Frequency-Selective Radar-Absorbing Composites Using Hybrid Core-Shell Spheres

Area of Science:

• Materials Science
• Electromagnetics
• Nanotechnology

Background:

• Radar-absorbing materials (RAMs) are vital for minimizing electromagnetic (EM) wave reflection from surfaces, crucial for stealth technology and electronic device stability.
• Existing RAM research often overlooks frequency selectivity, creating a need for tunable absorption capabilities across various EM spectra.
• Advanced stealth aircraft and electronic systems require robust protection against a wide range of EM radiation frequencies.

Purpose of the Study:

• To develop novel smart RAMs with frequency-selective absorption capabilities.
• To address the research gap in tunable frequency selectivity for RAMs.
• To create effective isotropic coverings for metallic surfaces with tailored EM wave absorption.

Main Methods:

• Incorporation of core-shell spheres (metal-shelled and graphene-shelled) within a polymer matrix.
• Tailoring X-band (8.2-12.4 GHz) absorption frequencies by adjusting interstitial spaces between metallic spheres.
• Utilizing graphene networks for efficient attenuation of scattered waves.

Main Results:

• A 2 mm-thick composite on a metal substrate achieved a maximum absorption efficiency of 99.3%.
• Demonstrated structural tunability and frequency-selective absorption properties.
• Successfully trapped and extinguished incident electromagnetic waves.

Conclusions:

• The proposed smart RAMs offer tunable, frequency-selective absorption in the X-band.
• The composite structure effectively attenuates scattered waves using graphene networks.
• This scalable approach provides functional isotropic coverings for diverse metallic surfaces.