Electromagnetic scattering of H-polarised cylindrical wave by a double-sided impedance circular strip

Abstract

The authors investigate electromagnetic scattering by a circular strip with impedance boundary conditions in detail. The excitation is obtained by the H-polarised line source and the impedance boundary condition with different impedance values on each surface of the circular strip is imposed. Electromagnetic scattering from circular strips is formulated employing an integral equation approach including the orthogonal polynomials while expressing the current densities on inner and outer surfaces. To consider the edge condition, the current density on the scatterer is expressed in terms of Gegenbauer polynomials with the weighting function. Unlike the previous studies, the authors investigate the behaviour of the EM field regarding the location of the cylinder source, the size of the aperture and the different impedance values. The convergence of the proposed approach, which is one of the analytical–numerical methods, is investigated for different impedance values; considering the results, resonators with impedance surfaces of certain complex values and certain locations of the cylinder source perform better than the known PEC and PMC resonators for some specific resonance cases. An effective analytical–numerical approach is proposed for such geometry with the impedance boundary condition. An extensive analysis and comparison with other methods are provided. The limit cases of the impedance boundary condition (Dirichlet and Neumann boundary conditions) are validated.