Ultra-Wideband and Wide-Angle Microwave Metamaterial Absorber

Area of Science:

• Electromagnetics
• Materials Science
• Metamaterials

Background:

• Radar absorbing materials (RAM) require wideband properties and large angles of incidence for enhanced performance.
• Achieving these properties while minimizing thickness is a key challenge in RAM development.
• The SAFAS (self-complementary surface with low signature) project aims to address these limitations.

Purpose of the Study:

• To develop an ultra-wideband microwave absorber with a low profile.
• To design a multilayered structure capable of wideband absorption and wide-angle performance.
• To validate the proposed absorber design using on-the-shelf materials.

Main Methods:

• Designing a multilayered structure incorporating dielectric layers, metasurfaces, and wide-angle impedance matching layers.
• Fabricating the absorber using readily available materials.
• Measuring the reflection coefficient and calculating the bandwidth ratio at various incidence angles.

Main Results:

• The developed absorber achieved a bandwidth ratio of 4.7:1 at normal incidence for a reflection coefficient below -10 dB.
• The total thickness of the absorber is 11.5 mm, corresponding to λ/7 at the lowest operating frequency.
• At an incidence angle of 60°, the bandwidth ratio was 3.8:1, maintaining ultra-wideband performance.

Conclusions:

• The proposed multilayered structure effectively functions as an ultra-wideband microwave absorber.
• The design achieves a low thickness while maintaining wideband and wide-angle performance.
• The use of on-the-shelf materials demonstrates the practical feasibility of the concept.