Bilateral Coupled Epsilon Negative Metamaterial for Dual Band Wireless Communications

Abstract

This work presents a dual band epsilon negative (ENG) metamaterial with a bilateral coupled split ring resonator (SRR) for use in C and X band wireless communication systems. The traditional split-ring resonator (SRR) has been amended with this engineered structure. The proposed metamaterial unit cell is realized on the 1.6 mm thick FR-4 printed media with a dimension of 10 × 10 mm2. The resonating patch built with a square split outer ring. Two interlinked inner rings are coupled vertically to the outer ring to extend its electrical length as well as to tune the resonance frequency. Numerical simulation is performed using CST studio suite 2019 to design and performance analysis. The transmission coefficient (S21) of the proposed unit cell and array configuration exhibits two resonances at 6.7 and 10.5 GHz with wide bandwidth extended from 4.86 to 8.06 GHz and 10.1 to 11.2 GHz, respectively. Negative permittivity is noted at frequencies between 6.76–9.5 GHz and 10.5–12 GHz, consecutively, with near-zero refractive index and permeability. The optimal EMR value depicts the compactness of the proposed structure. The 1 × 2, 2 × 2 and 4 × 4 arrays are analyzed that shows similar response compared to the unit cell. Measured results of the 2 × 2 array shows the close similarity of S21 response as compared to simulation. The observed properties of the proposed unit cell ascertain its suitability for wireless communications by enhancing the gain and directivity of the antenna system.