Inverse C-shaped Complementary Split-ring Resonator-based NRI Meta-atom for Wireless Applications

Abstract

This study investigates a meta-atom exhibiting a broad Negative Refractive Index (NRI). The meta-atom is constructed using a complementary circular-square split-ring resonator shaped in an inverse C design. The electromagnetic properties of the structure were analyzed through simulations using CST Microwave Studio, Ansys HFSS 3D software, and ADS. The meta-atom demonstrates three distinct resonant frequencies at 2.71 GHz, 4.19 GHz, and 5.60 GHz, spanning both the S- and C-bands. Its optimal Effective Medium Ratio (EMR) is 12.30, and the unit cell measures 9 mm × 9 mm with a substrate thickness of 0.508 mm. This design is notable for its compact dimensions, strong NRI performance, high EMR, and well-defined resonance points. The S-band, commonly used for radar, and the C-band, which supports high-speed Wi-Fi networks, are both covered by this structure. The paper outlines the design methodology and various parameter optimization processes. Simulation results from Ansys HFSS align well with those from CST and ADS. Additionally, the study includes an analysis of surface current distributions, as well as the electric (E-field) and magnetic (H-field) field patterns. Compared to alternative designs discussed in the article, this proposed structure offers superior performance, showcasing a high EMR, extensive NRI range, and a compact form factor suitable for radar and Wi-Fi applications.