Beam-steerable wideband circularly polarized helical antenna array based on sequential rotation technique

The paper describes the design and characteristics of a continuously beam-steerable, circularly polarized (CP) helical antenna array for wideband operation. The sequential rotation feeding technique is adopted to enhance the CP and broadband performance of the array, and the voltage-controlled phase shifters are used to realize a continuously steerable CP main beam. It is demonstrated that the proposed array works in a wide frequency range and has excellent axial ratio performance as well as low reflection coefficient. Besides, beam-fixed sequentially rotated arrays are also implemented using delay lines to clarify the influences of the phase shifters on array performance.