Boosting transparent electromagnetic interference shielding by multi-cavity resonances

Abstract

We propose a multi-cavity resonant architecture that is established by employing two opposing ultrathin silver-based films to form a Fabry–Pérot (F–P) cavity and inserting one or two metallic mesh layers in between. Compared with the single F–P cavity, the multi-cavity architecture with one metallic mesh layer experimentally exhibits a ∼ 37 % improvement in the average shielding effectiveness and maintains a transmittance over 80% at 550 nm. A more significant improvement of ∼ 108 % in shielding effectiveness (SE) can be achieved by inserting two metallic mesh layers. The proposed multi-cavity architecture provides a strategy for removal of the hindrance to transparent electromagnetic interference shielding.

Scalable-Manufactured Metamaterials for Simultaneous Visible Transmission, Infrared Reflection, and Microwave Absorption

“…These findings explain the reason the millimeter-thick dielectric spacer is indispensable to the ITO-based microwave metamaterial absorbers, since the sheet resistance of ITO generally varies from 12 to 100 Ω/□, 26−30 much higher than the required sheet resistances for submillimeter-thick microwave absorbers. By contrast, according to our previous work, 21,22,31 the sheet resistances of the SLSO and the metal mesh are generally 3−8 and 1−2 Ω/□, respectively, lower than the required sheet resistances, which brings about the possibility of achieving the near-perfect microwave absorbing only through a 0.5 mm-thick dielectric spacer. Therefore, instead of vertically integrating several single-spectral metamaterials, the standalone multispectral metamaterials are likely to be realized by an SLSO-based structure with simultaneous visible transmission, IR reflection, and microwave absorption.…”

“…Thus, TCMs are usually evaluated through a figure-of-merit (FoM), defined as FoM = 188.5/( R s (1/(√ T – 1) ( R s is the sheet resistance and T is the optical transmittance) . The typical FoM values of ITO, AgNWs, ultrathin metal, and metal mesh are 25.5, 121.6, 1095.9, and 1365.9, respectively. − As far as the FoM is concerned, ultrathin metal and metal mesh are better candidates for composing optically transparent metamaterials, compared with ITO and AgNWs.…”

“…Second, a laser scriber (HS0806-UV+GR, Han’s Laser Technology) was used to pattern the SLSO with a laser wavelength of 1064 nm, a repetition frequency of 40 kHz, and a photodiode current of 32 A. Meanwhile, the silver metal mesh was fabricated by a roll-to-roll nanoimprinting (Anhui Jingzhuo Optics and Display Technology) . Eventually, the patterned SLSO and the silver metal mesh were attached using an optically clear adhesive (OCA), completing the fabrication of the multispectral metamaterial samples.…”

“…Meanwhile, the silver metal mesh was fabricated by a roll-to-roll nanoimprinting (Anhui Jingzhuo Optics and Display Technology). 22 Eventually, the patterned SLSO and the silver metal mesh were attached using an optically clear adhesive (OCA), completing the fabrication of the multispectral metamaterial samples. The commercially available OCA (Dongguan Henghua Optical Products) is made of PET with acrylic glues on both sides.…”

MXene/Polylactic Acid Fabric-Based Resonant Cavity for Realizing Simultaneous High-Performance Electromagnetic Interference (EMI) Shielding and Efficient Energy Harvesting

“…The resonance valley was ascribed to the Fabry–Pérot resonance effect, which is the result of constructive interference of EM waves. The resonant condition of the S-MPF-RC can be described by the following equation , where φ 1 and φ 2 are the reflection phases at upper and lower reflectors, n is the average refractive index, d is the height of the RC, λ is the resonance wavelength, and m is the resonance order. Both φ 1 and φ 2 are close owing to the prominent conductivity of MXene.…”