Transparent transmission-selective radar-infrared bi-stealth structure.

Area of Science:

• Materials Science
• Electromagnetics
• Optics

Background:

• Metamaterials offer unique electromagnetic properties.
• Achieving simultaneous stealth across multiple spectrums (radar, infrared) is challenging.
• Integrating tunable microwave transmission with stealth is desirable for advanced applications.

Purpose of the Study:

• To develop a multifunctional metamaterial composite.
• To achieve broadband radar and thermal infrared bi-stealth.
• To incorporate an in-band microwave transmission window and optical transparency.

Main Methods:

• Fabrication of a four-layer metasurface composite using indium tin oxide (ITO) films.
• Tuning surface resistances of ITO films to control infrared emission, microwave absorption, and transmission.
• Characterization of reflectivity, transmission, emissivity, and optical transparency.

Main Results:

• Achieved broadband radar stealth with reflectivity <10% from 1.5-9 GHz.
• Demonstrated a microwave transmission peak of 50% around 3.8 GHz, stable up to 30-degree incident angles.
• Obtained low thermal emissivity (~0.52) in the infrared atmosphere window.
• Maintained high optical transparency.

Conclusions:

• The developed metamaterial composite successfully integrates broadband radar/infrared stealth with frequency-selective microwave transmission and optical transparency.
• The design utilizes ITO films with tailored surface resistances for sequential control of electromagnetic and thermal properties.
• This technology holds promise for communication-compatible multispectral stealth applications.