Open AccessFDTD Simulations of Modulated Metasurfaces with Arbitrarily Shaped Meta-atoms by Surface Impedance Boundary Condition
Author(s) -
Yating Hu,
Quanen Zhou,
Xikui Fang,
Mengmeng Li
Publication year - 2022
Publication title -
applied computational electromagnetics society journal
Language(s) - English
Resource type - Journals
eISSN - 1943-5711
pISSN - 1054-4887
DOI - 10.13052/2021.aces.j.361201
Subject(s) - finite difference time domain method , electrical impedance , impulse (physics) , boundary value problem , periodic boundary conditions , perfectly matched layer , wavelength , time domain , frequency band , boundary (topology) , computer science , physics , optics , mathematical analysis , topology (electrical circuits) , electronic engineering , mathematics , antenna (radio) , telecommunications , engineering , classical mechanics , quantum mechanics , combinatorics , computer vision
In this paper, we propose a reduced-complexity finite difference time domain (FDTD) simulations of modulated metasurfaces with arbitrary unit cells. The three dimensional (3D) physical structure of the metasurface is substituted by a spatially varying surface impedance boundary condition (IBC) in the simulation; as the mesh size is not dictated by sub-wavelength details, considerable advantage in space- and time-step is achieved. The local parameters of the IBC are obtained by numerical simulation of the individual unit cells of the physical structure, in a periodic environment approximation, in the frequency domain. As the FDTD requires an appropriate time domain impulse-response, the latter is obtained by broad-band frequency simulations, and vector fitting to an analytic realizable time response. The approach is tested on metasurface structures with complex unit cells and extending over 10 ××10 wavelengths, using a standard PC with 64GB RAM.