wideband fully distributed efficient power amplifier (FDEPA). The distributed structure is applied to both the auxiliary and main power amplifiers (PAs). This approach replaces the complex and bandwidth-limited input matching networks (IMNs) and phase alignment networks with artificial transmission lines (ATMLs), simplifying the design and saving chip area. A prototype GaN FDEPA has been fabricated with a chip size of only 3.6 mm x 2.55 mm. Measurement results show that, across the 3.1-5.5 GHz band (56% fractional bandwidth), the amplifier achieves a saturation output power of 40.3-41.6 dBm, or 1.16-1.58 W/mm² power density. The associated saturation drain efficiency (DE) is around 46%-55.4%, and the 9-dB PBO DE is around 30.3%-47.2%. Under 100-MHz OFDM signal excitation with an 8.5-dB PAPR, the ACPR of the FDEPA is enhanced to -49.5/-49.5 dBc at 3.7 GHz and -47.7/-48.8 dBc at 4.9 GHz. © 2024 IEEE.