A D-Band Variable-Gain Balanced Power Amplifier with 36% FBW, 18.2 dBm PSAT and Reconfigurable Adaptive Bias in 22-nm FD-SOI

This paper presents a wideband variable-gain balanced power amplifier (VGPA) for D-band applications in 22nm FD-SOI. Guanella transformers are employed in both the power combiner and the stacked amplifier stages for low-loss and broadband matching, with their center tap utilized for supply feed and current steering. An adaptive bias network boosts the output referred compression point (OP1dB) and enables reconfiguration of the VGPA to maximize either signal bandwidth or linearity. The proposed VGPA achieves a small-signal peak gain of 22.5 dB with a 3-dB fractional bandwidth (FBW) of 36% centered at 128.5 GHz, and a tuning range of 15 dB. The maximum measured saturated output power (PSAT), OP1dB, and peak power-added efficiency (PAE) are 18.2 dBm, 16.6 dBm, and 10%, respectively. The maximum measured data-rates are 20 Gb/s with 16-QAM in the high-BW configuration and 12 Gb/s with 64-QAM in the high-linearity configuration.