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A method, hereinafter referred to as discrete chaff cloud model (DCCM), for the electromagnetic modeling of general chaff clouds is presented, with which harmonic or wideband impulse scattering responses can be evaluated. The model applies to a wide range of scenarios, for any combination of illumination and observation angles and polarizations. The technique considers the geometry of the cloud and the statistical distributions of the elements, both in density and orientation. After a 1-D discretization of the cloud, the complete statistical response or single-experiment observations can be evaluated. The model is formulated in a very general form to extend its applicability as much as possible. Its limitations have been identified and assessed in relevant scenarios. Validation cases have been included, comparing results obtained with DCCM, other published formulations, and full-wave simulations. [ABSTRACT FROM AUTHOR]

The inclusion of thin lossy material layers, such as carbon-based composites, is essential for many practical applications for modeling the propagation of electromagnetic energy through composite structures such as those found in vehicles and electronic equipment enclosures. Many existing schemes suffer problems of late time instability, inaccuracy at low frequency (LF), and/or large computational costs. This paper presents a novel technique for the modeling of thin-layer lossy materials in finite-difference time domain (FDTD) schemes, which overcomes the instability problem at low computational cost. For this, a 1-D subgrid is used for the spatial discretization of the thin-layer material. To overcome the additional time-step constraint posed by the reduction in the spatial cell size, a Crank–Nicolson time-integration scheme is used locally in the subgridded zone, and hybridized with the usual 3-D Yee-FDTD method, which is used for the rest of the computational domain. Several numerical experiments demonstrating the accuracy of this approach are shown and discussed. Results comparing the proposed technique with classical alternatives based on impedance boundary condition approaches are also presented. The new technique is shown to have better accuracy at LFs and late time stability than existing techniques with low computational cost. [ABSTRACT FROM AUTHOR]

Computational solvers are increasingly used to solve complex electromagnetic compatibility (EMC) problems in research, product design, and manufacturing. The reliability of these simulation tools must be demonstrated in order to give confidence in their results. Standards prescribe a range of techniques for the validation, verification, and calibration of computational electromagnetics solvers including external references based on measurement or for cross-validation with other models. We have developed a modular test-suite based on an enclosure to provide the EMC community with a complex external reference for model validation. We show how the test-suite can be used to validate a range of electromagnetic solvers. The emphasis of the test-suite is on the features of interest for EMC applications, such as apertures and coupling to cables. We have fabricated a hardware implementation of many of the test-cases and measured them in an anechoic chamber over the frequency range to 1–6 GHz to provide a measurement reference for validation over this range. The test-suite has already been used extensively in two major aeronautical research programs and is openly available for use and future development by the community. [ABSTRACT FROM PUBLISHER]

An essential characteristic for the accurate simulation of wideband antenna systems is the modeling of their intricate geometrical details, including the feeding ports. In this article, we describe a leap-frog (LF) discontinuous Galerkin (DG) time-domain (TD) method combined with an efficient local time-stepping (LTS) strategy to deal with the high contrast in the element sizes for the electromagnetic modeling of these kinds of structures. The traditional delta-gap source model and a realistic coaxial port model are revisited. Numerical examples are presented and validated with measurements and commercial software simulations to demonstrate the applicability of the proposed approach. [ABSTRACT FROM AUTHOR]

In this paper, we show the application of numerical simulation for the virtual testing of a very complex system under high-intensity radiated fields (HIRF) conditions. Numerical results have been compared to measurements performed on a C-295 aircraft. The approach is based on the use of multiple tools for the preprocessing, computation, and postprocessing, all of them integrated under the same framework. This study is a part of the HIRF SE project, and the final step for the validation of the tools involved there, to introduce the use of simulation in the whole aircraft certification process in an HIRF environment. The main goal of the project is to provide the aeronautic industry with a numerical modeling computing framework, which could be used to predict the electromagnetic performance, and to carry out parametrical studies during the design phase, when changes are simpler and less costly. It could also lead in the future to a considerable reduction on the certification/qualification testing phase on air vehicles, to cross validate the results obtained from measurement and simulation providing best confidence in them, and to attain a more exhaustive analysis to achieve a higher level in the air vehicle safety. [ABSTRACT FROM PUBLISHER]