2023-08-162023-08-162023Somasundaram, G., Mayeda, J.C., Sweeney, C., Lie, D.Y.C., & Lopez, J.. 2023. Effective Digital Predistortion (DPD) on a Broadband Millimeter-Wave GaN Power Amplifier Using LTE 64-QAM Waveforms. Electronics (Switzerland), 12(13). https://doi.org/10.3390/electronics12132869https://doi.org/10.3390/electronics12132869https://hdl.handle.net/2346/95608© 2023 by the authors. cc-byWe 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 a two-stage common-source (CS)/2-stack PA that operates in the mm-Wave 5G FR2 band, and it is linearized with the generalized memory polynomial (GMP) DPD and tested using 4G (4th generation) long-term-evolution (LTE) 64-QAM (quadrature amplitude modulation) modulated signals with a PAPR (peak-to-average power ratio) of 8 dB. Measurement results after implementing GMP DPD indicate considerable broadband improvement in the adjacent channel leakage power ratio (ACLR) of 16.9 dB/17.3 dB/16.5 dB/15.1 dB at 24 GHz/28 GHz/37 GHz/39 GHz, respectively, with a common average POUT of 15 dBm using a 100 MHz LTE 64-QAM input signal. At a fixed frequency of 28 GHz, the GaN PA after GMP DPD achieved signal bandwidth-dependent ACLR improvement and root-mean-square (rms) EVM (error vector magnitude) reduction using 20 MHz/40 MHz/80 MHz/100 MHz LTE 64-QAM waveforms with a common average POUT of 15 dBm. The GaN PA thus achieved very good linearization results compared to that in other state-of-the-art mm-Wave PA DPD studies in the literature, suggesting that GMP DPD should be rather effective for linearizing mm-Wave 5G broadband GaN PAs to improve POUT, Linear.eng4G (4th generation)5G (5th generation)adjacent channel leakage power ratio (ACLR)carrier aggregation (CA)digital predistortion (DPD)error vector magnitude (EVM)gallium nitride (GaN)generalized memory polynomial (GMP)long-term evolution (LTE)millimeter-wave (mm-Wave)power amplifier (PA)quadrature amplitude modulation (qam)Article