PVT-Resilient 10–15 GHz Doherty Power Amplifier with On-Chip Power Sensing in 22-nm FD-SOI

Abstract

Sixth-generation (6G) radios require power amplifiers (PAs) that sustain high output power and efficiency under high peak-to-average power ratio (PAPR) signals and process, voltage, and temperature (PVT) variations. The Doherty PA (DPA) improves back-off efficiency through load modulation using a quarter-wavelength (λ/4) impedance inverter; however, in integrated realizations PVT drift shifts the effective inverter and matching, moves auxiliary turn-on, and distorts the intended main-path impedance trajectory from 2R<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">opt</inf> toward R<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">opt</inf>. This work presents a forward-power-aware DPA that senses the output forward-power level using an on-chip directional coupler and a complementary metal-oxide-semiconductor (CMOS) square-law power detector with root-mean-square (RMS)-equivalent calibration, and uses it to drive lookup-table (LUT)-based retuning of the output shunt-capacitor bank and the main/auxiliary cascode gate biases. Implemented in a 22-nm fully-depleted silicon-on-insulator (FD-SOI) process, circuit and electromagnetic (EM) co-simulations over 10–15 GHz show peak power-added efficiency (PAE) above 32% across the band and 6 dB back-off PAE up to ≈ 30.1% at 12.5 GHz. Across PVT corners, the proposed correction recenters the output matching condition and realigns auxiliary turn-on, recovering both peak and back-off efficiency toward the nominal Doherty trajectory. To the authors’ knowledge, this is the first 22-nm FD-SOI Doherty PA in the 10–15 GHz band incorporating forward-power-sensed PVT correction.