Design of an optically transparent ultrawideband absorber with high angular stability using ITO films

Area of Science:

• Electromagnetics and Metamaterials
• Optical Engineering
• Materials Science

Background:

• Development of efficient electromagnetic wave absorbers is crucial for applications like stealth technology and signal processing.
• Achieving wideband absorption with optical transparency and angular stability remains a significant challenge in metamaterial design.

Purpose of the Study:

• To design and demonstrate an optically transparent ultrawideband absorber with high angular stability.
• To investigate the absorption performance and optical properties of the proposed metamaterial absorber.

Main Methods:

• A stacked structure comprising indium thin oxide (ITO) conductive films and polydimethylsiloxane (PDMS) substrates was designed.
• Electromagnetic simulations were performed to analyze absorption bandwidth, angular stability, and optical transmittance.
• A prototype was fabricated and experimentally measured to validate simulation results.

Main Results:

• The absorber exhibits a 90% absorption band from 5 to 43.5 GHz, achieving a fractional bandwidth of 158.7%.
• High angular stability was observed for both TE (up to 50°) and TM (0° to 70°) modes.
• The absorber has a physical thickness of only 0.092 wavelengths and maintains 57.3% transmittance in the visible band.

Conclusions:

• The designed optically transparent ultrawideband absorber demonstrates excellent performance in terms of absorption bandwidth, angular stability, and transparency.
• The fabricated prototype confirms the simulated results, highlighting the potential of this design for various electromagnetic applications.