Dual-layer self-healing composites with temperature-responsive intelligent broadband microwave absorption

Area of Science:

• Materials Science
• Electromagnetics
• Nanotechnology

Background:

• Growing demand for effective microwave absorption (MA) materials due to increased electromagnetic interference (EMI) from wireless technologies.
• Need for broadband compatibility and adaptive tunability in MA materials for diverse applications.

Purpose of the Study:

• To develop a dual-layer intelligent broadband MA composite with complementary microwave loss characteristics.
• To achieve high-efficiency MA covering the entire 2-18 GHz frequency band.
• To enable dynamic tunability of MA properties.

Main Methods:

• Fabrication of dual-layer composite using plasma ball milling for carbonyl iron powder (CIP)/boron nitride (BN) and FeSiAl/BN/vanadium dioxide (VO2) powders.
• Utilizing BN coating to modulate dielectric properties and designing layers with complementary characteristic impedances.
• Incorporating VO2 for dynamic MA modulation via insulator-to-metal transition and a self-healing matrix for assembly.

Main Results:

• Achieved an ultra-wide effective absorption bandwidth (EAB) of 13.49 GHz at 3.70 mm thickness, covering 2-18 GHz.
• Demonstrated a 48% enhancement in EAB compared to single magnetic absorbers.
• Obtained a maximum tunable EAB range (ΔEAB) of 8.35 GHz in the Ku-band due to VO2.
• Successfully assembled layers adhesively-free using a dynamic poly(urethane urea) matrix.

Conclusions:

• The proposed dual-layer composite offers superior broadband MA performance and adaptive tunability.
• The material is highly promising for next-generation telecommunications (5G/6G), multi-band radar, and flexible electronic devices.
• The self-healing matrix facilitates practical, adhesive-free integration into devices.