Equivalent Modeling of Multilayered Conductive Composite Materials for EMI Shielding Applications

Abstract

This article develops a single-layer equivalent model for multilayered shielding materials using measurements of complex permittivity and permeability. Through rectangular waveguide transmission/reflection (T/R) measurements, electromagnetic (EM) parameters and shielding effectiveness (SE) are evaluated. The aim is to establish an equivalent single-layer structure matching the SE of the original multilayered structure. Initial validation involves testing on simulated and experimental data of a reference single-layer material. The methodology is then applied to a novel three-layer PANI- ${\text {Fe}_{{3}}}\text {O}_{{4}}$ /carbon nanotube (CNT)/PANI- ${\text {Fe}_{{3}}}\text {O}_{{4}}$ composite material. Unlike conventional approaches requiring new multilayered material synthesis, this approach combines existing and widely available materials, simplifying characterization and reducing cost and complexity to achieve the desired SE. Comparative analysis with analytical SE values from transmission line matrix (TLM) formulation is conducted using simulated data. The proposed approach is validated in the X-band frequency range using analytical TLM formulation, numerical simulation, and experimental data. The proposed approach exhibits good performance in reconstructing the equivalent model.