Nonlinear Mode Analysis and Optimization of a Triple-Push Oscillator

The triple-push oscillator architecture is an attractive application of a three element coupled oscillator array for high frequency signal generation. The desired solution to combine the power at the third harmonic and reject the first and second harmonics requires a 120 phase shift among the system elements. However, depending on the coupling strength and delay between the oscillators, the phase distribution varies, giving rise to different operating modes. Harmonic balance analysis is used to trace these multiple coexisting modes and their stability is investigated using envelope transient simulation. A design methodology is presented where optimum coupling parameters guarantee the operation of the system in the desired mode. A 13.8 GHz triple push oscillator is fabricated, and the various modes are investigated verifying the analysis.