EMI Shielding Performance of Thin and Thick Graphene Films Placed Within Integrated Power Modules

Abstract

This paper presents electromagnetic interference (EMI) analysis and the performance of graphene-enhanced shielding. Two types of graphene have practical relevance. The first is synthesized through Chemical Vapor Deposition (CVD) techniques as thin films (1–5 μm) that feature pristine quality and high conductivity. The second type is based on polymer composite films that typically have a thickness of 100–200 μm with lower electrical conductivity but effortless scalability. The first part of the paper studies the shielding effectiveness (SE) of the 5 μm graphene film that has 80% electrical conductivity of that of copper (Cu). Using the NSA 65-6 standard set-up, a SE of 25–36 dB was achieved in the frequency range of 30–100 MHz. Alternatively, using the IEEE 299 standard, the SE of the same graphene varies between 33–41 dB. The second part of the paper demonstrates two simulation scenarios for communication and mobile circuits. The first scenario represents the coupling between an inductor and a planar inverted F antenna (PIFA) antenna. The second scenario expresses the EMI between a PIFA antenna and an aggressor IC like Power Management Integrated Chip (PMIC) modeled by a patch antenna. Both scenarios operate at the LTE band frequency. In Scenario#1, an isolation of 60 dB is observed between the shielded inductor and the PIFA antenna using a graphene EMI shield. Based on the second scenario, graphene films are shown to be suitable for EMI shielding between active devices, such as PMIC, and RF components. This shielding helps to enhance the isolation by 10 dB compared to standard metal shields when operating in the WiFi band (2.4 GHz). The last part of the paper compares the SE of thin versus thick graphene composite films. Thick composite films with lower electrical conductivity offer higher SE than thinner films of higher electrical conductivity based on the NSA 65-6 standard. However, when using the IEEE 299 standard, both thick and thin graphene films exhibit the same SE.