X頻段電磁屏蔽石墨烯複合材料

Abstract

近年來，智能電子設備和無線通信的普及導致了電磁汙染越來越嚴重，電磁干擾影響了電子產品的使用與人體健康。EMI屏蔽材料廣泛應用於商業和科學電子、天線系統、太空探索和醫療設備等領域。EMI屏蔽材料主要是利用高導電性填料達到屏蔽的目的，主要可以分為三類：金屬類屏蔽材料、碳類屏蔽材料、MXene類屏蔽材料。其中碳類填料如：碳黑、奈米碳管和石墨烯奈米片，因其具有高長寬比、輕量、出色的機械性能、易加工性和高導電性而受到廣泛關注。石墨烯憑藉其優異的導電性、散熱性、機械性質和可調性，因此石墨烯在EMI屏蔽領域受到極大的重視。其中排列整齊的石墨烯複合材料具有優異的屏蔽性能、力學性能、導電性能、熱傳導性能和光學性能，對於各種應用領域具有廣泛的應用價值。有許多研究團隊致力於研發各種X頻段的屏蔽複合材料，但是都沒有模擬可以完整的模擬出屏蔽複合材料。複合材料由於內部結構非常複雜，並且填料與波長的尺度相差非常多，因此在模擬方面會因為網格太過複雜而產生計算資源的不足的問題。 本研究利用COMSOL Multiphysics建立一個合理的模型模擬出高度排列石墨烯複合材料，利用邊界條件的方法來模擬石墨烯達到減少網格的目的，以此減少計算資源。並且計算出了EMI 屏蔽的效果、等效材料特性與分析內部電磁效應。此模擬模型的EMI SE值與介電係數與濃度和頻率的趨勢都與文獻相符合。

In recent years, the widespread use of smart electronic devices and wireless communication has led to an increasing concern about electromagnetic pollution and its impact on the usage of electronic products and human health. EMI (Electromagnetic Interference) shielding materials have found wide applications in commercial and scientific electronics, antenna systems, space exploration, medical devices, and other fields. These materials primarily rely on highly conductive fillers to achieve shielding, and they can be broadly classified into three categories: metal-based shielding materials, carbon-based shielding materials, and MXene-based shielding materials. Among them, carbon-based fillers such as carbon black, carbon nanotubes, and graphene nanosheets have gained significant attention due to their high aspect ratio, lightweight, excellent mechanical properties, processability, and high conductivity. Graphene, in particular, has received great attention in the EMI shielding field due to its outstanding electrical conductivity, thermal conductivity, mechanical properties, and tunability. Highly ordered graphene-based composites exhibit excellent shielding performance, mechanical properties, electrical conductivity, thermal conductivity, and optical properties, making them highly valuable for various applications. Numerous research teams are dedicated to developing shielding composites for various frequency ranges, but there is currently no simulation that can accurately model the shielding composite materials. Composite materials have complex internal structures, and the scale difference between the fillers and the wavelength poses a challenge in simulation due to the complexity of the computational grid, leading to insufficient computational resources. In this study, we employ COMSOL Multiphysics to establish a reasonable model for simulating highly ordered graphene composites. We utilize boundary conditions to simulate graphene and reduce the complexity of the computational grid, thereby minimizing the computational resources required. Furthermore, we calculate the EMI shielding effectiveness, and equivalent material properties, and analyze the internal electromagnetic effects. The simulated EMI shielding effectiveness (SE) values and dielectric coefficients exhibit trends consistent with the literature, validating the accuracy of our simulation model.