Design of broadband metamaterial absorber utilized by flower-shaped unit loaded with lumped-resistor

Abstract

A metamaterial broadband absorber is designed by means of metal pattern and lumped resistance. The optimal structural parameters and resistance are scanned in certain steps to determine. The maximum absorbing bandwidth can achieve up to 8.2 GHz with 3 mm thickness. Subsequently, the angle stability of the absorber can be improved by adding vertical metal through holes. After optimization, the maximum absorbing bandwidth can be further increased to 9.1 GHz (8.3–17.4 GHz), and the effective absorption bandwidth of 3.7 GHz (9.53–13.25 GHz) can still be achieved when the incident angle is 60°. Further analysis reveals that the dissipation of the electromagnetic wave is achieved by ohmic loss caused by the resistive element and magnetic resonance caused by the induced circular current, rather than by temperature or other factors. Finally, to verify the real performance of the designed metamaterial absorber, a 30 cm × 30 cm sample was fabricated, and the reflection coefficient was tested by the NRL arch test method. The results showed that the measured return loss of the absorber was consistent with the simulation results.