Metal Mesh-Based Infrared Transparent EMI Shielding Window with Balanced Shielding Properties over a Wide Frequency Spectrum

Abstract

Metal mesh films have been shown to be a promising strategy to effectively mitigate the growing issue of electromagnetic interference (EMI) in optoelectronic systems. To achieve superior shielding effectiveness, it is common to increase the thickness of the mesh film. However, mesh-based shielding materials have frequency-dependent shielding effectiveness that decreases as the frequency increases. Simply increasing the thickness of the mesh cannot effectively enhance the EMI shielding effectiveness at high frequencies. This will further lead to challenges such as increased processing difficulties and higher costs. In this paper, we present an infrared transparent electromagnetic shielding window based on metal mesh with irregular patterns and proper thickness. The mesh coating is fabricated on a sapphire substrate using ultraviolet photolithography technology and exhibits an efficient electromagnetic shielding effectiveness of more than 20 dB over the wide frequency range of 1.7–18 GHz while maintaining high infrared optical transparency. More importantly, there is no distinct variation in shielding effectiveness between low and high frequency ranges, demonstrating a balanced shielding characteristic across a broad frequency band. This work could be crucial in designing cost-effective and efficient EMI shielding windows for optoelectronic systems.

Review on recent progress in epoxy‐based composite materials for Electromagnetic Interference(EMI) shielding applications

“…Liang et al, 106 employed XPS and FTIR to study the chemical and structural properties of the prepared NC. Liang et al, 107 used FTIR to study the IR transmittance of the NC. Morphology was studied with the aid of HRTEM 104 .…”

Flexible Embedded Metal Meshes by Sputter-Free Crack Lithography for Transparent Electrodes and Electromagnetic Interference Shielding

“…In contrast, metal meshes tend to maintain consistent uniform properties without percolation or contact issues. Several well-established methodologies have been developed for the fabrication of metal meshes, including photolithography, ,− imprint lithography, − 3D printing, , crack lithography, ,− electrodeposition, , e-beam direct writing, and self-assembly . Most of these methods, however, are costly, time-intensive, and often unsuitable for large-scale production.…”

Highly Transparent Ka-/W-Band Electromagnetic Shielding Films Based on Double-Layered Metal Meshes

“…In addition to causing malfunctions in sensitive commercial and military electronics, such adverse effects also pose a serious threat to human health. − Wireless networks until 4G were commercialized in frequency bands below 3 GHz, whereas 5G technology may be operated in a high-frequency range of more than 28 GHz owing to factors such as high data rate, ultralow latency, and high reliability. , The W-band, which has a frequency range of 75–110 GHz, has been integrated into various fields including automotive radar sensors − and synthetic aperture radar (SAR) imaging systems. − It has facilitated the need for EM-shielding films with high shielding effectiveness (SE) in the wide-band high-frequency range from the Ka to W-band. In addition to SE, optical transmittance is a crucial characteristic of EM-shielding films in the windows of autonomous vehicles, aircraft, and optoelectronic devices in the medical and military fields. − …”