Improved analysis of antenna radiation from a circular aperture covered by a dielectric hemispherical radome shell

A novel full-wave analysis of the antenna radiation due to an aperture flush-mounted on a ground plane and excited by a circular waveguide TE₁₁ wave is presented. The aperture is further covered by a dielectric hemispherical radome. Huygens´ equivalence principle and image theory are utilised to simplify the problem, and magnetic dyadic Green´s functions are employed to formulate both the reactional magnetic current distribution around the aperture and the inner near-zone and outer far-zone electromagnetic fields. The idea of reactional iteration is implemented in this work, and, hence, the final equivalent source is obtained in quite a compact form. Comparison between the results obtained and those published elsewhere in the literature shows the additional contributions to the equivalent magnetic source distribution and the near- and far-zone field patterns from the feedback of the electromagnetic fields reflected from the dielectric radome. Although applied only for a simple-layer dielectric radome, the method itself is not restricted by the number of layers and can easily be extended to a multi-layered radome or dielectric inhomogeneous radome