Ultrabroadband Linear Power Amplifier Using a Frequency-Selective Analog Predistorter

• Published in: IEEE transactions on circuits and systems. II, Express briefs Vol. 58; no. 5; pp. 264 - 268
• Main Authors: Seo, Mincheol, Kim, Kyungwon, Kim, Minsu, Kim, Hyungchul, Jeon, Jeongbae, Park, Myung-Kyu, Lim, Hyojoon, Yang, Youngoo
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.05.2011; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Analog predistorter; Broadband amplifiers; broadband power amplifier; Capacitance; Capacitors; Circuits; Compressing; Frequency modulation; frequency-selective predistorter; Gain; Intermodulation distortion; Linearization; Noise levels; Power amplifiers; Power generation; Predistortion; push-pull; Radio frequency
• ISSN: 1549-7747; 1558-3791
• DOI: 10.1109/TCSII.2011.2149170

This brief presents an ultrabroadband (2- to 600-MHz band) linear power amplifier using a compact frequency-selective analog predistorter, which includes a capacitor having an optimized capacitance and a biased Schottky diode connected in series. It is shunted at the input of the main amplifier and has a frequency-selective third-order intermodulation generation capability using its optimized capacitance. A two-stage push-pull power amplifier, which has an ultrabroadband operation range from 2 to 600 MHz, was implemented and linearized using the proposed analog predistorter. It exhibited high 1-dB compression point (P1 dB) and power-added efficiency characteristics of over 43 dBm and 32% at each P1 dB for the entire operating band, respectively. At an average output power level of 36 dBm for the two-tone signal input, which has a tone spacing of 1 MHz, its third-order intermodulation distortion over the entire band is no higher than -39.1 dBc after linearization, as compared with -34.2 dBc before linearization.