# Magnetoresponsive Fiber-Reinforced Periodic Impedance-Gradient Absorber: Design and Microwave Absorption Performance

## TL;DR

This paper introduces a lightweight, efficient microwave absorber that works across a wide frequency range and maintains mechanical strength.

## Contribution

A novel multilayer metamaterial absorber with dual-gradient electromagnetic parameter modulation for ultra-wideband absorption.

## Key findings

- The absorber achieves 94% absorption efficiency across X, Ku, and K bands with a thickness of 3.5 mm.
- The design is polarization-insensitive and stable at incident angles up to 60°.
- The fiber-reinforced structure improves mechanical load-bearing without sacrificing broadband performance.

## Abstract

In recent years, achieving ultra-wideband electromagnetic absorption has emerged as a critical challenge in confronting advanced broadband electromagnetic detection technologies. This capability is essential for effectively countering sophisticated radar systems. In this study, we present a novel multilayer metamaterial absorber that integrates an FR4 transmission layer, a periodic gradient dielectric structure designed for resonant impedance matching, and a magnetic skin layer for enhanced energy dissipation. By employing asymptotic gradients in both structure and composition, this design achieves dual-gradient electromagnetic parameter modulation, enabling efficient absorption across the X, Ku, and K bands (8.6–26.4 GHz) with a total thickness of 3.5 mm (effective thickness: 2 mm) and a density that is one-third that of conventional magnetic metamaterials. The proposed absorber demonstrates polarization insensitivity, stability across wide incident angles (up to 60°), and an absorption efficiency of 94%, as confirmed by full-wave simulations and experimental validation. Moreover, the fiber-reinforced hierarchical structure addresses the traditional trade-off between broadband absorption performance and mechanical load-bearing capacity.