Ku band second harmonic N-coupled push-push oscillator array using microstrip resonator

This paper presents the second harmonic push-push oscillator array. By using the push-push oscillator, a high frequency signal is easily generated with inexpensive low frequency devices. These push-push oscillators are connected with coupling circuits which are composed of microstrip resonators. The coupling circuit has two ports to connect the push-push oscillators. The reflection constant, S11 and S22, of the coupling circuit are controlled by a varactor diode. In the coupling circuit, the phase of S11 is almost constant, and the other S22 is changed by the reactance of the varactor diode. Therefore, the output signals of the push-push oscillators are generated with different phase. The second harmonic push-push oscillator array is designed and fabricated in Ku band. The basic performance of the oscillator array using two push-push oscillators is basically investigated. The phase shift introduced between two oscillators is 451 degrees at 14.75 GHz. The output power of the second harmonic signal is +0.67 dBm with the phase noise of -107.5 dBc/Hz at the offset frequency of 1 MHz.