Angular- and Polarization-insensitive Ultrathin Double-layered Metamaterial Absorber for Ultra-wideband Application

Area of Science:

• Electromagnetics
• Materials Science
• Nanotechnology

Background:

• Metamaterial absorbers (MMAs) are crucial for applications like stealth and sensing.
• Achieving ultra-wideband (UWB) absorption with polarization-insensitivity and wide incident angle stability remains a challenge.

Purpose of the Study:

• To propose and demonstrate an ultra-thin, polarization-insensitive metamaterial absorber (MMA) for ultra-wideband (UWB) operation.
• To achieve broadband absorptivity over a wide range of frequencies and incident angles.

Main Methods:

• Design of an MMA using double-layer symmetric split rings (SSRs) and orthogonally arranged bars.
• Incorporation of lumped resistors to enhance absorption bandwidth.
• Utilizing Ohmic loss and Fabry-Perot interference mechanisms for broadband absorption.

Main Results:

• Achieved ultra-wideband absorbance from 4-22 GHz.
• Demonstrated absorptivity over 60% (4-12 GHz) and 80% (12-22 GHz).
• The MMA exhibits polarization-insensitivity and stable performance at wide incident angles with an ultra-thin profile (2.4 mm).

Conclusions:

• The proposed MMA effectively achieves UWB absorption with excellent polarization and wide-angle stability.
• The design integrates multiple metallic layers, lumped resistors, and symmetric structures for enhanced performance.
• Numerical and experimental validation confirms the MMA's capability for UWB absorbance.