Multifunctional Green Electromagnetic Interference Shielding Material for the Sub-6-GHz Band

Abstract

Multifunctionality, green, flexibility, and low reflectivity are promising development tendencies of electromagnetic interference (EMI) shielding materials. However, it is still a challenge to effectively integrate multiple functions into a single material. Herein, we reported a multifunctional, green, and flexible EMI shielding material with low reflection. It is a multilayer structure consisting of a low-infrared emission layer, a polyvinyl chloride (PVC) compensation layer, and a microwave absorption layer. The shielding effectiveness (SE) of the proposed multifunctional material can reach above 28 dB with a green index g s ≥ 1 and reflection loss SE R < 3.01 dB in the sub-6 GHz band. Furthermore, an ultralow infrared (IR) emissivity of 0.17 within the 3–15 μm spectrum is obtained by optimizing the pattern of the indium tin oxide (ITO) part. The designed material is also optically transparent, flexible, wide-angle, low-profile, and polarization-insensitive. Excellent consistency between the experimental and simulation results demonstrates that this multifunction shielding material can find practical applications in signal shielding scenarios in the sub-6G microwave and 3–15 μm infrared regimes.

Molecular metal oxide cluster-soldered interpenetrating polymer network “hosts” carbon nanotube “guest” for green millimeter wave absorption

“…Therefore, achieving the ultimate goal of low reflection and high shielding capability for a designed shield material through outstanding impedance matching and absorption loss calculation of its green index is an essential mandate. 94 Thus, we have calculated the green index (using the formula as per eqn (S11), ESI†) to assess the sustainability and eco-friendliness of our fabricated charge-triggered Cu-POM-soldered IPN-CNT constructs and obtained green index ( g s > 1) for all the samples at 12.4 GHz. 95 The CT-Cu-POM-IPN-CNT-20 constructs integrated with impedance matching achieved the highest g s ∼1.7 with the highest SE T of ∼45 dB, indicating high-performing green EMI shielding materials.…”

Advancements in 3D-printed architectures for electromagnetic interference shields

“…Generally, an electromagnetic shielding material is considered to have shielded 99% of the electromagnetic waves in the current frequency band when the total electromagnetic shielding effectiveness (SE T ) reaches 20 dB, meeting civilian application requirements. [97][98][99][100][101][102][103] However, military equipment chassis demand a higher electromagnetic shielding effectiveness exceeding 60 dB, emphasizing the need for highly effective shielding materials. In specialized applications like precision instruments, it is crucial to absorb electromagnetic waves and minimize reection and transmission.…”

High-performance low-profile green electromagnetic interference shielding material for 5G mm-wave using characteristic mode theory

“…As shown in figure 2(a), the top etched shape ITO-PET (ITO etched onto PET film using sputtering technology) [48] layer can be equivalent to a series RLC circuit, the middle PVC dielectric layer can be equivalent to a lossless transmission line, the bottom 6 Ω/sq ITO-PET layer can be equivalent to a short circuit. The overall input impedance of the multifunction structure can be calculated, based on the transmission line theory [49] 1…”