Radiation From a Dielectric-Filled Waveguide Terminated by a Finite Metallic Flange of Arbitrary Shape

A diagnostic and design tool, based on the method of moments (MoM) technique, is presented for analysing the radiation from an aperture incorporating dielectric material and mounted on a metallic flange of finite size and arbitrary shape. The method can handle aperture problems with a wide variety of geometry and is therefor a very powerful design tool, which can be used to improve the antenna design. Using the equivalence principle, an equivalent problem is derived and when the appropriate boundary conditions are imposed a set of integral equations is obtained with surface currents on the waveguide as the unknowns. These integral equations are solved by the MoM to yield the surface currents, from which the radiation pattern is calculated. The software is validated by a comparison of simulated and measured antenna performances (patterns and SWR).