A Millimeter-Wave Variable-Gain Power Amplifier With P₁ dB Improvement Technique in 65-nm CMOS

A millimeter-wave (MMW) variable-gain power amplifier (VGPA) with $P_{\mathrm {1\,dB}}$ improvement technique is proposed. The proposed VGPA consists of a postdistortion power amplifier (PDPA) and a variable-gain amplifier (VGA), for realizing high output power 1-dB compression point ( $P_{\mathrm {1\,dB}}$ ) and variable gain, respectively. To improve the $P_{\mathrm {1\,dB}}$ performances, a postdistortion technique with peaking-mode gain response shaping is proposed. This new approach has less amplitude-to-amplitude (AM–AM) distortion. Fabricated in 65-nm CMOS process, the proposed VGPA achieves 16-dBm output $P_{\mathrm {1\,dB}}$ with 29.5% power added efficiency (PAE) and 16.7-dBm saturated output power ( $P_{\mathrm {sat}}$ ) with 34% peak PAE. The maximum gain reaches 33.1 dB with 3-dB bandwidth from 23.1 to 29 GHz and 31.1-dB dynamic range of gain adjustment.