Analysis Of The Double-negative Medium Over A Broad Frequency Band

The double-negative (DNG) meta-material is a kind of artificial composite material, in which both the dielectric permittivity and dielectric permeability are negative. This material is also called left-handed material. DNG meta-material has a lot of strange features, such as negative index of refraction material, backwards-wave meta-materials etc.. It has potential application in fields of electromagnetics, optics, and materials. Therefore, accurately analyzing the electromagnetic characters in the DNG meta-material is more and more important.Firstly, the paper introduces the significance of DNG meta-material and the electromagnetic transmission characteristics of it. The basic concepts and related knowledge of method of moments (MOM) is introduced. The asymptotic waveform evaluation (AWE), as a frequency-sweep analysis method, is applied to perfectly electrical conducting (PEC) objects and dielectric objects. The results obtained by AWE agree well with that of exact solution or direct MOM, and the computational efficiency is improved significantly by AWE.Secondly, the asymptotic waveform evaluation (AWE) technique is applied to electromagnetic scattering analysis of double-negative (DNG) meta-material. The PMCHWT equation of the DNG meta-material is deduced based on its constitutive relationship. And the surface currents and radar cross section (RCS) at a single frequency point is computed. The impedance matrix elements are processed to achieve high-order derivation computation. Then the AWE technique is applied to obtain broadband RCS frequency response of the DNG. meta-material. A good agreement can be seen between AWE and the exact solution. And the computational efficiency is improved significantly.Finally, in order to reduce the computation complexity of high-order derivation computation in AWE, model-based parameter estimation (MBPE) techniques is introduced. Since for the same matrix equation, the order of derivation for impedance matrix elements can be reduced, the MBPE has more advantages in the frequency-sweep analysis of double negative meta-material. The results of MBPE is also compared with that of exact solution, direct MOM and AWE, and the computational efficiency is improved significantly.