# I-Shaped Metamaterial Using SRR for Multi-Band Wireless Communication
## 1 Introduction  
The demand for multi-band operational metamaterials (MeTMs) has increased substantially because of the rapid growth of wireless communication applications. MeTMs are artificially engineered structures which have distinct electromagnetic properties not found in regular materials [1]. Certain materials display negative permittivity and permeability which are not present in nature. In 1945 and 1968, [PERSON] and [PERSON] proposed the concepts the Left Hand Medium (LHM) materials which exhibited negative permittivity and permeability [2, 3]. They also presented the general properties of electromagnetic wave propagation in such materials. A metallic structure with negative permeability was presented by [PERSON] et al. [4] in 1996. He, in collaboration with other researchers [5], also created metallic SRR which is a non-magnetic structure. Furthermore, in 2000, [PERSON] et al. [6] designed the SRR, proposed by [PERSON], on a printed circuit board (PCB) by integrating the SRR with set of copper strips. The electric permittivity (\(\epsilon\)) and the magnetic permeability (\(\mu\)) were extracted and analyzed. Transmission-line-based MeTMs was proposed in by [PERSON] et al. [7] and [PERSON] et al. [8]. As a result of their distinct electromagnetic characteristics, numerous researchers have proposed and presented several MeTMs for various uses. The application areas of MFT include design of electromagnetic absorbers [9], multi-band elements [10],reduction of specific absorption rate (SAR) [11], wireless communication [12; 13], sensing applications [14; 15], MeTM antennas [16], visibility cloaking [17; 18], filters [19; 20] etc. Certain metals exhibit negative permittivity by nature but finding a natural material with negative permeability is somewhat more challenging. Despite the use of artificial structures, negative permeability is difficult to accomplish. As a result, obtaining negative permittivity and permeability (\(0>\varepsilon\) & \(0>\mu\)) concurrently is quite challenging. To meet the growing demand for improved MeTM characteristics, various studies have been conducted from single to multi-band MeTMs unit cells and array structures. Broad bandwidth (BW) MeTMs have become a major interest area in recent years. Nevertheless, extensive design work has not been carried out for such materials [21]. A microwave MeTM with double S-shaped structure operating in a frequency band of 15.63 GHz with dimensions of 4 \(\times\) 4 mm\({}^{2}\) was presented by [PERSON] et al. [22]. This structure displays both permittivity and permeability at frequency range of 15.63 GHz and 17.8 GHz while the negative refractive index lies between 15.67 and 17.43 GHz. A MeTM antenna with dimensions of 30 \(\times\) 22 \(\times\) 0.8 mm\({}^{3}\) was proposed by [PERSON] et al. [23], operating at a single band. Moreover, its unit cell's MeTM properties were not discussed or validated. The design of a novel two-rectangular U-shaped negative MeTM was proposed by [PERSON] et al. [24] for various orthogonal structures. The structure has dimensions of 25 \(\times\) 25 \(\times\) 1 mm\({}^{3}\). A glass substrate, gold plate and a thin-plate graphite were used for the design of the unit cell. The structure exhibited the properties of permittivity and permeability with an operating frequency at 5 to 7 GHz. [PERSON] et al. [25] presented an Aztec shape MeTM structure with dimensions of 11 \(\times\) 12 \(\times\) 1.6 mm\({}^{3}\). FR-4 was used as the substrate material operating at a frequency range of 6.3, 8.9, 11.91 and 16.42 GHz. A V-shaped MeTM was proposed by [PERSON] et al. [26]. [PERSON] et al. [27] presented an I-shaped MeTM antenna with dimensions of 12.5 \(\times\) 12.5 mm\({}^{2}\). The structure resonates between 5 and 15 GHz. The structure was etched on a fused quartz substrate with dimension of 5 \(\times\) 5 \(\times\) 0.25 mm\({}^{3}\). At a frequency of 8.10 GHz, the structure exhibited double-negative characteristics. A novel Z-shaped MeTM was presented by [PERSON] et al.