The methods described herein were made by employee(s) under contract with the United States Government and may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefore.
There exists a need for a deployable antenna for various applications. Considerations include weight, portability, stowage, cost, and ease of manufacturing. Ideally, such an antenna would have a simple structure, be easy to deploy for use, and be easy to collapse into a compact configuration for storage. Example applications for use include military operations, remote industrial operations, surveillance, scientific outposts, and general remote outdoor activities such as camping, hiking, fishing, and mountain climbing. A specific example of an application is the use of a stowable and deployable antenna in combination with a wireless communications system such as a cellular telephone or a cellular modem. As the use and popularity of wireless communication systems combined with the popularity of remote outdoor activities increases, the need for stowable and deployable antennas will also increase.
Mobile communication systems, for example cellular, personal communication systems, and wireless Ethernet provide wireless communications between a base station and at least one portable subscriber unit. Each mobile subscriber unit contains an antenna apparatus for the reception of the forward link signals and for the transmission of the reverse or return link signals. A typical mobile subscriber unit is a digital cellular telephone handset or a personal computer coupled to a wireless network. In urban areas, there usually exists a base station within the range of a mobile subscriber unit's built-in or stock antenna. However, in remote areas, the availability of such a base station within the range of a mobile subscriber unit's built-in or stock antenna may not exist.
In general, the performance of an antenna depends upon its configuration or shape as well as its size. Wireless communications devices are limited in their antenna performance due to a built-in or stock, omnidirectional antenna design. Therefore, increasing the performance of the built-in antenna for remote operations may increase the likelihood of communication between a mobile subscriber unit and a base station. As an example, it is well known in the field that increasing the antenna gain in a wireless communication system typically has beneficial effects on system performance.
The present invention seeks to provide an antenna that overcomes or reduces the aforementioned problems and takes into account the aforementioned considerations.
Description
The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout.
The word “about” as used herein may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. For example, a quantitative temperature as disclosed herein may permissibly be different than the precise value if the basic function to which the temperature is related does not change. The word “generally” as used herein is used to indicate acceptable variance in a physical configuration so long as the variance doesn't change the basic function to which it is related. The word “radiate” or any form thereof for the purposes herein is defined as either transmitting electromagnetic waves, receiving electromagnetic waves, or both. The word “membrane” for the purposes herein is synonymous with the term “collapsible membrane.” The word “slot” for the purposes herein is defined as an opening of rectilinear, ellipsoidal, asymmetric, or arbitrary shape, which defines a nonconductive region contained in a conductive surface. The word “ring” for the purposes herein is defined as an object of rectilinear, ellipsoidal, asymmetric, or arbitrary shape with a vacant center. The phrase “radiating element” as used herein is defined as a basic subdivision of an antenna that in itself is capable of radiating, although it does not necessarily imply the smallest such subdivision. A radiating element may be a radiating slot. The phrase “cavity antenna element” as used herein is defined as a radiating element that has a ground plane. The ground plane may be abbreviated so that it is not shared with other radiating elements, or it may be extended and shared with at least one radiating element either locally truncated or globally truncated. Examples of cavity antenna elements include, but are not restricted to the following: resonant antennas such as microstrip patch antennas, planar inverted-F antennas (PIFA), and cavity-backed slots, as well as certain traveling wave antennas such as cavity-backed spirals. The cavity antenna element comprises a ground plane boundary component and one or more of the following: at least one top boundary component and at least one side boundary component. The phrase “current antenna element” as used herein is defined as the set of radiating elements, which do not have or require a ground plane. Examples of current antenna elements include, but are not restricted to the following: conductive loops, dipoles, bow-tie dipoles, slots, annular slots, and spirals. The phrase “boundary component” used in the context of a current antenna element is defined as the conductive pattern used to establish the functionality of that current antenna element. In a general context, the phrase “boundary component” is defined as a conductive pattern for either the cavity or current antenna elements to establish desired functionality over a predetermined band of operating frequencies. As an example, for resonant radiating elements (which may be of either cavity or current antenna types), the boundary component establishes resonances of the electric or magnetic (equivalent) currents or of the electric or magnetic fields at one or more predetermined operating frequencies. For the traveling wave type radiating elements, (which may be of either cavity or current antenna types), the at least one boundary component establish at least one guided wave that radiate in a predetermined manner as they travel away from the at least one feed point. The log-periodic and Archimedean spirals are examples of traveling wave antennas that are well documented in the literature. Furthermore, the phrase “parasitic element” as used herein is defined as a component of an antenna that is coupled electromagnetically; i.e, coupling to it is achieved without direct electrical connectivity. Since coupling occurs without direct electrical connectivity, at least one other component, in addition to the parasitic element, is required to form a complete radiating element. An example of an antenna with at least one driven element and at least one parasitic element is the Yagi-Uda antenna. Here, the phrase “driven element” is defined as a radiating element with electrical connectivity that may include a transmission line. It should be observed that the driven element individually may be referred to as a radiating element, and the collection, or set, of driven and parasitic elements may be referred to collectively as a single “radiating element.” In addition to being employed to guide a traveling wave, parasitic elements may be used to implement amplitude taper in an array antenna. This may serve to provide reduced sidelobe levels as is well known to those experienced in the art. The term “array” or “array antenna” as used herein is defined to encompass a collection of at least one radiating element or subarray and may further comprise at least one parasitic element. The term “subarray” as used herein is defined as a smaller array which may be duplicated one or more times to form a larger array.
Referring now to the drawings, and in particular to
As stated above, multiple embodiments exist for the boundary components of both cavity and current antenna elements. For example, multiple embodiments exist wherein the boundary components are formed from conductive material. In one embodiment, the boundary components may be formed from a conductive metal or alloy. In a second embodiment, the boundary components may be formed from conductive fabrics. In additional embodiments, some boundary components are formed from a conductive metal or alloy, while others are formed from conductive fabrics. Multiple embodiments for shapes and configurations also exist for the boundary components. In one embodiment, the boundary components may have a planar shape with multiple configurations (e.g., dipole, bow-tie, spiral). Wherein the boundary components have a general planar shape in one embodiment, as stated above, the boundary components may have a generally rectilinear, ellipsoidal, arbitrary, or asymmetrical shape
In a second embodiment, the boundary components of the radiating elements, either cavity or current type, has at least one slot in a general rectilinear, ellipsoidal, arbitrary, asymmetrical, “Vivaldi”, or “volcano” (as is known in the art) shape. Multiple embodiments exist wherein the radiating element is a radiating slot formed from at least one slot in a conductive material. This type of element is related to the embodiments defined above in a sense as described by Babinet's Principle. For example, in one embodiment, each slot may be cut out of conductive material such as conductive fabric.
Referring now to
Referring now to
Referring now to
Referring now to
As an example, an umbrella, as is commonly known in the art, is a fourth embodiment for collapsing a structure into a reduced volume (not shown). In an embodiment, a collapsible membrane formed of at least one layer of deformable, nonconductive material; at least one layer of deformable, conductive material; or both, wherein the collapsible membrane may be used as the umbrella's canopy material. The general structure and method of collapsing an umbrella may be used for a deployable antenna.
The various examples for multiple embodiments of collapsing a structure into a reduced volume and for collapsible membranes, are provided to illustrate a wide range of embodiments. A deployable antenna as defined herein has broad applications and is not limited to generally planar shapes. A wide range of three-dimensional shapes may be used, such as an umbrella shape. In addition, for example, the collapsible membrane may be in the shape of a deployable tent; a shirt that is unfolded and worn; a baseball cap that is unfolded and worn; a deployable pet water bowl; a deployable trash receptacle; a foldable bag such as a locker bag; or any arbitrary shape.
In one embodiment, a deployable antenna is comprised of a collapsible membrane and at least one boundary component, radiating element, or subarray attached to the collapsible membrane. In a second embodiment, each radiating element or subarray may be a cavity antenna element, or, more specifically, a microstrip or patch antenna. In a third embodiment, each radiating element or subarray may be a current antenna element. In a third embodiment, the deployable antenna may further comprise at least one transmission line electrically connected on one end to at least one boundary component, radiating element, or subarray. In a fourth embodiment, the deployable antenna may further comprise an antenna interface adapter electrically connected to one transmission line on the one transmission line's second end. The antenna interface adapter can be either a wire-based antenna interface adapter or wireless antenna interface adapter. In a fifth embodiment, the deployable antenna may further comprise a support means for supporting the membrane and overall antenna structure at a predetermined angle relative to a surface. A stand is one support means for supporting the membrane and overall structure at a predetermined angle relative to the surface. A platform is a second support means for supporting the membrane and overall structure at a predetermined angle relative to the surface. A rack is a third support means for supporting the membrane and overall structure at a predetermined angle relative to the surface. A mount is a fourth support means for supporting the membrane and overall structure at a predetermined angle relative to the surface. Examples of a mount include, but are not limited to, a clamp, suction, semi-permanent mount such as a base plate and screws, or a permanent mount such as a mount welded to a surface. In a sixth embodiment, the deployable antenna may further comprise at least one passive distribution network, active distribution network or both electrically connected to at least one transmission line on the at least one transmission line's second end. A distribution network may be at least one power divider, filter, amplifier, phase shifter, or any combination, where the term “power divider” is meant to describe a device that is used for either the splitting, combining, or splitting and combining of signals. In a seventh embodiment, the deployable antenna may further comprise a plurality of fasteners, or standoffs, of nonconductive material and of predetermined length wherein one end of each fastener is attached to the collapsible membrane and wherein the second end of each fastener is attached to a reflector. In an eighth embodiment, the deployable antenna may further comprise an independent power source and associated power distribution subsystem. In a ninth embodiment, the deployable antenna may further comprise a container for stowage purposes, carrying purposes, or both. In a tenth embodiment, the deployable antenna may comprise any combination of the embodiments described above.
As indicated by the multiple embodiments for a collapsible membrane describe above, multiple embodiments for a collapsible membrane relative to shapes, structures, and configurations may be used. The examples shown in
Multiple radiating means exist for transmitting electromagnetic waves, receiving electromagnetic waves, or both. For example, a radiating element is a first radiating means for transmitting electromagnetic waves, receiving electromagnetic waves, or both. A subarray is a second radiating means for transmitting electromagnetic waves, receiving electromagnetic waves, or both, where the subarray comprises at least one radiating element and may further comprise at least one parasitic element. An array antenna is a third radiating means for transmitting electromagnetic waves, receiving electromagnetic waves, or both. As described above, a radiating element may comprise at least one parasitic element in addition to at least one driven element.
Multiple embodiments of the radiating element, subarray, or array exist such that each radiating element, subarray, or array provides the bandwidth required for a given application. For example, in one embodiment, the radiating element is designed for a 100 MHz bandwidth centered at 850 MHz for application in a cellular telephone band. Such a radiating element may be a dual-side, printed dipole in a bow-tie configuration (not shown). In a second embodiment, the radiating element may be in a loop or spiral configuration (not shown) with at least one arm. In a third embodiment, the radiating element may comprise a bottom boundary component (e.g., a ground plane), a substrate, a feed network, and a top boundary component (e.g., a patch) (see
Multiple embodiments for attaching the radiating means to the collapsible membrane exist. For example, in one embodiment, stitching is a first attachment means for attaching the radiating means to the collapsible membrane. In a second embodiment, embroidering with conductive or nonconductive thread is a second attachment means for attaching the radiating means to the collapsible membrane. In a third embodiment, weaving is a third attachment means for attaching the radiating means to the collapsible membrane. In a fourth embodiment, placing the radiating means in a sleeve integrated into the collapsible membrane is a fourth attachment means. In a fifth embodiment, knitting is a fifth attachment means for attaching the radiating means to the collapsible membrane.
Multiple embodiments for a transmission line exist. For the purposes herein, the transmission line is defined as anything that provides transfer of electrical energy from one component to another component. A transmission network is defined as comprising at least one transmission line and at least one distribution network. A distribution network is defined as being a set of at least one component, which include filters, amplifiers, phase shifters, and power dividers, that multiplexes at least one input transmission line into at least one output transmission line, wherein the number of output transmission lines is not necessarily equal to the number of input transmission lines, and the relative amplitude and phase of each output transmission line with respect to the at least one input transmission line is predetermined. A power splitter/combiner is an example of a distribution network. Multiple embodiments for transmission line materials exist. For example, in one embodiment, the transmission line is comprised of a conductive, flexible material. In a second embodiment, the transmission line may comprise flexible printed circuit material. In a third embodiment, the transmission line may comprise conductive and insulative fabrics. Multiple embodiments for the transmission line (itself) exist. For example, in one embodiment, the transmission line is a coaxial line, either flexible or semi-rigid. In a second embodiment, the transmission line may be a stripline comprising two ground covers and a center conductor all formed of conductive fabric and two nonconductive fabrics to isolate the center conductor and ground covers. In a third embodiment, the transmission line may be a microstrip line which comprises a top conductor formed of conductive fabric, a substrate of nonconductive fabric, and a ground plane of conductive fabric. In a fourth embodiment, the transmission line may be a plurality of twin coupled coplanar strips. In a fifth embodiment, the transmission line may be formed of stacked and aligned strips of conductive fabric separated by a nonconductive fabric. In a sixth embodiment, the transmission line may be a coplanar waveguide. In a seventh embodiment, the transmission line is selected from a group consisting of a coaxial line, a slotline, a stripline, a microstrip, and a twin coupled line. Multiple embodiments for attaching the transmission line or transmission network to the collapsible membrane exist. For example, in one embodiment, stitching is a first transmission line and network attachment means for attaching the transmission line and transmission network to the collapsible membrane. In a second embodiment, embroidering is a second transmission line and network attachment means for attaching the transmission line and transmission network to the collapsible membrane. In a third embodiment, weaving is a third transmission line and network attachment means for attaching the transmission line and transmission network to the collapsible membrane. In a fourth embodiment, placing the transmission line and transmission network in a sleeve integrated into the collapsible membrane is a fourth transmission line and network attachment means for attaching the transmission line and transmission network to the collapsible membrane. In a fifth embodiment, knitting is a fifth transmission line and network attachment means for attaching the transmission line and transmission network to the collapsible membrane.
Multiple embodiments for the distribution network exist. In one embodiment, the distribution network is created using microstrip technology with conductive fabrics. In a second embodiment, the distribution network is created using stripline technology with conductive fabrics. In a third embodiment, the distribution network is created using conventional technologies for RF power distribution.
The antenna interface adapter generally provides an interface between the transmission network or transmission line and a mobile communication unit's transmission line. The antenna interface adapter may also provide an interface to a boundary component, a ground plane boundary component, or a radiating element. The antenna interface adapter functions to transform the transmission line technology from that used by the mobile communication unit to that used by the transmission network. In addition, the antenna interface adapter may provide at least one impedance transformation to avoid reflections at this interface. For example, in one embodiment, the transmission network for the deployable antenna is comprised of microstrip lines, and the mobile communication unit's transmission line is a coaxial cable. In this embodiment, the adapter will provide a transition from microstrip to coaxial cable. Multiple embodiments for an adapter exist. For example, in one embodiment, the adapter may comprise a thin laminate with a printed circuit. In a second embodiment, the adapter may comprise a balun. In a third embodiment, the adapter provides a transition from a coaxial transmission line to a fabric based transmission line. In a fourth embodiment, the adapter provides a transition from a coaxial transmission line to twin coupled strip, either horizontal or vertical, transmission line. In a fifth embodiment, the adapter is a wireless adapter that interfaces with a mobile communication unit's wireless system. In this embodiment, the adapter provides a region in which the signal is coupled electromagnetically between the mobile communication unit and the deployable array antenna.
In another embodiment, a deployable antenna is comprised of a collapsible membrane and at least one array antenna attached to the membrane (not shown). As described previously, an array antenna may comprise a plurality of at least one radiating element, at least one parasitic element, at least one subarray, or any combination. In a second embodiment, the deployable antenna may further comprise at least one transmission line electrically connected to at least one array antenna. In a third embodiment, the deployable antenna may further comprise at least one distribution network electrically connected to at least one transmission line. In a fourth embodiment, the deployable antenna may further comprise an antenna interface adapter electrically connected to one of the at least one transmission line. In a fifth embodiment, the deployable antenna may further comprise a support means for supporting the membrane and overall antenna structure at a predetermined angle relative to a surface. In a sixth embodiment, the deployable antenna may further comprise a plurality of fasteners of nonconductive material and of predetermined length and a reflector wherein one end of each fastener is attached to the membrane, and the second end of each fastener is attached to the reflector.
In another embodiment, a deployable antenna is comprised of a collapsible back layer, a collapsible front layer, and at least one radiating means attached to either the back layer or the front layer. Further, in this embodiment, the back and front layers may serve to provide weather-proof protection for the radiating means.
As stated earlier, multiple embodiments for a collapsible membrane relative to shapes, structures, and configurations may be used. For example, in one embodiment, the collapsible membrane may have at least one slot. In a second embodiment, each slot may be designed to reduce wind loads (not shown). Further, in a third embodiment, if the collapsible membrane is formed of conductive material, each slot may represent at least one radiating element (i.e., a radiating slot) in a sense described by Babinet's Principle. In a fourth embodiment, at least one non-perimeter structural support may be attached to the collapsible membrane (not shown). Also discussed earlier, several configurations may consist of a plurality of collapsible sections. In one embodiment, the number of radiating elements, parasitic elements, subarrays, or array antennas is equivalent with the number of sections (not shown). Multiple embodiments exist for arranging each radiating element, parasitic element, subarray, or array antenna on the membrane. For example, in one embodiment, one radiating element, parasitic element, subarray or array antenna is attached to one section. In a second embodiment, there may be a plurality of radiating elements, parasitic elements, subarrays, or array antennas attached to a section (not shown). In a third embodiment, the radiating element, parasitic element, subarray, or array antenna may cross over into a plurality of sections. In a fourth embodiment, the number of radiating elements, parasitic elements, subarrays, or array antennas is not equivalent with the number of sections. Further, in a fifth embodiment, at least one group of three radiating elements, parasitic elements, subarrays, or array antennas may be configured in a triangular pattern relative to each other, such as the triangular pattern illustrated in
Multiple embodiments for the number of collapsible membranes also exist. For example, in one embodiment, a deployable antenna is comprised of at least one collapsible membrane and at least one radiating element attached to the at least one collapsible membrane (not shown). In a second embodiment, an antenna may be comprised of a plurality of collapsible membranes; at least one radiating element attached to the plurality of collapsible membranes; and an antenna interface adapter electrically connected to the at least one radiating element (not shown). In a third embodiment, an antenna may comprise a plurality of collapsible membranes; a plurality of radiating elements attached to the plurality of collapsible membranes; at least one transmission line electrically connected to the plurality of radiating elements; and at least one distribution network electrically connected to the at least one transmission line (not shown).
Referring now to
Other embodiments, discussed previously, may be utilized to increase the antenna gain. In one embodiment, subarrays may be utilized in place of single radiating elements to populate a larger membrane (not shown). In a second embodiment, alternative spacing and pattern designs may improve antenna gain and minimize grating lobes (not shown). In a third embodiment, any combination of radiating elements, parasitic elements, subarrays, or array antennas, transmission lines, distribution networks, and antenna interface adapter are used. In a fourth embodiment, the radiating elements, subarrays, or arrays comprise current elements; and a reflector may be placed behind the radiating elements, parasitic elements, subarrays, or array antennas. In a fifth embodiment, the reflector is spaced at one-quarter wavelength from the radiating elements, parasitic elements, subarrays, or arrays, all of which are of the current element type. Multiple embodiments for the reflector exist. For example, in one embodiment, the reflector may comprise a flexible metallic mesh or screen. In a second embodiment, the reflector may be of a similar shape and design as the collapsible membrane. In a third embodiment, the reflector may comprise at least one printed or etched conductive sheet on deformable material. Spacers or fasteners may be placed in between the reflector and membrane to adequately separate these two components. In one embodiment, the fasteners or spacers may comprise nonconductive material.
In a traveling wave antenna, at least one radiating element, parasitic element, or boundary component function to guide a traveling wave that radiates while propagating along the guiding structure. Multiple embodiments exist for radiating means that are designed to guide a traveling wave. In one embodiment, the vector describing the principal direction of radiation lies in the plane of a collapsible membrane. One example of this embodiment is shown in
In another embodiment, a deployable antenna is a deployable wedge antenna that comprises the basic embodiments illustrated in
In another embodiment (not shown), a deployable antenna is a second deployable wedge antenna comprised of a first and second boundary component comprised of a first and second collapsible membrane, respectively, both formed of a flexible, conductive material; a first ring support attached to the first collapsible membrane at its perimeter; a second ring support attached to the second collapsible membrane at its perimeter; a feed probe electrically connected to the first collapsible membrane wherein the feed probe's first end is electrically connected to the first boundary component inside the perimeter of the first ring support, wherein the feed probe is not electrically connected to the second boundary component, wherein the feed probe passes through the second boundary component; and an antenna interface adapter electrically connected to the feed probe's second end. Further, in this embodiment, the first and second ring supports are coupled to each other in such a way as to allow folding the first and second rings with respect to each other, thus, capable of forming a wedge. The second deployable wedge antenna may further comprise a prop formed of a semi-rigid or rigid, nonconductive material and attached to the second wedge antenna in the second wedge antenna's deployed state to aid in sustaining the wedge. In still another embodiment, the elements described above remain the same with the exception that the feed probe is a loop-type feed (not shown). Specifically, the feed probe passes through the second boundary component, loops back and is electrically connected to the second boundary component on the feed probe's first end. In yet another embodiment, the elements and alternative embodiments as described above remain the same with the exception that there is one boundary component comprised of one collapsible membrane formed of a flexible, conductive material (not shown). In this embodiment the first and second ring supports are both attached to the single boundary component and do not come in physical contact with each other. Further, the first and second ring supports are both attached in such a way as to allow folding the first and second ring supports with respect to each other, thus capable of forming a wedge. The feed probe is electrically connected to the boundary component inside the perimeter of the first ring support on the feed probe's first end, wherein the feed probe passes through the perimeter of the second ring support and is attached to an antenna interface adapter on the feed probe's second end. Alternatively, the feed probe may be a loop-type feed wherein the feed probe passes through the boundary component inside the perimeter of the second ring support, loops back and is electrically connected to the boundary component inside the perimeter of the second ring support. In all the embodiments described above, two side boundary components, formed of a flexible, conductive material, may be electrically connected to the wedge antenna in such a manner as to further increase the directivity of the antenna or to alter the input impedance characteristics of the antenna in its deployed state. For example, if first and second boundary components are used, the side boundary components may be electrically connected to the first and second boundary components. In this manner, the deployable antenna may resemble, in its fully deployed state, a conventional horn antenna in appearance and function.
In another embodiment illustrated in
In still another embodiment of a deployable antenna, wherein the collapsible membrane also serves as a canopy for an umbrella as described above, at least one radiating element is attached to a collapsible membrane that provides the umbrella canopy (not shown). In an embodiment, the at least one radiating element is attached to a nonconductive collapsible membrane that provides the umbrella canopy, wherein the at least one radiating element is printed or etched from metal attached to a thin laminate material (not shown). In another embodiment, the at least one radiating element is attached to a conductive collapsible membrane that provides the umbrella canopy, wherein the at least one radiating element is formed of patterns of conductive fabric attached to a nonconductive fabric (not shown). In an embodiment, the at least one radiating element is a plurality of radiating wire elements attached to the collapsible membrane and arranged in a circular array (not shown). In this embodiment, a dipole may be centered at the umbrella center, or it may be offset. In the case wherein the dipole is centered at the umbrella center, opposite arms of the dipole are diametrically opposed on the umbrella canopy and a feed comes up through the center of the umbrella, along an umbrella's handle, or inside the umbrella's handle (not shown). In a second embodiment, the at least one radiating element is a plurality of radiating bow-tie dipole elements attached to the collapsible membrane and arranged in a circular array (not shown). In a third embodiment, the at least one radiating element is a plurality of radiating elements arranged in at least one “V” shape as is known in the art (not shown). In a fourth embodiment, the at least one radiating element is a plurality of radiating elements arranged in at least one “volcano” shape as is known in the art (not shown). In this embodiment, the collapsible membrane may be a plurality of layers comprising at least one layer of conductive material and at least one layer of nonconductive material. Further, in this embodiment, a slot may be cut out of the at least one layer of conductive material wherein the slot corresponds with the open area of the “volcano” shape (not shown). In an embodiment, the multiple embodiments described above further comprises a distribution network that provides power to the plurality of radiating elements, cross-members that support the collapsible membrane, or both and at least one transmission line electrically connected to the plurality of radiating elements and the distribution network (not shown). In another embodiment, the multiple embodiments described above may further comprise a weatherproof layer of nonconductive material wherein the at least one radiating element is contained between the weatherproof layer and the collapsible membrane (not shown). In the multiple embodiments described above wherein a plurality of radiating elements are arranged in a circular array, the plurality of radiating elements are excited with a sequential phasing so as to construct a radiation pattern that is circularly polarized.
In another embodiment (not shown) a deployable antenna is comprised of a collapsible membrane, a plurality of subarrays attached to the membrane in a rectilinear pattern, a plurality of transmission lines attached to the subarrays on one end of the transmission lines, and a distribution network comprised of a power divider attached to the plurality of transmission lines on the second end of the transmission lines. A sewn-in wire ring of spring-like material supports the membrane. The membrane is formed of a flexible, nonconductive fabric and collapses in a like method as illustrated in
In still another embodiment (not shown), a deployable antenna is comprised of a collapsible membrane wherein the collapsible membrane is formed of a nonconductive material; at least one radiating element of the cavity antenna element-type comprised of at least one top boundary component formed of a conductive material attached to the collapsible membrane; a ring support attached to the perimeter of the collapsible membrane wherein the ring support is formed of a spring-like material; a ground plane boundary component attached to the ring support at the perimeter of the ground plane boundary component wherein the ground plane boundary component is formed of a conductive material, a collapsible dielectric spacer contained between the collapsible membrane and ground plane boundary component wherein the collapsible dielectric spacer is formed of a material with a relative dielectric constant greater than or equal to 1; at least one probe feed electrically connected to the at least one top boundary component, extending through the collapsible membrane, collapsible dielectric spacer, and ground plane boundary component, wherein the at least one probe feed is not electrically connected to the ground plane boundary component, and wherein the at least one probe feed is formed of a conductive material; and an antenna interface adapter electrically connected to the at least one probe feed. In an embodiment, the ring support is formed of a conductive, spring-like material. In a second embodiment, the ring support is formed of a nonconductive spring-like material. In an embodiment, the deployable antenna is further comprised of at least one insulating grommet attached to the ground plane boundary component wherein the at least one probe feed extends through the at least one insulating grommet such that the at least one insulating grommet ensures the at least one probe feed is not electrically connected to the ground plane boundary component. In an embodiment, the at least one top boundary component is attached to the top side of the collapsible membrane wherein the top side is the side exposed to the environment. In a second embodiment, the at least one top boundary component is attached to the bottom side of the collapsible membrane wherein the bottom side is the side not exposed to the environment. In an embodiment, the at least one top boundary component is attached to the collapsible membrane and the collapsible membrane is attached to the ground plane boundary component by a nonconductive thread in a stitching fashion. In a second embodiment, nonconductive thread is stitched through the collapsible membrane, collapsible dielectric spacer, and ground plane boundary component to prevent unwanted movement of the collapsible dielectric spacer and help maintain a constant thickness. In an embodiment, the at least one top boundary component is an annular ring. In a second embodiment, the at least one top boundary component is an array. In an embodiment, the deployable antenna further comprises a distribution network attached to the at least one top boundary component and electrically connected to the at least one probe feed wherein the at least one probe feed is one probe feed. In another embodiment, the collapsible dielectric spacer is comprised of a first and second spacer layer and the deployable antenna further comprises a capacitive feed formed of a conductive fabric contained between the first and second spacer layer and wherein the at least one feed probe is electrically connected to the capacitive feed. In yet another embodiment, all elements and combination of elements described above remain the same with the following exceptions: the collapsible membrane is formed of a conductive fabric, the at least one top boundary component is comprised of at least one radiating slot cut out of the collapsible membrane, and the at least one probe feed is electrically connected to the collapsible membrane.
Multiple methods exist for operating a deployable antenna. For example, a method of operating a deployable antenna in combination with a mobile communication system may comprise the following steps in no particular order. Attach at least one radiating element, parasitic element, subarray, or radiating means to a collapsible membrane to form the deployable antenna. Attach at least one transmission line to the collapsible membrane and electrically connect each transmission line to each radiating element, subarray, or radiating means on one end of each transmission line. Attach at least one distribution network to the collapsible membrane and electrically connect each distribution network to at least one transmission line on the at least one transmission line's second end. Attach the antenna interface adapter to the other end of the distribution network. Collapse the deployable antenna in a reduced volume configuration. Stow the deployable antenna in its reduced volume configuration. Unstow the deployable antenna in its reduced volume configuration. Expand the deployable antenna to fully deployed configuration. Electrically connect the antenna interface adapter of the deployable antenna to the mobile communications system. Position and orient the deployable antenna to maximize the received signal strength, or point the boresight of the deployable antenna towards a known relay station or communication hub.
While the invention has been described with particular embodiments, it will be understood by those skilled in the art that various changes may be made and equivalent elements may be substituted for elements thereof with departing from the scope of the invention. In addition, modifications may be made to adapt a particular situation to the teachings of the present invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to any particular embodiment disclosed as the best mode contemplated for carrying out the invention, but that the invention will include all embodiments falling within the scope of claims.
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Number | Date | Country |
---|---|---|
WO 0180362 | Oct 2001 | WO |