In modern microwave and terahertz technology, one of the most hot topic areas of
using frequency selective surfaces is frequency filtering of electromagnetic signals. Such
structures make it possible to reduce the weight and dimension parameters of the radio
equipment, which is especially important for onboard systems of aviation and space technology
operating under harsh environment, which imposes high-reliability requirements on the units
and components of these systems. One of the trends in the development of filtering devices of
various types and different element bases has recently become the design of broadband and
ultra-wideband, as well as narrowband and ultra-narrowband systems.
Freestanding frequency selective surfaces with cross-shaped aperture elements are investigated
numerically and experimentally in the present chapter. Transmission characteristics of such
two-dimensional periodic structures as a function of sizes are analyzed using numerical
methods.Employing the conjugate-gradient method narrowband filters have been developed
and optimized. The results of measurements carried out in the present study agree well with the
obtained theoretical data.
Keywords: Band pass, Cross-shaped aperture, Electrical conductivity, Frequency response, Frequency selective surface, Mathematical model, Metal mesh filter, Numerical modeling, Scattering, Optimization, Reliability, W-range.
