Electromagnetic shields are usually employed to protect cables and other devices; however, these are generally not perfect, and may permit external magnetic and electric fields to penetrate into the interior regions of the cable, inducing unwanted current and voltages. The aim of this paper is to verify a circuit model tool with our previously proposed analytical model [1] for evaluating currents and voltages induced in the inner conductor of braided-shield cables. This circuit model will enable coupling between electromagnetic and circuit simulations.
Metamaterials research has developed perfect absorbers from microwave to optical frequencies, mainly featuring planar metamaterials, also referred to as metasurfaces. In this study, we investigated vertically oriented metamaterials, which make use of the entire three-dimensional space, as a new avenue to widen the spectral absorption band in the infrared regime between 20 and 40 THz. Vertically oriented metamaterials, such as those simulated in this work, can be experimentally realized through membrane projection lithography, which allows a single unit cell to be decorated with multiple resonators by exploiting the vertical dimension. In particular, we analyzed the cases of a unit cell containing a single vertical split-ring resonator (VSRR), a single planar split-ring resonator (PSRR), and both a VSRR and PSRR to explore intra-cell coupling between resonators. We show that the additional degrees of freedom enabled by placing multiple resonators in a unit cell lead to novel ways of achieving omnidirectional super absorption. Our results provide an innovative approach for controlling and designing engineered nanostructures.
This paper provides an overview of the electromagnetic frequency domain simulation capabilities of the Electromagnetic Theory department at Sandia National Laboratories via a description of two of its codes. EIGER is a Method of Moments code for electromagnetic simulations, but it only runs on traditional CPUs, not on new architectures. Gemma is in development to replace EIGER and will run on many architectures, including CPUs, GPUs, and MICs, by leveraging the Kokkos library.
Metamaterials provide a means to tailor the spectral response of a surface. Given the periodic nature of the metamaterial, proper design of the unit cell requires intimate knowledge of the parameter space for each design variable. We present a detailed study of the parameter space surrounding vertical split-ring resonators and planar split-ring resonators, and demonstrate widening of the perfect absorption bandwidth based on the understanding of its parameter space.