Circuit modeling of multiband high-impedance surface absorbers in the microwave regime

Abstract

In this paper, we present a simple circuit model to study the absorption of electromagnetic waves by a multilayer structure with a high impedance surface in the microwave regime. The absorber consists of a stack of twodimensional arrays of sub-wavelength meshes or patches separated by dielectric slabs and backed by a metallic ground plane, with a single resistive sheet placed on the top layer. We observe the appearance of low-frequency resonances of total absorption, which have been identified as the resonances of Fabry-Pérot type associated with the individual reactively loaded dielectric slabs (that are strongly coupled through the subwavelength grids). It is shown that these resonances lie within certain characteristic frequency band defined by the structural parameters of the absorber. The observed resonances are characterized by studying the electromagnetic field behavior using the circuit model and full-wave numerical program. In addition, we show that the patch array absorber provides stable resonances with respect to the angle and the polarization of obliquely incident plane waves.

Line-source excitation of realistic conformal metasurface cloaks

“…The analytical grid-impedance expressions used in this work were originally derived and validated for planar surfaces and plane-wave incidence. 18,19,[21][22][23][24][25] In Ref. 17, we have successfully shown and verified the accuracy of these expressions for tailoring the required surface reactance of cylindrical metasurfaces, under far-field plane-wave illumination.…”

“…17 for plane-wave incidence are still very effective, even for near-field excitation, for both dielectric and conducting cylinders covered with slotted and printed metasurface mantle cloaks. We consider a variety of 2-D arrays with subwavelength periodic elements, such as mesh grids and patches, [18][19][20][21][22][23] and Jerusalem crosses. 24,25 The scattering problem is solved using the analytical eigenfunction-expansion method, which employs sheet impedance boundary conditions on the mantle cloak surface.…”

Design of a tunable absorber based on graphene in the terahertz band

“…2. In the circuit model analysis, the surface of the graphene-based patch array in each layer can be characterized by homogeneous surface impedance [18,19] …”

“…In this paper, we will use the idea of a resistive sheet adapted to a graphene-based structure, and display that the absorber shows tunable multiple peaks for both polarizations over a wide spectral range in the THz frequency. In addition, we use the equivalent circuit model (ECM) [16][17][18] to analysis the unit cell of the graphene-based structure.…”

Multilayered Wire Media: Generalized Additional Boundary Conditions and Applications

“…However, the analytical results shown in Fig. 12(b) are obtained using the circuit theory model given in [20,24,25]. By comparing Figs.…”