Electromagnetic plane wave scattering by arbitrary two-dimensional cavities: Rigorous approach

Abstract

Scattering of an E-polarised plane wave from an arbitrary two-dimensional cavity is examined. The cavity may be represented as an infinitesimally thin open contour with sharp edges or more realistically, as an open (slotted) arbitrary profiled cylinder with finite thickness walls and smoothly rounded edges. The studies of the reflectivity of open 2-D cavities are based on a rigorous Method of Regularisation applicable in a wide frequency range from Rayleigh scattering (passing through the interval of resonance scattering) to high-frequency scattering, where the wavelength is much less than the characteristic size of a cavity. Implementation produces the infinite system of the linear algebraic equations of the second kind. Boundedness and compactness of the system operator allows the use of truncation methods for numerical analysis, where the predetermined accuracy of computations is guaranteed by proper choice of truncation number. Backscattering of some general cavities with infinitesimally thin walls is examined over a wide frequency range. Special focus is on resonance scattering by cavities possessing a spectrum of high Q-factor oscillations. The developed algorithm is directly applicable to examine scattering of plane acoustic waves by arbitrary acoustically soft two-dimensional cavities.