The present invention relates in general to phasing structures, and more particularly to a deployable phasing structure for reflecting microwaves within an operating frequency band.
In modern antenna and communication systems, reflective surfaces have been designed with specific geometries over specific operating frequency bands. In general, microwave structures include a reflective surface for reflecting microwaves within an operating frequency band. However, conventional antenna systems are not easily transported without significant limitations.
Conventional antenna systems have relied upon separating antenna structures into separate components to facilitate transportation. However, separation of antenna components may lead to loss, damage or separation of antenna components. In addition, packaging and reassembling of antenna components may provide great inconvenience. Further, in situations where time is of the essence (e.g., combat), such limitations in antenna design may cause costly delays, including injury and loss of life.
The use of electromagnetically emulating curved reflective surfaces of any geometry, using a substantially planar microwave reflector antenna configuration, has been suggested. U.S. Pat. No. 4,905,014 issued to Gonzalez et al., Feb. 27, 1990, the contents of which are fully incorporated herein by reference, teaches a phasing structure emulating desired reflective surfaces regardless of the geometry of the physical surfaces to which the electrically thin microwave phasing structure is made to conform. This technology, known as FLAPS (Flat Parabolic Surface), is accomplished by using a dipole antenna placed in front of a ground plane. A low-windload structure has been suggested to provide another version of FLAPS technology. U.S. Pat. No. 6,198,457, issued to Walker et al., Mar. 6 2001, the contents of which are fully incorporated herein by reference, teaches a low-windload phasing structure including FLAPS technology.
However, known FLAPS phasing structures suffer from the same drawbacks of not being easily deployable in situations where time, space or terrain are otherwise limited or restrictive.
Disclosed and claimed herein is an apparatus for a deployable microwave phasing structure. In one embodiment, the deployable phasing structure includes a reflective surface having a first reflective surface geometry. The deployable phasing structure is configured to reflect microwaves within an operating frequency band and to emulate a reflective property of a second reflective surface geometry. According to another embodiment of the invention, the deployable microwave phasing structure includes an interconnect for arranging the phasing structure into a plurality of states. In another embodiment of the invention, the deployable microwave phasing structure includes a phasing arrangement of electromagnetically-loading structures supported by the reflective surface.
Other aspects, features, and techniques of the invention will be apparent to one skilled in the relevant art in view of the following detailed description of the invention.
One aspect of the invention is to provide a deployable phasing structure having a reflective surface configured to reflect microwaves. According to another embodiment, the phasing structure may emulate a desired reflective surface. Curved (e.g., parabolic) reflective surfaces may be emulated by a reflective surface of the deployable phasing structure using Flat Parabolic Surface (FLAPS) technology. As such, the phasing structure may include a plurality of dipole antennas placed in front of a ground plane. According to one embodiment, the deployable phasing structure may comprise a foldable design. As such, deployment of the phasing structure may be facilitated where space, weight, or physical conditions would otherwise prevent such installation or deployment.
According to another aspect of the invention, the phasing structure design may provide expansion of a reflective surface from a planar collapsed state to a deployed state. To that end, the deployed state may be configured as one of a planar and non-planar profile. The phasing structure may include a plurality of sub-panels forming a reflective surface when in the deployed position. Sub-panels of the phasing structure may be inter-connected by a plurality of joints for example, such that a reflective surface of the phasing structure may be placed in any of a deployed state, an intermediate state and a planar collapsed state. According to another embodiment, a plurality of joints may be provided to inter-connect the sub-panels. The phasing structure may also include a support sub-structure for securing the reflective surface in each of the deployed state and planar collapsed state. Further, transportation of the phasing structure may be facilitated by its foldable design.
It may be appreciated that sub-panels of the reflective surface may be detached from each other to replace a defective sub-panel if necessary. Similarly, a joint configured to inter-connect sub-panels of the reflective surface may be separable. In yet another embodiment of the invention, a low windload phasing structure may be provided having a reflective surface providing low resistance to wind.
According to another aspect of the invention, a phasing structure may include an actuator for deployment of the reflective surface. The reflective surface may be configured to deploy from a planar collapsed state to a deployed state from mechanical forces applied by the actuator to the sub-panels, sub-panel joints, or any combination there of. In another embodiment of the invention, the reflective surface may be expanded using one or more of a mechanical actuator, manual expansion of the panels by a user, a hydraulic element, motorized expansion and expansion through motion of the phasing structure.
As used herein, the terms “a” or “an” shall mean one or more than one. The term “plurality” shall mean two or more than two. The term “another” is defined as a second or more. The terms “including” and/or “having” are open ended (e.g., comprising). The term “or” as used herein is to be interpreted as inclusive or meaning any one or any combination. Therefore, “A, B or C” means any of the following: A; B; C; A and B; A and C; B and C; A, B and C. An exception to this definition will occur only when a combination of elements, functions, steps or acts are in some way inherently mutually exclusive.
Reference throughout this document to “one embodiment”, “certain embodiments”, “an embodiment” or similar term means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of such phrases or in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner on one or more embodiments without limitation.
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According to one embodiment of the invention, phasing structure 300 may be provided including a reflective surface, wherein the reflective surface includes a plurality of replaceable sub-panels (i.e., sub-panels 3051 to 305n). It may be appreciated that sub-panels 3051 to 305n of phasing structure 300 may be detached to replace a defective sub-panel if necessary. According to another aspect of the invention, a joint (i.e., joint 310) configured to inter-connect sub-panels of the reflective surface may be separable.
According to another aspect of the invention, phasing structure 300 may be deployed through one or more of a mechanical actuator, manual expansion of the panels by a user, a hydraulic element, motorized expansion and expansion through motion of the phasing structure. When deployed through motion, phasing structure 300 may be manipulated such that components (i.e., sub-panels 3051 to 305n) of phasing structure 300 are unfolded as the phasing structure 300 is manipulated. In one embodiment, gravitational forces acting of the reflective surface may aid in deployment. In a further embodiment of the invention, the reflective surface of the phasing structure 300 may be deployed through expansion of the reflective surface by a user. In one embodiment of the invention, material of the reflective surface may be configured to fold onto itself. One principal advantage of the phasing structure 300 according to one embodiment of the invention, may be that deployment may be achieved with minimal time delay.
According to another aspect of the of the invention, the dimensions, orientation and interspacing of electromagnetically-loading structures within phasing structure 300 may be determined by through one of computer-aided design system, a three-dimensional ray tracing (i.e., path length) model of the microwave phasing surface and the desired reflective surface of selected geometry as disclosed in more detail in previously incorporated U.S. Pat. No. 4,905,014. Metallic layers may be provided on the other side of the dielectric substrate. A composite pattern corresponding to the determined arrangement of electromagnetically-loading structures may be generated. Portions of the metallic layer may be removed, using in the preferred embodiment a photo-etching process, thereby leaving remaining therein the generated composite pattern corresponding to the arrangement of electromagnetically-loading structures.
While certain exemplary embodiments have been described and shown in the accompanying drawings, it is to be understood that such embodiments are merely illustrative of and not restrictive on the broad invention, and that this invention not be limited to the specific constructions and arrangements shown and described, since various other modifications may occur to those ordinarily skilled in the art. Trademarks and copyrights referred to herein are the property of their respective owners.
The present application is related to U.S. patent application Ser. No. ______, entitled A DEPLOYABLE PHASING SYSTEM FOR EMULATING REFLECTIVE SURFACES, filed on even date herewith, assigned to Assignee hereof.