Modeling and radiation analysis of uniform circular array

The radiation characteristics of a uniform circular array with linear centrally-fed dipole elements is analyzed. This array is suitable for wireless base station which apply smart antenna technique. The radiation patterns and the gain of the array over a single element are derived based on the thin-wire model. Numerical simulations using the thin-wire model and the method of moment have been conducted and compared for a half-wavelength dipole array. It is shown that the thin-wire model is only applicable for analyzing the radiation pattern in the azimuthal direction and is inaccurate for analyzing the elevation pattern. For uniform supply with progressive phase shift, the sinusoidal current distribution is shown to be a good approximation only when the wire diameter is one-hundredth of a wavelength or less and all the elements are in phase.