A Highly Efficient and Compact Pulse-Modulated Class-E RF Power Amplifier with 24.2-dBm Psat and 40% Peak PAE for NB-IoT and GNSS in 22nm FD-SOI CMOS

This paper presents a pulse-modulated Class-E RF digital power amplifier (DPA) operating in the 1.4 GHz to 1.9 GHz frequency range, targeting GNSS and NB-IoT frequency bands. The proposed DPA achieves a saturated output power (Psat) of 24.2 dBm and a peak power-added efficiency (PAE) of 40% with the DPA core occupying 0.56mm². It supports the transmission of GMSK, BPSK, π/4-DQPSK and QPSK modulated signals using a polar transmitter configuration. The pulse modulation approach enhances average power efficiency, delivering an average PAE of 37.7% with an error vector magnitude (EVM) of 0.7% for GMSK signals at a data rate of 30 Msymbols/s. For π/4-DQPSK signals at the same data rate, the DPA achieves an average PAE of 36.7% and an EVM of 7.7%. With the integration of a power combiner, the output power dynamic range can be extended by 9.2 dB while the average PAE of the proposed design outperforms by 4% the conventional Class-E RF PA. The chip is fabricated using GlobalFoundries’ 22nm FD-SOI CMOS technology (GF22FDX).