A Simple Method to Increase the Stability of a Class E Power Oscillator

This work investigates the operation of the class E oscillator appended with an additional oscillatory circuit in the form of transmission line stub connected to the transistor's input network, that synchronizes the oscillator frequency. The oscillator operation with artificial half-wave and quarter-wave transmission lines was simulated. The characteristics of the prototype class E oscillator operating at 6.78 MHz frequency were experimentally measured for various schemes of the transmission line stubs connection. The obtained results demonstrate that the proposed approach may represent a simple way to increase the operation stability of power class E oscillators. Compared with the case of mutually synchronized oscillators connected with a line stub, the influence of the line characteristics on the oscillator characteristics is much weaker due to the absence of the mutual link between the two oscillators.