Going Beyond Perfect Absorption: Reconfigurable Super-directive Absorbers

Fuente: arXiv
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Autores principales: Li, Yongming, Ma, Xikui, Wang, Xuchen, Tretyakov, Sergei A.
Formato: Preprint
Publicado: 2024
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author Li, Yongming
Ma, Xikui
Wang, Xuchen
Tretyakov, Sergei A.
author_facet Li, Yongming
Ma, Xikui
Wang, Xuchen
Tretyakov, Sergei A.
contents In the context of electromagnetic absorption, it is obvious that for an infinite planar periodic structure illuminated by a plane wave, the maximum attainable absorptance, i.e., perfect absorption, is theoretically limited to 100% of the incident power. Here we show that an intriguing possibility of overcoming this limit arises in finite-size resonant absorbing arrays. We present a comprehensive analysis of a simple two-dimensional strip array over an infinite perfectly conducting plane, where the strips are loaded by reconfigurable impedance loads. The absorptance is defined as the ratio of the dissipated power per unit length of the strips to the incident power on the unit length of the array width. The results show that even regular arrays of impedance strips can slightly overcome the limit of 100% absorptance, while using aperiodic arrays with optimized loads, absorptance can be significantly increased as compared with the scenario where the strips are identical. In principle, by tuning the reconfigurable loads, high super-unity absorptance can be realized for all angles of illumination.
format Preprint
id arxiv_https___arxiv_org_abs_2402_11971
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Going Beyond Perfect Absorption: Reconfigurable Super-directive Absorbers
Li, Yongming
Ma, Xikui
Wang, Xuchen
Tretyakov, Sergei A.
Applied Physics
In the context of electromagnetic absorption, it is obvious that for an infinite planar periodic structure illuminated by a plane wave, the maximum attainable absorptance, i.e., perfect absorption, is theoretically limited to 100% of the incident power. Here we show that an intriguing possibility of overcoming this limit arises in finite-size resonant absorbing arrays. We present a comprehensive analysis of a simple two-dimensional strip array over an infinite perfectly conducting plane, where the strips are loaded by reconfigurable impedance loads. The absorptance is defined as the ratio of the dissipated power per unit length of the strips to the incident power on the unit length of the array width. The results show that even regular arrays of impedance strips can slightly overcome the limit of 100% absorptance, while using aperiodic arrays with optimized loads, absorptance can be significantly increased as compared with the scenario where the strips are identical. In principle, by tuning the reconfigurable loads, high super-unity absorptance can be realized for all angles of illumination.
title Going Beyond Perfect Absorption: Reconfigurable Super-directive Absorbers
topic Applied Physics
url https://arxiv.org/abs/2402.11971