Analysis and measurement of scattering from a dihedral corner reflector and a finite circular hollow cone

Abstract

The separation of variables and mode matching technique (MMT) were used to analyze the electromagnetic scattering by a perfectly conducting dihedral corner reflector and a finite circular hollow cone. In addition, analytic techniques were used to obtain an analytic series solution. The mode matching technique can be generalized by using the separation of variables as the normal modes and tangential modes with respect to the boundary. This leads to dual series equations, which are also two matrix equations. These matrix notations can simplify the analysis. First, the dihedral corner reflector as a 2-dimensional finite singular shape is analyzed for plane wave incidence. Both $TM_z$ and $TE_z$ polarizations are treated. To check the accuracy of the present method based on the mode matching technique, numerical data are compared with those obtained by the moment method (MM), uniform geometrical theory of diffraction (UTD) and experimental results. This shows that the accuracy of numerical results by using mode matching technique is higher than that of other methods. We also analyzed the radiations and performances of a corner reflector antenna and the scattering problem from a line source. The present method can be applied to reflectors with arbitrary internal angles. The procedure is relatively simple. It always provides the exact solution because no approximation is used in the analysis. The finite circular hollow cone, as a 3-dimensional finite singular shape, is analyzed for the plane wave incidence. Using the spherical mode expansion and boundary conditions, we get the dual series equations for the scattering of a $TM_x$ (or $TE_x$) polarized plane wave incidence. The results of the measurements are in good agreement with these of the numerical method. The results for the finite hollow cone are new and not yet well understood. They explain the complex waves in which cavity modes, reflected waves, edge-diffracted waves, and creeping waves interact to pro...