Closed-form low frequency solutions for electromagnetic waves through a frequency selective surface

摘要: A simple closed-form approximate solution is given to the problem of transmission a low-frequency electromagnetic wave through frequency selective surface (FSS). FSS are periodic metal plates (or their complimentary apertures) sandwiched between dielectric slabs. At low frequencies, induced currents on may be approximated by known function with constant coefficient determined boundary conditions. Based such "one-mode" approximation, we derive for scattered field multiple narrow rectangular slots, single wide aperture, and circular aperture. When compared available exact solutions, find that one-mode approximation valid when period a/\lambda small enough no grating lobe appears, e.g., normal incidence.