Field patterns of resonant noncircular closed-loop arrays

Abstract

Recent studies have shown that large circular arrays of perfectly conducting vertical dipoles with only two dipoles driven possess very narrow resonances. The remaining dipoles are parasitic and unloaded. The field pattern of the resonant circular array is adequately determined from a continuous-current model of the discrete array. This field pattern is omnidirectional in the azimuth. In this paper, the continuous-current model is generalized to the case of resonant noncircular closed-loop arrays, and the resulting field patterns are determined. A class of closed curves is considered, the shape of which is nearly circular. It is shown that the radiation field can be drastically different from that of the circular array and that, for proper choices of the parameters, the field pattern in the azimuth plane consists of a single, very narrow radiated beam.