Impedance boundary conditions for finite planar or curved frequency selective surfaces embedded in dielectric Layers

Dyadic Green's Function of an Elementary Point Source Above a Periodically-Defected-Grounded Dielectric Slab

“…The problem now is converted into obtaining the reflection coefficients Γ T E/T E and Γ T M/T E for the periodically defected grounded dielectric slab at different values of k x0 and k y0 by using an appropriate technique like method of moment [16][17][18][19]27] or by using experimental data. The results in the present paper are based on obtaining these reflection coefficients by using method of moment.…”

“…Fortunately, such specular reflection can be calculated by using simple equivalent network that can be obtained by fitting the reflections for few angles of incidence [16][17][18][19][20][21]. Then by applying this equivalent network in the spectral integration, one can obtain the integrand for any spectral point by using simple forms.…”

A Physical Optics Approach to the Analysis of Large Frequency Selective Radomes

“…Then the curved or finite FSS is treated in a ray-tracing framework, and to each ray the pertinent reflection and transmission coefficient is applied -possibly taking into account multiple internal reflections [28][29][30][31]. Alternate approaches relies on equivalent impedance boundary conditions which are, anyway, computed on the equivalent, planar, infinite, FSS [32]. Yet the problem of the curved FSS of a radome is critical since the surface periodicity is disrupted as the periodic cell cannot be deformed without significantly altering its frequency behavior and hence Floquet theory cannot be applied at all; applications to curved FSS, when available, are anyway limited or quite complex to implement [33].…”

Sufficient uniqueness conditions for the solution of the time harmonic Maxwell’s equations associated with surface impedance boundary conditions

“…To circumvent these difficulties, a possible approach is to replace the FSS by a uniform sheet (thus avoiding to mesh the unit cells) on which an IBC is prescribed. The strictly local, low-order, IBC proposed in [17] for a single FSS in free-space, and generalized for multiple FSSs embedded in materials [19], is efficient only for a given angle of incidence. High-order IBCs that are valid in a large angular range have then been proposed [18,19].…”

“…The strictly local, low-order, IBC proposed in [17] for a single FSS in free-space, and generalized for multiple FSSs embedded in materials [19], is efficient only for a given angle of incidence. High-order IBCs that are valid in a large angular range have then been proposed [18,19]. Implemented in an IE or FE formulation, they allow to model complex structures.…”