A Theoretical Method to Optimize the Control Signal Power for High-Efficiency Symmetrical Load Modulated Balanced Amplifier Designs
Peng Chen, Qi Lin, Jing Xia, Ruijia Liu, Jipeng Chen, Luqi Yu, Xiao‐Wei Zhu, Chao Yu, Wei Hong
Abstract
The novelty of this letter is proposing a theoretical method to guide the optimization of the control signal power (CSP) in a symmetrical load-modulated balanced amplifier (SLMBA) design. Theoretical analysis reveals that the magnitude optimization of the CSP needs to trade off the back-off efficiency and the output back-off (OBO) range, while the phase offset of the CSP should be optimized close to 180°. To verify the proposed theoretical method, a 1.9–3.2 GHz high-efficiency SLMBA is realized. Measured results show that the SLMBA achieves the drain efficiency (DE) of 47%–65% at saturation, 40%–62% at 6 dB back-off, and 42%–60% at 10 dB back-off, respectively. Tested by a 20 MHz 5G New Radio (NR) signal with use of digital predistortion (DPD), the adjacent channel leakage ratio (ACLR) levels of the SLMBA are better than −45.5 dBc across the band.