An Ultra-Thin Triple-Band Polarization-Independent Wide-Angle Microwave Metamaterial Absorber

An ultra-thin triple-band metamaterial resonant structure has been proposed in this communication. The absorber is ultra-thin and compact (λo110\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \frac{\lambda_o}{110} $$\end{document}) concurrent to the lowest absorption frequency 3.44 GHz. The simulated results show the suitability of the absorber for triple-band frequency operation. The absorber has absorption spectra of 3–12 GHz having three absorption peaks at 3.44 GHz, 6.36 GHz, and 11.51 GHz and more than 90% absorption corresponding to S, C, and X bands. The full width half maximum (FWHM) is 110 MHz (3.49–3.38 GHz), 300 MHz (6.52–6.22 GHz), and 660 MHz (11.9–11.24 GHz) at the corresponding frequencies. The proposed absorber has also been examined for its angle and polarization insensitivity and the absorption was found to be polarization insensitive and has more than 90% absorption for both TE and TM modes of propagation. The absorption mechanism is substantiated by the E-field, H-field, and surface current distribution plots. The proposed absorber has been fabricated and measured. The experimental results agree with numerical results. The absorber is appropriate for potential microwave frequency applications.