A compact quad-square negative-index metamaterial: Design, simulation, and experimental validation for microwave applications

This research provides a detailed explanation of the design, simulation, and experimental of quad-square metamaterial-based negative-index unit cells for S-band applications. The Computer Simulation Technology 2022 licensee version was utilized to design and obtain numerical results for the unit cell. The proposed unit cell for the metamaterial has dimensions of 5 × 5 × 1.57 mm3. The substrate chosen was FR-4, resulting in a substantial effective medium ratio value of 19.07. A series of systematic parametric studies were conducted to optimize the quad square metamaterial structure. Key parameters, such as substrate types, unit cell arrays, thicknesses of substrate, and split gaps, were varied to determine their impact on the structure. The validated equivalent circuit result was compared to the simulated results, showing a significant agreement. The demonstrated correlation between simulation and experimental data highlights the dependability of the proposed quad-square metamaterial, positioning it as a viable option for a range of electromagnetic applications, such as communication systems, sensors, and imaging devices.