Superdirective dimers of coupled self-resonant split ring resonators: Analytical modelling and numerical and experimental validation

Superdirective antennas developed over the last century have received renewed interest in recent years from the development of metamaterials. These arrays of electromagnetic resonators (or meta-atoms) carrying short wavelength electro- and/or magneto-inductive waves support current distributions wit...

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Auteurs principaux: Vallecchi, A, Radkovskaya, A, Li, L, Faulkner, G, Stevens, C, Shamonina, E
Format: Journal article
Publié: Springer Nature 2020
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author Vallecchi, A
Radkovskaya, A
Li, L
Faulkner, G
Stevens, C
Shamonina, E
author_facet Vallecchi, A
Radkovskaya, A
Li, L
Faulkner, G
Stevens, C
Shamonina, E
author_sort Vallecchi, A
collection OXFORD
description Superdirective antennas developed over the last century have received renewed interest in recent years from the development of metamaterials. These arrays of electromagnetic resonators (or meta-atoms) carrying short wavelength electro- and/or magneto-inductive waves support current distributions with very high spatial frequency as required by the classical conditions for superdirectivity. As meta-atoms can have both electric and magnetic dipole characteristics (and hence radiation properties), developing antennas exploiting these distributions can challenge conventional intuitions regarding the optimal configurations required. In this work we are reporting the development of a genuinely superdirective array using split ring resonators (SRRs). We provide a comprehensive analytical model characterizing the radiation from SRR dimers in which excitation of only one split ring leads to superdirective radiation via mutually coupled modes. Our model exploits simple circuit descriptions of coupled resonant circuits, combined with standard radiation formulae for curvilinear current distributions. Using this simple model we are able to map directivity against possible SRR locations and orientations in two dimensions and identify the unique optimal configuration which meets the requirements for superdirective emission. We validate the theoretical findings by comparison to both full wave simulations and experiments showing that our SRR dimer achieves endfire directivity very close to the maximum theoretical value.
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spelling oxford-uuid:8b18f1f5-2d0a-43e2-bb69-47d5a528ed9b2022-03-26T22:35:51ZSuperdirective dimers of coupled self-resonant split ring resonators: Analytical modelling and numerical and experimental validationJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:8b18f1f5-2d0a-43e2-bb69-47d5a528ed9bSymplectic Elements at OxfordSpringer Nature2020Vallecchi, ARadkovskaya, ALi, LFaulkner, GStevens, CShamonina, ESuperdirective antennas developed over the last century have received renewed interest in recent years from the development of metamaterials. These arrays of electromagnetic resonators (or meta-atoms) carrying short wavelength electro- and/or magneto-inductive waves support current distributions with very high spatial frequency as required by the classical conditions for superdirectivity. As meta-atoms can have both electric and magnetic dipole characteristics (and hence radiation properties), developing antennas exploiting these distributions can challenge conventional intuitions regarding the optimal configurations required. In this work we are reporting the development of a genuinely superdirective array using split ring resonators (SRRs). We provide a comprehensive analytical model characterizing the radiation from SRR dimers in which excitation of only one split ring leads to superdirective radiation via mutually coupled modes. Our model exploits simple circuit descriptions of coupled resonant circuits, combined with standard radiation formulae for curvilinear current distributions. Using this simple model we are able to map directivity against possible SRR locations and orientations in two dimensions and identify the unique optimal configuration which meets the requirements for superdirective emission. We validate the theoretical findings by comparison to both full wave simulations and experiments showing that our SRR dimer achieves endfire directivity very close to the maximum theoretical value.
spellingShingle Vallecchi, A
Radkovskaya, A
Li, L
Faulkner, G
Stevens, C
Shamonina, E
Superdirective dimers of coupled self-resonant split ring resonators: Analytical modelling and numerical and experimental validation
title Superdirective dimers of coupled self-resonant split ring resonators: Analytical modelling and numerical and experimental validation
title_full Superdirective dimers of coupled self-resonant split ring resonators: Analytical modelling and numerical and experimental validation
title_fullStr Superdirective dimers of coupled self-resonant split ring resonators: Analytical modelling and numerical and experimental validation
title_full_unstemmed Superdirective dimers of coupled self-resonant split ring resonators: Analytical modelling and numerical and experimental validation
title_short Superdirective dimers of coupled self-resonant split ring resonators: Analytical modelling and numerical and experimental validation
title_sort superdirective dimers of coupled self resonant split ring resonators analytical modelling and numerical and experimental validation
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AT lil superdirectivedimersofcoupledselfresonantsplitringresonatorsanalyticalmodellingandnumericalandexperimentalvalidation
AT faulknerg superdirectivedimersofcoupledselfresonantsplitringresonatorsanalyticalmodellingandnumericalandexperimentalvalidation
AT stevensc superdirectivedimersofcoupledselfresonantsplitringresonatorsanalyticalmodellingandnumericalandexperimentalvalidation
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