Effective Digital Predistortion (DPD) on a Broadband Millimeter-Wave GaN Power Amplifier Using LTE 64-QAM Waveforms

We demonstrate in this work effective linearization on a millimeter-wave (mm-Wave) broadband monolithic gallium nitride (GaN) power amplifier (PA) using digital predistortion (DPD). The PA used is two-stage common-source (CS)/2-stack that operates the mm-Wave 5G FR2 band, and it linearized with generalized memory polynomial (GMP) DPD tested 4G (4th generation) long-term-evolution (LTE) 64-QAM (quadrature amplitude modulation) modulated signals PAPR (peak-to-average ratio) of 8 dB. Measurement results after implementing GMP indicate considerable improvement adjacent channel leakage ratio (ACLR) 16.9 dB/17.3 dB/16.5 dB/15.1 dB at 24 GHz/28 GHz/37 GHz/39 GHz, respectively, common average POUT 15 dBm 100 MHz LTE input signal. At fixed frequency 28 GaN achieved signal bandwidth-dependent ACLR root-mean-square (rms) EVM (error vector magnitude) reduction 20 MHz/40 MHz/80 MHz/100 waveforms dBm. thus very good compared to other state-of-the-art studies literature, suggesting should be rather for linearizing PAs improve POUT, Linear.