Shrinking a gradient index lens antenna system with a spaceplate

Fuente: arXiv
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Main Authors: Mrnka, Michal, Whittaker, Thomas, Phillips, David B., Hendry, Euan, Whittow, Will
Format: Preprint
Published: 2024
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author Mrnka, Michal
Whittaker, Thomas
Phillips, David B.
Hendry, Euan
Whittow, Will
author_facet Mrnka, Michal
Whittaker, Thomas
Phillips, David B.
Hendry, Euan
Whittow, Will
contents The miniaturisation of optical systems is an ongoing challenge across the electromagnetic spectrum. While the thickness of optical elements themselves can be reduced using advances in metamaterials, it is the voids between these elements -- which are necessary parts of an optical system -- that occupy most of the volume. Recently, a novel optical element coined a `spaceplate' was proposed, that replaces a region of free space with a thinner optical element that emulates the free-space optical response function -- thus having the potential to substantially shrink the volume of optical systems. While there have been a few proof-of-principle demonstrations of spaceplates, they have not yet been deployed in a real-world optical system. In this work, we use a bespoke-designed spaceplate to reduce the length of a gradient index (GRIN) lens microwave antenna. Our antenna is designed to operate at 23.5 GHz, and the incorporation of a nonlocal metamaterial spaceplate enables the distance between the antenna feed and the GRIN lens to be reduced by almost a factor of two. We find the radiation patterns from a conventional and space-squeezed antenna are very similar, with a very low cross-polarisation, and only a minor increase in the side-lobe levels when introducing the spaceplate. Our work represents a first example of a spaceplate integrated into a functional optical system, highlighting the potential for this concept to reduce the physical size of optical systems in real-world applications.
format Preprint
id arxiv_https___arxiv_org_abs_2405_00043
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Shrinking a gradient index lens antenna system with a spaceplate
Mrnka, Michal
Whittaker, Thomas
Phillips, David B.
Hendry, Euan
Whittow, Will
Applied Physics
Optics
The miniaturisation of optical systems is an ongoing challenge across the electromagnetic spectrum. While the thickness of optical elements themselves can be reduced using advances in metamaterials, it is the voids between these elements -- which are necessary parts of an optical system -- that occupy most of the volume. Recently, a novel optical element coined a `spaceplate' was proposed, that replaces a region of free space with a thinner optical element that emulates the free-space optical response function -- thus having the potential to substantially shrink the volume of optical systems. While there have been a few proof-of-principle demonstrations of spaceplates, they have not yet been deployed in a real-world optical system. In this work, we use a bespoke-designed spaceplate to reduce the length of a gradient index (GRIN) lens microwave antenna. Our antenna is designed to operate at 23.5 GHz, and the incorporation of a nonlocal metamaterial spaceplate enables the distance between the antenna feed and the GRIN lens to be reduced by almost a factor of two. We find the radiation patterns from a conventional and space-squeezed antenna are very similar, with a very low cross-polarisation, and only a minor increase in the side-lobe levels when introducing the spaceplate. Our work represents a first example of a spaceplate integrated into a functional optical system, highlighting the potential for this concept to reduce the physical size of optical systems in real-world applications.
title Shrinking a gradient index lens antenna system with a spaceplate
topic Applied Physics
Optics
url https://arxiv.org/abs/2405.00043