A Metasticker Composed of Indium-Tin-Oxide-Square-Fractal Rings for Broadband Absorption.

Area of Science:

• Electromagnetics
• Materials Science
• Nanotechnology

Background:

• Metasurface absorbers (MAs) are crucial for controlling electromagnetic wave interactions.
• Achieving broad absorption bandwidth and wide-angle performance remains a key challenge in MA design.

Purpose of the Study:

• To propose and demonstrate a novel design and fabrication method for a broadband electromagnetic metasurface absorber.
• To optimize the metasurface absorber for maximum design freedom and widest possible absorption bandwidth.

Main Methods:

• A square-fractal ring was chosen as the metapattern for its design flexibility and optimized using a genetic algorithm.
• Indium-tin-oxide (ITO) films were laser-cut to fabricate the square-fractal rings, forming a metasticker on an adhesive film.
• The metasticker was attached to a dielectric substrate backed by a copper sheet to create the final MA.

Main Results:

• The fabricated MA exhibited a broad -10 dB reflectance bandwidth (BW) from 4.39 to 7.51 GHz (52.44% fractional BW) for normal incidence.
• A fractional BW of 4.35% was measured across a wide incident angle range (0° to 60°) for both transverse electric (TE) and transverse magnetic (TM) polarizations.

Conclusions:

• The proposed laser-cutting fabrication method enables simple and efficient production of complex metasurface patterns.
• The optimized square-fractal ring metasurface absorber demonstrates excellent broadband absorption performance and wide-angle stability, suitable for various electromagnetic applications.