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In this study, an X-band band-stop frequency selective surface (FSS) consisting of aligned finite length periodic conductive cylindrical fibers embedded in a dielectric host material is designed, manufactured, and electrically tested in the frequency range of 2 to 18 GHz. Furthermore, an equivalent circuit model is developed to estimate the electrical characterization of the band-stop FSS. Finally, the transmission results obtained from simulations are experimentally validated using a free-space setup. Moreover, a quasi-isotropic multilayer band-stop FSS is recommended to design a polarization-independent FSS. [ABSTRACT FROM PUBLISHER]

This study covers the design, manufacturing, and experimental electrical tests for a novel three-dimensional (3-D) band-pass frequency selective surfaces (FSS) containing continuous and discontinuous conductive fibers. The proposed FSS is designed based on 3-D numerical simulations to operate in the frequency range 8–12 GHz with resonant frequency at around 9.5 GHz. An equivalent circuit model of the proposed FSS is constructed to predict and understand the electrical behavior of the structure. Moreover, the experimental result of a fabricated prototype is obtained to demonstrate the validity of both the simulation results and the equivalent circuit model prediction. Furthermore, a quasi-isotropic multilayer FSS having fibers with different orientations is considered to provide a band-pass filter performance under various incident angles for both transverse electric (TE) and transverse magnetic (TM) polarizations. [ABSTRACT FROM PUBLISHER]

A mixing rule in the theory of composites is intended to describe an inhomogeneous composite medium containing inclusions of one or several types in a host matrix as an equivalent homogeneous medium. The Maxwell Garnett mixing rule is widely used to describe effective electromagnetic properties (permittivity and permeability) of composites, in particular, biphasic materials, containing inclusions of canonical shapes (spherical, cylindrical, or ellipsoidal). This paper presents a procedure for deriving an equivalent Debye model that approximates the geometry-based Maxwell Garnett model for randomly distributed cylindrical inclusions. The derived Debye model makes the equivalent dielectric material suitable for any time-domain electromagnetic simulations. [ABSTRACT FROM AUTHOR]

A semianalytical approach to obtain an equivalent Debye frequency dependence of effective permittivity for biphasic materials with random spherical inclusions from the well-known Maxwell Garnett (MG) mixing rule is proposed. Different combinations of frequency characteristics of mixture phases (host and inclusions) are considered: when at least one of the phases is frequency independent; lossy (with dc conductivity); or with a known single-term Debye frequency dependence. The equivalent Debye models approximate very well the frequency characteristics obtained directly from MG mixing rule. In some cases, there is an exact match between the two models, and a good approximation is achieved in the other cases and is quantified by the feature selective validation technique. The parameters of the derived equivalent Debye model can be employed in full-wave time-domain numerical electromagnetic codes and tools. This will allow for efficient wideband modeling of complex electromagnetic structures containing composite materials with effective dielectric parameters obtained through MG mixing rule. [ABSTRACT FROM AUTHOR]