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The electromagnetic problem of calculating the pulsed radiation from a horizontal magnetic dipole in the presence of a planar thin conductive screen is solved analytically in the time domain via a modified Cagniard-de Hoop approach. The components of the relevant time-domain electric and magnetic dyadic Green's functions are expressed by simple one-dimensional integrals over a finite integration domain. Expressions for the transient electromagnetic fields can thus easily be obtained and numerical results are provided that illustrate the main time-domain shielding characteristics. [ABSTRACT FROM AUTHOR]

The three-dimensional potential time-domain Green's function for a vertical electric dipole radiating in vacuum in the presence of a graphene sheet is derived in a semi-analytical form, by assuming a local Drude-like model for the graphene conductivity in the intraband regime, through a modified Cagniard-de Hoop approach. The derived expression is simple and requires only a straightforward evaluation of a finite smooth one-dimensional integral. Moreover, for the particular and practical case of source and observer along the same vertical axis, the result is provided in a closed form thus allowing for an extremely efficient calculation of the pulsed time-domain field. Numerical results are provided that validate the proposed formulation and assess its computational efficiency against a direct numerical inversion of the relevant spectral-domain potential. [ABSTRACT FROM AUTHOR]

The classical problem represented by a planar thin conductive shield in the presence of vertical dipole field sources (electric or magnetic) is solved analytically in the time domain via the Cagniard-de Hoop technique. Comparisons with numerical solutions carried out by means of efficient integration algorithms are provided and discussed. [ABSTRACT FROM AUTHOR]

The 3-D time-domain Green’s function (GF) for the vector potential excited by a transient vertical electric dipole in the presence of a thin sheet with high-contrast dielectric and conductive properties is derived using a modified Cagniard–de Hoop approach. The resulting expression involves the numerical evaluation of a 2-D integral over a finite integration domain, computationally much less expensive than the direct numerical evaluation of the inverse Laplace/Hankel transform of the relevant spectral-domain GF. Expressions for the transient electromagnetic fields can thus be obtained, and numerical results are provided, which illustrate their salient features and validate the proposed formulation. [ABSTRACT FROM AUTHOR]

During transients involving multiconductor lines, the importance of the ground finite conductivity is well known and various techniques and expressions have been presented in literature for the inclusion of its contribution into the per unit length parameters. The direct time domain approach based on the introduction of the transient parameters and on the numerical solution of the telegrapher's equations demonstrated to be accurate and efficient for the analysis of typical transients. In this letter, the expressions for the ground transient resistance for underground cables, based on the closed-form inverse Laplace transform of the classical Pollaczek expressions (valid for the low-frequency-range), are presented and discussed. [ABSTRACT FROM AUTHOR]

The analysis of the shielding performance is conducted on the basis of the classical IEEE Standard 299, which is typically a local and frequency-domain approach, may be not sufficient for the thorough appraisal of protection levels achievable through actual enclosures in the presence of transient electromagnetic fields. Stemming from a victim point of view, a new, global approach is proposed for the assessment of average and minimum guaranteed shielding performance directly in the time domain, in the presence of either near fields or plane waves. The method is suitable for the analysis of all the typical transient EMI phenomena and recommended for the analysis of protection levels of mission-critical devices or systems. An elementary statistical analysis of performance data is also presented. [ABSTRACT FROM PUBLISHER]

The shielding performance of different buildings in presence of indirect lightning return strokes are investigated directly in the time domain. To this end, a sensitivity analysis is conducted by varying the channel geometrical characteristics and considering three different buildings. The performance is evaluated by adopting the time-domain shielding parameters recently proposed, which appear to be suitable for shielding studies in presence of lightning electromagnetic pulses. The results confirm the usefulness of introducing different parameters to fully characterize the shielding behavior of buildings exposed to lightning electromagnetic fields. [ABSTRACT FROM PUBLISHER]

The assessment of the shielding effectiveness of enclosures under transient conditions calls for an accurate analysis of fundamental aspects. Stemming from a correct understanding of the coupling mechanism and from a victim point of view, new shielding parameters are proposed as figures of merit to designate the actual effectiveness of an electromagnetic enclosure. Their suitability is tested in different configurations excited by typical transient electromagnetic threats. [ABSTRACT FROM PUBLISHER]