Abstract
In this paper, we study the existence of a surface wave on bianisotropic metasurfaces (BMS) by using electric and magnetic polarizabilities. These polarizabilities connect the local electric and magnetic fields on BMSs with electric and magnetic surface polarizations. We have chosen the method based on surface polarizations because applying boundary conditions using surface polarizations gives a better physical insight than the other methods including surface impedance-based methods. Variations of the electric and magnetic surface polarizations are equivalent to electric and magnetic surface currents, respectively; so, the Variations lead to discontinuities of the magnetic and electric fields on the BMS’s surface. In BMS structures, one of the challenges is the cross-polarization between TE and TM modes, because of both the anisotropy and bi-isotropy of these structures. Using the electric and magnetic polarizabilities gives a better physical insight to the cross-polarization. To obtain surface wave excitation conditions, on a general BMS in the presence of an electric line source, we should firstly apply the boundary conditions and obtain the unknown coefficients in terms of the electric and magnetic polarizabilities. In the last step, we extract the dispersion equation by using the polarizabilities. To verify the results we have simulated an array of $\Omega $ -particle metasurface and a planar periodic array with non-identical coupled square conducting patches imprinted on two sides of a dielectric slab. The comparison between the dispersion curves obtained with the theoretical method and the simulation results reveals an overall good agreement.
Highlights
Nowadays, metamaterials are more practical for designing than natural structures due to their unusual electromagnetic properties, and their greater degrees of freedom for achieving specific responses [1]–[4]
In this paper, the conditions for surface wave excitation on a bianisotropic MS, in the presence of an external electric line source have been investigated by using the concept of electric and magnetic polarizabilities
We have investigated the cross-polarization between the TE and Tm modes with respect to the structure polarizabilities
Summary
Metamaterials are more practical for designing than natural structures due to their unusual electromagnetic properties, and their greater degrees of freedom for achieving specific responses [1]–[4]. The boundary conditions for electric and magnetic fields in MS structures have been extracted as follows, in Equations (3) and (4): z × H+t The wave equation for an electric vector potential in the presence of a magnetic current (JM ) and using the surface polarizations of a BMS structure, could be simplified to:
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