Conference Agenda

This paper investigates the optimization of time-domain shielding effectiveness for a thin, time-varying dielectric layer excited by pulsed electromagnetic waves. By varying the layer's capacitance harmonically over time, the study demonstrates significant enhancements in key shielding effectiveness metrics, including the peak and time-derivative reduction shielding effectiveness. Both local and global optimization algorithms are employed to solve the single-objective optimization problem. Results highlight the limitations of gradient-based local optimization methods and showcase the efficacy of global approaches for such a complex time-domain optimization problem. Particularly, algorithms based on differential evolution strategies, namely DE and SHADE, delivered very promising results in terms of accuracy and consistency compared to other algorithms.

This paper presents an innovative solution for electromagnetic attenuation at the board level: a silver ink spray-deposited on a polymer substrate manufactured by fused deposition modeling (FDM). The attenuation provided by this Board Level Shield (BLS) was evaluated between 1 MHz and 8.5 GHz using various characterization techniques: a Gigahertz Transverse ElectroMagnetic (GTEM) cell, a near-field magnetic probe, and onboard coupling. A copper BLS was also used as a reference to compare results and validate the employed methods. Finite element modeling (FEM) simulations were conducted to validate our approach, justify the observed phenomena, and extend our analysis to different configurations.

This research contributes to the growing field of advanced materials for electromagnetic compatibility, offering a solution that combines the benefits of additive manufacturing with high-performance shielding capabilities.

The absorber consists of a textile substrate sandwiched between a metallic layer, acting as a perfectly conductive ground plane, and a surface composed of polyvinylidene fluoride (PVDF) filled with graphene nanoplatelets (GNPs), which exhibit a frequency-dependent complex permittivity. Novel analytical expressions are derived to determine the optimal thicknesses of both the graphene-based surface and the textile spacer as functions of the incidence angle. The proposed model is validated through numerical simulations, leveraging both the developed analytical framework and full-wave simulations using CST Microwave Studio. The reflection coefficients for TM and TE polarizations are analysed over the 6 GHz to 18 GHZ frequency range, considering incidence angles up to 30°.

Effective shielding against electromagnetic interference (EMI) is essential to ensure the functionality of electronic systems and to limit their radiation. In automobiles, for example, where space is limited and many electrical components are used, such interference can affect safety-critical systems such as driver assistance systems. To achieve required electromagnetic shielding, metals are often used. Due to lower carbon footprint and lower production costs, the use of plastics is increasing, either with electroplated conductive layers or with conductive additives such as iron particles, carbon fibers or graphite. These materials are suitable for injection molding, the most efficient production technology for plastics products. However, the precise design of such components is challenging due to factors such as filler content, geometry, and orientation of the additives. Simulation methods play a key role in optimization, but require a comprehensive understanding of the material properties. In addition, process-related effects, especially in the case of discontinuous fibers or particles, require detailed measurements of electrical properties and influence on the manufacturing process.

Due to these challenges, the goal of this work is to measure the fiber content as well as the orientation dependent electrical conductivities and use them for the simulations. In addition, the local orientation differences across the thickness of the component must be correctly modeled and represented in the simulation in order to represent the true anisotropic material behavior.