Backscattering From a Soft–Hard Strip: Primary Edge Waves Approximations

High-frequency approximation is constructed for backscattering from a strip with one face soft and the other face hard (i.e., with Dirichlet and Neumann boundary conditions, respectively). This approximation is based on the solution of the canonical problem for a wedge with the same boundary conditions. Its exact solution belongs to Malyuzhinetz (Ann. Phys., vol. 6, no. 1-2, pp. 107-112, 1960). Here, we utilize its approximations presented in Ufimtsev's work (IEEE Antennas Propag. Mag., Dec. 2013) and derive simple asymptotics for backscattering. Only primary edge waves are taken into account. The influence of the secondary diffraction is estimated asymptotically to validate this approach. The results are compared to the physical optics (PO) and Physical Theory of Diffraction (PTD) approximations.