A 38 GHz Pre-Distortion Power Amplifier With OP1dB and IM3 Improvement in 65-nm CMOS Process

A Ka-band power amplifier (PA) with linearity enhancement is designed in 65-nm bulk CMOS process. A cold-mode linearizer with additional transmission line is applied to improve OP1dB efficiency, 3
^rd
inter-modulation (IM
₃
) distortion and amplitude-to-phase modulation (AM-PM) for 5G communication. By enabling the linearizer, OP1dB is increased from 13.2 to 14.2 dBm with 5% PAE
_1dB
improvement, the average output power under -30 dBc IMD3 is increased from 8.1 to 10.5 dBm for two-carrier continuous wave (CW) measurement, and AM-PM is reduced close to 0° until the OP1dB region. In addition, the average output power under -25 dBc error vector magnitude (EVM) is enhanced from 8.2 to 9.4 dBm with 5.2 dB adjacent channel leakage ratio (ACLR) improvement for 1.5 Gb/s 64-QAM.