# A New Compact Double-Negative Miniaturized Metamaterial for Wideband Operation
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examinations to test its unusual properties in 2000. Because of these intriguing electromagnetic properties, metamaterials can be utilized as a part of numerous important applications, such as super-lenses, waveguides, filters [4], antenna design [5; 6], invisibility cloaking [7], reduction of SAR [8], electromagnetic absorbers, and electromagnetic band gaps [9]. At present, multi-band metamaterials or arrays of metamaterials with wide negative refractive index bandwidths have become a promising methodology for specialists, although very few studies have concentrated on designing such materials [10; 11; 12]. Intrinsic negative permittivity can be found in some metals, but a natural medium with negative permeability is harder to find. Even using artificial structures, it is relatively difficult to realize negative permeability. As a result, simultaneous negative refractive indexes (\(\varepsilon<0\) and \(\mu<0\)) are very difficult to obtain. Numerous alphabetical metamaterial structures have been proposed for particular applications; for instance, [PERSON] et al. [13] proposed a double \"S-shape\" metamaterial in the microwave range, which showed a negative refractive index from 15.67 to 17.43 GHz. [PERSON] et al. [14] introduced a rectangular \"U-shape\" metamaterial that displayed left-handed attributes at approximately 5, 6, and 11 GHz for various array structures. [PERSON] et al. [15] presented a \"V-shape\" metamaterial, and the structure exhibited double-negative attributes at 8.10 GHz. [PERSON] et al. [16] designed an \"F-shape\" DNG metamaterial for K- and Ka-band, which had a 2.3-GHz negative refractive index bandwidth from 22.5 GHz to 24.8 GHz. An \"S-shape\" 15 \(\times\) 15-mm\({}^{2}\) chiral metamaterial was designed by [PERSON] et al. [17] for X- and Ku-band, but the shape's effective medium ratio was less than 4. [PERSON] et al. [18] proposed an \"H-shape\" metamaterial for multiband microwave applications, and negative index qualities were seen in the C (bandwidth of 0.5 GHz) and S (bandwidth of 0.3 GHz) bands. The dimensions of the metamaterial unit cell were 30 \(\times\) 30 mm\({}^{2}\). [PERSON] et al. [19] presented two \"G-shape\" double-negative metamaterials for different unit cells and array sizes, which were appropriate for the S- and C-band. Moreover, [PERSON] et al. [20] designed an 8 \(\times\) 8-mm\({}^{2}\) \"Hexagonal-shape\" double-negative medium metamaterial, for which the refractive index regions were obtained from 1.68 to 3.43 GHz (bandwidth of 1.75 GHz) and 5.04 to 6.0 GHz (bandwidth of 0.96 GHz). In this study, the designed Modified-Z-shape structure exhibits resonance at C- and X-bands with a wider negative refractive index bandwidth from 3.482 to 7.096 GHz (bandwidth of 3.61 GHz), 7.876 to 10.047 GHz (bandwidth of 2.171 GHz), and 11.594 to 14 GHz (bandwidth of 2.406 GHz), which is a larger bandwidth than that of [19; 20]. Moreover, the proposed structure's dimension is 10 \(\times\) 10 mm\({}^{2}\), which is quite a bit smaller than the metamaterial unit cell presented in [17; 18]. As a result, the effective medium ratio of the unit cell is more than 4, and it is suitable for operating the sub-wavelength regime. Moreover, double-negative metamaterial properties appear at 8.79 GHz for unit cells and in case of array configurations at 8.60 GHz. The commercially available electromagnetic simulator CST Microwave Studio has been used to monitor the reflection coefficient (\(S_{11}\)) and transmission coefficient (\(S_{21}\)) to determine the effective permittivity, permeability, and refractive index for the proposed metamaterial structure. The paper is organized in the following manner. Construction of the proposed unit cell is described in Section 2. The methodology is explained in Section 3. An equivalent circuit model is discussed in Section 4. Experimental results are elaborately explained in Section 5, and Section 6 concludes this paper.