Cross coupled interlinked split ring resonator based epsilon negative metamaterial with high effective medium ratio for multiband satellite and radar communications

Abstract

In this paper, a cross coupled interlinked split ring resonator based (CCI-SRR) based metamaterial has been presented. Epsilon negative (ENG) with a highly effective medium ratio (EMR) is attained in this metamaterial. The metamaterial unit cell consists of one square shaped split ring resonator and two rectangular rings. The rectangular rings reside within the outer square split ring. Two internal rings are coupled together by using a cross-shaped metal segment. These inner rings are also interlinked to the outer ring by using metal strips. Coupling causes to increase the electrical length and modifies the inductance of the unit cell. Multiple resonances covering C, X and Ku-band are achieved due to the interconnection of rings. The symmetric nature of the CCI-SRR unit cell exhibits unique quality to minimize noise and harmonics effect. The unit cell is designed on FR4 substrate with a thickness of 1.6 mm. The overall dimension of the unit cell is 0.124λ × 0.124λ, where λ is the wavelength calculated at a lower resonance frequency of 4.15 GHz. Three resonances are obtained for |S21| at frequencies of 4.15 GHz, 10.38 GHz and 14.93 GHz performing numerical simulation in CST microwave studio. Permittivity, permeability, refractive index and impedance are explored by using the Newton-Ross-Weir (NRW) method. ENG performance is observed in frequencies ranging from 3.95 to 5.65 GHz, 9.57–11.46 GHz, 13.68–16 GHz. Near-zero refractive index is attained within the frequency ranges, 4.16–5.75 GHz, 10.16–11.58 GHz, 14.46–16 GHz. An LC equivalent circuit is designed, and component values are achieved by Advanced Design Software (ADS) justifying |S21| with CST result. The study of electromagnetic wave interaction between the unit cell and the double positive medium reveals that the unit cell exhibits evanescent wave properties. The compact nature of the unit cell is confirmed by calculating EMR with a value of 8.03. The electromagnetic coupling effect is examined for 2 × 2 array in various orientations. The |S21| performance of 2 × 2, 4 × 4 and 8 × 8 is matched with the unit cell. Due to symmetric patterns, near-zero refractive index, negative permittivity and high EMR, the proposed unit cell can be used to enhance the performance of microwave devices used for C, X and Ku-bands, especially Satellite and Radar communications.