A Compact E-Band Load-Modulation Balanced Power Amplifier in 65-nm CMOS

A compact E-band Doherty-like load-modulated balanced power amplifier (LMBA) with coupled transmission-line (CTL) output network is proposed and implemented in 65-nm CMOS process. The proposed CTL simplifies the design of output matching networks and improves the quality factor of matching networks. A single transmission line (TL) is inserted between the main power amplifier (PA) path and the auxiliary PA path to tune the phase difference, eliminating the need of an additional extra phase shifter (PS) circuity which can be lossy and area-consuming in E-band. The proposed LMBA achieves a measured peak power-added efficiency (PAE) of 34.9%, a saturated output power (Psat) of 22.1-dBm, and an OP1dB of 21.1-dBm with a maximum power gain of 17.8-dB. At 6 dB power back-off (PBO) from Psat, the PA achieves a PAE of 12.1%. Furthermore, modulation measurement shows that the proposed E-band PA supports 3.6-Gb/s 64-quadrature amplitude modulation (QAM) and 3.2-Gb/s 256-QAM modulated signals with error vector magnitudes (EVMs) of -31.1/-29.9 dB and average output powers of 13.1/11.2-dBm, respectively. The core area of the PA is only 0.28 mm2.