Abstract
In this work, a modified RLC-based resonator with a large bandwidth of the negative refractive index (NRI) equal to almost 3.40 GHz has been realized in its operating region by adding a tunnel structure, and its electric and magnetic properties are determined by investigating the tunneling effect produced by a conventional split-ring resonator (SRR). It is found that the NRI bandwidth of the conventional SRR is increased by almost a factor of two after tunnel insertion. The CST Microwave Studio electromagnetic simulator is used to design the structure, extract scattering parameters, and determine structural characteristics, whereas the Advance Design Software is utilized to perform simulations for the equivalent circuit of the proposed resonator. The measured scattering parameters and data obtained for the equivalent circuit are further used to verify the CST-based simulation results. Moreover, the simulated resonance frequency (8.84 GHz) as well as the corresponding experimental magnitude (8.86 GHz) and value obtained for the equivalent circuit (8.74 GHz) are all located in the X-band of the microwave region. The developed metamaterial tunneling structure can be potentially used in many areas including the defence sector.