The principles of beam-scanning in phased-arrays are well known. In conventional phased array, a constant phase progression is established using electrically-controlled phase-shifters at each array element. The disadvantage of this method arise mainly in connection with complicated circuit and cost as increasing array element number. Moreover, feeding loss due to phase shifter reduces EIRP. Therefore, active array antenna without phase shifter should be studied.
Patch antenna is used as a resonator of oscillator because it can be thought as a cavity. Each array element is composed of oscillator integrated with patch antenna. For beam control, we use coupled oscillator theory without phase shifter. In other words, Using mutual coupling between array elements through coupled microstrip lines, we control the phase of the array elements. In this paper, we design and fabricate beam control active phased array antenna without phase shifter.
Because we don't use phase shifter, problem of EIRP reduction results from feeding loss when using phase shifter is solved.
