Patent Grant
11909092
This application is a 371 National Stage Application of International Application No. PCT/NL2019/050740, filed Nov. 13, 2019 and published as WO 2020/101488 A1 on May 22, 2020, and further claims priority to Netherlands Application Ser. No. 2021987, filed Nov. 13, 2018.
The invention relates to a rollable antenna mat, and in particular, though not exclusively, to a rollable antenna mat for sports timing, a rollable antenna mat assembly, a stackable antenna mat assembly, an antenna mat roll, a carrier for lifting and transporting a rollable antenna mat and a sports timing system comprising a rollable antenna mat or rollable antenna mat assembly.
Sports timing systems for sports and race events, in particular mass events such as marathons, triathlons, bicycle races, etc., should be able to reliably time hundreds of tags passing over a timing line every minute. Preferably such systems should function in harsh conditions, e.g. wet outdoor surroundings, should be relatively light and should be designed for easy and fast handling, e.g. fast installing and de-installing the sports timing system. For example, an organiser of a sports event is allowed to close roads that are part of the race track only shortly, e.g. just before the start of the actual race, in order to minimize the impact on traffic and public infrastructure. Furthermore, usually a plurality of timing lines needs to be installed along the race track, e.g. at different points of a race track. Hence, an organiser of the event usually has limited time for installing many timing lines. Therefore, these timing lines should be configured such that they can be quickly and easily installed as a plug and play system without any specialized knowledge. Additionally, regulations such as labor law regulations may require that the weight of the timing equipment should be special handling tools, e.g. carrying tools, for carrying the equipment, in particular the antenna that is used for detecting passing tags, if the weight of the equipment exceeds a certain weight, e.g. 25 kg.
US 2018/0152010 A1 discloses a timing system including a plurality of foldable mat antenna elements. Each mat element comprises an UHF antenna encapsulated in a hard-cover protective casing for protecting the antenna from external influences (e.g. forces, moisture, heat, etc.). In operation, the mat is unfolded so that the mat elements are positioned side by side forming an elongated antenna mat which may be positioned over a track. Each of the mat elements may be connected to a controller which may operate the mat elements in an alternating manner in order to reduce interference between neighbouring mat elements to detecting and register UHF tags passing the mat.
The antenna mats are interlinked by means of pivot bearings which enabling folding the mat elements into a stack and unfolding the stack of mat elements into an antenna mat. Although the stackability of the mat elements allows some improvement during installing and deinstalling the mat elements, its handling is still cumbersome and the weight of the total stack can be substantial. More importantly, as the mat element is connected with one or more coax cables to a controller, folding and unfolding of the antenna mats (including the coax cables connected to the antennas), will affect the integrity of the coax cables at the position of the pivot points and ultimately the function and reliability of the mat antenna itself.
A further prior art document U.S. Pat. No. 8,525,647 describes an elongated linear leaky waveguide type antenna mat which can be positioned over a track to detect passing UHF tags. The waveguide antenna comprises a long microstrip positioned at a predetermined position over an elongated metal foil. The antenna mat can be used as a single element, which can be rolled up. The inventors acknowledge the fact that in order to preserve the carefully designed radiation pattern, the distance between the microstrip and the metal foil should remain constant, while at the same time the antenna structure needs to be sufficiently flexible so that it can be rolled up. To that end, the microstrip was embedded in a semirigid foam. It is apparent however that such antenna structure is not prone to deformation when an athlete steps onto the antenna mat. This is even more evident, in case of a marathon, e.g. the start of a marathon, wherein hundreds of athletes will pass the antenna mat in a very short time thereby exerting considerable forces onto the mat which will substantially deform the antenna structure in time thereby considerably affecting the performance and reliability of the antenna mat. Hence, it is clear that the suggested antenna is not suitable for reliably timing sporting events, in particular mass sporting events such as a marathon. More generally, the foldable or rollable antenna mat structures known from the prior art are not robust that they can withstand rolling up and unrolling the mat many times over a long period. The rolling action will affect the integrity and performance of the antenna mats.
In light of the above, there is a need in the art for a rollable antenna mat which is suitable for sports timing, in particular for sports timing of a mas sporting event. In particular, there is a need in the art for an antenna mat comprising one or more antenna elements, wherein the weight of the antenna mat is relatively light and can be rolled up and rolled out many times without affecting the performance of the antenna mat.
One aspect of this disclosure relates to a rollable antenna mat for sports timing which may comprise one or more planar antenna structures, preferably a planar antenna structure including at least one ultra-high frequency, UHF, patch antenna and/or slotted antenna, connected to one or more transmission lines, preferably UHF coaxial transmission lines, for conveying signals to and/or from the one or more planar antenna structures; each of the one or more planar antenna structures, preferably rectangular antenna structures, comprising at least one conductive plate positioned above a conductive ground plane, a spacer element positioned between the conductive ground plane and the conductive plate, the planar antenna structure being configured to generate a radiation field, the radiation field having a main axis that is substantially perpendicular to the conductive plate; and, the planar antenna structure and at least one transmission line being embedded in a flexible elongated sheet structure of one or more elastomeric materials, the flexible elongated sheet structure comprising the embedded one or more planar antenna structures being suitable to be rolled up in a roll, the axis of the roll being substantially perpendicular to the longitudinal axis of the flexible elongated sheet structure.
In an embodiment, the spacer structure may provide an out-of-plane compression stiffness to the planar antenna structures, which is higher than the out-of-plane compression stiffness of the flexible sheet structure. In another embodiment, the spacer structure may provide a bending stiffness to the planar antenna structures, which is higher than the bending stiffness of the flexible sheet structure.
The rollable antenna mat thus includes antenna structures embedded in flexible a longitudinal sheet structure. The antenna structures have a planar configuration of a radiative conductive plate positioned over a conductive ground plane, wherein a spacer element provides out-of-plane compression stiffness and a bending stiffness to the antenna structures so that in the rolled state the antenna structure may slightly bend without damage and in the unrolled state the antenna structures retain original shape. Additionally, the out-of-plane stiffness protects the antenna structures from (permanent) deformation when e.g. heavy objects, e.g. cars, trolleys or even busses move over the antenna mat during e.g. installation or just after the event. The rollable antenna structure thus provides a robust rollable structure that allows fast installation and de-installation of a timing line which does not require lifting the antenna mat or dragging the antenna mat over the ground.
In an embodiment, the length of the flexible sheet structure may be selected between 1 and 15 meter, preferably between 2 and 8 meter. In another embodiment, the width of the flexible sheet structure may be selected between 30 and 120 cm, preferably 40 and 100 cm. In another embodiment, the (maximal) thickness of the flexible sheet structure may be selected between 2 and 6 cm, preferably between 2 and 5 cm. In yet another embodiment, the dimensions the antenna structure may be selected between 5 cm and 50 cm, preferably between 14 and 20 cm, more preferably between 15 and 18 cm. In a further embodiment, the diameter of the roll may be selected between 100 and 25 cm, preferably between 80 and 28 cm, more preferably between 60 and 30 cm.
In an embodiment, the spacer element comprises a honeycomb structure, preferably the honeycomb structure including cells, the cells including at least on of: (circular-cored) hexagonal cell, (circular-cored) triangular cells, (circular-cored) square cells and/or combinations thereof. In another embodiment, the spacer element may comprise a plastic material, preferably a polyethylene, more preferably a high-density polyethylene (HDPE). Optionally, additionally or alternatively to HDPE, the spacer element comprises a material having similar material characteristics, such as a similar flexibility, as HDPE.
In an embodiment, the flexible sheet structure may comprise one or more laminated and/or bonded sheets of one or more flexible elastomeric materials, preferably the flexible sheet structure including at least a first sheet and a second sheet, wherein the one or more planar antenna structures and the one or more transmission lines are positioned between the first and second sheet.
In an embodiment, the first sheet may include a first rubber material, preferably a styrene and/or butadiene rubber material (e.g. a styrene-butadiene rubber, SBR); a butyl rubber material and/or nitrile rubber (NBR) material; and/or, the one or more flexible elastomeric materials comprising a polyurethane material; and/or, wherein the second sheet includes a second rubber material, preferably an ethylene propylene diene monomer, EPDM, rubber material. Optionally, additionally or alternatively to the EPDM rubber, the second sheet includes a material having similar material characteristics, such as a similar flexibility, as EPDM rubber.
In an embodiment, the least one of the first and second flexible sheet comprises one or more regions which have a honeycomb structure. The honeycomb structure may include a plurality of cells, the cells including at least on of: (circular-cored) hexagonal cells, (circular-cored) triangular cells, (circular-cored) square cells and/or combinations thereof.
In an embodiment, the least one of the first and second flexible sheet may comprise one or more recessed spaces in the flexible material, the one or more recessed spaces being shaped for housing the one or more planar antenna structures and the one or more one or more transmission lines.
In an embodiment, each of the one or more transmission lines may include a signal line connected to the conductive plate and a ground line connected to the conductive ground plane. In an embodiment, the signal line may be connected to an edge of the conductive plate. In an embodiment, each of the one or more transmission lines may run from a short side of the elongated flexible sheet structure along a long side of the elongate flexible sheet structure towards at least one of the one or more planar antenna structures.
In an embodiment, the signal line may be connected to the conductive plate via a microstrip formed in the conducting plate. In an embodiment, the microstrip may be formed by at least two slots in the conducting plate, wherein the slots extend from the edge of the conductive plate towards a center line of the conductive plate. In an embodiment, the antenna structure may be configured as a so-called an inset microstrip line fed patch antenna structure.
In an embodiment, each of the one or more coaxial transmission lines may comprise: an inner conductor forming a signal line, an outer conductor around the inner conductor forming a ground line and a dielectric between the inner and outer conductor; the inner conductor being connected to the conductive plate and the outer conductor being connected to the conductive ground plane.
In an embodiment, an end part of the coaxial transmission line may be oriented parallel to an edge of the antenna structure, the edge of the antenna structure being parallel to the roll axis of the roll, preferably an end part of the coaxial transmission line comprising an end part of the inner conductor.
In an embodiment, at the connection point between the inner conductor and the conductive plate, the inner conductor may be oriented parallel to the roll axis of the antenna mat.
In an embodiment, the antenna mat may include one or more test device, preferably one or more (passive) UHF transponders, being positioned at fixed position relative to at least one of the one or more planar antenna structures. In an embodiment, a test device may be configured to receive a test signal from at least one of the one or more planar antenna structures and/or to transmit a test signal to at least one of the one or more planar antenna structures.
In an embodiment, a flexible conductive sheet may be provided below the one or more planar antenna structures for reducing signal dissipation into the ground when the antenna mat is positioned across the race track, preferably the flexible conductive sheet being in electrical contact with the ground plane of the patch antenna.
In a further aspect, the invention may relate to a rollable antenna mat assembly comprising: a rollable antenna mat according to one or more of the preceding claims; and, a cylindrically shaped roll element, the roll element having a curved surface the antenna mat can be wound around the roll element, preferably the antenna mat being (at least partially) wound around the roll element and/or the roll element comprising edges for enabling stacking of the rollable antenna mat assembly on top of another rollable antenna mat assembly.
In an embodiment, the rollable antenna mat may be mechanically and electrically connectable to the roll element. In an embodiment, the roll element may include UHF connectors which are electrically connected to the one or more transmission lines of the rollable antenna mat. In another embodiment, the roll element may comprise an antenna controller connected to the one or more transmission lines of the rollable antenna mat.
In an embodiment, the assembly may further comprise: a carrier structure for transporting and lifting an antenna mat roll, preferably the carrier structure including a rectangular tray, the tray including edges positioned along the sides of the tray wherein the edges are configured to stop the antenna mat from sliding of the tray during transportation; more preferably a first frame structure being connected to the tray positioned along a first side of the tray and a second frame structure connected to the tray positioned along a second side of the tray, opposite to the first side of the tray.
In yet another embodiment, the invention may relate to a carrier structure for lifting, carrying and/or transporting a rollable antenna mat as described above in a rolled-up state according. In an embodiment, the carrier structure may comprise wheels. In another embodiment, the carrier structure is stackable.
The antenna mat may be understood to have a length extending in a longitudinal direction and a width extending in a traverse direction and the antenna mat may be understood to be suitable to be rolled up and unrolled along its length. In such case, the roll axis of the antenna may be understood to be parallel to the traverse direction. Typically, if the antenna mat is in a rolled-out state, the length of the antenna mat extends across the race track, i.e. extends along the longitudinal axis of the antenna mat, in particular of the flexible elongated sheet, and the width of the antenna mat is substantially parallel to the direction of participants on the race track. In one example, when the antenna mat is rolled up into a cylindrically shaped roll it may take the form of a hollow cylinder having two annular bases. The axis of a cylinder may be understood to be the line joining the respective centers of the bases of a cylinder or, in case the roll forms a hollow cylinder, the line joining the centers respectively defined by the annular bases.
The antenna mat may be flexible such that the antenna mat can be wrapped around the curved surface of a cylinder having a circular base, the circular base having a diameter of 1 meter, preferably 0.5 meter, more preferably 0.35 meter, without damaging the antenna mat or any of its components.
In general, the bending rigidity of a material may be expressed by its minimum bend radius, which is the minimum radius a sheet, pipe, tube, cable, hose or mat can be bent without kinking it and/or damaging it and/or shortening its life and/or permanently deforming it. The smaller the minimum bend radius of a material, the greater its flexibility and the lower its bending rigidity. The flexible sheet may have a first bending rigidity, and the spacer structure may have a second bending rigidity, wherein the second bending rigidity is higher than the first bending rigidity. The minimum bend radius of the flexible material can be measured by bending the flexible sheet (without any components), and observing at which bend radius the sheet permanently deforms and/or is damaged. The minimum bend radius of the spacer structure can be measured by bending the spacer structure, and observing at which bend radius the sheet permanently deforms and/or is damaged.
The device passing the antenna mat typically is a transponder carried by an athlete or mounted in or on a vehicle, such as a car or bicycle. Such transponder may be an active or passive transponder. An active transponder comprises its own power source for transmitting signals, whereas a passive transponder uses energy that was obtained through the reception of another signals to transmit a signal. The transponder may be configured to, in response to a signal received from one of the plurality of patch antennas, transmit a response signal back to the antenna mat, in particular to one of the patch antennas of the antenna mat. A signal received from the device passing the antenna mat, such as the above-described response signal may comprise an identifier of the device. Hence, a timing system that is connected to the antenna mat will be able to determine a passing time of the particular device.
The predetermined distance between the ground plane and patch may be constant for one patch antenna and may be the same for all patch antennas.
The plurality of antennas may be positioned within, on and/or underneath the antenna mat. In one example, a plurality of patch antennas is glued onto the flexible material, wherein the flexible material is continuous along the full length of the antenna mat. The antenna mat being in rolled-up state may be understood as the antenna mat being wound around a curved surface, e.g. around a tube, and/or as the timing may having been turned over and over on itself without folding. Unrolling the antenna mat may be understood as opening out the antenna mat from the rolled-up state substantially without toppling or tumbling.
In one embodiment, the elongated sheet comprises at least a first elongated first sheet of first flexible material positioned over at least a second elongated second sheet of a second flexible material, wherein the at least one patch antenna is positioned between the first and second sheet. This embodiment allows to make use of different material characteristics of the different sheets. To illustrate, the sheet of the antenna mat that is facing the ground when installed across a race track is preferably very rough in order to prevent any sliding of the mat over the ground when it is installed across the track.
In one embodiment, the first flexible material comprises, e.g. essentially consists of, rubber, such as styrene-butadiene rubber. Preferably, the rubber is pressure molded such that it also comprises cavities for receiving a coaxial transmission line and test devices that are described below. Advantageously, rubber can serve as a flexible and/or bendable and very durable layer in which the patch antenna(s) and other elements of the antenna mat may be embedded.
In one embodiment, the second flexible material comprises, e.g. essentially consists of, rubber, such as ethylene propylene diene monomer (EPDM) rubber, wherein preferably the second flexible sheet is continuous along substantially the entire length of the timing mat. EPDM rubber advantageously is rough and durable.
The connection between the coaxial cable and the patch antenna may be a relatively weak point in the antenna mat. The orientation of the connector pin parallel to the roll axis advantageously prevents high mechanical stresses on the pin, which could damage the connection. If the connector pin would be oriented for example perpendicular to the roll axis, for example in the longitudinal direction of the antenna mat, then rolling up the antenna mat would, at least to a higher extent, cause the connector pin to bend. Such a bend may damage the connection between the pin and patch antenna.
Such honeycomb structure may reduce the weight of the antenna mat, yet without significantly weaken the antenna mat. A honeycomb structure is namely a lightweight structure that can withstand relatively high deforming forces.
In one embodiment, the mat comprises a plurality of patch antennas connected, each of the plurality of patch antennas being connected a coaxial cable for conveying signals to and/or from the at least one patch antenna. Each patch antenna comprises a conductive patch positioned above a conductive ground plane, a spacer element positioned between the conductive ground plane and the conductive patch, the dimensions of the patch antenna being associated with ultra-high frequency UHF signals. Each patch antenna and at least part of the one or more coaxial cables are embedded in a flexible elongated sheet that can be rolled up, preferably that can be rolled up into a cylindrically shaped roll, the axis of the cylindrically shaped roll being substantially perpendicular to the longitudinal axis of the flexible elongated sheet.
In one embodiment, the plurality of patch antennas comprises a plurality of pairs of patch antennas. In this embodiment, each pair comprises two patch antennas that are positioned behind each other as viewed in a longitudinal direction of the antenna mat. Further, the distance between the pairs is larger than the distance between two antennas forming such pair.
It should be understood that the antennas forming a pair may be neighboring antennas. The plurality of pairs may be distributed across the longitudinal direction of the antenna mat.
A method for operating the antenna mat may comprise controlling a pair of antennas to simultaneously transmit during a first time period and to refrain from transmitting during a second time period so that the pair of antennas can receive signals from the device passing the antenna mat during the second time period. Especially if the antennas forming the pair are positioned close to each other, it is important that the first and second time period for both antennas are synchronized. If one antenna of the pair would transmit a signal while the other antenna of the pair would “listen” to signals, the other antenna would receive the signal transmitted by the one antenna, which would distort measurements. By connecting each antenna pair to one electrical cable that conveys signals to and from the antenna pair, the above described synchronization can be easily secured.
Preferably, the distance between two patch antennas forming a pair is comparable to an average width of an athlete's shoe. This distance between two antennas forming a pair may be selected between 5 and 15 cm, preferably between 8 and 12 cm. Such a distance between a pair is associated with a small probability that a pressure exerted by one shoe touching the antenna mat simultaneously detune both of the antennas forming the pair. For this to happen, an athlete must namely step precisely in between the two antennas. Furthermore, such a distance is also associated with a small probability that two shoes belonging to two different athletes simultaneously and respectively detune both antennas. For this to happen, two athletes must namely run very close next to each other, which is unlikely.
Preferably, an antenna mat comprising a plurality of patch antennas as disclosed herein is formed as a single unit, meaning that such antenna mat is not formed by releasably connected antenna modules, wherein each module has one and only one antenna.
In one embodiment, each of the plurality of patch antennas is connected to a respective coaxial cable, or each of the plurality of patch antennas is connected to a bus system for conveying signals to and/or from the patch antennas. Such configuration allow for efficiently conveying signals between patch antennas and a controller for example.
The antenna mat according to one or more of the preceding claims, the antenna mat comprising at least one test device having a fixed position relative to at least one to be tested patch antenna, the test device being configured to receive a test signal from and/or to transmit a test signal to said at least one to be tested antenna.
In one embodiment, the antenna mat comprises at least one test device having a fixed position relative to at least one to be tested patch antenna. The test device is configured to receive a test signal from and/or to transmit a test signal to said at least one to be tested antenna. Preferably, the antenna mat comprises a test device for each antenna of the plurality of antennas or for each antenna pair.
This embodiment enables to assess the performance of the to be tested patch antenna. Since the test device has a fixed position relative to the to be tested antenna, the signal strength of a test signal as received by either one of the test device or antenna does not vary in dependence of the distance between the test device and to be tested patch antenna and does not vary in dependence of the relative positions of the test device and to be tested patch antenna with respect to each other. Therefore, if the strength of the test signal as transmitted is predetermined and the same for every test, in principle, the signal strength as received should also have the same value. If the received signal strength is varies among performed tests, that could be an indication that either the antenna is not properly receiving and/or transmitting the test signal and/may thus not function properly. In an example, the test device is a passive transponder. In this example, the to be tested antenna would transmit a signal having a predetermined strength to the test device. Then the test device would, upon reception of this signal, transmit the test signal back to the antenna, which would in turn measure the signal strength of the test signal as received.
In one embodiment, a flexible conductive sheet is provided below each patch antenna for reducing signal dissipation into the ground when the antenna mat is positioned across the race track, the flexible conductive sheet being in electrical contact with the ground plane of the patch antenna. This flexible sheet prevents signal dissipation as well as shields the patch antenna from external radiation.
One aspect of this disclosure relates to a system comprising an antenna mat as described herein and a cylindrically shaped element, such as a tube, the element having a curved surface such that the element is rollable and such that the antenna mat can be wound around the cylindrically shaped element.
In one embodiment of this system, the cylindrically shaped element comprises a controller for controlling the patch antenna or the plurality of patch antennas, wherein a coaxial transmission line is provided between the one or more patch antennas and controller for conveying signals between the one or more patch antennas and the controller.
One aspect of this disclosure relates to a carrier structure for carrying the antenna mat in a rolled-up state. The carrier structure comprises wheels and preferably the carrier structure being stackable. This carrier structure enables to easily transport the antenna mat.
One aspect of this disclosure relates to an antenna mat, such as a sports timing mat. The antenna mat comprises flexible material such that the antenna mat is suitable for being rolled up and unrolled across a race track. Further, the antenna mat comprises a patch antenna for receiving from and/or transmitting to a device that is passing the antenna mat a signal. The patch antenna comprises a conductive ground plane and a conductive patch that are separated a predetermined distance apart. The antenna mat also comprises a rigid structure at the patch antenna, the rigid structure being configured to inhibit change of the predetermined distance due to pressure exerted on the antenna mat while the antenna mat is in a rolled-out state. It is easily understood that the features described in this disclosure can be implemented in this antenna mat. To illustrate, this antenna mat can be in an at least partially rolled-up state and/or the patch antenna(s) can be embedded in flexible material, such as rubber, e.g. in the sense that the patch antenna(s) are embedded in a flexible sheet described herein and/or the patch antennas may be similar to the patch antennas described herein and/or the patch antennas may be positioned in the mat as described herein and/or the patch antennas may form pairs of antennas as described herein and/or the antenna mat may comprise at least one test device as described herein and/or the antenna mat may be dimensioned as described herein and/or the patch antenna(s) may be configured to transmit and/or receive UHF signals, et cetera.
Due to the rigid structure, the distance between the ground plane and the patch remains constant even if the flexible material surrounding the antenna deforms. Such deformation may be a permanent deformation caused by the repeated rolling up and unrolling of the antenna mat and/or a temporary deformation that may be caused by a person stepping on the antenna mat. The ability of the antenna mat to function properly even if the flexible material is deformed, is beneficial because the distance between ground plane and patch is an important design parameter that greatly influences the functioning of the antenna. Any change of this distance may cause the antenna to function improperly. Thus, the antenna mat disclosed herein is robust in the sense that its functioning will not be severely impacted by persons stepping on the antenna mat and/or by the repeated rolling up and unrolling of the antenna mat.
The rigid structure does not need to extend throughout the entire length of the antenna mat, because the enhancement of the antenna mat's rigidity is only required at the patch antenna, thus only required locally. A (temporary) deformation of the flexible antenna mat at a position away from a patch antenna namely does not necessarily distort timing measurements, because such a deformation does not necessarily cause a change of the distance between the patch and the conductive ground plane. As a result of the rigid structures not extending throughout the entire length of the antenna mat, the antenna mat as a whole can still be rolled up and unrolled.
The flexible material may have a first rigidity and the rigid structure may have a second rigidity, wherein the second rigidity is higher than the first rigidity. The flexible material may have a first rigidity and the rigid structure may have a second rigidity, wherein the second rigidity is higher than the first rigidity.
In one embodiment, the antenna mat comprising the rigid structure comprises a plurality of patch antennas for receiving a signal from and/or transmitting to a device that is passing the antenna mat a signal. Each patch antenna comprises a conductive ground plane and a conductive patch that are separated a predetermined distance apart. The antenna mat comprises a rigid structure at each patch antenna. At each patch antenna, the rigid structure is configured to inhibit change of said predetermined distance due to pressure exerted on the antenna mat. This embodiment further eases installation, because it enables to position several antennas with the single action of rolling out the antenna mat.
The flexible material may be connector material that physically connects the plurality of patch antennas. The connector material may have a rigidity that is lower than the rigidity of the rigid structure. Preferably, the connector material connecting two antennas is continuous, which may be understood as that the connector material between these two antennas forms an unbroken whole without additional connector elements such as hinges. The connector material between all neighbouring antennas may be continuous. This enables to make the antenna mat even more robust, because no connector elements are required. In one embodiment, the rigid structure at the or each patch antenna is a spacer structure for separating the conductive ground plane and the conductive patch the predetermined distance apart, for example a spacer element mentioned above.
In one embodiment, the rigid structure is a rigid structure at least partially surrounding the assembly of ground plane and conductive patch, which structure is configured to prevent, or at least reduce, forces being exerted on the ground plane and/or the conductive patch due to pressure exerted on the antenna mat. The structure may be understood to shield the patch antenna from external forces.
One distinct aspect of this disclosure relates to an antenna mat, e.g. a sports timing mat, comprising an antenna for receiving a signal from and/or transmitting a signal to a device that is passing the antenna mat, wherein the timing system comprises at least one test device having a fixed position relative to at least one antenna that is to be tested, the at least one test device being configured to receive a test signal from and/or to transmit a test signal to said at least one to be tested antenna. Optionally both the test device and the antenna may be embedded in said mat.
Another aspect of this disclosure relates to a method for assessing a performance of an antenna, e.g. a patch antenna, of a timing system. The timing system comprises a test device having a fixed position relative to the antenna. Further, the test device is configured to transmit a test signal to the antenna and/or to receive a test signal from the antenna. The method comprises steps i-iv. Step i comprises causing the antenna to transmit the test signal to the test device. Causing the antenna to transmit a signal may comprise controlling the antenna to transmit the signal, for example by feeding the signal to the antenna through a coaxial transmission line. Step ii comprises receiving from the test device the test signal as received by the test device. Step iii comprise comparing the test signal as received by the test device with a reference signal. Step iv comprises, based on this comparison, determining that the antenna malfunctions. Additionally or alternatively to steps i-iv, the method comprises steps v-viii. Step v comprises causing the test device to transmit the test signal to the antenna. Causing the test device to transmit the test signal to the antenna may comprise controlling the antenna to transmit a signal to the test device upon which the test device transmits a test signal back to the antenna. In such case, the test signal may be a backscatter signal. Note that the test device may be a passive transponder tag. Step vi comprises receiving from the antenna, the test signal as received by the antenna. Step vii comprises comparing the test signal as received by the antenna with a reference signal. Step viii comprises based on this comparison, determining that the antenna malfunctions.
In response to determining that the antenna malfunctions, the method may comprise outputting an indication that the antenna malfunctions, such as displaying an alert on a computer screen.
The reference signal may be a test signal as received that was measured when steps i and ii, or steps v and vi, were performed shortly after fabrication of the timing system, e.g. during a calibration procedure.
Preferably, each antenna of sub group of antennas of the timing system has an associated test device positioned at a fixed position relative to the antenna or sub group of antennas. This allows the method for assessing the performance to be executed separately and reliably for each antenna. The antenna may have a fixed position in a protective casing and/or in protective material and the test device may have a fixed position in this protective casing and/or in this protective material.
In an example, the test signal as received and the reference signal may be compared in the sense that a value for the strength of the test signal as received is compared with a reference signal strength value. If the test signal strength then deviates more than a certain threshold from this reference value, the method comprises determining that the antenna malfunctions.
With this method, the performance of a patch antenna of the antenna mat as described above can be assessed. Then, the test device may be embedded in the connector material, just as the patch antennas.
The above described method may be a computer-implemented method in which case the test can be automatically performed. For example, with a single user instruction, the test method may be performed subsequently for each of the plurality of patch antennas. Optionally, each patch antenna has its own test device. Alternatively, two or more patch antennas share a single test device. Thus, in an example, a user can with one interaction with a computer, e.g. with the controller as described herein, verify that all patch antennas in the antenna mat are working properly.
One aspect of this disclosure relates to a computer program or suite of computer programs, that, when executed, causes a data processing system to perform the above described method or any other method described in this disclosure that can be executed by a data processing system.
One aspect of this disclosure relates to a computer comprising a computer readable storage medium having computer readable program code embodied therewith, and a processor, preferably a microprocessor, coupled to the computer readable storage medium, wherein responsive to executing the computer readable program code, the processor is configured to perform one or more steps of the methods described herein.
The invention will be further illustrated with reference to the attached drawings, which schematically will show embodiments according to the invention. It will be understood that the invention is not in any way restricted to these specific embodiments.
In an embodiment, flexible sheet structure may comprise one or more (laminated and/or bonded) sheets of a flexible material that has a large abrasion resistance, tear strength, chemical resistance, temperature compatibility and aging. In an embodiment, flexible material may include a rubber material, for example a (synthetic) rubber elastomeric material based on styrene and/or butadiene, e.g. a styrene-butadiene rubber (SBR) material. Alternatively, one or more other elastomeric materials may be used including but not limited to butyl rubber and/or nitrile rubber (NBR). Alternatively and/or in addition, the flexible sheet structure may comprise one or more sheets of an elastomeric polyurethane material. Preferably, at least part of the sheets may be fabricated and structured using a moulding technique.
In an embodiment, the (rigid) cylindrical roll 10 or tube may be used to roll the antenna mat into a rolled-up state. As shown in the figure, the roll axis 5 of the roll (the x-direction in
The antenna mat 2 may comprise one or more planar ultra-high frequency UHF antenna structures. In an embodiment, the one or more UHF antenna structures may be implemented as patch and/or slotted antenna structures. A planar UHF antenna structure may comprise at least one conductive plate, e.g. a patch, positioned above a conductive ground plane, wherein a (dielectric) spacer element is positioned between the conductive ground plane and the conductive plate. The planar UFH antenna structure may be configured to generate a radiation field, wherein the radiation field has a main axis that is substantially perpendicular to the conductive plate.
Each of the planar antenna structures may be connected to a coaxial transmission line 7a,7b, such as a low-loss UHF coax cable, for providing an UHF connection between a planar antenna structure and an antenna controller. At least part of the transmission lines may be embedded in the elongated flexible sheet structure of the antenna mat. In an embodiment, one end of the antenna mat may be mechanically connectable to the roll. In one example, the antenna mat is affixed to the roll by means of one or more screws. In that case, in an embodiment, the antenna structures embedded in the antenna mat may also be electrically connectable to UHF transmission lines in the roll. In an embodiment, at least one side (a base) of the (hollow) roll may include a wall comprising UHF connectors 15a,15b wherein each of the UHF connectors is connected via at least one transmission line to one of the antenna structures.
In an embodiment, the antenna mat may be part of an RFID system, wherein an antenna controller controls the antennas to generate a radiation field at a certain frequency, wherein the (main) axis of the radiation field points in an upward direction away from the antenna mat (e.g. in the positive z-direction perpendicular to the plane of the mat). If a transponder, e.g. an active or passive UHF tag, moves into the radiation field, the transponder 8 may be triggered to transmit one or more signals back to the antenna mat, which may be detected by one of the patch antennas. The transponder 8 may be worn by an athlete, for example on a shoe or bib worn by a participant of the sports event. Alternatively, the transponder 8 may be attached to a vehicle of a participant of a sports event, such as a race car, motorcycle or a flying drone. The transponder signal may include a unique identifier associated with the transponder which can be linked with a participant.
In an embodiment, the RFID system may be a sport timing system for determining a passing time of the transponder 8. In for example, the antenna mat may be used as a detection antenna of a sports timing system as e.g. described in WO2015/140271A1, which is hereby incorporated by reference into this application. Typically, the transponder is configured to transmit one or more signals comprising an identifier ID to the antenna mat, which will detect and analyse the transponder signals so that the passing time of the transponder can be detected.
As shown in the figure, the rollable antenna mat allows very fast and efficient installation and setup of a timing line. An organizer of a race event merely needs to position an antenna mat roll at one side of the race track 4 and to unroll the mat in order to position the antenna. In the unrolled state, the antennas and the wiring are embedded in and protected by the elongated flexible sheet structure and thus optimally positioned in the mat. In case the roll includes the electrical connectors, the UHF connectors, the mat can be directly connected to an antenna controller.
Different arrangements of planar antenna structures may be possible.
As shown in
In one embodiment, the controller 18 may be configured to control the plurality of antennas. In a first time period the controller may control a first subset of one or more antennas out of the plurality of antennas to transmit signals for triggering UHF tags passing the antenna mat to transmit tag signals back to the antenna mat. Then, in a subsequent second time period the controller may control a second subset of one or more antennas out of the plurality of antennas to transmit signals for triggering UHF tags passing the antenna mat, wherein first subset and second subset include different antennas. In an embodiment, when a first subset of antennas is in a transmitting mode, the second subset of antennas may be in a signal receiving mode in which the antennas are configured to receive UHF tag signal. Likewise, when the second subset is in the transmitting mode, the first set is in the signal receiving mode.
In one embodiment, a first antenna and second antenna of an antenna pair may belong to different antenna subsets, e.g. one in the first subset so that this one antenna transmits during the first time period and the two neighbouring antennas on either side in the second subset so that these neighbouring antennas transmit during the second time period.
In yet another embodiment, the plurality of antennas may comprise more than two subsets, such as three subsets of antennas. In this case, the first subset may transmit during a first time period, the second during a second time period, the third during a third time period, et cetera. These time periods preferably follow directly after each other. In one example, the plurality of antennas consists of as many subsets as antenna, each subset comprising one and only one antenna. Then, during a first time period, a first antenna may be in transmitting mode, during the second time period a second antenna may be in transmitting mode, during the third time period a third antenna may be in transmitting mode, et cetera. These time periods may follow directly after each other.
In one embodiment, a pair of patch antennas belongs to the same subset. In this embodiment, preferably, pairs of antennas belong to a different subset, so that two neighbouring pairs do not transmit simultaneously. In case the plurality of antennas comprises more than two subsets, the plurality of antennas may comprise as many subsets as there are antenna pairs in the antenna mat, wherein each subset comprises one and only one antenna pair. Then, a first pair may be in transmitting mode during a first time period, a second pair during a second time period, a third pair during a third time period, et cetera. Again these time periods may follow directly after each other.
The above described transmission schemes advantageously reduce cross-talk between the antennas, which can distort measurements. Cross-talk may be understood to occur when an antenna sitting in a signal receiving mode receives a signal directly, e.g. without the signal being backscattered from a device that is passing the timing mat, from another antenna that is transmitting a signal. The above-described time periods in which an antenna transmits a signal typically last 3 ms.
A test protocol may be executed by the antenna controller, wherein the test protocol may include controlling a planer UHF antenna structure to transmit an antenna test signal of a predetermined amplitude and phase. In response, the antenna test signal may trigger the test device, e.g. a (passive or active) transponder, to measure one or more signal strengths of the test signal transmitted by the antenna structure and to transmit a transponder test signal back to the antenna structure, wherein the transponder test signal may include the one or more measured signal strengths. The test may include comparing the transponder test signal, in particular the one or more signal strengths, with a reference signal. Based on the comparison, the controller may determine whether the antenna structure functions according to the specifications or not. The test protocol may be performed for each antenna structure in the antenna mat.
The antenna mat structures described with reference to
The materials and the dimensions (especially the thickness) of the elongated flexible sheet structure of the antenna mat may be selected to have a relative low bending rigidity, whereas the materials and dimensions (especially the thickness) of the planar antenna structures may be selected to form a structure of a bending rigidity that is higher than the bending rigidity of the flexible sheet structure. Thus, the bending rigidity of the flexible sheet structure and the planar antenna structure may be expressed in terms of the flexural or bend modus of the materials that are used for the flexible sheet structure and the antenna structure respectively. The flexural or bend modus may be determined based on a standardized measurement protocol, e.g. ASTM D790 and ISO 178 test methods.
To illustrate, in the embodiment of
The antenna mat, in particular the flexible material, may comprise at least one region 36 comprising honeycomb structures. Such an area is advantageous because it reduces the weight of the antenna mat without significantly weakening the mechanical strength of the antenna mat 2. In an embodiment, the honeycomb structure may include cells. The shape of the cells may include at least one of: (circular-cored) hexagonal cell, (circular-cored) triangular cells, (circular-cored) triangular cells, (circular-cored) square cells and/or combinations thereof.
The flexible sheet element may further comprise one or more protrusions 38a at a first short side of the sheet element and one or more recessed spaces at the second short side (opposite the first short side) wherein the one or more recessed spaces are shaped to receive protrusions of a further sheet element. Hence, the flexible sheet element may be used to form an long flexible sheet by mechanically connecting elements using the protrusions and corresponding recessed spaces at the short sides of the sheet elements. This way, during manufacture of an antenna mat, multiple sheet elements may be used to form a long flexible top sheet of an antenna mat. After positioning the one or more protrusions 38 of one antenna mat into the one or more cavities 40 of another antenna mat. Such modular approach allows easy and flexible manufacturing of rollable antenna mats of different lengths.
In a further embodiment, flexible sheet element may further comprise a channel 35 for receiving a coaxial transmission line, wherein the channel may guide a coaxial transmission line from a first longitudinal side of the antenna mat to the second longitudinal side of the antenna mat. Such channel 35 allows rerouting of coaxial transmission lines from a side channel on one long side of the antenna mat to a side channel 34d on the other long side of the antenna mat 2. These one or more coaxial transmission lines are then connected to patch antennas that are positioned in another antenna mat (not shown). In an embodiment, flexible sheet elements as depicted in
A method for manufacturing the antenna mat may comprise moulding, e.g. low-pressure moulding, a flexible material into a structured flexible sheet element including recessed structures for planar antenna structures and coaxial transmission lines connected to the planar antenna structures, positioning the planar antenna structures and coaxial transmission lines into the recessed structures and sealing the antenna mat structure using the cover layer 46 (which may also be referred to as bottom layer). As such, the cover layer and the structured flexible sheet elements form a layered flexible sheet structure in which a plurality of planar antenna structures are embedded wherein a layered flexible sheet structure forms an antenna mat which can be rolled up.
In one embodiment, the antenna mat may comprise a conductive layer 48, e.g. a metal foil or a metallized film, which will be explained in more detail with reference to
It is submitted that structure of the antenna mat is not limited to the figures. For example, in further embodiments, instead of and/or in addition to the use of a flexible structured top sheet, the bottom layer may also include structures, e.g. recessed spaces and/or honeycomb structures, for embedding the antenna structures in the antenna mat and/or for providing a light flexible structure that has advantageous mechanical properties, e.g. in terms of (out of plane) compression stiffness and/or bending stiffness.
The planar UHF antenna structure may comprise at least one conductive plate 50 positioned above a conductive ground plane 52 and a spacer element 54 positioned between the conductive ground plane and the conductive plate. The planar UFH antenna structure is configured to generate a radiation field, wherein the radiation field may have a main axis that is substantially perpendicular to the conductive plate. Thus, at least a large part of the radiation field will be generated directly above the antenna structure in a direction perpendicular to the plane of the conductive plate. In an embodiment, the antenna structure includes a patch antenna, wherein the radiative element is conductive patch over a ground plane as e.g. depicted in
In addition, in an embodiment, a conductive shielding layer may be positioned under the antenna structures. The shielding layer which is electrically separated from the ground plane and the metal plate will shield the antenna structures from dielectrical and/or electromagnetical effects originating from objects and/or sources underneath the antenna mat. Further, the shielding layer will direct the radiation generation by the antenna structure in a direction normal to the shielding layer away from the ground.
The shielding layer may be connected to the ground plane 52 and is positioned substantially parallel to ground plane 52. The dimensions of the conductive foil 48 may larger than the dimensions of conductive ground plane 52 so that the conductive foil 48 can provide additional shielding for the patch antenna from external radiation and/or so that signals emitted by the patch antenna are directed upwards. The latter prevents that energy is wasted by transmitting electromagnetic radiation into the ground.
The shielding layer and the antenna plates, i.e. the conductive plate and the ground plate, may be made from any suitable conductive material, preferably a copper or another suitable metal.
As shown in the figures a coaxial transmission line is guided along the longitudinal axis of the antenna mat towards an antenna structure. When the transmission line approaches the antenna structure, the coaxial transmission line is guided in a direction that is substantially perpendicular to the longitudinal axis of the antenna mat and substantially parallel to an inner edge of the antenna structure. As will be described hereunder in more detail, the signal line of the coaxial transmission line is connected to a side of the conductive plate such that the mechanical load on the UHF connection due to the winding up and unwinding of the antenna mat roll is minimal.
The spacer structure 54 provides a stable separation between the ground plane and the conductive plate of the antenna. It is designed to inhibit changes to the separation due to pressure exerted on the antenna mat. In one embodiment, the spacer structure may comprise (or essentially consists of) a plastic, such as high-density polyethylene (HDPE).
One or more test devices 56a-56b, e.g. a passive tag, that, may be positioned in a fixed position with respect to an antenna structure 6a,6b. A test device 56 may be mounted on the spacer structure 54 or in a space in the spacer structure, e.g. pockets 58a, 58b, 58c, 58d. This way, the test device is positioned at a peripheral area of the antenna structure close to the radiation plate of the antenna.
As shown in
In one embodiment, the coaxial transmission lines may be configured as coax cables using a SubMiniature version A (SMA) type connector for connection e.g. the antenna controller. The inner conductor 60a, 60b, of the coaxial transmission line is connected to the conductive plate of the antenna structure. As depicted in the figure, at the connection point 60a,60b between the conductive plate and the transmission line 44,42, the longitudinal axis of the end of the transmission line (i.e. points A′ and A″ in
In an embodiment, antenna structures 6a and 6b may be a pair of patch antennas that is to be controlled to simultaneously emit signals (e.g. as described with reference to
As shown in the figures, the hand truck may include a shaft 11 wherein a first end of the shaft is connected to a base 13 and the second end of the shaft include one or more handles 15. As shown in
In an embodiment, the antenna mat roll may be positioned in the tray such that the roll axis 94 of the antenna mat roll may be parallel to the axis 91 connecting the center of the two wheels. The tray may include rising edges 92a,92b positioned along the sides of the tray wherein the rising edges are configured to stop the antenna mat from sliding of the tray during transportation. In an embodiment, the height of one rising edge, e.g. the rising edge 92b at a second side opposite to the first side, may be lower than the height of the rising edges along the other (three) rising edges of the tray.
In an embodiment, a first frame structure 96a connected to the tray is positioned along a second side of the tray and a second frame structure 96b connected to the tray is positioned along a third side of the tray (opposite to the second side of the tray), wherein the second and third sides of the tray are perpendicular to the first side of the tray. The height of the first and second frame structure is higher that the height of the antenna mat roll positioned in the tray. Further, in an embodiment, the second end of the shaft may be connected to the base using a detachable connection structure. Thus, in this embodiment, the shaft may be detached resulting in an assembly comprising an antenna mat roll positioned in the tray including first and second frame structures, which enables a user to easily handle and lift the antenna mat roll.
As shown in
When removing the shaft of the antenna mat assembly as depicted in
The tray structure may be a substantially rectangular tray structure including four sides, wherein a first side may include a connector 101 for removably connecting a shaft connected to a handle (as described with reference to
The structures and assemblies depicted in the figures are non-limiting and are used for illustrating the advantageous features and functionalities provided by the invention. Many other variants of the embodiments are possible without departing the essence of the invention. For example,
Similarly,
Some embodiments of the invention may be implemented as a program product for use with a computer system, where the program(s) of the program product define functions of the embodiments (including the methods described herein). In one embodiment, the program(s) can be contained on a variety of non-transitory computer-readable storage media, where, as used herein, the expression “non-transitory computer readable storage media” comprises all computer-readable media, with the sole exception being a transitory, propagating signal. In another embodiment, the program(s) can be contained on a variety of transitory computer-readable storage media. Illustrative computer-readable storage media include, but are not limited to: (i) non-writable storage media (e.g., read-only memory devices within a computer such as CD-ROM disks readable by a CD-ROM drive, ROM chips or any type of solid-state non-volatile semiconductor memory) on which information is permanently stored; and (ii) writable storage media (e.g., flash memory, floppy disks within a diskette drive or hard-disk drive or any type of solid-state random-access semiconductor memory) on which alterable information is stored. The computer program may be run on the processor 1002 described herein.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of embodiments of the present invention has been presented for purposes of illustration, but is not intended to be exhaustive or limited to the implementations in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the present invention. The embodiments were chosen and described in order to best explain the principles and some practical applications of the present invention, and to enable others of ordinary skill in the art to understand the present invention for various embodiments with various modifications as are suited to the particular use contemplated.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. The embodiment was chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021987 | Nov 2018 | NL | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/NL2019/050740 | 11/13/2019 | WO |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2020/101488 | 5/22/2020 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 8525647 | Varpula | Sep 2013 | B2 |
| 10348072 | Gaiser et al. | Jul 2019 | B2 |
| 10686306 | Gaiser et al. | Jun 2020 | B2 |
| 20070004363 | Kusaka | Jan 2007 | A1 |
| 20090160612 | Varpula | Jun 2009 | A1 |
| 20100265801 | Ehelen et al. | Oct 2010 | A1 |
| 20170327051 | Bromfield | Nov 2017 | A1 |
| 20180076530 | Kawahata et al. | Mar 2018 | A1 |
| 20180152010 | Gaiser | May 2018 | A1 |
| 20190296532 | Gaiser et al. | Sep 2019 | A1 |
| Number | Date | Country |
|---|---|---|
| 3298668 | Mar 2019 | EP |
| 3298668 | Mar 2019 | EP |
| 2018-046391 | Mar 2018 | JP |
| 2009011600 | Jan 2009 | WO |
| 2009113948 | Sep 2009 | WO |
| WO-2009113948 | Sep 2009 | WO |
| 2016188798 | Dec 2016 | WO |
| Entry |
|---|
| International Search Report and Written Opinion for corresponding International Patent Application No. PCT/NL2019/050740 dated Dec. 17, 2019. |
| Office Action in corresponding Japanese application No. 2021-525763 dated Dec. 5, 2023. |
| Number | Date | Country | |
|---|---|---|---|
| 20210408660 A1 | Dec 2021 | US |
