A fast circuit model description of the shielding effectiveness of a box with imperfect gaskets or apertures covered by thin resistive sheet coatings

TY - JOUR

T1 - A fast circuit model description of the shielding effectiveness of a box with imperfect gaskets or apertures covered by thin resistive sheet coatings

AU - Konefal, T

AU - Dawson, J F

AU - Marvin, A C

AU - Robinson, M P

AU - Porter, S J

PY - 2006/2

Y1 - 2006/2

N2 - This paper presents an intermediate level circuit model (ILCM) for the prediction of the shielding effectiveness (SE) of a rectangular box containing one or more rectangular gaskets of known transfer impedance or constitutive parameters. The box may also possess a rectangular aperture covered by a thin resistive sheet. The ILCM takes into account multiple waveguide modes and is thus suitable for use at high frequencies and with relatively large boxes. The gaskets may be positioned anywhere in the irradiated front face of the box, and the SE at any point within the box may be found when irradiated by a plane wave. Solution times using the ILCM technique are three orders of magnitude less than those required by traditional numerical methods such as finite difference time domain (FDTD), transmission line matrix (TLM), or method of moments (MoM), even when using a relatively slow interpreted language such as MATLAB. Accuracy, however, is not significantly compromised. Comparing the circuit model with TLM over eight data sets from 4 MHz to 3 GHz resulted in an rms difference of 3.90 dB and a mean absolute difference of 2.35 dB in the predicted SE values. The ILCM accurately reproduces the detailed structure of the SE curves as a function of frequency and observation point.

AB - This paper presents an intermediate level circuit model (ILCM) for the prediction of the shielding effectiveness (SE) of a rectangular box containing one or more rectangular gaskets of known transfer impedance or constitutive parameters. The box may also possess a rectangular aperture covered by a thin resistive sheet. The ILCM takes into account multiple waveguide modes and is thus suitable for use at high frequencies and with relatively large boxes. The gaskets may be positioned anywhere in the irradiated front face of the box, and the SE at any point within the box may be found when irradiated by a plane wave. Solution times using the ILCM technique are three orders of magnitude less than those required by traditional numerical methods such as finite difference time domain (FDTD), transmission line matrix (TLM), or method of moments (MoM), even when using a relatively slow interpreted language such as MATLAB. Accuracy, however, is not significantly compromised. Comparing the circuit model with TLM over eight data sets from 4 MHz to 3 GHz resulted in an rms difference of 3.90 dB and a mean absolute difference of 2.35 dB in the predicted SE values. The ILCM accurately reproduces the detailed structure of the SE curves as a function of frequency and observation point.

KW - circuit model

KW - gaskets

KW - multiple modes

KW - shielding effectiveness (SE)

KW - ELECTROMAGNETIC SCATTERING

KW - RECTANGULAR APERTURES

KW - ENCLOSURES

KW - TRANSMISSION

U2 - 10.1109/TEMC.2006.870703

DO - 10.1109/TEMC.2006.870703

M3 - Article

SN - 0018-9375

VL - 48

SP - 134

EP - 144

JO - IEEE Transactions on Electromagnetic Compatibility

JF - IEEE Transactions on Electromagnetic Compatibility

IS - 1

ER -