Superdirective aerial array containing only one fed element

Bacon, Jean; Medhurst, R.G.

doi:10.1049/piee.1969.0066

Cited by 10 publications

(5 citation statements)

References 5 publications

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“…On the experimental front an early, unjustly forgotten, paper by Bacon and Medhurst [10] needs to be quoted. They built a four-element endfire array with elements unequally spaced and with only one element fed.…”

Section: Introductionmentioning

confidence: 99%

“…We should also mention here a classical paper by Toraldo di Francia [6] that relates superdirectivity to optical resolution and three further papers by Chu [7], Harrington [8] and Pozar [9] based on the expansion of spherical harmonics. On the experimental front an early, unjustly forgotten, paper by Bacon and Medhurst [10] needs to be quoted. They built a four‐element endfire array with elements unequally spaced and with only one element fed.…”

Section: Introductionmentioning

confidence: 99%

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Maximum directivity of arbitrary dipole arrays

Shamonina

Solymár

2015

IET Microwaves, Antennas & Propagation

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A fully analytical form, more general than any reported previously, for the optimum current distribution and maximum directivity of an arbitrary array consisting of dipoles parallel with each other, is derived. For an array configuration consisting of several hundred elements, a calculation takes a fraction of a second making many-element superdirective arrays candidates for adaptive antenna applications. Examples for two-dimensional (2D) and 3D arrays are given and some earlier superconductive arrays are revisited. It is also shown in further examples that superconductivity is not incompatible with moderate values of the quality factor.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Maximum directivity of arbitrary dipole arrays

Shamonina

Solymár

2015

IET Microwaves, Antennas & Propagation

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“…Experimentally, four-element arrays with only one element fed were studied by Bacon and Medhurst [16] and by Newman and Schrote [17]. More recently, experiments on superdirective structures comprising two [18], [19] or three [20] electrically small elements were reported.…”

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confidence: 99%

A Method for Optimising Superdirectivity of Coupled Meta-Atoms via Planar Directivity Evaluation

Yan

Radkovskaya

Khromova

et al. 2020

IEEE Open J. Antennas Propag.

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We propose a simple and rapid way of optimising directivity in metamaterial-inspired endfire antenna arrays with strong interelement coupling. We introduce, in addition to the traditional 3D directivity, also its planar equivalents defined as the ratio of the power density in the desired endfire direction to the average power density calculated either in the horizontal (azimuthal) or vertical (elevation) plane. Using dimers of magnetically coupled split-ring resonators with only one element driven by an external source, we derive conditions that must be satisfied in order to realise superdirective current distributions. The superdirective conditions link the quality factor of the resonators and their coupling constant to the array size and the operating frequency. We demonstrate that a rapid measurement in the azimuthal plane can be used as a reliable indicator for whether the superdirective conditions for the 3D directivity are satisfied. Analytical calculations are verified by CST simulations in the MHz frequency range for meta-atoms of circular and square shape. Our method can be extended to arrays comprising larger number of meta-atoms of various shape and would enable rapid prototyping of 3D-printed meta-atoms with desired radiation properties.

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“…5−7 The first experimental demonstration of the phenomenon was reported in 1969 for antenna arrays operating at radio frequencies (RF). 8 It was later shown that the concept of superdirectivity could be applied to the optical regime. 9 A brief overview of the history and theory of superdirective arrays can be found in the literature.…”

mentioning

confidence: 99%

“…The creation of superdirective antennas has been the Holy Grail for physicists and engineers ever since the concept was first postulated nearly a hundred years ago . While pioneering work in the field has shown that unlimited directivity can theoretically be achieved with arrays of ideal perfectly conducting elements, − this superdirectivity comes at the cost of extreme sensitivity to electrical and mechanical errors, low radiation efficiency, and a very narrow bandwidth. − The first experimental demonstration of the phenomenon was reported in 1969 for antenna arrays operating at radio frequencies (RF) . It was later shown that the concept of superdirectivity could be applied to the optical regime .…”

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confidence: 99%

Existence of Superdirective Radiation Modes in Thin-Wire Nanoloops

Pantoja

Nagar

et al. 2017

ACS Photonics

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The problem of obtaining broadband superdirective radiation from an electrically small, easy to manufacture antenna is among the most challenging and elusive problems in electromagnetics. Superdirective arrays tend to be narrowband and sensitive to tolerancing, while a single superdirective radiator typically requires a very complicated and difficult to manufacture design. In this Article, we report on a new and transformative discovery, the fact that broadband superdirectivity naturally occurs for a single thin-wire nanoloop of the appropriate material composition and size. Full-wave simulations have revealed end-fire directivity of above 4.0 (6 dBi) for a nanoloop with radius less than 0.2 wavelength. This surprising phenomenon is explained in two ways: by comparison with two-element superdirective arrays and via a spherical multipole decomposition. This finding offers a solution to the problem of the inherently short-range communication of nanodevices and thus had the potential to strongly impact the fields of sensors, electronics, and wireless communications.

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Superdirective aerial array containing only one fed element

Cited by 10 publications

References 5 publications

Maximum directivity of arbitrary dipole arrays

Maximum directivity of arbitrary dipole arrays

A Method for Optimising Superdirectivity of Coupled Meta-Atoms via Planar Directivity Evaluation

Existence of Superdirective Radiation Modes in Thin-Wire Nanoloops

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