A Compact Dual-Mode Dual-Band CMOS Power Amplifier Covering 5G FR1 and FR2

This article presents a dual-mode, dual-band power amplifier (PA) capable of covering both the fifth-generation (5G) FR1 and FR2 bands for 5G user equipment driver applications. The common-mode (CM) path, often overlooked in a typical differential-mode (DM) CMOS PA, is analyzed and utilized as an alternative path to cover a second frequency band. A universal topology is proposed for the utilization of both DM and CM in PA and other RF circuits. By assigning the millimeter-wave (mm-Wave) and sub-7 GHz bands to DM and CM paths, respectively, this PA achieves coverage of both 3.5 and 27 GHz bands with only one amplifying stage and consequently a compact layout. On the DM path, the proposed PA achieves a ${P}_{1{\text{dB}}}$ and ${\mathrm {PAE}}_{1{\text {dB}}}$ of 18.1 dBm and 32.4% at 24 GHz, while on the CM path, the corresponding performance is 15.3 dBm and 35.5% at 3.7 GHz. The proposed PA exhibits an adjacent channel leakage ratio (ACLR) of −25.9 dBc, an average power-added efficiency (PAE) of 17%, and an average output power of 12.4 dBm at −24.7 dB EVMRMS with a 64 QAM 200 MSym/s modulation signal at 26 GHz in DM. Similarly, with 256 QAM 50 MSym/s modulation at 3.6 GHz in CM, the PA demonstrates −35.6 dBc ACLR, 22.5% average PAE, and 10.7 dBm average power at −31.1 dB EVMRMS. Furthermore, measurements with two carriers at 24 and 3.7 GHz indicate that the PA has the potential for concurrent operation in both modes. The PA is fabricated in a 65 nm CMOS process with a core area of 0.32 mm2.