## 3 Results  
Simulations were performed to find the change in resonant frequency as a function of offseting the I-shaped metallic bar. The verified data were then compared with data from the same study, only with the assumption that there is a thin dielectric layer in vicinity of the metasurface. The film thickness in the design was considered to be 15 \(\upmu\)m, as most film solutions on the market assume a thickness from 6/7 \(\upmu\)m upwards [18]. Reviewing the simulation results, many relationships can be seen. While studying the behavior of eSRR under various geometries, the behavior of resonant frequency was evaluated. With some eSRR geometries, more than one resonant frequency appeared in the considered frequency band. Given the goal of this study, the possibility of having an eSRR whose resonant frequency changes when the geometry changes was explored; additionally, more stable resonances were omitted whenever possible, with the focus being on the larger and visibly changing ones. All simulations were performed in the COMSOL Multiphysics 5.4 environment. The creation of a numerical model suitable for subsequent simulations requires the completion of several necessary work steps. The first of these is the creation of the structure. This stage includes the following: Creating the cuboid in which the eSRR will be placed (Figure 4a). The dimensions used in the design to create the cuboid are 100 \(\times\) 100 \(\times\) 140 \(\upmu\)m. A substrate layer must then be created, for the eSRR this will be a dielectric substrate on which the SRR geometry will be created from conductive elements. The dimensions of the substrate (Figure 4b) are 100 \(\times\) 100 \(\times\) 20 \(\upmu\)m, respectively. The final step in the construction of the elementary cell structure is to apply the geometry of the conductive parts. The second stage of the SRR model design is to assign physical properties to the individual elements. The conductive layers were given the physical parameters of gold, for which the electrical conductivity was determined as 4.09 \(\times\) 107 (S/m). The relative permittivity (\(\varepsilon\)R) of the substrate is 3.9 and the void space (defined as air) in the solid is equal to 1. Figure 4: Simplified (single element) structure of the metasurface model: (**a**) proposed metasurface structure; (**b**) proposed metasurface structure with very thin additional dielectric layer. The third and final step in creating the numerical model is to define the boundary conditions. Thus, the following roles have been assigned to the planes present in the geometry: ports, perfect electrical conductors, perfect magnetic conductors, impedance and transition boundary conditions. Ports are used because electromagnetic energy is supplied and received into the model. The port allows and supports the calculation of the scattering parameter, but can also be used to excite the model. The boundary condition of an ideal electric conductor is a special case of the electric field boundary condition, which sets the tangential component of the electric field to zero. The boundary condition of an ideal magnetic conductor, on the other hand, is a special case of the boundary condition of the of the surface current, which sets the tangential component of the magnetic field, and therefore the and the surface current density to zero. The impedance boundary condition is useful at boundaries where the electromagnetic field penetrates only a short distance beyond the boundary. In contrast, the transient boundary condition is based on the assumption, that the wave propagates in the normal direction in a thin film. It represents a discontinuity in the tangential electric field. The position of the boundary conditions described above in the model is shown in Figure 5. For the model prepared in this way, a computational mesh was generated and then computations were performed using a direct solver. An FEM (Finite Element Method)-type analysis was performed to check the electromagnetic field distribution.