A Hybrid Numerical Technique to Predict the Electromagnetic Field in Penetrable Conductive Boxes (original) (raw)
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IEEE Transactions on Electromagnetic Compatibility, 1999
Impedance network boundary conditions (INBC's) are implemented in the finite-difference time-domain (FDTD) method to analyze the electromagnetic field around penetrable shield structures. The shield region is eliminated from the computational domain and the INBC's are applied on the new boundary surfaces, i.e., shield surfaces, to take into account the field discontinuity produced by the shield. The INBC's represent an important extension of the well-known surface impedance boundary conditions (SIBC's) since the INBC's model accurately the coupling of the electromagnetic fields through penetrable shields and lead to a significant reduction of the number of the FDTD unknowns. The INBC expressions are given analytically in both frequency and time domains, and the INBC implementation in a FDTD code is discussed. The proposed INBC-FDTD method is numerically efficient because the resulting convolution integrals are recursively solved. Furthermore, approximate time-constant INBC's are proposed which are valid for many practical applications. The analysis of transient electromagnetic fields around penetrable conductive shields in simple test configurations are presented and compared with the analytical solutions.
ESD field penetration into a populated metallic enclosure a hybrid time-domain approach
IEEE Transactions on Electromagnetic Compatibility, 2002
This paper presents a method for the analysis of the electromagnetic field inside a metallic enclosure populated by printed circuit boards (PCBs) and a comparison with an analogous field into an empty box is also reported. The field source is represented by an electrostatic discharge (ESD) current flowing along a monopole and producing an electric field coupling into a shielded structure through a slot. The model is based on a time domain approach and the solution of the electromagnetic problem is achieved by a hybrid method, characterized by the combination of the Method of Moments in Time Domain (MoMTD) and Finite Difference in Time Domain (FDTD); this technique allows to investigate the complex geometry of the problem and to evaluate the strong coupling between the source and the victim structure. All simulated results are validated by measurements.
Radio Science, 2013
1] The perfect electromagnetic conducting (PEMC) boundary, a nonreciprocal generalization of both perfect electric conducting (PEC) and perfect magnetic conducting (PMC) boundaries, is modeled in the finite difference time domain (FDTD) method. Since the PEMC boundary condition requires collocation of same components of both electric and magnetic fields at the boundary grids, which is not compatible with the original FDTD algorithm, its implementation in FDTD is challenging and requires modification in the algorithm. To do this task, first, the original FDTD cell is modified by inserting the required field components not present in the original cell. Then, a novel formulation is developed for updating fields' components at the boundary. Modeling of a PEMC planar interface, a corner point, and a wedge point are presented. Finally, numerical examples are presented to show stability, accuracy, and applicability of the proposed approach. Validation is achieved by comparisons with existing analytic methods and/or conventional FDTD for special cases of PEC and PMC boundaries. Citation: Nayyeri, V., M. Soleimani, and M. Dehmollaian (2013), Modeling of the perfect electromagnetic conducting boundary in the finite difference time domain method, Radio Sci., 48, 453-462,
An accelerated hybrid TLM-IE method for the investigation of shielding effectiveness
Advances in Radio Science
A hybrid numerical technique combining timedomain integral equations (TD-IE) with the transmission line matrix (TLM) method is presented for the efficient modeling of transient wave phenomena. This hybrid method allows the full-wave modeling of circuits in the time-domain as well as the electromagnetic coupling of remote TLM subdomains using integral equations (IE). By using the integral equations the space between the TLM subdomains is not discretized and consequently doesn't contribute to the computational effort. The cost for the evaluation of the time-domain integral equations (TD-IE) is further reduced using a suitable planewave representation of the source terms. The hybrid TD-IE/TLM method is applied in the computation of the shielding effectiveness (SE) of metallic enclosures.
Comparison of FDTD and MoM for shielding effectiveness modelling of test enclosures
IEEE 1997, EMC, Austin Style. IEEE 1997 International Symposium on Electromagnetic Compatibility. Symposium Record (Cat. No.97CH36113), 1997
The FDTD (Finite Difference Time Domain) method and the MOM (Method of Moments) are two well known methods for the numerical solution of EMC problems. In this paper, both methods areused tocalculatetheshieldingeffectiveness(SE)ofatestenclosure with one or two large apertures. For validation purposes, the simple case of an infinite screen with a single rectangular aperture or slot is considered first. The electric and magnetic near field SE is determined for a wide range of slot widths. Very good agreement (less than 2 dB difference between both methods) is obtained for frequencies up to 1 GHz. A larger discrepancy was found for more realistic shielding structures such as the test enclosure, but both methods are still within 5 dB of the experimental results for frequencies below the first resonance of the enclosure.
Full-wave analysis of shielded cable configurations by the FDTD method
IEEE Transactions on Magnetics, 2002
A numerical method is proposed to model transients in a shielded cable embedded in a three-dimensional field domain by using the finite-difference time-domain (FDTD) method. The coaxial shielded cable is assumed to be a multiconductor transmission line (MTL). The in cell voltage and the current on the external shield surface are calculated by a full-wave method, while the core current and the core-to-shield voltage are analyzed by assuming the validity of the quasi-TEM propagation mode inside the shield. The internal and external shield surfaces are coupled by the transfer admittance and by the transfer impedance of the cable shield. The solution is obtained by the FDTD method combining the MTL equations with the field equations. The proposed time-domain method takes into account the frequency-dependent parameters of the cable conductors by recursive convolution techniques. The validation of the procedure is performed in simple test configurations. Index Terms-Electromagnetic compatibility/interference (EMC/EMI), finite-difference time-domain (FDTD) method, multiconductor transmission lines (MTL), shielded cables.
ESD field penetration through slots into shielded enclosures: a time domain approach
IEEE Transactions on Electromagnetic Compatibility, 1997
This paper presents a time domain approach for the analysis of the coupling between an electrostatic discharge (ESD) current and the internal region of a shielded enclosure with a slot. The application of the equivalence principle allows us to obtain an integro-differential equation for the unknown distribution of the aperture electric field. The numerical solution is obtained by an iterative procedure developed by the method of moment (MoM) in time domain.
Progress In Electromagnetics Research, 2002
The paper presents electromagnetic coupling of an electrical fast transient plane wave penetrating through slots or apertures perforated in one side of a shielding metallic enclosure. Numerous slots and apertures of different configurations and dimensions have been developed, which include a single slot of different length, a single aperture of different width, multiple-angular apertures of different geometry, multiple-cell aperture of different cell numbers, multiple thin slots, an aperture-cell array making up the whole side of the enclosure, and a miscellany case simulating a PC main frame. FDTD numerical method is applied to the EMI/EMC model, while time-domain outputs are converted to frequency-domain responses for further analyses using a FFT program. Practical conclusions and recommendations are drawn to aid shielding enclosure design and electromagnetic interference protection.
Comparison of FDTD algorithms for subcellular modeling of slots in shielding enclosures
1997
Abstract Subcellular modeling of thin slots in the finite-difference time-domain (FDTD) method is investigated. Two subcellular algorithms for modeling thin slots with the FDTD method are compared for application to shielding enclosures in electromagnetic compatibility (EMC). The stability of the algorithms is investigated, and comparisons between the two methods for slots in planes, and slots in loaded cavities are made.