Design of a $V$ -Band 20-dBm Wideband Power Amplifier Using Transformer-Based Radial Power Combining in 90-nm CMOS

Abstract

This paper presents a $V$ -band 1.2-V wideband power amplifier (PA) with a compact four-way radial power combiner in a 90-nm CMOS process. A transformer-based radial power combiner with a 1-dB insertion loss at 60 GHz and a 0.043-mm $^{\mathrm { {2}}}$ compact size is designed for high-output-power combining and wideband load-pull matching. This PA achieves the saturated output power ( $P_{\mathrm { {SAT}}})$ of 20.6 dBm, the maximum power-added efficiency ( $\textit {PAE}_{\mathrm { {max}}})$ of 20.3%, and a 20.1-dB small-signal gain ( $S_{\mathrm { {21}}})$ at 60 GHz. The PA maintains a flat 20-dBm $P_{\mathrm { {SAT}}}$ with $\textit {PAE}_{\mathrm { {max}}}$ better than 17.3% within 50–64 GHz, and it has a 3-dB bandwidth (BW) of 24.5 GHz (41.8–66.3 GHz). The chip area without pads is 0.432 mm $^{\mathrm { {2}}}$ . To the best of the author’s knowledge, this $V$ -band PA with a flat frequency response of 20-dBm $P_{\mathrm { {SAT}}}$ presents the widest large-signal BW (50–64 GHz) compared with the reported 60-GHz CMOS high-output PAs.