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We introduce a novel local time-stepping technique for marching-in-time algorithms. The technique is denoted as Causal-Path Local Time-Stepping (CPLTS) and it is applied for two time integration techniques: fourth order low-storage explicit Runge-Kutta (LSERK4) and second order Leapfrog (LF2). The CPLTS method is applied to evolve Maxwell's curl equations using a Discontinuous Galerkin (DG) scheme for the spatial discretization.Numerical results for LF2 and LSERK4 are compared with analytical solutions and the Montseny's LF2 technique. The results show that the CPLTS technique improves the dispersive and dissipative properties of LF2-LTS scheme.

The inclusion of thin lossy, material layers, such as carbon based composites, is essential for many practical applications 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, and/or large computational costs. This work presents a novel technique for the modeling of thin-layer lossy materials in FDTD schemes which overcomes the instability problem at low computational cost. For this, a 1D-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 3D 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 low frequencies, and late time stability than existing techniques with low computational cost.

Abstract-The increased use of carbon-fiber composites in Unmanned Aerial Vehicles is a challenge for their EMC assessment by numerical solvers. For accurate and reliable simulations, numerical procedures should be tested not only for individual components, but also within the framework of complete systems. With this aim, this paper presents a benchmark test case based on experimental measurements coming from direct-current injection tests in the SIVA unmanned air vehicle, reproduced by a numerical Finite-Difference-Time-Domain solver that employs a new subgridding scheme to treat lossy composite thin panels. Validation was undertaken by applying the Feature Selective Validation method, which quantifies the agreement between experimental and numerical data.

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As part of the technology research engaged in the EU Clean Sky 1 project, we present in this paper an electrical structure network (ESN) designed to prevent the impact on an electronic equipment of unwanted voltage drops appearing when nonmetal composite materials are used for grounding. An iterative process has been followed to reach an optimal tradeoff solution meeting all the aircraft requirements: structural, safety, low weight, electrical, etc. Guidelines on the design of a low-impedance metal ESN, to minimize the inductive behavior of the power distribution network, are outlined in this paper. To this end, we employ the UGRFDTD simulation tool, combining finite-difference time domain to analyze the general EM problem, and a multiconductor transmission-line network to handle internal coupling between cables running along coinciding routes. The capability of this tool to create time-domain snapshots of surface currents is shown to provide a useful way to optimize the ESN, thanks to the insight gained on the physics of the problem. Index Terms-Carbon-fiber-reinforced plastic (CFRP), electrical structure network, electromagnetic compatibility (EMC), finite-difference time domain (FDTD), green regional aircraft (GRA). I. INTRODUCTION T HE design of an aircraft (A/C) must comply with the aerodynamic, structural, safety, fuel efficiency, cost, and electromagnetic (EM) requirements, among many others, this requiring the parallel work of several departments. Clean Sky 1 is one of the largest European R&D projects focused on the design of the A/C of the future: low-CO 2 and highly cost-efficient air-transport system. Its objective is to speed up the technological breakthrough developments and to shorten the time-to-market for new solutions that introduce green technology into aviation. Within the framework of Clean Sky 1, this paper deals with the design of low-weight configurations Manuscript

Petri dishes of different types are widely used in bioelectromagnetic experiments for the assessment of the non-thermal biological effects of electromagnetic radiation. Two important qualities required for the experimental setups are to guarantee a sufficiently high level of exposure and to maintain uniformity of the fields affecting the cell culture under study. In this paper, we apply two novel techniques to improve both parameters: the use of dishes with an elliptical shape and the addition of metallic patches underneath the Petri dish. Results for plane-wave illumination at 2.5 GHz are shown. This methodology can also be extended to Petri dishes inside waveguide applicators.