Advancements in electromagnetic microwave absorbers: Ferrites and carbonaceous materials

Abstract

Overview

Heightened levels of electromagnetic (EM) radiation emitted by electronic devices, communication equipment, and information processing technologies have become a significant concern recently. Significant efforts have been devoted to developing novel materials with high EM absorption properties. This critical review article provides an overview of advancements in understanding and developing such materials and highlights the health and safety importance of effective EM radiation mitigation.

Findings

• Interactions with Materials: The article explores the interactions between EM radiation and absorbing materials, focusing on phenomena like multiple reflections, scattering, and polarization.
• Loss Mechanisms: Various types of losses impacting microwave absorber performance are discussed, including magnetic and dielectric loss, each playing a crucial role in reducing harmful EM emissions.
• Material Types: The review offers detailed insights into different microwave-absorbing materials, such as metal composites, magnetic materials, conducting polymers, and carbonaceous materials (including composites with carbon fiber, porous carbon, carbon nanotube, graphene oxide, etc.).
• Composite Optimization: The article emphasizes that optimal microwave absorption cannot be achieved with single-component systems, but rather with carefully formulated composites that combine dielectric and magnetic fillers.

Conclusions

• Exceptional Capabilities: Magnetic and carbon-based dielectric composites possess exceptional microwave absorption abilities, combining optimized impedance matching, interfacial polarization, conductive network formation, and precisely engineered microstructures for maximum EM attenuation.
• Challenges and Outlook: Key challenges remain, including the need for in-depth exploration of EM loss characteristics, defect engineering for improved performance, expanding the effective frequency range for broader device protection (lower than 8.0 GHz), and simplifying the preparation methods for scalable production.
• Future Directions: Development of novel composites with balanced filler compositions and intricate design is crucial for mitigating electromagnetic pollution, a known health hazard, and for protecting sensitive environments from EM interference.

The study reinforces the strong connection between electromagnetic field (EMF) exposure and public safety, emphasizing the ongoing need for advanced absorber design to reduce the risks associated with EM radiation.