A.O. Pergushev1, V.A. Sorotsky2

1,2 Peter the Great St. Petersburg Polytechnic University (St. Petersburg, Russia)

1 pergushev.aleksey@mail.ru; 2 sorotsky@mail.spbstu.ru

The use of linear power amplifiers in the case of signals with a high peak-to-average power ratio is accompanied by a significant decrease in efficiency. Among the known methods of overcoming this disadvantage the most interesting for specialists are the Dougherty, Kahn and outphasing methods. The last two methods are interesting because they use a switching-mode, which allows achieving a higher efficiency of the power amplifier than the Doherty method. However, these methods are not without disadvantages that can have a noticeable effect on the characteristics of the amplifiers. In particular, when implementing amplifiers using the Kahn method, it is quite difficult to ensure the bandwidth required for the signals generated using digital modulation algorithms that are widely used today. In power amplifiers using the outphasing method, the problems occur due to the relatively small dynamic range of signals.

To overcome the listed problems, it is advisable to implement power amplifiers based on the combined use of pulse-width modulation (PWM) and outphasing methods. In this case, the expanding of the amplifier bandwidth can be achieved by using the outphasing method, and the required dynamic range of signals changes is achieved by using a pulse-width modulator.

The paper aims to consider the features of constructing a power amplifier based on the combined principle, as well as to determine its characteristics.

The paper considers an analytical model of the proposed power amplifier, the adequacy of which is confirmed using computer simulation. It is shown that the proposed combined method for constructing a power amplifier makes it possible to expand its bandwidth by no less than 8 times compared to an amplifier implemented using the Kahn method, provided that the efficiency is at least 80%.

Pergushev A.O., Sorotsky V.A. Expanding the bandwidth of power amplifiers for high peak-to-average power ratio signals. Radiotekhnika. 2025. V. 89. № 3. P. 24−31. DOI: https://doi.org/10.18127/j00338486-202503-03 (In Russian)

1. Zhancang Wang. Envelope tracking power amplifiers for wireless communications. Boston-London: Artech House. 2014. 343 p.
2. Kazimierczuk M.K. RF Power Amlifiers. Third edition. U.S.: Wiley. 2015. 658 p.
3. Ivanjushkin R.Ju., Kozyrev V.B. i dr. Radioperedajushhie ustrojstva: uchebnik dlja vuzov. Pod obshh. red. R.Ju. Ivanjushkina. M.: Gorjachaja linija – Telekom. 2021. 1200 s. (in Russian)
4. Doherty W.H. A new high efficiency power amplifier for modulated waves. Proc. Inst. Radio Eng. Sept. 1936. V. 24. № 9.
   Р. 1163–1182.
5. A.s. №14140. Poljanskij-Majkov K.S., Rassadin B.I. MO SSSR. 1953 (in Russian).
6. Kahn L. Single sideband transmission by envelope elimination and restoration. in Proc. IRE. 1952. Р. 803-806.
7. Chirex H. High power outphasing modulation. Proceedings of the Institute of Radio Engineers. November 1935. V. 23.
   Р. 1370-1392.
8. Qureshi A.R., Acar M., Qureshi J., Wesson R., de Vreede L.C. A 112W GaN dual input Doherty-outphasing power amplifier. IEEE MTT-S Int. Microw. Symp. Dig. May 2016. Р. 1-4.
9. Furumoto R., Yasunobu D., Nishikawa K. Analysis of the operation of a Hybrid amplifier based on the Doherty amplifier. Proc. of 2022 Asia-Pacific Microwave Conference. Dec. 2022. Р. 737-739.
10. Chen Y., Cheng Z., Zhu Y., Liu G. Broadband Doherty-Outphasing RF Power Amplifier for S-Band. 2019 8th International Symposium on Next Generation Electronics (ISNE). 2019.
11. Lopes I.C., Nunes L.C., Cabral P.M., Pedro J.C. Dual-input mixed-mode doherty-outphasing power amplifier. 2023 International Workshop on Integrated Nonlinear Microwave and Millimetre-Wave Circuits (INMMIC). November 2023. Р. 8-11.
12. Tunç A., Yelten M.B. Linearity Issues in Dual Input Doherty-Outphasing Hybrid Power Amplifier Topology. 2023 30th IEEE International Conference on Electronics, Circuits and Systems (ICECS). December 2023. Р. 4-7.
13. Liang C., Niubo-Aleman T., Hahn Y., Roblin P., Reynoso‑Hernandez J.A. Optimal two-way hybrid Doherty-outphasing power amplifier. Proc. IEEE Topical Conf. RF/Microwave Power Model for Radio Wireless Appl. (PAWR). Jan. 2020. Р. 26-29.
14. Liang C., Roblin P. The analytic Doherty-outphasing power amplifiers continuum theory: (Invited paper). Proc. IEEE 22nd Annu. Wireless Microw. Technol. Conf. (WAMICON). Apr. 2022. Р. 1-4.
15. Tunç A., Yelten M.B. The Design Overview of the Hybrid Doherty-Outphasing Technique. 2021 13th International Conference on Electrical and Electronics Engineering (ELECO). 2021. Р. 1-4.
16. Nghe C.T., Maassen D., Boeck G., Guan J., Aref A., Negra R. 160 W peak highly linear multilevel outphasing transmitter. Proc. 46th Eur. Microw. Conf. (EuMC). Oct. 2016. Р. 1091-1094.
17. Kayyil A.V., Qiao B., Allstot D. A digitally configurable outphasing switched-capacitor-based RF transmitter. 2023 IEEE 66th International Midwest Symposium on Circuits and Systems (MWSCAS). August 2023. Р. 6-9.
18. Chen Z., Wei Z., Zhu J. Delay mismatches analysis for multi-level outphasing digital transmitters. Proc. IEEE 22nd International Conference on Communication Technology(ICCT). Nov. 2022. Р. 346-350.
19. Litchfield M., Popovic Z. Multi-level Chireix outphasing GaN MMIC PA. Proc. IEEE Compound Semiconductor Integrated Circuits and Technology Symp. 2015. Р. 1-4.
20. Mueller S., Negra R. Optimising the image rejection in phase-only multilevel LINC transmitters. 2024 15th German Microwave Conference (GeMiC). 11-13 March 2024. Р. 288-291.
21. Litchfield M., Cappello T., Florian C., Popovic Z. X-band GaN multi‑level chireix outphasing PA with a discrete supply modulator MMIC. Compound Semiconductor Integrated Circuit Symposium (CSICS) 2016 IEEE. 2016. Р. 1-4.
22. Beltran R., Raab F.H., Velazquez A. HF outphasing transmitter using class-E power amplifiers. Proc. IEEE MTT-S Int. Microw. Symp. Dig. 2009. Р. 757-760.
23. Zhang X., Larson L.E., Asbeck P.M. Design of linear RF outphasing power amplifiers. MA. Boston: Artech House. 2003.