Enhanced Broadband Metamaterial Absorber Using Plasmonic Nanorods and Muti-Dielectric Layers Based on ZnO Substrate in the Frequency Range from 100 GHz to 1000 GHz
by Ahmed Emara 1,2,*,Amr Yousef 1,2,Basma ElZein 1,3,Ghassan Jabbour 4 and Ali Elrashidi 1,2
1Department of Electrical Engineering, University of Business and Technology, Jeddah 21432, Saudi Arabia
2Department of Engineering Physics, Alexandria University, Alexandria 21544, Egypt
3Sustainable Development, Global Council for Tolerance and Peace, VLT1011 Valletta, Malta
4Advanced Materials and Devices Laboratories, University of Ottawa, 75 Laurier Ave. E, Ottawa, ON K1N 6N5, Canada
*Author to whom correspondence should be addressed.
Academic Editor: Academic Editor(s): George KenanakisCrystals2022, 12(10), 1334; https://doi.org/10.3390/cryst12101334 (registering DOI)Received: 30 August 2022 / Revised: 14 September 2022 / Accepted: 18 September 2022 / Published: 21 September 2022(This article belongs to the Special Issue Novel ZnO-Based Nanostructures: Synthesis, Characterization and Applications)
Abstract
A broadband thin film plasmonic metamaterial absorber nanostructure that operates in the frequency range from 100 GHz to 1000 GHz is introduced and analyzed in this paper. The structure consists of three layers: a 200 nm thick gold layer that represents the ground plate (back reflector), a dielectric substrate, and an array of metallic nanorods. A parametric study is conducted to optimize the structure based on its absorption property using different materials, gold (Au), aluminum (Al), and combined Au, and Al for the nanorods. The effect of different dielectric substrates on the absorption is examined using silicon dioxide (SiO2), aluminum oxide (Al2O3), titanium dioxide (TiO2), and a combination of these three materials. This was followed by the analysis of the effect of the distribution of Al, and Au nanorods and their dimensions on the absorption. The zinc oxide (ZnO) layer is added as a substrate on top of the Au layer to enhance the absorption in the microwave range. The optimized structure achieved more than 80% absorption in the ranges 100–280 GHz, 530–740 GHz and 800–1000 GHz. The minimum optimized absorption is more than 65% in the range 100 GHz to 1000 GHz.Keywords: electromagnetic absorbers; metamaterial absorbers; SiO2; Al2O3; TiO2; ZnO; microwave absorbers; plasmonic metamaterial absorbers; absorption spectrum; FDTD