Fully Integrated Ka-Band Power Amplifier with Parallel Power Combiner using Single-Winding Transformer
Abstract
This paper presents a Ka-band linear CMOS power amplifier (PA) with a parallel power combiner using single-winding transformer to increase the output power with low loss in 65nm CMOS technology for fifth generation (5G) applications. Two differential cascode unit PAs are combined with the proposed parallel power combiner as a current combining topology. Compared with the conventional transformer power combining techniques, the proposed parallel power combiner can offer high output power with a compact die area. Upon simulation with a 28 GHz continuous-wave signal, the proposed PA achieves a saturated output power (PSAT) of 25.0 dBm, output 1-dB compression power (PO,1dB) of 22.6 dBm, and peak power added efficiency (PAE) of 34.7%, respectively. A power gain of 28.1 dB is achieved with a 3 dB bandwidth of 5 GHz. This PA achieves one of the highest figures-of-merit (FOM) among the recently reported 5G millimeter-wave (mmwave) PAs in CMOS.