###### Abstract  
The electromagnetically induced transparency effect of terahertz metamaterials exhibits excellent modulation and sensing properties, and it is critical to investigate the modulation effect of the transparent window by optimizing structural parameters. In this work, a unilateral symmetrical metamaterial structure based on the cut-wire resonator and the U-shaped split ring resonator is demonstrated to achieve electromagnetically induced transparency-like (EIT-like) effect. Based on the symmetrical structure, by changing the structural parameters of the split ring, an asymmetric structure metamaterial is also studied to obtain better tuning and sensing characteristics. The parameters for controlling the transparent window of the metamaterial are investigated in both passive and active modulation modes. In addition, the metamaterial structure based on the cut-wire resonator, unilateral symmetric and asymmetric configurations are investigated for high performance refractive index sensing purposes, and it is found that the first two metamaterial structures can achieve sensitivity responses of 63.6 GHz/RIU and 84.4 GHz/RIU, respectively, while the asymmetric metamaterial is up to 102.3 GHz/RIU. The high sensitivity frequency response of the proposed metamaterial structures makes them good candidates for various chemical and biomedical sensing applications. t 20 May 2022008 July 202208 July 2  
fishing net structure [13], dipole-coupled quadrupole [14] have also been investigated to achieve EIT-like phenomenon. For example, in 2008, [PERSON] et al. [15] found that plasma induced transparency (PIT) can be generated through the near-field coupling of \"bright-mode\" structure and \"dark mode\" structure, and demonstrated an EIT-like effect using electromagnetic metamaterials. In 2013, [PERSON] et al. [16] realized a broadband EIT-like effect by using a transverse tangent and four open resonant rings. In 2019, [PERSON] et al. [17] realized the EIT-like effect by using SSRR and CSRR. Most research works focused on the design of the metamaterial structures and further analysis of coupling mechanism between each component of the metamaterial device. However, the transparent windows of these studies have been realized at a fixed frequency. It is essential to reconstruct the geometries or modify the substrates if the resonance needs to be tuned to different working frequencies. In order to improve the sensor performance, many materials are adopted to construct EIT-like structures including graphene and 3D Dirac semimetals. The optical response of graphene can be dynamically adjusted by the Fermi energy or the coupling strength between the two layers. For example, [PERSON] et al. [18] designed a PIT metamaterial structure, which is composed of a sinusoidally curved and a planar graphene layer. [PERSON] et al. [19] proposed and simulated a novel tunable EIT in terahertz metal-graphene metamaterial. The amplitude of EIT window can be modulated by changing the Fermi level of graphene. [PERSON] et al. [20] designed a double layer of gold multipattern swastika (DLMP) resonator based on SiO\({}_{2}\) substrate. Although graphene possesses outstanding optical properties, enabling dynamic control of electromagnetic waves, its coupling with light is not strong enough to enable it to be used directly in practice owing to its ultrathinness in space. The 3D Dirac semimetal is also called '3D graphene'. [PERSON] et al. [21] proposed a complementary BDS metamaterial structure to achieve a tunable EIR effect with a high Q-factor. However, the dielectric constants of 3D Dirac semimetals are dynamically regulated mainly by changing their Fermi energy. For some 3D Dirac semimetals such as PdTe\({}_{2}\), PdSe\({}_{2}\), and PtTe\({}_{2}\), the Dirac point is far from the Fermi surface, which makes experimental modulation more difficult. In some practical applications, it is very important to modulate the transparent window of the EIT-like phenomenon, which can realize terahertz modulators and the terahertz switches.