Extracting Electromagnetic Parameters of Metamaterials Using the NRW Method

The NRW method serves as a computational approach for extracting electromagnetic parameters of metamaterials, fundamentally relying on numerical calculations and data processing techniques. In practical implementation, this method involves collecting scattering parameter data (S-parameters) from simulated or measured results, followed by executing inversion algorithms to determine permittivity and permeability values. The core algorithm typically involves solving transcendental equations derived from transmission line theory, where key computational steps include calculating refractive index and impedance from S11 and S21 parameters. Additionally, the methodology requires referencing two seminal research papers that provide detailed theoretical foundations and application case studies. These publications offer comprehensive insights into NRW method implementation, including handling phase ambiguity issues and validation techniques for metamaterial characterization. Consequently, for researchers investigating electromagnetic properties of metamaterials, the NRW method represents a fundamental analytical framework worth considering, particularly when implementing parameter extraction algorithms in programming environments like MATLAB or Python with numerical computation libraries.