Mesoscopic effective material parameters for thin layers modeled as single and double grids of interacting loaded wires

TL;DR

This paper develops a method to determine effective mesoscopic material parameters for thin layered structures modeled as grids of interacting loaded wires, including cases with negative parameters, and compares these with traditional S-parameter retrieval.

Contribution

The paper introduces a rigorous approach to assign mesoscopic parameters to thin wire grid layers, accounting for interactions and loading effects, and discusses their physical significance.

Findings

Double grids can exhibit negative effective parameters within certain frequency ranges.

The proposed method aligns well with S-parameter retrieval results for double-grid structures.

Properly loaded grids can be characterized by meaningful mesoscopic parameters despite negative values.

Abstract

As an example of thin composite layers we consider single and double grids of periodically arranged interacting wires loaded with a certain distributed reactive impedance. Currents induced to the wires by a normally incident plane wave are rigorously calculated and the corresponding dipole moment densities are determined. Using this data and the averaged fields we assign mesoscopic material parameters for the proposed grid structures. These parameters depend on the number of grids, and measure the averaged induced polarizations. It is demonstrated that properly loaded double grids possess polarization response that over some frequency range can be described by assigning negative values for the mesoscopic parameters. Discussion is conducted on the physical meaningfulness to assign such material parameters for thin composite slabs. The results predicted by the proposed method for the double-grid structures are compared with the results obtained using the commonly adopted S-parameter retrieval procedure.