System and method for folding and unfolding a flexible antenna.

Abstract

System and method for folding and unfolding a flexible antenna. An antenna having a predetermined shape from a shape memory material and an electrically conductive fabric connected thereto, the antenna being configured to be connected via a bidirectional switch to a voltage supply, wherein the antenna is in a folded state and the switch is in a first position in which energy from the voltage supply at a first frequency is converted into energy to unfold the antenna into the predetermined shape; and wherein the antenna has been unfolded and the switch is in a second position and voltage is supplied at a second frequency, different from the first frequency, in which the antenna operates to transmit or receive radiation. Abstract Figure: Figure 3a

Description

Title of the invention: System and method for folding and unfolding a flexible antenna. Technical field

[0001] The present invention relates to a system and method for folding and unfolding a flexible antenna. State of the art

[0002] Antennas are used in many situations and can come in different shapes and sizes. An antenna is a device for sending and receiving electromagnetic waves and is generally used to transmit or receive radiation associated with communications and broadcasts. For many applications, the antenna is both bulky and heavy, making it difficult to move and orient and a limiting factor in the type of antenna that can be implanted in a device. Orientation of the antenna is an important function, and its weight and size make it even more difficult. In the field of microwaves, radio communications and electromagnetic links, parabolic antennas are known for their usefulness, which allows, through focusing, to obtain a power gain in particular orientations.Metamaterial antennas also make it possible to reproduce the performance of a dish from a metamaterial antenna disc.

[0003] It is also common to use deployable antennas. In some cases, these antennas have elements that can be moved to a specific location to give the antenna the desired shape. An example is a type of parabolic antenna called a "folding petal antenna." Having deployable antennas solves some problems, but also creates new ones. The antennas become complex and require deployment mechanisms that increase their weight and size. In addition, the deployment itself requires energy and therefore a power supply.

[0004] Lighter textile antennas have been proposed, but problems with deployment and mechanisms contributing to weight and size remain.

[0005] One of the objectives of the present invention is to solve at least some of the problems associated with known antennas.

[0006] Another objective is to provide a compact, lightweight, and easy-to-deploy antenna that does not require an independent source of power or energy for its deployment. Statement of the invention

[0007] According to at least one of its embodiments, the invention relates to an antenna formed with a predetermined shape from a shape memory type material and an electrically conductive fabric connected thereto, the antenna configured in use to be connected via a bidirectional switch to a voltage supply, the antenna is folded and the switch is in a first position in which energy from the voltage supply at a first frequency is converted into energy to unfold the antenna into the predetermined shape; and wherein the antenna has been unfolded and the switch is in a second position and voltage is supplied at a second frequency, different from the first frequency, in which the antenna operates to transmit or receive radiation.

[0008] According to at least one embodiment of the present invention, the antenna further comprises a deployable or received transmitter configured to transmit or receive radiation.

[0009] According to at least one embodiment of the present invention, the supply voltage is converted by a voltage management and storage unit.

[0010] According to at least one embodiment of the invention, the voltage management and storage unit comprises a rectifier bridge diode device.

[0011] According to at least one embodiment of the invention, the antenna further comprises a storage cell for storing the energy converted for the deployment of the antenna.

[0012] According to at least one embodiment of the invention, the antenna deployment system further comprises a voltage supply and a control unit.

[0013] According to at least one embodiment of the invention, the control unit is capable of providing frequency-controlled control of the antenna using different shape configurations to navigate and control the antenna in use.

[0014] According to at least one of its embodiments, the invention also relates to a method of deploying an antenna from a folded position to an unfolded position, the antenna having a predetermined shape from a shape memory type material and an electrically conductive fabric connected thereto, the method comprising: the antenna in a folded state and a switch in a first position, converting energy from a voltage supply at a first frequency into energy for unfolding the antenna into a predetermined shape; and the antenna unfolded and the switch in a second position, providing a voltage at a second frequency, different from the first frequency, in which the antenna operates to transmit or receive radiation.

[0015] According to at least one of its embodiments, the invention also relates to a method of frequency-controlled control of an antenna as previously described, in which a control unit is capable of providing frequency-controlled control of the antenna using different shape configurations to navigate and control the antenna in use. Brief description of the figures

[0016] Other characteristics and advantages of the invention will appear during the reading of the detailed description which follows for the understanding of which reference will be made to the appended drawings in which:

[0017] [Fig.l] is a simplified diagram of an antenna deployment system according to one aspect of the present invention.

[0018] [Fig.2] is a schematic view of an antenna used in the system of [Fig.l].

[0019] Figures 3a and 3b are simplified diagrams of the antenna of [Fig.2] to show the antenna folded and unfolded, according to one aspect of the invention.

[0020] [Fig.4] is a simplified diagram showing a deployment circuit for deploying the ready-to-use antenna, according to one aspect of the invention.

[0021] [Fig.5] is a diagram of the steps required to deploy and use an antenna in the system of [Fig.l]. Detailed description

[0022] There are many types of antennas used in a multitude of situations. An antenna can be used to transmit a signal from a source to a destination or to receive a signal from a destination to be used at a source. Each antenna has a specific set of requirements for operational purposes. Many characteristics can influence how the antenna can be used.

[0023] Generally, the following characteristics are the primary considerations when designing an antenna: the required frequency range, beam characteristics including radiation pattern, gain, focusing requirements, efficiency, and impedance matching. Impedance matching is the process of designing the antenna's input impedance or matching it to the corresponding output impedance of an associated radio frequency (RF) circuit. The gain and frequency range covered by the antenna are generally related to the antenna's dimensions. Other characteristics are also important when using an antenna. For example, the mass and dimensions of the antenna can impact its portability and navigation capabilities. Mechanical characteristics, and in particular deformation due to wind, temperature or any other environmental conditions, are also attributes to consider.

[0024] Balancing the different characteristics for each use case is complex and difficult. In different situations, the most important characteristics may be different. For example, for a large terrestrial antenna, weight and size are not constraints. On the other hand, for an antenna intended to be deployed in space, for example, weight and size are very important, at least for routing the antenna in space. This is also the case in aeronautics and drone systems. Then, a robust and easy-to-deploy antenna is necessary to cope with the extreme conditions in which the antenna is used. Damage to the reflector surfaces can have a significant impact on the antenna's performance.

[0025] The present invention relates to an antenna which can be constrained into a compact and lightweight shape before deployment and which, once deployed, is a robust and solid structure configured to transmit or receive signals. Also disclosed is a technique for deploying the antenna without the need for a specific power source. This technique has a number of advantages. The size and weight are reduced due to the absence of a battery or other power source. The antenna can be completely self-contained and can be easily deployed remotely based on a pre-configured shape and the application of a normal antenna operating signal, as described below.

[0026] This technique can also be used to add a folding function based on the same approach.

[0027] The selectivity of the radiocommunication function, unfolding and folding, is associated with a frequency choice and a specific construction of the architecture of the antenna system.

[0028] [Fig.l] is a simple diagram of an antenna system 100. The system 100 includes an antenna 102 supported by and connected to a control unit 104. The antenna 102 is flexible and shown as a parabolic antenna with a parabolic reflector surface 106 supported by a support 108 and a receiver or transmitter 110 positioned above the antenna. The receiver or transmitter may be supported in a manner different from that shown and is essentially located at the focal point of the reflector at a predetermined frequency or frequency range. The antenna is described in more detail below. The control unit 104 is configured to control the deployment and operation of the antenna. The control unit 104 controls the folding and unfolding of the antenna, the transmission and / or reception of signals and, once deployed, the navigation or orientation of the antenna in a given direction.

[0029] The control system may further communicate with and operate in conjunction with any local resources to provide the necessary communications and functionality. The control unit typically includes a computer system having processors and memory and configured to execute computer-executable programs or media. The control unit may also be configured to allow the antenna to be unfolded (deployed) and retracted so that, when not in use, it is closed and protected from potential damage.

[0030] [Fig. 2] shows an antenna 200 according to the present invention. The antenna 200 is formed from a fabric 202 composed of fibers that have been woven or otherwise combined and that, before use, has been applied to a mold 204 composed, for example, of a shape memory material 206. An example of a shape memory material 206 is nickel titanium (NiTinol). The fabric 202 has the function of a radiating panel configured for and capable of functioning as an antenna when it has the shape defined by the shape memory material 206. In the present invention, fabric is understood to mean a surface constituted by a regular or irregular assembly of interlaced, woven or meshed threads. Of course, the threads can be made of any material such as cotton, synthetics, plastics, metals, thermoplastics, shape memory materials, and many other materials.

[0031] The fabric may be made from any suitable material and is generally electrically conductive and made of electrically conductive fibers, alone or in combination with other materials. The electrical conductivity may be modulated by varying the mixtures of components, and materials for electrical conduction (e.g., based on metals such as copper, silver, stainless steel, aluminum or any other metal or alloy or any conductive structure) may be combined.

[0032] Thus, for example, at least one of the fibers comprising the fabric is a fiber comprising a first yarn of electrically conductive material and a second yarn of deformable thermoformable material. For example, the first and second yarns are interwoven. More than two yarns may be used to form the fabric, for example, a third textile yarn may be added to the first and second yarns when combining them. The fabric is shown as being woven, but it could be joined by knitting or in some other way, combined or simply arranged in close proximity to each other.

[0033] It should be noted that any material compatible with thermoforming can be used in the present invention, such as polymers, filled polymers, doped polymers, copolymers whose hardness or elasticity can be modulated, resins, ethylene-vinyl acetate (EVA), polystyrene (PS), polyethylene (PE), polypropylene (PP), polycarbonate (PC), acrylonitrile butadiene styrene (ABS), polyvinyl chloride (PVC), polymethyl methacrylate (PMMA), high impact polystyrene (SB), Nylon, etc. The polymers or resins can be filled with EVA to modulate the elasticity of the fibers or yarns that make up the fabric.

[0034] The interlacing of the first and second yarns to form a fabric may, for example, be achieved using an overlapping technique. Filix, for example, offers such yarns. Any other technique may also be used. Alternatively, the yarns may be interlaced (manually or by machine) to form one or more fibers.

[0035] Thus, the present invention, according to certain variants, makes it possible to benefit from the great flexibility associated with the characteristics of the textile fiber. The fibers can be relatively rigid or flexible depending on the use case.

[0036] The antenna 200 is applied to the shape memory type material 206 before use. A predetermined shape of the shape memory material 206 is determined, and the shape memory material is formed accordingly so that the fabric 202 adheres to the shape memory material by passing a current through the fabric to generate an electric current that heats the underlying shape memory material 206 to attach the fabric 202 to the shape memory material 206. After the current is removed, the combination of the fabric 202 and the shape memory material 206 remains in contact, but the shape is not necessarily maintained, and the resulting antenna 200 may be compressed or folded for storage and / or transportation.

[0037] In [Fig. 2], the fabric 202 is bonded to the inner surface 208 of the shape memory material 206. It will be appreciated that the shape and nature of the shape memory material can vary to give rise to different shapes and sizes of antenna 200. Furthermore, the fabric 202 can be applied to different support materials in different ways and is not limited to the shape memory material 206 described above. The antenna 200 can thus have any desired three-dimensional configuration before being deployed.

[0038] A common feature of the present invention is that after folding or compression, the antenna structure combining the fabric 202 and the shape memory material 206 can be unfolded by applying heat, an electrical current or another signal so as to unfold and return to the predetermined shape.

[0039] Figures 3a and 3b show, in [Fig.3a], a folded antenna and, in [Fig.3b], an unfolded and deployed antenna. [Fig.3a] shows a folded antenna 200 comprising the shape memory material 206 with the attached fabric 202 on an interior portion of the folded shape memory material 206. The folded combination also includes a transmitter or receiver 300 between the folded sides of the shape memory material 206. [Fig.3b] shows the antenna 200 in a deployed state with the shape memory material 206 supporting the fabric 202 and the transmitter or receiver placed in an operational position. The manner in which deployment occurs will now be described.

[0040] An antenna 200 of the type described herein is configured to operate at a specific frequency or frequency band. The antenna 200 radiates at the specific frequency and has an impedance matched to the transmitter. In use, electromagnetic energy is converted to radiation and emitted by the antenna 200. If the frequency is not a radiation frequency, the antenna 200 behaves as a short circuit that reflects the electromagnetic energy back to the transmitter and does not radiate it. The present invention intentionally uses this situation to apply energy to the antenna 200 for deployment.

[0041] The control unit 104 includes a voltage management and storage unit 400, as illustrated in [Fig. 4]. In one example, the voltage management and storage unit 400 includes a diode bridge rectifier 402, also referred to as an RF energy harvesting rectifier circuit, as illustrated in [Fig. 4]. The voltage management and storage unit 400 converts energy applied at frequencies outside the operating frequency of the antenna 200 by an AC power supply 404 into a DC voltage to be stored in a storage cell 406. At another time, the voltage stored in the storage element 406 is delivered to the antenna 200 to cause it to unfold into the shape defined by the shape memory type material 206. There is no need for a storage cell if the voltages are applied directly.The AC power supply 404 is further configured to generate the radiation to be emitted by the antenna 200 at a wide range of frequencies, including the operational frequency required for antenna functionality.

[0042] The voltage management and storage unit 400 is an example of a circuit that can convert the supply voltage into stored energy. It will be appreciated that other devices and / or circuits may be used, including non-storage devices that deploy the antenna in a first application of the required energy.

[0043] The antenna 200 is switchably connected to both the AC power supply 404 for operational purposes and the voltage management and storage unit 400 for deployment via a switch 408. In some aspects of the invention, the switch is frequency dependent and closes to connect to the voltage management and storage unit 400 at one or more first frequency bands and closes to connect to the antenna at the frequencies at which the antenna 200 is set to operate. Other types of switches could be used.

[0044] The antenna 200 is configured to operate at one or more specific frequencies and, outside of these specific frequencies, the antenna is poorly suited or unsuitable for operation as an antenna. Accordingly, the applied voltage passes through the voltage management and storage unit 400 and a voltage is stored. This stored voltage is then directed to the antenna 200 to heat the shape memory material 206 with the attached fabric 202 to deploy the antenna 200. The choice of the operational frequency is based on the intended use and design of the antenna which will be known prior to deployment, so that voltages that generate frequencies outside the operational range are used to deploy the antenna before applying the operational frequencies.

[0045] The frequency of the electromagnetic energy for the deployment procedure does not correspond to the operating frequency of the antenna. Since the source provides many frequencies, it is possible to use frequencies outside of the specific frequency(ies) to store energy for deployment; and for other functions beyond the transmitting functionality described in the present invention. For example, the stored energy can be used to fold the antenna when not in use and to orient the antenna after deployment or for any other function.

[0046] For example, it is easy to achieve, using frequency filtering, the coexistence of at least three functionalities: antenna communication function, unfolding function and folding function. Indeed, if the filtering system allows: 1) For the antenna function, to let through the frequencies used for radio communications but blocks these frequencies on the folding and unfolding functions 2) For the unfolding function, let the frequencies used for unfolding pass by converting the electromagnetic signal into unfolding energy on the opening wire area. The frequencies being blocked on the folding function. The antenna function could possibly not be blocked 3) For the folding function, allow the frequencies used for folding to pass by converting the electromagnetic signal into unfolding energy on the closing wire area. The frequencies being blocked on the unfolding function. The antenna function could possibly not be blocked.

[0047] The unfolding and folding functions can also be replaced by configuration 1 and configuration 2 functions corresponding to geometric states.

[0048] Thus, it is possible to generate the operating frequency of the antenna 200 and to transmit or receive a radiated signal or to use another frequency and, in this case, the energy will be transformed into stored energy and then used by the intermediary in the control unit to deploy the antenna 200.

[0049] The voltage management and storage unit 400 converts any inappropriate frequency signal connected to the antenna 200 that is not a radiation frequency of the antenna into energy for controlling the shape of the antenna material so as to automatically deploy the antenna 200. The control unit is configured to allow frequency changes such that electromagnetic energy is stored and converted into deployment or folding energy.

[0050] A possible example is that the antenna 200 in the folded position does not radiate as in its folded configuration and therefore the antenna 200 cannot transmit signals. The energy generated in this situation is applied immediately or after being stored by the control unit to unfold the antenna. Once the antenna is unfolded, the control unit applies the energy which is now used for transmission or reception purposes, because the frequency matching occurs and the device promotes radiation and normal operation of the antenna.

[0051] [Fig. 5] is a simple diagram illustrating the method 500 for deploying the antenna. In step 502, the antenna is positioned at the location required for operation. This can be any location and can be implemented automatically or under the control of a machine or a human being. In step 504, a voltage is applied. As the antenna is folded, the voltage is used to unfold the antenna 506 as described above. The voltage required to deploy the antenna may have been previously stored by applying the voltage before deployment. Once the antenna is deployed, any further energy application is applied to the antenna 508 at predetermined frequencies so that the antenna operates normally.

[0052] It will be appreciated that the system can power another device allowing the antenna to fold when it is not needed. This means that the antenna is protected against possible accidental damage. In order for the antenna to fold, a different stimulus is created. For example, this is the case if the stimulus is a frequency chosen to power the folding function.

[0053] Variants are possible with this approach once the system has coexisting functions: radio communication function, function of converting electromagnetic energy into configuration energy and use of energy with or without storage for a configuration modification.

[0054] List of numerical references. Antenna system Antenna Control unit Parabolic reflector surface Support Issuer Antenna Fabric Mold Shape memory type material Interior surface Receiver Voltage storage Diode bridge rectifier Alternating current power supply Storage cell Method Antenna is positioned Voltage is applied Voltage is used to unfold the antenna Energy is applied to the antenna.

Claims

Claims

1. An antenna (102, 200) formed with a predetermined shape from a shape memory type material (206) and an electrically conductive fabric (202) connected thereto, the antenna configured in use to be connected via a bidirectional switch (408) to a voltage supply (404), the antenna (200) is folded and the switch is in a first position in which energy from the voltage supply at a first frequency is converted into energy to unfold the antenna into the predetermined shape; and wherein the antenna has been unfolded and the switch is in a second position and voltage is supplied at a second frequency, different from the first frequency, in which the antenna operates to transmit or receive radiation.

2. The antenna (102, 200) of claim 1, further comprising a deployable or received transmitter configured to transmit or receive radiation.

3. The antenna (102, 200) of claim 1 or claim 2, wherein the supply voltage is converted by a voltage management and storage unit (400).

4. The antenna (102, 200) of claim 3, wherein the voltage management and storage unit (400) comprises a rectifier bridge diode device (402).

5. The antenna (102, 200) of claim 4, further comprising a storage cell (406) for storing the converted energy for deployment of the antenna.

6. A system (100) for deploying an antenna (102, 200) according to any preceding claim, further comprising a voltage supply and a control unit (104).

7. A system (100) for deploying an antenna (102, 200) according to claim 6, wherein the control unit is capable of providing frequency-controlled control of the antenna using different shape configurations to navigate and control the antenna in use.

8. A method of deploying an antenna (102, 200) from a folded position to an unfolded position, the antenna having a predetermined shape from a shape memory type material (206) and a

9. electrically conductive fabric (202) connected thereto, the method comprising: the antenna (200) in a folded state and a switch in a first position, converting energy from a voltage supply at a first frequency into energy for unfolding the antenna into a predetermined shape; and the unfolded antenna and the switch in a second position, providing a voltage at a second frequency, different from the first frequency, in which the antenna operates to transmit or receive radiation. A method of frequency controlled control of an antenna according to one of claims 1 to 7, wherein a control unit is capable of providing frequency controlled control of the antenna using different shape configurations to navigate and control the antenna in use.

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