The Pml-fdtd Method In The Analysis Of Two-dimensional Negative Refractive Index Materials

Started with the characteristics and present study situation of Negative Refractive Index materials (DNG), this paper first gives a brief introduction of the development, actualities and prospects of DNG as well as its basic principles and electromagnetic specialty. Next, based on the current FDTD Method, Drude Model is introduced and subsequently the difference time Domain equation of two-dimensional in DNG is established. While the perfectly matched layer (PML) is applied at the absorbing boundary, the index difference equation is deduced. As a result, the unstable phenomena in the leapfrog process got avoided. "Poyntings' Vector S goes opposite to wave vector K and under certain conditions, a flat made of DNG can form perfect lens". According to these two electromagnetic specialties and the new difference equation, a DNG flat's perfect lens forming gets stimulated. After the stimulating result comparison with the positive refractive index materials, it comes to a conclusion that stimulating result from the new difference equation goes with the electromagnetic characteristics of DNG, which serves as a proof of the correctness of equation deduction. Meanwhile, with the gauss impulse as a stimulative source, the 1-D periodic structure formed with DNG flats is simulated. According to the result analysis, it reaches the conclusion that this band gap structure is selective to transparence frequency besides the DNG's coherence with electromagnetic specialty, which also provides the proof of its one-dimensional photonic crystal.The key point of this paper lies in the 2-dimision equation and the deduction and stimulationvalidation of index difference equation in PLM layer after the introduction of Drude Model.With the precondition of FDTD methods' stability, this method provides a precision-improving stimulation idea. The deduced equation and the stimulation idea become a beneficial supplement to the DNG materials analysis.