Design of multi-ellipse broadband metamaterial absorber

Abstract

In this paper, two types of ellipse-pattern broadband metamaterial absorbers with high absorptivity are designed and analyzed. The single-ellipse periodic absorber can achieve more than 90% absorption in the range of 8.8 to 12.5 μm, and the average absorption in this range is 96.5%. Further exploration of its electromagnetic field's distribution revealed that the coupling of propagating surface plasmon resonance and localized surface plasmon resonance is responsible for its character. An optimized four-ellipse periodic absorber can achieve 89.5% average absorption in the range of 8 to 15 μm, and the absorption is insensitive to the incident angle. The variations of absorption of the absorber under different polarization and incident angles are also discussed. This design has potential application value in uncooled infrared detectors and other fields.