Computational Analysis of Metasurfaces

Abstract

Metasurfaces represent one of the most vibrant fields of modern science and technology. A metasurface is a complex electromagnetic structure, that is typically deeply subwavelength in thickness, electrically large in transverse size and composed of subwavelength scattering particles with extremely small features; it may generally be bianisotropic, spacevarying and time-varying, nonlinear, curved and multiphysics. With such complexity, the design of a metasurface requires a holistic approach, involving synergistic synthesis and analysis operations, based on a solid model. The Generalized Sheet Transition Conditions (GSTCs), combined with bianisotropic surface susceptibility functions, provide such a model, and allow now for the design of sophisticated metasurfaces, which still represented a major challenge a couple of years ago. This paper presents this problematic, focusing on the computational analysis of metasurfaces via the GSTC-susceptibility approach. It shows that this analysis plays a crucial role in the holistic design of metasurfaces, and overviews recently reported related frequency-domain (FDFD, SD-IE, FEM) and time-domain (FDTD) computational techniques.

Smart radio environments empowered by reconfigurable AI meta-surfaces: an idea whose time has come

“…A meta-surface is, in practice, an electromagnetic discontinuity, which can be defined as a complex electromagnetic structure that is typically deeply sub-wavelength in thickness, is electrically large in transverse size, and is composed of sub-wavelength scattering particles with extremely small features [31]. In simple terms, a metasurface is made of a two-dimensional array of sub-wavelength metallic or dielectric scattering particles that transform the electromagnetic waves in different ways [36].…”

Comparison of Tensor Boundary Conditions With Generalized Sheet Transition Conditions

“…(11)]. 2 The only restriction of GSTCs as given in [1] in terms of generality is the fact that they are restricted to first-order discontinuities, i.e., to discontinuities that involve only the Dirac delta distribution and none of its derivatives, as the conventional boundary conditions. However, this is a rather minor restriction: this formulation seems to cover most of the practical sheet discontinuities.…”

“…(generally 36 parameters, and often 16 tangential parameters) metasurfaces by Achouri and Caloz [1], [9]. GSTCs may also apply to two-dimensional materials constituted of a single layer or a small number of atomic layers, such as graphene, molybdenum disulfide or black phosphorous [2].…”

“…R Ecently, the Generalized Sheet Transition Conditions (GSTCs) have been abundantly and successfully used as an electromagnetic model to synthesize and analyze metasurfaces [1], [2]. GSTCs are generalizations of the conventional boundary conditions [3], relating the field differences at both sides of a sheet discontinuity not only to surface currents but also to surface polarisations [4] (Eqs.…”

“…(1)- (3) and Appendix A therein). They were originally introduced by Idemen [5], [6], next expressed in terms of surface polarizability or susceptibility tensors for metasurfaces by Kuester and Holloway [7], [8], and finally extended to the most general 2…”