Analysis and Verification of Shielding Effectiveness Enhancement of Double-Layer Metal Mesh Conductive Film

In this brief, the shielding effectiveness (SE) enhancement mechanism of double-layer metallic mesh is studied and verified, proving that SE is closely related to the distance between two layers. It is analyzed by using a multi-layer equivalent model, while the theoretical foundation and action mechanism of SE enhancement are given by derivation. Based on the theoretical analysis, the SE of the double-layer spacing increases monotonously from zero to
$\lambda $
/4 of upper frequency. As the spacing continues to increase, SE will decrease with the interval increasing until about
$\lambda $
/2, and different extreme values appear at the corresponding frequency points. Besides the theoretical analysis above, the double-layer square mesh sample on a soda-lime glass substrate is prepared to verify the noticeable SE enhancement effect by simulation and experiment. The double-layer mesh can enhance the SE by up to 40 dB or more under the premise of less loss of optical transmittance in the Ku band, achieving a huge SE improvement. The mechanism analysis of the double-layer structure not only provides a clear physical explanation for the design of high-shielding optical windows but can also be applied to the realization of band-pass performance.