Class E high-efficiency tuned power oscillator

The class E high-efficiency transistor tuned power oscillator, which is based on the class E power amplifier, is discussed. Theoretical conditions for optimum operation of the oscillator are given. A new feedback-loop circuit is proposed, and a corresponding oscillator design procedure is presented. Experimental results show that the collector-voltage and collector-current waveforms and the collector efficiency of the oscillator are the same as in the class E amplifier having the same transistor and operating at the same frequency. The collector efficiency is measured at over 95% with 3 W output at 2 MHz. It is noted that the proposed oscillator is especially applicable at high frequencies because it minimizes the power dissipated during the transistor off-to-on transition, even if the switching time is an appreciable fraction of the signal period.