Redefining the optimum RF Class-E switch-voltage waveform, to correct a long-used incorrect waveform

In the 1970s, authors referred to the Class-E RF power amplifier circuit as “optimum” Class E if the switch-voltage waveform had zero voltage and zero voltage-slope at the switch turn-on time. “Optimum” was a misnomer; the correct term for that condition is now known to be “nominal” Class E. The optimum switch-voltage waveform has a positive voltage (assuming an NPN or N-channel transistor switch) and near-zero voltage-slope at the switch turn-on time. Automatic and manual optimization methods are discussed; the automatic method is shown to be far superior to the manual method. Optimization typically reduces the power dissipation of the nominal Class-E amplifier by about 30%. A typical example is shown, comparing a nominal Class-E design and an optimized version of that design; the optimized version reduced the power dissipation of the nominal version by 28%.