An injection locked coupled push-push 3-oscillators array using unilateral coupling circuits is proposed. The circuit consists of unit oscillators and coupling circuits. For the unit oscillator, a dual-band push-push oscillator which generates the fundamental signal (f₀) and the second harmonic signal (2f₀) is adopted. The output signal of the oscillator array is the second harmonic signal. The fundamental signal is used for the injection signal to synchronize oscillators. These adjoining unit oscillators are connected by the coupling circuits. The coupling circuit is composed of a buffer amplifier and a phase shifter. Due to the advantage of the push-push oscillator, the phase shift between the adjoining oscillators is twice as large as that of the phase shift in the coupling circuit. The oscillator array is designed in Ku-band. Three push-push oscillators are arrayed and include two coupling circuits which are designed and fabricated. The phase shift of 190.0 degrees between the adjoining unit oscillators is demonstrated.