An analysis of a circuit for the generation of high-order harmonics using an ideal nonlinear capacitor

A particular harmonic generator circuit using an ideal nonlinear capacitor is analyzed and theoretical expressions are obtained for the loss involved in generating a high-order harmonic. The harmonic energy is developed in a load resistor either as an exponentially decaying sine wave or as a pulse. The analysis is valid for harmonics of about the tenth or greater. The results are presented in a graphical form that allows the losses involved to be found easily and it is thus shown that the minimum loss in generating a high-order harmonic by this circuit is about 8.5 db independent of the order of the harmonic. The degree to which a charge storage diode approximates to an ideal nonlinear capacitor is then discussed and some experimental results using such a diode are presented.