A crank-line array antenna radiating a circularly polarized wave

An array antenna composed of crank-line elements is investigated on the basis of the element current distributions determined by the method of moments. A technique of gradually increasing the antenna height above the ground plane is adopted to enhance the gain. It is found both numerically and experimentally that a gain of approximately 30 dB is obtained with an axial ratio of less than 3 dB over a frequency bandwidth of 2.5%.