Millimeter-Wave Wideband CMOS Power Amplifier Using Inductive-Compensation Distributed Active Transformer

This article proposes a millimeter-wave wideband power amplifier (PA) featuring an inductive-compensation distributed active transformer (DAT) fabricated using a 90-nm CMOS process. The DAT is designed with a compact size of 0.004 mm2, aiming for high power-combining efficiency (PCEFF) and wideband performance. The PA achieves a saturated output power ( $P_{\text {SAT}}$ ) of 20.6 dBm, a maximum power-added efficiency (PAEmax) of 16.7%, and a 21.1 dB small-signal gain at 60 GHz. A flat 19.6 dBm $P_{\text {SAT}}$ with PAEmax exceeding 14.6% is demonstrated within the 32–65 GHz frequency range. The PA exhibits a 3-dB gain bandwidth of 35 GHz (31–66 GHz), and the chip area, excluding pads, is only 0.025 mm2. Notably, according to the author’s knowledge, this PA with a 19.6 dBm $P_{\text {SAT}}$ showcases the widest large-signal bandwidth with a flat frequency response compared with previously reported 60 GHz CMOS high-output PAs.