Bowtie Nanoantenna Array Integrated With Artificial Impedance Surfaces for Realizing High Field Enhancement and Perfect Absorption Simultaneously

Autor: Mohamad Khoirul Anam, Sangjo Choi
Jazyk: angličtina
Rok vydání: 2020
Předmět:
Zdroj: IEEE Access, Vol 8, Pp 99858-99869 (2020)
Druh dokumentu: article
ISSN: 2169-3536
DOI: 10.1109/ACCESS.2020.2997680
Popis: High field enhancement and near-perfect absorption in nanoantennas were realized by using in-plane (between nanoantenna arms), out-of-plane (between nanoantenna and reflector), and array coupling (between nanoantennas in an array); however, it was challenging to satisfy both conditions at the same time. In this paper, we show that a bowtie nanoantenna array integrated with an artificial impedance surface can simultaneously satisfy both high field enhancement and perfect absorption. The artificial impedance surface is implemented as a metallic patch array on a grounded 50 nm-thick SiO2 substrate with reactive impedance surface (RIS) or high impedance surface (HIS) characteristic. Through the proposed design methodology, we designed a bowtie nanoantenna array on an optimum RIS patch array and achieved a high field enhancement factor (E/E0) of 228 and a nearly perfect absorption rate of 98% at 230 THz. This novel design outperforms the previously reported nanoantenna structures and the same bowtie nanoantenna array designed using a conventional grounded SiO2. We also show that the HIS-integrated bowtie antenna array cannot realize both goals at the same time because the highly reflective HIS cannot guarantee perfect absorption. The proposed RIS-combined nanoantenna array with high field enhancement and near-perfect absorption can be used for efficient infrared (IR) and optical detectors, sensors, and energy harvesting devices.
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