A Frequency-Tunable GaN Switching Power Amplifier with Digital Pulse Encoding

Abstract—We present a highly efficient, all-digital GaN-based power amplifier (PA) for compact, frequency-agile transmitters. Using a look-up-table (LUT) based pulse encoder (PE) and a differential input of 1 Vpp, the PA achieves peak system efficiencies at peak output powers of 62% at 37.7dBm and 54% at 37dBm for 1 GHz and 2 GHz carriers respectively. At 6.5 dB back-off, system efficiencies of 27.3% and 20% are achieved respectively. One- and two-tone measurements confirm linear operation with negligible memory effects for bandwidths (BW) up to 20 MHz. This architecture replaces conventional analog blocks with encoders and switching PAs, providing a scalable solution for FPGA or ASIC implementations of fully digital, energy-efficient transmitter chains.