Advancements in electromagnetic microwave absorbers: Ferrites and carbonaceous materials

Abstract

Advancements in electromagnetic microwave absorbers: Ferrites and carbonaceous materials Mohapatra PP, Singh HK, Dobbidi P. Advancements in electromagnetic microwave absorbers: Ferrites and carbonaceous materials. Adv Colloid Interface Sci. 2024 Dec 14;337:103381. doi: 10.1016/j.cis.2024.103381. Abstract Heightened levels of electromagnetic (EM) radiation emitted by electronic devices, communication equipment, and information processing technologies have become a significant concern recently. So, substantial efforts have been devoted for developing novel materials having high EM absorption properties. This critical review article provides an overview of the advancements in understanding and developing such materials. It delves into the interaction between EM radiation and absorbing materials, focusing on phenomena like multiple reflections, scattering, and polarization. Additionally, the study discusses various types of losses that impact microwave absorber performance, like magnetic loss, and dielectric loss. Each of these losses has distinct implications for microwave absorbers' effectiveness. Furthermore, the review offers detailed insights into different microwave-absorbing materials, such as metal composites, magnetic materials, conducting polymers, and carbonaceous materials (composites with carbon fiber, porous carbon, carbon nanotube, graphene oxide, etc.). Overall, it highlights the progress achieved in microwave-absorbing materials and emphasizes optimizing various loss mechanisms for enhanced performance. Conclusions This study provides a comprehensive overview of recent advancements in magnetic and carbon-based dielectric composites, showcasing their potential as promising materials for microwave absorption. The examples underscore that a single dielectric or magnetic system alone cannot consistently achieve optimal microwave absorption performance, necessitating the formulation of composite mixtures that incorporate dielectric and magnetic fillers. These composites' exceptional microwave absorption capabilities can be attributed to several key factors: optimizing intrinsic properties: The amalgamation of a carbon-based material with dielectric components yields distinctive complementary responses in their intrinsic properties, resulting in optimized impedance matching. Inducing Interfacial Polarization: Ample heterogeneous interfaces between different components effectively induce strong interfacial polarization, enhancing the overall microwave absorption performance. Facilitating Conductive Networks: Integrating multiple components facilitates the formation of a conductive network, hopping electrons and fostering the migration and fortifying conductivity loss. Precision in Microstructure Design: Meticulously designed microstructures offer additional propagation paths for incident electromagnetic waves, stimulating multiple reflections and scatterings that efficiently consume electromagnetic energy. Despite remarkable progress in carbon-based dielectric systems, persistent challenges warrant a strategic approach: In-Depth Exploration of EM Loss Characteristics: A meticulous exploration of the electromagnetic loss characteristics of each component is crucial. It emphasizes the need for a rational combination of elements rather than arbitrarily preparing multicomponent composites. Defect Engineering: While defects like grain boundaries, atom vacancies, and heteroatoms positively affect polarization and conductivity losses, the intricate relationship between defect sites and microwave absorption performance necessitates further exploration. Defect engineering is pivotal in guiding the fabrication of high-performance magnetic and carbon-based dielectric composites. Expanding the Effective Frequency Range: The effective frequency range of most composites is confined to 8.0– 18.0 GHz, limiting their applicability in the electronics industry, where many devices operate at frequencies lower than 8.0 GHz. A rational construction approach for multicomponent composites with well-designed microstructures holds the potential to overcome this limitation and enhance low- frequency attenuation capabilities. Simplified Preparation Methods: The preparation methods, especially for multicomponent composites, are often complicated, posing challenges for large-scale production. Streamlining these methods is crucial for overcoming production difficulties. In conclusion, the future outlook for high-performance materials against electromagnetic pollution lies in developing novel carbon-based dielectric systems, magnetic fillers with well-balanced compositions, and intricate microstructures. Addressing the outlined challenges will contribute to realizing these materials' potential to mitigate electromagnetic interference. pubmed.ncbi.nlm.nih.gov

AI evidence extraction

Main findings

This critical review summarizes advances in microwave-absorbing materials (including ferrites, magnetic materials, and carbonaceous composites) and discusses mechanisms affecting absorber performance (e.g., magnetic/dielectric loss, impedance matching, interfacial polarization, conductive networks, microstructure design). It concludes that composite mixtures combining dielectric and magnetic fillers are generally needed for optimal microwave absorption, and notes challenges including limited effective frequency range (often 8–18 GHz) and complex preparation methods.

Outcomes measured

• Microwave absorption performance of materials
• Electromagnetic interference (EMI) mitigation (materials-focused)

Limitations

• Narrative/critical review; no primary experimental or epidemiologic results reported in the abstract
• No specific exposure metrics (e.g., frequency, power density, SAR) or standardized performance outcomes provided in the abstract
• Focus is on materials engineering rather than health outcomes

Suggested hubs

• engineering (0.95)
  Paper is a materials/engineering review on microwave absorbers and EMI mitigation rather than health effects or policy.

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        "source": "electronic devices/communication equipment (general)",
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    "outcomes": [
        "Microwave absorption performance of materials",
        "Electromagnetic interference (EMI) mitigation (materials-focused)"
    ],
    "main_findings": "This critical review summarizes advances in microwave-absorbing materials (including ferrites, magnetic materials, and carbonaceous composites) and discusses mechanisms affecting absorber performance (e.g., magnetic/dielectric loss, impedance matching, interfacial polarization, conductive networks, microstructure design). It concludes that composite mixtures combining dielectric and magnetic fillers are generally needed for optimal microwave absorption, and notes challenges including limited effective frequency range (often 8–18 GHz) and complex preparation methods.",
    "effect_direction": "unclear",
    "limitations": [
        "Narrative/critical review; no primary experimental or epidemiologic results reported in the abstract",
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        "Focus is on materials engineering rather than health outcomes"
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