V.A. Sorotsky1, H.D. Pham2

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

1 sorotsky@spbstu.ru; 2 phamduc2511997@gmail.com

The paper presents a Class E power amplifier (PA) characteristics analysis when amplifying radio frequency signals with a non-constant envelope. The relevance of the study proceeds from the use of various types of digital modulation to increase bit rate, which leads to signals peak-to-average power ratio (PAPR) growing. At the same time, it turns out that the specific for the Class E PA turn-on conditions of transistor with zero voltage switching (ZVS) and zero derivative voltage switching (ZDVS) at the drain-source terminals get broken, resulting in increased switching losses. An additional factor that can have a noticeable effect on the forming circuit capacitance overcharging, and consequently on Class E PA power efficiency is a sufficiently large increase in the output capacitance of the transistor when the supply terminal voltage is lowered.

The paper proposes an analytical model of a Class E PA, which allows taking into account the above-mentioned effects, the adequacy being confirmed by simulation.

It is shown that a decrease in the power efficiency of a Class E PA in the case of using the envelope elimination and restoration (EER) method for signals with a PAPR of up to 15 dB can amount to 12...14%.

Sorotsky V.A., Pham H.D. Efficiency of class-E power amplifiers for nonconstant envelope modulation. Radiotekhnika. 2026. V. 90.
№ 3. P. 5−15. DOI: https://doi.org/10.18127/j00338486-202603-01 (In Russian)

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