A Simplified Broadband Design Methodology for Linearized High-Efficiency Continuous Class-F Power Amplifiers

作者：Tuffy Neal^*; Guan Lei; Zhu Anding; Brazil Thomas J

来源：IEEE Transactions on Microwave Theory and Techniques, 2012, 60(6): 1952-1963.

DOI：10.1109/TMTT.2012.2187534

• Broadband
• Class-F
• digital predistortion (DPD)
• high efficiency
• power amplifier (PA)

This paper describes the design approach employed for achieving approximated continuous Class-F power amplifier (PA) modes over wide bandwidths. The importance of the non-linear device capacitance for wave-shaping the continuous Class-F voltage and current waveforms is highlighted, thus reducing the device sensitivity to second and third harmonic impedance terminations. By identifying the high-efficiency regions on the reactance plane for harmonic band placement, the design can be reduced to a fundamental matching problem. The distributed simplified real frequency technique synthesis algorithm can then be utilized to achieve wideband operation. Using a 10-W Cree GaN HEMT device, greater than 70% efficiency has been measured over a 51% bandwidth from 1.45 to 2.45 GHz, with output powers of 11-16.8 W. The nonlinear PA was then linearized using digital predistortion with 20-MHz long-term evolution and 40-MHz eight-carrier W-CDMA excitation signals, to attain adjacent channel power ratios below -53 and -49 dBc, respectively. To the best of the authors%26apos; knowledge, the measured results represent the best performance obtained from a broadband switch-mode PA, and the best linearized switch-mode performance using 20-and 40-MHz modulated signals.

• 出版日期2012-6