High-Q Coupled-Coil Power-Combining Technique for Fully Integrated CMOS Power Amplifier

This paper presents a stacked hard-switching power amplifier (PA) integrated with a novel power-combining structure. The PA topology requires no RF chokes and employs a unique combination of SLVT PMOS and HVT NMOS transistors to minimize the active circuit footprint. A high-Q non-inverting delta coupled coil with negligible amplitude and phase imbalance is used as part of the power combiner. Design equations for the combiner are derived with its I/O ports matched to any given complex impedances, hence requiring no matching circuit. Designed in 22nm FDSOI CMOS process, the PA achieves 21.6 dBm output power and 58% drain efficiency at 5.4 GHz with a 3 dB output power bandwidth of 39%.