Bilayer magnetic composite systems made of random anisotropy hexaferrite and soft metallic magnets for stealth technology

Abstract

An experimental strong increase of the reflection loss (from 25 up to 35 dBs) and an extension of the absorption bandwidth up to 20% is measured in a set of novel functional bilayer systems. We focus our work on studying the samples in an anechoic chamber under far-field real radar conditions. Each layer consists of a composite material, typically a dielectric matrix filled with random anisotropy hexaferrite and soft metallic materials (powder or wires). Combining the two types of materials into a submillimetric bilayer structure has shown unprecedented improvements in microwave absorption capacities compared to the former absorption of each layer. The capacity to improve the shielding behavior is strongly related to each layer’s permittivity, permeability, and thickness leading, therefore, to a strong control over the design of novel materials for stealth applications.