An array antenna composed of outer-fed curl elements

An array antenna consisting of four outer-fed curl elements is analyzed using the method of moments. It it found that, when the starting winding angle of each curl element is appropriately chosen, the array antenna can radiate a circularly polarized wave with an axial ratio of 0.1 dB. The calculation also shows that the bandwidth for a 3-dB axial ratio criterion is 5%, where a gain of approximately 13 dB is obtained.