Design of Coupled Oscillator Arrays for Second Harmonic Radiation

A design method for phased arrays based on coupled oscillators, radiating the second harmonic is proposed. The oscillators are coupled at the fundamental frequency, and radiation of the second harmonic allows for extended scanning range. A model of the array steady state is developed based on a first order perturbation of the free-running single element steady state, taking into account both harmonics. Stability analysis based on the two harmonic model is also performed. The model parameters can be easily calculated from a harmonic balance analysis of the single array oscillator element only. The proposed methodology is applied to the design of a three element active antenna oscillator array radiating the second harmonic at 8.6 GHz.