Electromagnetic Scattering From Bi-Periodic Fabric Structures

Abstract

Abstract-We develop an efficient semi-analytical technique to calculate the electromagnetic scattering from fabric structures modeled as crossed gratings of circular coated fibers of any material composition, arranged arbitrarily in yarns. The method relies on a matrix formulation based on multipole expansion for modeling conical scattering from uniaxial gratings of fibers, and employs a scattering matrix approach to obtain co-and cross-polarized transmission and reflection coefficients. The lattice sums are evaluated using an efficient adaptive algorithm based on Shank's transformation. The method can be employed for analyzing the scattering characteristics of fabric structures embedded in any arbitrary layered media. The validity of the method is verified through comparison with full-wave finite-difference time-domain simulations. A substantial performance gain is obtained, which makes the proposed method applicable to solve large-scale fabric structures.

Electrically Tunable Metamaterials Based on Multimaterial Nanowires Incorporating Transparent Conductive Oxides

“…the magnetic field is along the nanowires axis (TE z ). Due to the high refractive index of silicon, rotation of the electric current can give rise to magnetic resonances while electric resonances cannot be excited as in this case the induced modes inside the nanowires are purely TE (since there is no cross-polarized coupling when the incident wave does not have out-of-plane variation) and the magnetic field cannot form closed loops 44 . The geometrical parameters of the design are chosen such that the structure exhibits a magnetic resonance resonance at the operating wavelength of 1550 nm at no-bias condition.…”

Time-varying metamaterials based on graphene-wrapped microwires: Modeling and potential applications

“…The method has evolved quite dramatically ever since and has been adapted to solve several problems involving periodic and aperiodic arrangements of cylindrical objects [46][47][48][49] . In particular, the authors have extended the method to take into account for multiple scattering between cylinders and layered substrates 50 as well as crossed configurations of cylinders 51,52 . Here, we develop a novel semi-analytical framework by extending the T-matrix formulation to solve electromagnetic scattering from substrate-supported periodic and aperiodic arrays of cylindrical structures wrapped by time-varying graphene layers.…”

“…The semi-infinite summations in (22) are called lattice sums which are slowly convergent. However, they can be efficiently and accurately evaluated using recurrence formula 48 or series acceleration techniques such as Shank's transformation 51 . Once the unknown scattering coefficients are obtained, the Fourier integral representation of Hankel functions can be used to expand the scattered fields in terms of a summation of reflected and transmitted plane waves 48 over different frequency harmonics and spatial diffraction orders as:…”

“…For the periodic case, a similar procedure can be adopted. However, it is more convenient to use a scattering matrix approach to obtain reflection and transmission coefficients of the layered system through recursive formula 48,51 as it does not involve numerical evaluation of Weyl-type integrals.…”

Metafabrics for Thermoregulation and Energy-Harvesting Applications

“…The method can handle large-scale fabric structures with a significant efficiency. 31 In addition to the computational gain afforded by the method, this modeling scheme is more realistic and sophisticated compared to the 2D models used before 11 and takes into account the microscopic structure of yarns rather than using an effective description. 12 Moreover, it can be regarded as a reduced order model for the woven fabrics since it imposes a fraction of its computational cost and is expected to capture all the essential features and underlying physics.…”