A Study on Superdirectivity in HF band

摘要

For many years, there are few practical applications of superdirective antennas for its low efficiency, narrow bandwidth and tolerance sensitivity. In this paper, these difficulties were analyzed and the application of superdirectivity in HF is proved to be feasible. The properties of circular arrays are studied, and some principles in HF superdirective circular array design are given. By these principles, a 5-elment superdirective circular array in HF was designed. The size of designed array is much smaller than the conventional Chebyshev (element spacing is λ/2 ) array with the same directive gain.