Multiscale modeling and simulation methods for electromagnetic and multiphysics problems

Numerical modeling and simulation of many electromagnetic (EM) multiphysics problems encounter challenges from geometrical material complexities, large-scale issues, multiscale issues. Examples include the complex microwave devices systems, design integrated circuits packages, natural or artificial materials, antenna arrays, analysis EM wave propagation in environments, optimization parameters inverse scattering problems. The past few decades have witnessed a fast exciting development computational methods techniques that contributed to successful resolution some aforementioned challenges. Noticeable developments use high-order basis functions, algorithms, domain decomposition methods, parallel computing based on CPUs GPUs. As modern technologies evolve, overall electrical size systems integration density components keep increasing, leading higher power density, stronger thermal effect, more critical phenomena. All these pose new current electromagnetics. This Special Issue includes 10 high-quality papers addressing continues shrink, performance plays an increasingly important role device. In this Issue, three-dimensional (3-D) transient algorithm spectral element method has been proposed. By using curvilinear hexahedral elements, nodal efficient stable time-stepping schemes, enjoys both high efficiency improved flexibility. Heat conduction processes networks rockets studied. electronic devices, isolated conductors with unknown potential values are usually encountered. hybridizable discontinuous Galerkin (HDG) is developed simulate electrostatic floating conductors, where equipotential condition undefined/floating value enforced surface conductor. Compared traditional finite (FEM) implementation, HDG implementation much straightforward. unknowns global problem only associated nodes mesh skeleton, which comparable those FEM implementation. Carbon nanotube (CNT)-based nanocomposites attracted attentions recent years due their extraordinary properties, including conductivity, low percolation threshold, good dielectric mechanical properties. One article studies electric conductivity CNT/polymer analysis. A numerical model taking into account nonlinear tunneling effect proposed evaluate effective CNT nanocomposites, formulation quantities for homogenization. introduced novel acoustic (SAW) chipless radio frequency identification (RFID) tags. Several structures RFID described, advantages long reading distance strong anti-interference ability. SAW-based RFIDs different investigated through modal analyses COMSOL. concerns extremely (ELF) Earth. mode-conversion coefficient ELF over mixed path theoretically studied applied interpret interference at various distances. Earth–ionosphere modeled as waveguide sections representing transitions between land sea. far-field region, by WKB solution while successively cascaded determine junction fast, efficient, accurate forward solver required be performed efficiently. intelligence (AI) surrogate-based nonuniform microstrip transmission line (NTL) band pass filters. To computationally process, 3-D unit NTL generate training testing data sets. An AI-based used predict respect variation parameters. S-parameters then calculate equivalent obtain response desired filter. layered media applications well logging, imaging, remote sensing. reported element-free mode-matching static time-harmonic fields calculation orthogonal-plano-cylindrically media. work, (NMM) combined (EFG) efficiently waves cylindrically multiple horizontal beds. implement NMM scheme efficiency, EFG utilized replace traditionally discretization along radial direction. resulting meshless EFG-NMM avoids complexity generation improves accuracy compared FEM. Two articles address computation complicated approach characteristic functions (CBFs) large blocks Sherman–Morrison–Woodbury algorithm. While better compression rate CBF can achieved increasing block CBFs, cost increases significantly electrically blocks, especially case excitations. article, combines (SMWA) CBFs reduced impedance matrix increased efficiency. another perfectly matched layer (PML) finite-difference time-domain (FDTD) method. method, exponential time differencing (ETD) PML, Taylor expansion alternative simple auxiliary differential equation It shown numerically ETD reduce peak relative reflection error PML other implementations. Based cyclic code theory, encoding decoding self-correction big product tracing system. With construction principle, specific OpenMP accelerated than 36 times. coding patterns literature, error-correcting achieves balance complexity, rate, time. editors thank all contributors anonymous reviewers contributions Issue.