A 38-GHz-Band Power Amplifier with Analog Pre-Distortion for 1600-MHz Transmission Bandwidth 64-QAM OFDM Modulated Signal
A 38-GHz-band transformer based high linear power amplifier with analog pre-distortion for wideband modulated signal in 65-nm GP CMOS process is presented in this paper. The output power is based on the two-way transformer current combining structure. The driver amplifier which is biased in deep class-AB acts as an AM-AM pre-distorter to produce better OP1dB and improve the third order intermodulation distortion ( IMD3). Also a PMOS capacitor is used to compensate the AM-PM distortion of the input capacitor at the driver stage. In the continuous-wave measurement, this power amplifier achieves 14.4-dB small-signal power gain, 20.7-dBm PSAT, 35% PAEMAX, 20.2-dBm OP1dB, and 32.8% PAE1dB at 39 GHz. In the modulated signal measurement, this power amplifier achieves 13.2-dBm output power, 7.1% PAE, and EVM < -25 dBc at 1600-MHz channel bandwidth of 64-QAM OFDM with 38-GHz carrier frequency. The highest transmission data rate of the proposed power amplifier reaches up to 6.98 Gb/s.