Two-dimensional (2D) periodic structures of the microwave and terahertz ranges are
becoming more and more widespread as the basic elements of instruments and devices for
controlling the parameters of electromagnetic signals in radio astronomy, nuclear physics,
medical technologies, electronic engineering, instrumentation, and radar technology. They are
known in the literature as “Frequency Selective Surfaces” (FSS). Their electrodynamic
performance depends not only on the geometric dimensions and physical properties of materials
but also on the periodical spacing of their constituent elements. In the case when their
dimensions are much less than the wavelength of the incident radiation, they are called
“metasurfaces”. This chapter analyzes the effect of dimensions and electrophysical properties
of structural materials on the transfer characteristics of frequency-selective surfaces with crossshaped apertures.
Keywords: Complex shaped apertures, Dielectric substrate, Frequency selective surface, Fractional bandwidth, Generalized sheet-transition conditions, Microwave range, Resistive elements, Wave impedance.
