Effect of gate-to-drain and drain-to-source parasitic capacitances of MOSFET on the performance of Class-E/F₃ power amplifier

摘要

In this study, the Class-E/F3 power amplifier with linear gate-to-drain and nonlinear drain-to-source capacitance is proposed. The analysis for the effect of the parasitic capacitance in the mixed mode Class-E/F3 with square and sinusoidal gate-to-source voltage has been done. Most of the design equations in this study do not have analytical solutions, and the numerical analyses are used. As can be seen, there is little difference between the results related to the sinusoidal and square gate-to-source voltage. So, only the simulation and experimental result for Class E/F3 with square gate-to-source voltage at operating frequency of 4 MHz has been done. The results in this study indicate that it is important to consider the effect of the MOSFET gate-to-drain capacitance for achieving the ZVS/ZDS conditions in the Class-E/F3 power amplifier. The PSpice simulation and measured results are agreed with the analytical expressions, which show the validity of the presented analytical expressions. Finally, the waveforms of Class E/F3 are compared with equivalent waveforms of Class-E power amplifier, in order to indicate its advantages.