Impact of GaN power amplifier nonlinearity on signal transmission in wireless communication systems

This paper investigates the nonlinear characteristics of a 4.9 GHz GaN power amplifier and their impact on wireless communication system performance. Experimental testing of a self-developed GaN amplifier reveals key RF parameters: a linear gain of 39.9 dB, saturation power of $39 \mathrm{dBm}, 1 \mathrm{~dB}$ compression point $\left(\mathrm{P}_{1 \mathrm{~dB}}\right)$ at 32.30 dBm, and notably, a 3 dB compression point ($\mathrm{P}_{3 \mathrm{~dB}}$) at $\mathbf{3 5. 4 0} \mathrm { dBm }$ and a 6 dB compression point ($\mathrm { P } _ { 6 \mathrm { dB } }$) at 38.17 dBm, with third-order intermodulation distortion (IMD3) exceeding 24.5 dBc at this output level. Analyzing the amplifier’s nonlinearity effects through spectrum analysis, system error vector magnitude (EVM), and signal-to-noise ratio (SNR) in 64QAM modulation mode show a significant degradation of the performance of the communication system under the influence of amplifier nonlinearity.