Simulation of transmission waves through multilayered thin conducting sheets by FDTD method

Abstract

SUMMARYDue to their great fabrication flexibility, multilayered conductive thin films are used as a shielding material by thin film metal plating on a dielectric body. In the simulation of the shielding effect of these multilayered thin conducting films by the FDTD method, it is necessary to use a cell size less than the conductor thickness in direct modeling. However, since the shield material generally is much thicker than the metal thin film, the number of cells needed in such modeling is prohibitive and calculation becomes difficult. In this paper, as a subcell method in the FDTD approach, an infinitesimally thin resistive film that has a transmission coefficient equivalent to the multilayered conducting thin film is introduced. By this technique, modeling becomes possible without increasing the number of cells unnecessarily.

FDTD Analysis of Effectiveness of Shielding Clothes in Suppressing Electromagnetic Field in Phantom Model

“…In this case the material thickness exceeding the skin depth and oblique incidence cause the error to increase. In this paper we improve the method in reference (6), and then suggest a method that agrees well with the theoretical result for the SE of the shielding material thicker than the skin depth and for the problem caused by oblique incidence (7) .…”

“…Next, since the plane of incidence (x'-z' plane) in Fig.1 changes according to the propagation direction of EM wave, it is necessary to change to the basic x-y-z coordinates system as shown in Fig.2. Thus, the electromagnetic fields in the x-y plane are expressed by equations (4) and 5, respectively, and the theoretical transmission coefficients T x and T y of the components in the x-y plane can be obtained by equation (6).…”

“…In this case, however, the error increases depending on the material thickness and frequency. Further, another case has been reported that the transmission problem is calculated by introducing the shielding material into FDTD method as an infinite thin resistive film (5) (6) . In this case the material thickness exceeding the skin depth and oblique incidence cause the error to increase.…”

“…When dealing with an extremely thin shielding material as compared with the wavelength in FDTD analysis, it is possible to derive effective formulation by using the theoretical transmission coefficient T and surface resistance R s of the shielding material (6) (7) . Here, we extend it to the 3-D model, which has not been reported so far with the oblique incidence.…”

FDTD Simulation of Shielding Effectiveness of Metal-Coated Plastics for Pulsed Electromagnetic Fields

“…This becomes especially difficult for a multi-layer structure [6], [7] such as the metal-coated plastics. To cope with this problem, an approach with a transmission line model was made in [8], in which the transmission coefficient of the multi-layer structure was approximately derived and was replaced with that of an infinitely thin resistive film being formulated via its surface impedance in the FDTD method. This approach was reported to be superior to that in [6] for a multi-layer structure.…”