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Download as PDFLossless Multi-Way Power Combining and Outphasing for Radio-Frequency Power Amplifiers
For applications requiring the use of power amplifiers (PAs) operating at high frequencies and power levels, it is often preferable to construct multiple low-power PAs and combine their output powers to form a high-power PA. Moreover, such PAs must often be able to provide dynamic control of their output power over a wide range and maintain high efficiency across their operating range. This research work introduces a new power combining and outphasing system that provides both high efficiency and dynamic output power control [1] . The system combines power from four or more PAs (Figure 1) and overcomes the loss and reactive loading problems of previous outphasing systems [2] [3] [4] . It provides ideally lossless power combining, along with nearly-resistive loading of the individual power amplifiers over a very wide output power range. The theoretical fundamentals underlying the behavior and operation of this new combining system were thoroughly developed. Additionally, a straight-forward combiner design methodology was provided. The prototype design of a 27.12 MHz, four-way power combining and outphasing system was presented and implemented (Figure 2), and its performance was experimentally validated over a 10W-100W (10:1) output power range [5] .
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- Figure 1: A four-way implementation of the proposed multi-way power combiner with four input-power ports Pin,A-Pin,B and one output-power port Pout. The combiner is realized using only six reactive elements, and thus, it is ideally lossless.
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- Figure 2: A photograph of the implemented four-way combiner PCB (9.8 cm x 5.6 cm) designed to operate at 27.12 MHz over a 10W – 100W output power range.
- A. S. Jurkov and D. J. Perreault, “Design and control of lossless multi-way power combining and outphasing systems,” Midwest Symposium on Circuits and Systems, pp. 1-4, Aug. 2011. = [↩]
- H. Chireix, “High power outphasing modulation,” Proc, of the IRE, vol. 23, no. 11, pp. 1370-1392, Nov. 1935. [↩]
- F. H. Raab, “Efficiency of outphasing RF power-amplifier systems,” IEEE Transactions on Communications, vol. 33, no. 9, pp. 1094-1099, Oct. 1985. [↩]
- A. Birafane and A. Kouki, “On the linearity and efficiency of outphasing microwave amplifiers,” IEEE Transactions on Microwave Theory and Techniques, vol. 52, no. 7, pp. 1702-1708, July 2004. [↩]
- A. S. Jurkov and D. J. Perreault, “Lossless multi-way power combing and outphasing for high-frequency resonant inverters,” IEEE Transactions on Power Electronics and Motion Control, to be published [↩]