Magnetically-coupled resonant wireless power transfer systems (WPTs) operating in the
megahertz range is well-suited for mid-range transmission of moderate power levels. The
class-E power amplifier (PA) is attractive for the MHz WPT applications due to the high-
efficiency and soft-switching properties. However, since the output power and the efficiency
of the class-E PA strongly depends on the output load, any change in the mutual inductance
of coupling coils, which leads to the PA load variation, results in a dramatic loss in the …