In order to realize an active phased array antenna, we have investigated a phased array behavior of a microwave coupled oscillators system which has locking sources at both ends and is controlled by phases of the injection signals and frequency change of the oscillator. By approximate and numerical analyses, we show that the phased array behavior can be realized controlled by phase differnecs between two injection signals and frequency change of the oscillator at one end. An experiment on a system of waveguide type oscillators has confirmed the phased array behavior. Finally, we have scanned electromagnetic wave using five active patch antennas array mounted with Gunn diode.