ERECTABLE SPACE ANTENNA
United States Patent 3707720
An umbrella type antenna for delivery and use in space which includes an elongated tube and a cellular panel extending substantially radially of one end of the tube; the panel having support means for holding the panel in a collapsed or closed position during the delivery phase to a desired location and for maintaining the panel radially in an open, position during use, the support means also including a number of support ribs that are pivotally mounted at spaced intervals circumferentially of the tube and at one end thereof; the panel being composed of a plurality of expandable adjacent honeycomb-like cells which cells are disposed in closed condition when the panel is disposed in a closed position on the tube, the cells being disposed in open condition with the panel extending substantially radially outwardly from the tube in the open position, the honeycomb-like cells being formed of interconnected sheets of material which are preliminarily assembled with the cells in the opened positions and the sheets being in tension in the cell-closed condition when the panel is disposed in the closed position whereby the tension sustained in the interconnected sheets forming the closed cells if unrestrained, will cause the panel and ribs to expand from the closed position to the open position, means for releasably holding the ribs and panel in the closed position, each cell containing means for reflecting electromagnetic waves to a focus point on the tubular member, electromagnetic wave-receiving means on the tubular member at the focus point, the whole being coordinated so that the tension-sustained sheets forming the closed cells cause the panel and ribs to expand from the closed position to the open position upon release of the means for holding the ribs and panel in the closed position.
US Patent References:
Buoy supported collapsible radar reflector
Golian et al. - December 1950 - 2534710
Collapsible parasol-like reflector utilizing flexible honeycomb shell
Kelly - November 1966 - 3286270
Buoy supported collapsible radar reflector
Golian et al. - December 1950 - 2534710
Collapsible parasol-like reflector utilizing flexible honeycomb shell
Kelly - November 1966 - 3286270
Inventors:
Staehlin, John H. (Baltimore, MD)
Hacker, Philip S. (Silver Spring, MD)
Hacker, Philip S. (Silver Spring, MD)
Application Number:
05/077552
Publication Date:
12/26/1972
Filing Date:
10/02/1970
View Patent Images:
Export Citation:
Assignee:
Westinghouse Electric Corporation (Pittsburgh, PA)
Primary Class:
Other Classes:
343/915, 343/840, 343/897
International Classes:
H01Q15/16; H01Q15/14
Field of Search:
343/708,DIG.2,753,754,755,840,897,912,915
Primary Examiner:
Lieberman, Eli
Claims:
What is claimed is
1. An erectable space antenna comprising a tubular member, a plurality of radially extendable arms pivotally mounted on the tubular member at spaced intervals for movement from a collapsed position to an expanded position, the arms being substantially parallel to the tubular member when in the collapsed position and extending radially outwardly from the member when in the expanded position, an expandable cellular panel extending between and supported by the arms, the panel being composed of interconnected sheets of material forming a plurality of adjacent honeycomb-like cells, the cells being disposed in closed condition with the panel forming a tubular structure around the tubular member when the arms are in the collapsed position, the cells being disposed in open condition with the panel extending substantially radially outwardly from the tubular member when the arms are in expanded position, means for releasably holding the arms and panel in the collapsed position, means for reinforcing the panel in the expanded position, the interconnected sheets of material forming the honeycomb cells being preliminarily assembled with the cells in the open position and the sheets being sustained in tension with the cells closed when the panel is in the collapsed position, means in the cells for reflecting electromagnetic waves to a focus point on the tubular member, electromagnetic wave-receiving means on the tubular member at the focus point, the tension sustained sheets forming the collapsed cells cause the panel and arms to expand from the collapsed position to the expanded position upon release of the means for releasably holding the arms and panel in the collapsed position.
2. The antenna of claim 1 wherein the panel comprises top and bottom sides that are substantially perpendicular to the axis of the tubular member when in the expanded position, and the interconnected sheets forming the cells are disposed in planes that are substantially perpendicular to the top and bottom sides.
3. The antenna of claim 1 wherein the interconnected sheets forming the cells are composed of metal and the contacting cell sides of adjacent sheets are welded together.
4. The antenna of claim 1 wherein the electromagnetic wave-reflecting means in the cells are metallic strips or wire extending across the open cells.
5. The antenna of claim 4 wherein the metallic strips or wires in the cells are progressively grouped in wavelength bands wherein the strips radially nearer the tubular member are spaced longitudinally farther away from the focus point than are the strips in the cells radially father away from the tubular member.
6. The antenna of claim 1 wherein the radially extending arms are pivotally mounted on the tubular member at a location that is longitudinally spaced from the focus point, and the antenna reinforcing means include a guy wire extending from the tubular member to the extremity of each arm in the expanded position.
7. The antenna of claim 1 wherein the antenna reinforcing means include an extension of the tubular member which extension is telescopically disposed within the member in the collapsed position and is extended therefrom on the side of the panel remote from the focus point in the expanded position, and include a guy wire extending from the extremity of the tubular member extension to the extremity of each arm.
8. The antenna of claim 6 wherein the reinforcing means include a tubular member extension that is telescopically disposed in the member and is movable from a collapsed position within the member to an extended position of the member when the panel is expanded, and include a guy wire extending from the tubular member to the extremity of each arm in the expanded position and to the extremity of the extension.
1. An erectable space antenna comprising a tubular member, a plurality of radially extendable arms pivotally mounted on the tubular member at spaced intervals for movement from a collapsed position to an expanded position, the arms being substantially parallel to the tubular member when in the collapsed position and extending radially outwardly from the member when in the expanded position, an expandable cellular panel extending between and supported by the arms, the panel being composed of interconnected sheets of material forming a plurality of adjacent honeycomb-like cells, the cells being disposed in closed condition with the panel forming a tubular structure around the tubular member when the arms are in the collapsed position, the cells being disposed in open condition with the panel extending substantially radially outwardly from the tubular member when the arms are in expanded position, means for releasably holding the arms and panel in the collapsed position, means for reinforcing the panel in the expanded position, the interconnected sheets of material forming the honeycomb cells being preliminarily assembled with the cells in the open position and the sheets being sustained in tension with the cells closed when the panel is in the collapsed position, means in the cells for reflecting electromagnetic waves to a focus point on the tubular member, electromagnetic wave-receiving means on the tubular member at the focus point, the tension sustained sheets forming the collapsed cells cause the panel and arms to expand from the collapsed position to the expanded position upon release of the means for releasably holding the arms and panel in the collapsed position.
2. The antenna of claim 1 wherein the panel comprises top and bottom sides that are substantially perpendicular to the axis of the tubular member when in the expanded position, and the interconnected sheets forming the cells are disposed in planes that are substantially perpendicular to the top and bottom sides.
3. The antenna of claim 1 wherein the interconnected sheets forming the cells are composed of metal and the contacting cell sides of adjacent sheets are welded together.
4. The antenna of claim 1 wherein the electromagnetic wave-reflecting means in the cells are metallic strips or wire extending across the open cells.
5. The antenna of claim 4 wherein the metallic strips or wires in the cells are progressively grouped in wavelength bands wherein the strips radially nearer the tubular member are spaced longitudinally farther away from the focus point than are the strips in the cells radially father away from the tubular member.
6. The antenna of claim 1 wherein the radially extending arms are pivotally mounted on the tubular member at a location that is longitudinally spaced from the focus point, and the antenna reinforcing means include a guy wire extending from the tubular member to the extremity of each arm in the expanded position.
7. The antenna of claim 1 wherein the antenna reinforcing means include an extension of the tubular member which extension is telescopically disposed within the member in the collapsed position and is extended therefrom on the side of the panel remote from the focus point in the expanded position, and include a guy wire extending from the extremity of the tubular member extension to the extremity of each arm.
8. The antenna of claim 6 wherein the reinforcing means include a tubular member extension that is telescopically disposed in the member and is movable from a collapsed position within the member to an extended position of the member when the panel is expanded, and include a guy wire extending from the tubular member to the extremity of each arm in the expanded position and to the extremity of the extension.
Description:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a space antenna that is deliverable to a desired location in space and that is self-openable upon suitable triggering to an open position at such location. More particularly, the invention pertains to an umbrella type antenna comprising a large area honeycomb cell structure.
2. Description of the Prior Art
With increased interest in outer space operations and developments a concomitant need for a space antenna has occurred. In particular there is a need for a large reflector having a diameter of at least 100 feet, and a feed assembly in the vicinity of a planet. A reflector with such a large diameter would be extremely useful in picking up electromagnetic signals from a planet or from other distant places. However, an antenna having a reflector that large would be extremely difficult to send by currently known vehicles, i.e., missiles launched from earth.
Various types of antenna have been proposed for such use and have been negated for numerous reasons. Suffice it to say a need has arisen for a space antenna which is deliverable in space to to the desired location in a collapsed position and which is self-erectable to an expanded position when it arrives at the desired location. Such an antenna satisfies the basic pre-requisite of relatively lightweight and stability.
SUMMARY OF THE INVENTION
In accordance with this invention it has been found that the foregoing difficulties may be overcome by providing an umbrella type antenna which is self-openable from a collapsed to an expanded position which antenna includes an elongated tube and a cellular panel, the panel being mounted on support ribs which are pivotally attached at spaced intervals around one end of the tube, the ribs being disposed in position substantially parallel to the tube during the delivery phase of the antenna with the panel disposed in a collapsed tubular position around the tube, the ribs extending radially outwardly from the tube in the expanded position with the panel disposed substantially radially outwardly from the tube, and the panel being composed of interconnected sheets of material forming a plurality of adjacent honeycomb-like cells, the cells being disposed in closed conditions with the panel forming a tubular structure around the tube when the ribs are in the collapsed position, the cells being disposed in open conditions with the panel extending substantially radially outwardly from the tube when the ribs are in the expanded positions, means for releasably holding the ribs and panel in the collapsed positions, means for reenforcing the antenna in the expanded position, the interconnected sheets of material forming the honeycomb-cells being preliminarily assembled with the cells in the open positions in the sheets being sustained in tension with the cells closed when the panel is a tubular structure in the collapsed position, means in the cells for reflecting electromagnetic waves to a focus point on the tube, and electromagnetic wave-receiving means on the tube at the focused point.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the antenna in the closed position;
FIG. 2 is a perspective view of the antenna in a partially opened position;
FIG. 3 is a perspective view of the antenna in a nearly completed opened position;
FIG. 4 is a perspective view of the antenna in the completely opened position;
FIG. 5 is a vertical sectional view through the antenna in the closed position;
FIG. 6 is a sectional view through the antenna in the completely open position;
FIG. 7 is an enlarged vertical sectional view through the antenna; and
FIG. 8 is a horizontal sectional view taken on the line VIII--VIII of FIG. 7.
DESCRIPTION OF THE PREFERRED EMBODIMENT
An erectable space antenna of the present invention is generally indicated at 10 in FIGS. 1 to 4. As shown more particularly in the completely open position of FIG. 4, the antenna 10 includes a tubular member 12, a plurality of radially extending arms or ribs 14, a flexibly expandable cellular panel or grating 16, and means 18 (FIG. 1) such as a band for holding the antenna in the closed position.
In addition the antenna includes means for reinforcing the antenna in the fully expanded position and means for receiving electromagnetic wave signals.
The tubular member 12 is shown more particularly in FIG. 5. It is the main support member of the antenna and one end of the member 12 is closed by an end plate or disk 20 having a diameter greater than that of the member and providing a peripheral edge portion 22 around the member 12. A plurality of spaced openings 24, equal to the number of ribs 14 are provided in the tubular member 12 in the end portion near the disk 20. The openings 24 receive dielectric guide wires or cords 26, one for each opening, which wires are part of the means for reinforcing the antenna as set forth hereinbelow.
The lower end of the tubular member 12 is open. In the embodiment of the antenna shown an extension 28 is telescopically disposed within the lower end portion of the tubular member 12 when the antenna is in the closed position as shown in FIG. 5. The extension 28 is slidable longitudinally and outwardly of the open end of the member 12 to a position substantially shown in FIG. 6 in the open position in a manner to be described hereinbelow. The lower ends of the guide wires 26 are secured at 30 to spaced locations about the periphery of the lower end of the extension 28.
The arms 14 are disposed at radially spaced intervals about the tubular member 12 and in the closed condition of the antenna as shown in FIG. 5 the arms are disposed in positions substantially parallel to the axis of the tubular member 12. The lower end of each arm 14 is pivotally mounted at 32 to the outer end of an arm portion 34 which portion extends substantially radially outwardly from the member 12. Each arm portion 34 is secured in any suitable manner such as a weld 36 to the member 12 at a location substantially at or near the lower end of the member. All of the arm portions 34 are aligned in the same radial zone.
The panel 16 is disposed between the spaced arms 14 and is supported thereby in the closed position of FIG. 5 as well as the opened or expanded position of FIG. 6. In FIG. 5, the panel 16 is disposed in a circular cylindrical configuration the axis of which is substantially that of the axis of the tubular member 12. The panel is coextensive with the arms 14 as well as the arm portions 34. In FIG. 6, where the antenna is in the opened position the panel is disposed radially outwardly of the tubular member 12 and coextensive with the arms 14.
The flexibly expandable cellular panel 16 is of a grid or grating configuration composed of intersecting sheets of material forming a plurality of adjacent honeycomb-like cells 38 (FIG. 8) preferably of hexagonal cross section. The material of which the sheets forming the walls of the cells 38 are composed is preferably a metal film such, for example, as aluminum, beryllium, or copper or alloys thereof such as 1 percent beryllium copper alloy. At the inner sections of the sheets forming the walls of the cell the sheets are welded together (along the corners of the cell walls) with the panel in the open position. The panel 16 is then placed on and attached to the several arms 14 in any suitable manner such as by welding. The arms 14 of the antenna are then moved from the open positions of FIG. 6 to the closed position of FIG. 5, whereby the open cells 38 are collapsed to closed conditions with the sheets forming the walls in surface to surface contact. In the closed position of the panel as shown in FIG. 5 the panel is compressed against the restraining tension of the band 18. The panel is readily collapsed because the thin sheets are welded together to form the honeycomb cells 38 in the open condition. Compression of the cells to the closed position creates a tension in each cell which will cause the antenna to open from the closed position of FIG. 5 to the open position of FIG. 6 upon release of the restraining means or band 18.
The band 18 extends circumferentially around the collapsed antenna as shown in FIGS. 1 and 5. Thus, the band 18 circumscribe the outer surfaces of the collapsed antenna including the several guide wires 26. The band 18 includes a release means 40, such as an explosive charge which is operative or triggered by an appropriate radio signal to a suitable electronic receiver and electric spark or firing means (not shown). Release of the band 18 causes the closed antenna to open because of the built in inertia or memory of the collapsed cells in the panel 16.
As shown in FIG. 1 the antenna 10 in the collapsed position includes an outer housing of longitudinally extending metal housing sections 42. As shown more particularly in FIG. 2 housing sections 42 are disposed on each side of each arm 14 so that as the antenna opens the sections 42 on adjacent arms 14 separate, thereby exposing the expanding portions of the honeycomb panel 16.
As shown in FIG. 5 the guide wires 26 extend from the interior of the tubular member 12 over and around the upper ends of the arm 14, downwardly along the arms to the lower ends thereof and then to the secured at the spaced locations 30 at the lower end of the extension 28. The guide wires 26 as well as the extension 28 serve to guide and reinforce the arms 14 as they expand to the fully deployed or open position of FIGS. 4 and 6. For that purpose the ends of the guide wires 26 are payed out of the member 12 through the apertures 24 where the inner ends of the guide wires are loosely contained in a suitable manner such as a container for preventing the wire ends from extending to positions too remote from the openings 24. At the same time the extension 28 is released and it continues to move out of the member 12 until the panel 16 is in the fully opened position in which position a portion of the extension 28 is retained within the open end of the member 12 and the guide wires, having enlarged inner end portions are retained tautly in place as shown in FIG. 6.
The reinforcing means of the antenna also includes a brace for each arm 14 including a link 44 and a collar 46. Each link 44 is pivotally mounted at 48 to a corresponding arm 16. The opposite end of each link is pivotally mounted at 50 to the collar 46. Accordingly, as the antenna opens the collar 46 slides downwardly along the member 12, offering a minimum resistance to the inertial forces causing the panel 16 to open to the fully open position.
The reinforcing means of the antenna may also include a plurality of cords or wires 51 that extend radially from the lower end of the member 12 (FIG. 4) to a chordal cord or wire 53 extending between the outer ends of the ribs 14.
In its fully open position the panel 16 provides a continuous reflecting surface of the honeycomb cells 38 which are disposed in a substantially flat zone perpendicular to the axis of the member 12. The cells 38 are used as waveguides and are terminated at the proper depth by means for reflecting electromagnetic waves such as a pair of radiation reflecting wires or strips 52 and 54 of metal which are preferably crossed to reflect incoming microwaves of an electromagnetic field to a focus point, namely the disk 20 at the upper end of the member 12. The reflected waves are in turn sent to a receiver 56 disposed within the member 12 or within the extension 28 as shown in FIG. 7. More particularly, the vertical position of the crossed wires 52 and 54 within each cell 38 is dependent upon the radial distance of the cell from the axis of the tubular member 12.
In order to reflect an outer portion 58 of an electromagnetic wave to the disk 20 the crossed wires or strips 52 and 54 in the outermost cells 38 are disposed in a higher position than are corresponding crossed wires 52 and 54 in another cell 38a which is radially closer to the axis of the member 12. Accordingly, another portion 58a of the same electromagnetic wave extends further into the cell 38a before it is reflected by corresponding crossed wires 52 and 54a to the disk 20. Correspondingly, for cells 38 intermediate of the cells 38 and 38a the crossed wires 52 and 54 are disposed at correspondingly intermediate positions for the outermost cells 38 and the innermost cells 38a. In short, the wires 52 and 54 are progressively spaced higher with the radial distance from the center until a one wavelength path adjustment has been effected. At that point the wire positions return to the original location and again are spaced higher with radial position for each wavelength path or band. When the cells 38 are in the closed position the crossed wires 52 and 54, being substantially ribbon-like members, collapse and fold in conformity with and between the walls of the collapsed cell. Thus, the electrical depth of the cells 38 is electronically controlled in depthwise fashion. Such control might be desirable if any extensive damage or failure of the erecting structure is deemed likely. This circumstance can be met by installing a set of diodes in place of the crossed wires 52 and 54 at the termination of each cell. The diodes would give the cell one electrical depth when energized and another when not energized.
Thus, the honeycomb reflector or panel 16 is fabricated of very thin metal plates or films that are welded together to form a continuous cellular structure. The antenna is self-erecting and forms an inherently stable structure. For operation in the "S" band of the electromagnetic spectrum, a 250 foot diameter reflector fabricated of aluminum sheet of 0.001 inch, the antenna would weigh approximately 1,000 pounds. In other words, an antenna designed with such a reflector panel has a weight that is sufficiently below the maximum pay load of some of the rockets that are presently available for delivery of the antenna at the antenna at the desired location.
Accordingly, the self-erecting antenna for space applications is provided which may incorporate a launch vehicle structure as a detachable part of the antenna and in the expanded or fully deployed position a planar reflector panel is formed from sections of honeycomb cells as the radiating surface.
It is understood that the above specification and drawings are merely exemplary and not in limitation of the invention.
1. Field of the Invention
This invention relates to a space antenna that is deliverable to a desired location in space and that is self-openable upon suitable triggering to an open position at such location. More particularly, the invention pertains to an umbrella type antenna comprising a large area honeycomb cell structure.
2. Description of the Prior Art
With increased interest in outer space operations and developments a concomitant need for a space antenna has occurred. In particular there is a need for a large reflector having a diameter of at least 100 feet, and a feed assembly in the vicinity of a planet. A reflector with such a large diameter would be extremely useful in picking up electromagnetic signals from a planet or from other distant places. However, an antenna having a reflector that large would be extremely difficult to send by currently known vehicles, i.e., missiles launched from earth.
Various types of antenna have been proposed for such use and have been negated for numerous reasons. Suffice it to say a need has arisen for a space antenna which is deliverable in space to to the desired location in a collapsed position and which is self-erectable to an expanded position when it arrives at the desired location. Such an antenna satisfies the basic pre-requisite of relatively lightweight and stability.
SUMMARY OF THE INVENTION
In accordance with this invention it has been found that the foregoing difficulties may be overcome by providing an umbrella type antenna which is self-openable from a collapsed to an expanded position which antenna includes an elongated tube and a cellular panel, the panel being mounted on support ribs which are pivotally attached at spaced intervals around one end of the tube, the ribs being disposed in position substantially parallel to the tube during the delivery phase of the antenna with the panel disposed in a collapsed tubular position around the tube, the ribs extending radially outwardly from the tube in the expanded position with the panel disposed substantially radially outwardly from the tube, and the panel being composed of interconnected sheets of material forming a plurality of adjacent honeycomb-like cells, the cells being disposed in closed conditions with the panel forming a tubular structure around the tube when the ribs are in the collapsed position, the cells being disposed in open conditions with the panel extending substantially radially outwardly from the tube when the ribs are in the expanded positions, means for releasably holding the ribs and panel in the collapsed positions, means for reenforcing the antenna in the expanded position, the interconnected sheets of material forming the honeycomb-cells being preliminarily assembled with the cells in the open positions in the sheets being sustained in tension with the cells closed when the panel is a tubular structure in the collapsed position, means in the cells for reflecting electromagnetic waves to a focus point on the tube, and electromagnetic wave-receiving means on the tube at the focused point.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the antenna in the closed position;
FIG. 2 is a perspective view of the antenna in a partially opened position;
FIG. 3 is a perspective view of the antenna in a nearly completed opened position;
FIG. 4 is a perspective view of the antenna in the completely opened position;
FIG. 5 is a vertical sectional view through the antenna in the closed position;
FIG. 6 is a sectional view through the antenna in the completely open position;
FIG. 7 is an enlarged vertical sectional view through the antenna; and
FIG. 8 is a horizontal sectional view taken on the line VIII--VIII of FIG. 7.
DESCRIPTION OF THE PREFERRED EMBODIMENT
An erectable space antenna of the present invention is generally indicated at 10 in FIGS. 1 to 4. As shown more particularly in the completely open position of FIG. 4, the antenna 10 includes a tubular member 12, a plurality of radially extending arms or ribs 14, a flexibly expandable cellular panel or grating 16, and means 18 (FIG. 1) such as a band for holding the antenna in the closed position.
In addition the antenna includes means for reinforcing the antenna in the fully expanded position and means for receiving electromagnetic wave signals.
The tubular member 12 is shown more particularly in FIG. 5. It is the main support member of the antenna and one end of the member 12 is closed by an end plate or disk 20 having a diameter greater than that of the member and providing a peripheral edge portion 22 around the member 12. A plurality of spaced openings 24, equal to the number of ribs 14 are provided in the tubular member 12 in the end portion near the disk 20. The openings 24 receive dielectric guide wires or cords 26, one for each opening, which wires are part of the means for reinforcing the antenna as set forth hereinbelow.
The lower end of the tubular member 12 is open. In the embodiment of the antenna shown an extension 28 is telescopically disposed within the lower end portion of the tubular member 12 when the antenna is in the closed position as shown in FIG. 5. The extension 28 is slidable longitudinally and outwardly of the open end of the member 12 to a position substantially shown in FIG. 6 in the open position in a manner to be described hereinbelow. The lower ends of the guide wires 26 are secured at 30 to spaced locations about the periphery of the lower end of the extension 28.
The arms 14 are disposed at radially spaced intervals about the tubular member 12 and in the closed condition of the antenna as shown in FIG. 5 the arms are disposed in positions substantially parallel to the axis of the tubular member 12. The lower end of each arm 14 is pivotally mounted at 32 to the outer end of an arm portion 34 which portion extends substantially radially outwardly from the member 12. Each arm portion 34 is secured in any suitable manner such as a weld 36 to the member 12 at a location substantially at or near the lower end of the member. All of the arm portions 34 are aligned in the same radial zone.
The panel 16 is disposed between the spaced arms 14 and is supported thereby in the closed position of FIG. 5 as well as the opened or expanded position of FIG. 6. In FIG. 5, the panel 16 is disposed in a circular cylindrical configuration the axis of which is substantially that of the axis of the tubular member 12. The panel is coextensive with the arms 14 as well as the arm portions 34. In FIG. 6, where the antenna is in the opened position the panel is disposed radially outwardly of the tubular member 12 and coextensive with the arms 14.
The flexibly expandable cellular panel 16 is of a grid or grating configuration composed of intersecting sheets of material forming a plurality of adjacent honeycomb-like cells 38 (FIG. 8) preferably of hexagonal cross section. The material of which the sheets forming the walls of the cells 38 are composed is preferably a metal film such, for example, as aluminum, beryllium, or copper or alloys thereof such as 1 percent beryllium copper alloy. At the inner sections of the sheets forming the walls of the cell the sheets are welded together (along the corners of the cell walls) with the panel in the open position. The panel 16 is then placed on and attached to the several arms 14 in any suitable manner such as by welding. The arms 14 of the antenna are then moved from the open positions of FIG. 6 to the closed position of FIG. 5, whereby the open cells 38 are collapsed to closed conditions with the sheets forming the walls in surface to surface contact. In the closed position of the panel as shown in FIG. 5 the panel is compressed against the restraining tension of the band 18. The panel is readily collapsed because the thin sheets are welded together to form the honeycomb cells 38 in the open condition. Compression of the cells to the closed position creates a tension in each cell which will cause the antenna to open from the closed position of FIG. 5 to the open position of FIG. 6 upon release of the restraining means or band 18.
The band 18 extends circumferentially around the collapsed antenna as shown in FIGS. 1 and 5. Thus, the band 18 circumscribe the outer surfaces of the collapsed antenna including the several guide wires 26. The band 18 includes a release means 40, such as an explosive charge which is operative or triggered by an appropriate radio signal to a suitable electronic receiver and electric spark or firing means (not shown). Release of the band 18 causes the closed antenna to open because of the built in inertia or memory of the collapsed cells in the panel 16.
As shown in FIG. 1 the antenna 10 in the collapsed position includes an outer housing of longitudinally extending metal housing sections 42. As shown more particularly in FIG. 2 housing sections 42 are disposed on each side of each arm 14 so that as the antenna opens the sections 42 on adjacent arms 14 separate, thereby exposing the expanding portions of the honeycomb panel 16.
As shown in FIG. 5 the guide wires 26 extend from the interior of the tubular member 12 over and around the upper ends of the arm 14, downwardly along the arms to the lower ends thereof and then to the secured at the spaced locations 30 at the lower end of the extension 28. The guide wires 26 as well as the extension 28 serve to guide and reinforce the arms 14 as they expand to the fully deployed or open position of FIGS. 4 and 6. For that purpose the ends of the guide wires 26 are payed out of the member 12 through the apertures 24 where the inner ends of the guide wires are loosely contained in a suitable manner such as a container for preventing the wire ends from extending to positions too remote from the openings 24. At the same time the extension 28 is released and it continues to move out of the member 12 until the panel 16 is in the fully opened position in which position a portion of the extension 28 is retained within the open end of the member 12 and the guide wires, having enlarged inner end portions are retained tautly in place as shown in FIG. 6.
The reinforcing means of the antenna also includes a brace for each arm 14 including a link 44 and a collar 46. Each link 44 is pivotally mounted at 48 to a corresponding arm 16. The opposite end of each link is pivotally mounted at 50 to the collar 46. Accordingly, as the antenna opens the collar 46 slides downwardly along the member 12, offering a minimum resistance to the inertial forces causing the panel 16 to open to the fully open position.
The reinforcing means of the antenna may also include a plurality of cords or wires 51 that extend radially from the lower end of the member 12 (FIG. 4) to a chordal cord or wire 53 extending between the outer ends of the ribs 14.
In its fully open position the panel 16 provides a continuous reflecting surface of the honeycomb cells 38 which are disposed in a substantially flat zone perpendicular to the axis of the member 12. The cells 38 are used as waveguides and are terminated at the proper depth by means for reflecting electromagnetic waves such as a pair of radiation reflecting wires or strips 52 and 54 of metal which are preferably crossed to reflect incoming microwaves of an electromagnetic field to a focus point, namely the disk 20 at the upper end of the member 12. The reflected waves are in turn sent to a receiver 56 disposed within the member 12 or within the extension 28 as shown in FIG. 7. More particularly, the vertical position of the crossed wires 52 and 54 within each cell 38 is dependent upon the radial distance of the cell from the axis of the tubular member 12.
In order to reflect an outer portion 58 of an electromagnetic wave to the disk 20 the crossed wires or strips 52 and 54 in the outermost cells 38 are disposed in a higher position than are corresponding crossed wires 52 and 54 in another cell 38a which is radially closer to the axis of the member 12. Accordingly, another portion 58a of the same electromagnetic wave extends further into the cell 38a before it is reflected by corresponding crossed wires 52 and 54a to the disk 20. Correspondingly, for cells 38 intermediate of the cells 38 and 38a the crossed wires 52 and 54 are disposed at correspondingly intermediate positions for the outermost cells 38 and the innermost cells 38a. In short, the wires 52 and 54 are progressively spaced higher with the radial distance from the center until a one wavelength path adjustment has been effected. At that point the wire positions return to the original location and again are spaced higher with radial position for each wavelength path or band. When the cells 38 are in the closed position the crossed wires 52 and 54, being substantially ribbon-like members, collapse and fold in conformity with and between the walls of the collapsed cell. Thus, the electrical depth of the cells 38 is electronically controlled in depthwise fashion. Such control might be desirable if any extensive damage or failure of the erecting structure is deemed likely. This circumstance can be met by installing a set of diodes in place of the crossed wires 52 and 54 at the termination of each cell. The diodes would give the cell one electrical depth when energized and another when not energized.
Thus, the honeycomb reflector or panel 16 is fabricated of very thin metal plates or films that are welded together to form a continuous cellular structure. The antenna is self-erecting and forms an inherently stable structure. For operation in the "S" band of the electromagnetic spectrum, a 250 foot diameter reflector fabricated of aluminum sheet of 0.001 inch, the antenna would weigh approximately 1,000 pounds. In other words, an antenna designed with such a reflector panel has a weight that is sufficiently below the maximum pay load of some of the rockets that are presently available for delivery of the antenna at the antenna at the desired location.
Accordingly, the self-erecting antenna for space applications is provided which may incorporate a launch vehicle structure as a detachable part of the antenna and in the expanded or fully deployed position a planar reflector panel is formed from sections of honeycomb cells as the radiating surface.
It is understood that the above specification and drawings are merely exemplary and not in limitation of the invention.