## 1 Introduction  
Metamaterials (MMs) and their planar versions--metasurfaces (MS)--have been growing in popularity in recent decades and their applications are being expanded into new diverse fields [1]. Electromagnetic MMs are artificial materials whose properties depend on the physical characteristics of their elements but also on the geometry and dimensions of the unit cell [2]. A metamaterial is created by a lattice of metallic wires and other shape objects, such as split-ring resonators (SRRs), and its unique properties are associated with the negative indexes of magnetic permeability and dielectric permittivity [3]. These extraordinary properties can be engineered and artificially refined, unlike ordinary, naturally occurring materials whose properties are limited by chemical composition [2, 4]. Moreover, we can tailor these properties to our needs by designing tunable metamaterials. The term tunable MM (or MS) refers to a structure in which electromagnetic behavior can be intentionally modified during the normal operation of the device, e.g., having the effect of changing the geometry of the unit cell [5, 6, 7]. More specifically, many of the examples in the literature are about tunable devices that use individual resonators (commonly a split-ring resonator (SRR)) [5, 8]. A number of methods are known in the literature for tuning dynamic changes in metamaterial performance through direct changes in the unit cell circuit model. The tuning of metamaterials is accomplished by using chemically, electrically, or thermally sensitive materials or by changing the geometry of a unit cell by stretching, moving, or deforming all or part of it [5, 9, 10]. Some of these methods include micro-electro-mechanical systems (MEMS) technology, thermal annealing, phase-transition materials, two-dimensional material, laser pumping, and liquid crystals [11; 12]. Among these tuning mechanisms, the efficient method is to geometrically change the configurations of the unit cells because the effective properties of metamaterials are determined by them [2; 7; 8; 9; 10; 13]. Such change can be obtained using MEMS technology. The concept of a meta-surface also carries with it many different properties. Such exotic properties as epsilon-near-zero and perfect absorption can also be distinguished. The concept of such quantities were already discussed, for example, by [PERSON], [PERSON] et al. [14]. They presented a novel universal coupled theory for metamaterial Bound states in the continuum (BIC) and quasi-BIC, which allows for ultra-high resonances of metamaterial devices. In turn, [PERSON], [PERSON] et at. [15] discussed the phenomenon of time-dependent change in the refractive index of material. They experimentally demonstrated such an effect and determined that the frequency change of an optical beam passing through that medium can be significantly enhanced by a nonlinear epsilon-near-zero-based (ENZ-based) plasmonic metasurface. Typical MEMS-based metamaterials exploit several actuating methods, such as electrostatic actuators (ESAs), electrothermal actuators (ETAs), and electromagnetic actuators (EMAs) [11]. The unit cells at different reconfiguration states tune the amplitude, frequency, and bandwidth [2; 7]. In 2020, [PERSON] et al. [16] proposed a tunable metamaterial structure using an electrostatically electric spit-ring resonator for the realization of an excellent switching performance [16]. In their work, their electrostatically eSRR is fabricated on a silicon (SI) layer on an insulator (SOI) substrate. The eSRR consists of anchored rectangular SRRs and a movable I-shaped metal rod. The rod is connected to an electrostatic comb driver. This special construction affects the electromagnetic responses of eSRR, which could be switched under the different polarization states among the THz frequency range. In this paper, a similar (slightly modified) geometry to that proposed in [16] is used to investigate and find resonant frequencies.