Design of multioctave high‐efficiency power amplifier based on extended continuous Class‐B/J modes

Abstract

The bandwidth covered by contemporary communication technologies has reached over an octave. But most existing power amplifier (PA) configurations cannot meet this requirement while at the same time maintaining a high efficiency. Therefore, a novel structure for bandwidth enhancement at a high efficiency level is proposed together with the systematic design methodology in this article. The difficulty lies in the overlap of the fundamental and harmonic frequencies. On this issue, the extended continuous Class‐B/J mode can extend the impedance of the second harmonic to a resistive‐reactive and relax design requirements for overlapping design space of fundamental and second harmonic frequencies. Specifically, the presented innovative circuit structure uses the multiple frequencies matching method to manipulate four fundamental and the corresponding second harmonics frequency points simultaneously, which can further effectively expand the bandwidth on the basis of the extended continuous Class‐B/J PA. To verify the validity of the proposed theory, a gallium nitride multioctave PA is designed, implemented, and measured. Measured results show a fractional bandwidth of 148.4% from 0.4 to 2.7 GHz, with drain efficiency of 63%‐78%, saturated output power greater than 39 dBm, and large signal gain larger than 9 dB. For the single carrier WCDMA signal with a channel bandwidth of 3.84 MHz and a peak to average power ratio of 6 dB, the adjacent channel power ratio of −47.5 to −35 dBc and −42.8 to −31.5 dBc at an average output power of 33 and 36 dBm separately are achieved over the whole frequency band.

A broadband GaN HEMT power amplifier based on feeding capacitance compensation method

“…Several broadband enhancement techniques have been reported in the literature. Distributed and balanced configurations 7–9 and various matching technique such as reactive filter synthesis and real‐time frequency techniques 10–14 are proposed. Although distributed and balanced power amplifiers (PAs) have certain advantages in the performance of reflection loss and wideband, it inherently suffers from low power efficiency and large size, making it unsuitable for low cost and low power applications 1 .…”

Design of wideband high‐efficiency power amplifier based on continuous inverse modes

“…Therefore, to save bandwidth resources and lower cost, more and more researchers focus on the design of broadband and high efficiency PAs. [1][2][3][4][5][6] For improving efficiency of the PA, different kinds of design configurations have been widely adopted, such as class-E, 7,8 class-D, 9 class-F, 10 inverse class-F, [11][12][13] Doherty, 14,15 out-phasing 16 and envelope tracking. 17,18 Due to the limitation of device switched speed, class-E and class-D PAs are not operating at microwave frequency, appropriately.…”

“…For example, above 70% of the power consumption is from PAs in the communication system. Therefore, to save bandwidth resources and lower cost, more and more researchers focus on the design of broadband and high efficiency PAs 1‐6 . For improving efficiency of the PA, different kinds of design configurations have been widely adopted, such as class‐E, 7,8 class‐D, 9 class‐F, 10 inverse class‐F, 11‐13 Doherty, 14,15 out‐phasing 16 and envelope tracking 17,18 .…”

Design of bandwidth‐enhanced power amplifier based on class‐EF modes

“…WITH the rapid evolution of modern communication technology, the radio frequency front‐end systems of the fifth generation (5G) mobile communication require highly efficient power amplifiers (PAs), which can operate multiple signal standards at different frequencies 1‐56 . Therefore, as an energy‐efficient DC‐to‐RF power converters, switch mode Class‐E and harmonic‐tuned Class‐F PAs have attracted great attention based on the ability of wave‐shaping through appropriate harmonic termination 7‐12 .…”