Transparent Low-Profile and Wideband ITO-Glass Microwave Absorber

This paper proposes a transparent wideband microwave absorber by integrating Indium Tin Oxide (ITO) with glass in order to achieve both high microwave absorption and optical transparency. The design is constructed from three layers of glass substrate with etched ITO with different sheet resistance on each layer. The absorber features a combination of high dielectric constant material to accomplish the low-profile design and matching layer to achieve wide absorption bandwidth. The absorber demonstrates 115.64% fractional bandwidth from 3.48 GHz to 13.02 GHz with a structure thickness of 0.077 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda_{\min}$ </tex-math></inline-formula>, where <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda_{\min}$ </tex-math></inline-formula> is the free-space wavelength at the lowest operating frequency. The proposed absorber design shows wide absorption bandwidth with a low profile, which outperforms the reported designs in the literature. The development process of the absorber is detailed, showcasing the evolution from a single-layer to a triple-layer design, addressing challenges in fabrication and enhancing performance. The absorber’s effectiveness is validated through simulations and measurements of a fabricated prototype, highlighting its potential in applications requiring both microwave absorption and optical transparency.