Recent progress in some composite materials and structures for specific electromagnetic applications

Abstract

This review aims to summarise the progress in some materials and structures for electromagnetic applications, such as microwave absorption, electric shielding and antenna designs, which have been developed in recent years. Composites with spherical powders for microwave absorption focus mainly on those based on ferrites (especially hexagonal), carbonyl iron and related alloys and various newly emerged nanosized materials. Composites with long conductive fibres as fillers will be summarised, with speical attentions to prediction, measurment and evaluation of their performances. Metamaterials include structures for microwave absorbing applications, tunable materials or structures with reflection or transmission coefficients that are tunable by external magnetic or electric fields, and specially designed structures for microwave absorbing applications, with thickness much smaller than that of conventional composite materials and performances that can be optimised by the physical properties of substrates, and new metamaterials constructed with ferrite cores wound by metallic wire coils that exhibited unique magnetic properties, with extremely high real and imaginary permeability, which are adjustable or tunable by varying their configurations. Magnetodielectric materials, with matching permeability and permittivity, together with sufficiently low magnetic and dielectric loss tangents, with potential applications in antenna miniaturisation, will be discussed.

Keywords:

• Electromagnetic absorption
• Electromagnetic shielding
• Composites
• Ferrites
• Carbonyl iron
• Magnetic alloys
• Nanomaterials
• Nanoparticles
• Conductive fibres
• Magnetic alloy microwires
• Metamaterials
• Tunable materials and structures
• Magnetodielectric materials
• Review

This work was financially supported by the Defence Research and Technology Office (DRTech), Mindef, Singapore. The authors would like to thank H. Lim, S. K. J. Ting, K. Y. Lum, C. K. Ong, A. Y. Qing, Y. B. Gan, L. F. Chen, X. S. Rao, G. Q. Lin, K. M. Hock, X. Xu and K. N. Rozanove for their supports or assisstances in one way or another. They also would like to acknowledge the publishers offering permissions to reuse figures and tables from their journals. One of the authors (LL) would like to appreciate the financial support from the National High Technology Research and Development Program of China (863 Program, No. 2012AA030401), the introduction of innovative R & D team program of Guangdong Province (No.2009010005) and the Guangdong Key Project of Core Technology in Strategic Emerging Industry (No. 2011A091103003).