WO2015049483A1

WO2015049483A1 - A protective garment comprising an antenna

Info

Publication number: WO2015049483A1
Application number: PCT/GB2014/000384
Authority: WO
Inventors: Simon John HOLDEN
Original assignee: The Secretary Of State For Defence
Priority date: 2013-10-02
Filing date: 2014-09-30
Publication date: 2015-04-09
Also published as: GB2521028B; GB201317428D0; EP3052887A1; GB2521028A; WO2015049483A8; GB201417156D0

Abstract

There is provided a protective garment (1) comprising an antenna, the antenna comprising a plurality of antenna elements (6), wherein the protective garment comprises a plurality of armour elements (5) arranged in an array for protecting against explosively driven projectiles, and wherein each armour element (5) comprises one of the antenna elements (6).

Description

A PROTECTIVE GARMENT COMPRISING AN ANTENNA

Technical Field of the Invention

This invention relates to a protective garment comprising an antenna. The protective garment may be suitable for protecting a human from explosively driven projectiles when the human is wearing the garment. The antenna is suitable for receiving and/or transmitting electromagnetic radiation.

Background to the Invention

Protective garments are commonly used for protecting humans from explosively driven projectiles, and may comprise armour elements to help block projectiles from penetrating through the protective garment.

It is known to integrate an antenna into a garment, so that the antenna does not need to be carried separately from the garment. The research article "High-Gain Textile Antenna Array System for Off-Body Communication,", Maria Lucia Scarpello, Luigi Vallozzi, Hendrik Rogier, and Dries Vande Ginste, International Journal of Antennas and Propagation, vol. 2012, Article ID 573438, 12 pages, 2012. DOL 10.1155/2012/573438, discloses four patch antennas integrated within a garment, the four patch antennas enabling antenna beam- steering. However, the integration of an antenna into a protective garment can be more problematic, due to the armour elements of the protective garment physically and/or electromagnetically interfering with the antenna. This either reduces the performance of the antenna, or prevents the antenna from being incorporated into the garment at all. It is therefore an aim of the invention to provide a protective garment with an improved antenna. Summary of the Invention

According to an embodiment of the invention, there is provided a protective garment comprising an antenna. The antenna comprises a plurality of antenna elements, and the protective garment comprises a plurality of armour elements arranged in an array for protecting against explosively driven projectiles. Each armour element comprises one of the antenna elements.

The inventor has recognised that protective garments sometimes include armour elements arranged in an array, and that these armour elements may be used for supporting the individual antenna elements of an antenna.

Since the antenna elements may be combined with respective armour elements, the antenna elements do not need to be separately implemented on an additional layer of the I protective garment, saving weight and cost by avoiding the need for the additional layer.

Furthermore, the armour elements do not block or interfere with electromagnetic radiation as much as they would if an additional layer to support the antenna elements was placed underneath the armour elements.

The antenna elements are individual parts of the overall antenna, and the antenna elements may be used together in conjunction with one another to collectively send or receive a signal. The armour elements are typically separate portions of material that are able to move with respect to one another, to provide flexibility to the protective garment.

The protective garment is designed to protect a wearer from explosively driven projectiles, for example in combat situations. The projectiles may include objects such as stone, sand, grit, metal, glass, ceramic, plastic or composites of various masses, shapes, sizes or velocities. The protective garment may for example be a jacket, vest or a pair of trousers.

The armour elements of the protective garment may be configured to provide at least a protection level of a V50 of 380 m/s against a 1.1 gram (17 Grain) untumbled chisel nosed fragment simulating projectile (FSP) as specified in STANAG 2910 edition 2. Such a protection level is easily achievable by those skilled in the art using known techniques for forming armour elements.

The protective garment may comprise a plurality of electrical conductors that are connected to the antenna elements, the electrical conductors for electrically connecting the antenna elements to one or more transceivers. The electrical conductors may carry transmit and receive signals between the one or more transceivers and the antenna elements, and may for example be formed of conductive strings or cables that are woven into a supporting layer of the protective garment.

The supporting layer may support the plurality of armour elements. The armour elements may be stitched, adhered, or otherwise attached to the supporting layer, for example embedded within the supporting layer. The supporting layer typically comprises materials known for their ballistic qualities in protecting against projectiles, for example Kevlar™, Spectra™, Dyneema™, Aramid, Ultra High Molecular Weight Polyethylene (UHMWPE) fibres, etc, as will be apparent to those skilled in the art.

The one or more transceivers may form part of the protective garment, and may be connected to the armour elements via the electrical conductors. The one or more transceivers may be configured to control an overall radiation pattern of the antenna by controlling a phase at each antenna element of a transmitted or a received signal. For example, the phases at the antenna elements may be controlled so that constructive/destructive interference of the transmitted signal means that the overall transmitted signal strength is much higher in some directions than other directions.

The one of more transceivers preferably have a common control point to co-ordinate the relative phases at each antenna element, for example there may be only one transceiver that is connected to all of the antenna elements and a phase controller for co-ordinating the relative phases at each antenna element, or there may be one transceiver per antenna element with each transceiver having a- connection to the phase controller for co-ordinating the relative phases at each antenna element. Phase control of multiple antenna elements of an antenna to produce a desired overall radiation pattern of the antenna is known to those skilled in the art, and so will not be discussed in detail herein. Advantageously, the protective garment may further comprise an orientation sensor for detecting a physical orientation of the protective garment. At least one phase controller may be coupled to the orientation sensor, the at least one phase controller configured to control a phase at each antenna element of a transmitted or a received signal based on an orientation indicated by the orientation sensor. Then, the orientation of the radiation pattern relative to a surrounding environment may be controlled to remain substantially the same even as the orientation of the protective garment relative to the surrounding environment is changed. The orientation of the protective garment relative to the surrounding environment may for example change due to movement of a wearer of the garment between standing . upright or lying down. The at least one phase controllers may be incorporated within the one or more transceivers, or within the master controller if present.

The at least one phase controller may be configured to steer an overall radiation pattern of the antenna based on the orientation sensor to provide greatest antenna sensitivity in a substantially horizontal direction. Additionally, or alternatively, the at least one phase controller may be programmable by a wearer of the garment to set a desired direction in which the antenna is to be made most sensitive.

Each armour element may comprise a respective solid body; and a conductive element on the solid body or embedded in the solid body, the conductive element, forming the antenna element of the armour element. Accordingly, the solid body may provide both protection against incoming projectiles, and a base for the antenna element.

Arranging the antenna element on the solid body may help reduce interaction between the antenna element and the body of the wearer of the garment, particularly when the antenna element is arranged on a surface of the solid body that faces away from an interior of the garment where the wearer's body will be located, such that the solid body is between the antenna element and the wearer.

Embedding the antenna element within the solid body may help protect the antenna element from damage, for example if the antenna element has a complex shape or could easily be damaged by abrasion against other surfaces. The antenna element may be a conductive layer on the solid body or a conductive layer embedded in the solid body, for example if the antenna elements are patch antenna elements. Alternatively, the antenna elements may be dipole or monopole antenna elements, or more complex antenna elements.

The conductive layer may be formed as a conductive coating on the solid body, or as a conductive layer that is adhered to the solid body by an adhesive. Each solid body may be a solid body of ceramic or polymer, for example a ceramic tile or a UHMWPE tile.

Alternatively, each solid body may be a metallic body, the metallic body forming the antenna element of the armour element.

Brief Description of the Drawings

Embodiments of the invention will now be described by way of example only and . with reference to the accompanying drawings, in which:

Fig. 1 shows a schematic diagram of a protective garment according to a first embodiment of the invention;

Fig. 2 shows a plan schematic diagram of an antenna for incorporating into a protective garment according to a second embodiment of the invention;

Fig. 3 shows a plan schematic diagram of an antenna element of an antenna for incorporating into a protective garment according to a third embodiment of the invention;

Fig. 4 shows a plan schematic diagram of an antenna element of an antenna for incorporating into a protective garment according to a fourth embodiment of the invention;

Fig. 5 shows a plan schematic diagram of an antenna element of an antenna for incorporating into a protective garment according to a fifth embodiment of the invention; and

Fig. 6 shows a cross-sectional diagram of the antenna element of Fig. 5.

The drawings are purely illustrative and are not to scale. Same or similar reference signs denote same or similar features. Detailed Description

A first embodiment of the invention will now be described with reference to the schematic diagram of Fig. 1 , which shows a person wearing a protective garment 1. The protective garment 1 comprises a supporting layer 2 that is formed of Aramid fibres, and a plurality of armour elements 5 that are held by the supporting layer 2 to overlap one another.

Fig. 1 includes an exploded view of nine of the armour elements 5, showing that each one of the armour elements 5 comprises an antenna element 6 at the surface of the armour element, >

Fig. 1 also includes an exploded view of one of the armour elements 5, showing that each one of the armour elements 5 further comprises an antenna feed 8 that is connected to the antenna element 6, and an antenna feed termination 10 that is connected to the antenna feed 8. Each armour element 5 is a ceramic tile, and the antenna element 6 and antenna feed 8 are applied as a metallic coating (printed) on the surface of the armour element 5. The armour elements 5 each provide a protection level of a V50 of 380 m/s against a 1.1 gram (17 Grain) untumbled chisel nosed fragment simulating projectile (FSP) as specified in STANAG 2910 edition 2, although higher protection levels may be provided in alternate embodiments.

The antenna feed 8 and antenna element 6 are formed on an outer side of the armour element 5 that faces towards the external environment rather than towards the person. The non-conductive nature of the Aramid fibre supporting layer 2 means that electromagnetic radiation can easily reach the antenna elements 6 beneath the supporting layer 2.

The antenna feed termination 10 provides a termination where a coaxial cable 13 is connected to the armour element 5, so that the antenna element 6 can be driven via the coaxial cable 13. There is one coaxial cable 13 connected to each armour element 5, and the coaxial cables 13 are connected at their other ends to a transceiver 12. Each antenna element 6 is a dipole antenna, having ground and signal conductors connected to ground and signal conductors of the coaxial cable via the antenna feed 8. The antenna feed 8 is used to help match the impedance of the coaxial cable 13 to that of the antenna 6. Only a few of the coaxial cables 13 are shown in Fig. 1 for clarity. The transceiver 12 comprises a variable phase transmit/receive module for each one of the coaxial cables 13 that are connected to the transceiver 12. The phase of each

transmit/receive module is controlled by a phase controller 14 connected to the transceiver 12. The phase controller sets the phase of each one of the transmit/receive modules so that the radiation patterns of the antenna elements 6 constructively and destructively interfere with one another to form an overall radiation pattern of the whole antenna, as will be apparent to those skilled in the art.

The protective garment 1. further comprises an orientation sensor 16 that is connected to the phase controller 14. In use, based on the input from the orientation sensor 16, the phase controller 14 adjusts the overall radiation pattern of the antenna elements 6 to help maintain a main lobe of the radiation pattern in a substantially horizontal direction, even as the person wearing the protective garment moves between standing up and bending over. The phase controller 14 also comprises a switch to allow the person to specify the overall radiation pattern, either to specify that the radiation pattern should be concentrated in one direction to improve sensitivity, or to specify that the radiation pattern should be kept broad to receive signals from widely differing directions.

The phase controller 14 is linked to a radio (not shown in Figs) for transmitting and receiving a signal collectively via the antenna elements 5. Clearly, the armour elements 5 could be applied to other protective garments than the jacket shown in Fig. 1. For example, the antenna elements could be applied to trousers.

In the first embodiment, the transmit/receive modules for the armour elements are all integrated together within the transceiver 12, although it.will be Understood that each transmit/receive module could alternatively be formed on the corresponding armour element, . for example on an opposite side of the armour element 5 -from the side having the antenna element 6. A second embodiment of the invention will now be described with reference to the schematic diagram of Fig. 2. The second embodiment is the same as the first embodiment, except for that the arrangement of the armour elements has been changed and that another type of antenna element has been used. Specifically, Fig. 2 shows a portion 20 of a protective garment, the portion 20 comprising a plurality of armour elements 22 that collectively form an antenna. The armour elements 22 are slightly spaced apart from one another within pockets of a supporting layer 21 formed of Aramid fibres. The portion 20 may be used in conjunction with an array of armour tiles (not shown in Figs) that is slightly offset from the armour elements 22, to help cover the gaps between the armour elements 22, and to help provide protection against any projectiles that impact the portion 20 at the gaps.

Each one of the armour elements 22 is a UHWMPE tile comprising an antenna element 24. The antenna element 24 is a fractal UWB (Ultra Wide Band) antenna for sending and receiving UWB signals, and is formed by ground 27 and signal 28 copper plates that are adhered to a front face of the corresponding armour element 22. Each antenna element 24 is fed by a respective antenna feed 26 that extends through the UHWMPE tile arid to a back face of the tile where one of the coaxial cables 13 is connected.

The schematic diagram of Fig. 3 shows a front plan view of an armour element 30 that could be incorporated within the pockets of the supporting layer 20 of Fig. 2, instead of the armour elements 22, according to a third embodiment of the invention. The armour element 30 comprises steel tile 31 , a dielectric layer 32 adhered to a front face of the steel tile 31, and a copper patch 33 adhered to the dielectric layer 32 opposite from the steel tile 31. A ground sheaf of the corresponding coaxial cable 13 is connected to the steel tile 31 to form a ground plane, and a signal conductor of the coaxial cable 13 is connected to the copper patch 33 via a hole through the steel tile 31 and dielectric layer 32. The copper patch 33 and steel tile 31 therefore together form an antenna element of the armour element 30.

The schematic diagram of Fig. 4 shows a front plan view of an armour element 40 that could be incorporated within the pockets of the supporting layer 20 of Fig. 2, instead of the armour elements 30 or 22, according to a fourth embodiment of the invention. The armour element 40 is the same as the armour element 30, except for that the steel tile 31 has been substituted for a lighter weight ceramic tile 41, and that a copper layer 44 has been adhered to a back face of the ceramic tile 41, opposite the dielectric layer and copper patch on the front face. Since the ceramic tile 41 is insulative, the dielectric layer could be omitted and the copper patch applied directly to the front face.

The schematic diagram of Fig. 5 shows a front plan view of an armour element 50 that could be incorporated within the pockets of the supporting layer 20 of Fig. 2, instead of the armour elements 40, 30, or 22, according to a fifth embodiment of the invention.

The armour element 50 comprises a UHWMPE tile 1 that includes a patch antenna element 52 within the UHWMPE tile 51. The UHWMPE material was moulded around the patch antenna element 52 during manufacture to embed the patch antenna element 52 inside the UHWMPE tile 51. The armour element 50 further comprises a copper layer 53 that has been adhered to a back face of the ceramic- tile 51. The copper layer 53 and patch antenna element 52 form an antenna element that is connected to one of the coaxial cables 13. The schematic diagram of Fig. 6 shows a cross section taken through the armour element 50, along line AA marked on Fig. 5. The patch antenna element 52 comprises a feed line 52a that extends to a back side of the armour element 50, and which is connected to a signal conductor 13S of the coaxial cable 13, through a hole in the copper layer 53. The coaxial cable 13 also comprises a ground sheaf 13G, and this is connected to the copper layer 53.

Clearly, the armour elements 30, 40, and 50 could be arranged in a different manner to that shown in Fig. 2, for example the armour elements may be arranged in a tessellation, or the armour elements may be arranged to overlap one another, for example similar to the arrangement of the armour elements 5 shown in Fig. 1.

Further embodiments falling within the scope of the appended claims will also be apparent to the skilled person.

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Claims

1. A protective garment comprising an antenna, the antenna comprising a plurality of antenna elements, wherein the protective garment comprises a plurality of armour elements arranged in an array for protecting against explosively driven projectiles, and wherein each armour element comprises one of the antenna elements.

2. The protective garment of claim 1 , wherein the protective garment further comprises a plurality of electrical conductors that are connected to the antenna elements, the electrical conductors for electrically connecting the antenna elements to one or more transceivers.

3. The protective garment of claim 2, further comprising one or more transceivers connected to the plurality of electrical conductors, the one or more transceivers configured to control an overall radiation pattern of the antenna by controlling a phase at each antenna element of a transmitted or a received signal.

4. The protective garment of any preceding claim, further comprising an orientation sensor for detecting a physical orientation of the protective garment, and at least one phase controller coupled to the orientation sensor, the at" least one phase controller configured to control a phase at each antenna element of a transmitted or a received signal based on an orientation indicated by the orientation sensor.

5. The protective garment of claim 4, wherein the at least one phase controller is configured to steer an overall radiation^, pattern of the antenna based on the orientation sensor to provide greatest antenna sensitivity in a substantially horizontal direction.

6. The protective garment of any preceding claim, wherein the antenna elements together form the antenna.

7. The protective garment of any preceding claim, wherein each armour element comprises a solid body, and a conductive element on the solid body or embedded in the solid body, the conductive element forming the antenna element of the armour element.

8. The protective garment of claim 7, wherein the conductive element is a conductive layer on the solid body or a conductive layer embedded in the solid body.

9. The protective garment of claim 8, wherein the conductive layer is a conductive coating on the solid body. · .

10. The protective garment of claim 8, wherein the conductive layer is adhered to the solid body by an adhesive.

11. The protective garment of any one of claims 7 to 10, wherein each solid body is a solid body of ceramic or polymer.

12. The protective garment of claim 11, wherein each solid body is a ceramic tile or an Ultra High Molecular Weight Polyethylene (UHMWPE) tile.

13. The protective garment of any one of claims 1 to 6, wherein each armour element comprises a metallic body, the metallic body forming the antenna element of the armour element.

14. The protective garment of any preceding claim, wherein the protective garment comprises a supporting layer to which the plurality of armour elements are attached.

15. The protective garment of any preceding claim, wherein the supporting layer comprises Aramid, or UHMWPE fibres.

16. A protective garment substantially as described herein with reference to the accompanying drawings.