| Double-negative (DNG) metamaterials, refer to artificially created materials both having negative permittivity and effective permeability at a given frequency. In the last several years, double negative metamaterials attract a great deal of attention from scientists.;In the area of high frequency application, transmission line serves as the fundamental building blocks. Due to the different application purposes, two kinds of microstrip are widely studied, shielded and open. In 2003, Krowne published his numerical results for shielded microstrip line with double negative metamaterials.;In this research, Chebyshev polynomials are chosen for the current basis functions and diverse model structures are analyzed. Spectral domain approach (SDA) is used to explore the electric guiding-wave properties of specific structures with DNG metamaterials, containing dispersion curves, field distributions, power flow, and characteristic impedance. Convergence test of the dispersion constant over different sizes of current basis is analyzed for the open microstrip. The numerical results show that propagating mode or complex mode is found at different frequencies and geometric setups. Field distributions show the significant difference from that of double positive (DPS) materials. To improve the calculation efficiency, numerical acceleration techniques are included and implemented. The numerical analysis implies that the shielding walls have great impact on the propagating properties in the shielded microstrip line. The open microstrip line filled with DNG metamaterials exhibits significant loss in its fundamental mode, indicating that it is not a good candidate for transmission line. |
