A 3-D discrete analysis of cylindrical radomes using dyadic Green´s functions

A three-dimensional discrete method, which makes use of the cylindrical dyadic Green´s functions (DGF) together with the field equivalence principle, is developed in this paper for characterizing the electromagnetic transmission through a cylindrical antenna radome of arbitrary cross sections. By the use of the dyadic Green´s functions for multilayered circular cylinders, this discrete method takes into consideration the curvature effects of the radome shell, which is usually ignored in classical approaches such as the ray-tracing method and the plane wave spectrum analysis technique. First, the discretized field distribution elements on the outer surface of the cylindrical radome shell are obtained from an arbitrarily distributed source. Then, the re-radiation of these elements are analyzed. Various effective radii and oblique transmission coefficients are discussed and their corresponding results further examined. With the developed discrete method, results of radiation power patterns of antennas, boresight errors, and peak-gain attenuations are obtained and compared with some existing results. Although more attention was paid to the elliptical radome shell of various thicknesses with different scanning angles, the discrete method developed in this paper is valid for a very accurate analysis on the electromagnetic transmission through a cylindrical antenna radome shell with arbitrary curved surface.