Deployable antenna apparatus with inflatable latching mechanism

Abstract

An AMC antenna device includes a ground plane and a layer of flexible antenna elements over the ground plane. The ground plane includes a conductive base surface, a plurality of flexible conductors, and a frequency selective surface (FSS) layer over the base surface, where the FSS layer includes a plurality of conductive patches separated from one another. Each of the flexible conductors electrically connects one of the conductive patches to the base surface. A latching mechanism is disposed between the base layer and the FSS layer. An inflatable bladder system between the base layer and the FSS layer is configured to receive a gas input and inflate to generate a force sufficient to cause the latching mechanism to transition from an unlocked state to a locked state in which the conductive base surface is fixedly separated from the FSS layer by a predetermined distance during deployment of the antenna device.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Provisional Application No. 63 / 091,909, filed October 14, 2020, with the United States Patent and Trademark Office, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure generally relates to storage and deployment techniques for antennas with a ground plane; and to artificial magnetic conductor (AMC) antennas. Background Technology

[0004] In conventional antennas above a ground plane, the radiating element is spaced a quarter wavelength (λ / 4) from the ground plane to achieve constructive interference of the reflected signal, thereby increasing directivity. However, at relatively low frequencies, the λ / 4 distance may be longer than desired, resulting in a thick antenna profile (e.g., 25 cm at 300 MHz).

[0005] For artificial magnetic conductor (AMC) ground planes, the spacing between the ground plane and the radiating element is significantly smaller, and the antenna can achieve comparable directivity performance. An AMC ground plane can comprise a conductive substrate surface and a "frequency selective surface" (FSS) consisting of multiple conductive patches separated from each other. The conductive patches can be electrically connected to the substrate surface via corresponding wires typically embedded in a low-loss dielectric. While the resulting structure is thinner than conventional ground plane-based antennas, it is rigid and cumbersome to transport, especially for large-aperture antennas configured for frequencies below 1 GHz. Summary of the Invention

[0006] In this disclosure, an artificial magnetic conductor (AMC) antenna device includes a ground plane and a flexible antenna element layer, the flexible antenna element layer including at least one antenna element above the ground plane. The ground plane includes a conductive substrate surface, a plurality of flexible conductors, and a frequency selective surface (FSS) layer above the substrate surface, wherein the FSS layer includes a plurality of conductive patches separated from each other. Each of the flexible conductors electrically connects one of the conductive patches to the substrate surface. A latching mechanism is arranged between the substrate layer and the FSS layer. An inflatable airbag system is disposed between the substrate layer and the FSS layer and configured to receive a gas input and inflate during deployment of the antenna device to generate a force sufficient to transition the latching mechanism from an unlocked state to a locked state, in which the conductive substrate surface is fixedly separated from the FSS layer by a predetermined distance.

[0007] The AMC antenna device may further include a retaining structure configured to hold (i) an antenna element layer, (ii) a ground plane having an FSS layer that tapers toward a substrate surface, and (iii) an inflatable airbag system when the AMC antenna device is retracted. The retaining structure can hold the antenna element layer, the ground plane, and the inflatable airbag system in a rolled-up state.

[0008] The AMC antenna device may further include at least one actuator configured to remove the antenna element layer, ground plane, and inflatable airbag system from the retaining structure.

[0009] On the other hand, a method is provided for deploying an AMC antenna on an unmanned vehicle. The AMC antenna includes: (i) an antenna element layer; and (ii) a ground plane having a conductive substrate surface, an FSS layer, and a plurality of flexible conductors electrically and mechanically coupling the conductive substrate surface to the FSS layer. The method involves, during the deployment of the AMC antenna: removing the AMC antenna from a holding structure using an actuator; and inflating an inflatable airbag to generate a force sufficient to transition a latching mechanism from an unlocked state to a locked state. In the locked state, the conductive substrate surface is fixedly separated from the FSS layer by a predetermined distance. Attached Figure Description

[0010] The above and other aspects and features of the disclosed art will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which like reference numerals indicate like elements or features. Various elements of the same or similar type can be distinguished by attaching a reference label with an underlined / dashed line and a second label (e.g., _1, _2) to differentiate like / like elements, or by directly attaching a reference label with the second label. However, if a given description uses only the first reference label, it applies to any like / like element having the same first reference label, regardless of the second label. Elements and features may not be drawn to scale in the drawings.

[0011] Figure 1 This is a perspective view of an example AMC antenna device in an operational configuration according to an embodiment.

[0012] Figure 2 It is shown Figure 1 A cross-sectional perspective view of a portion of the structure of an AMC antenna device.

[0013] Figure 3 This indicates that during the collapsing period... Figure 1 A perspective view of the retaining structure of the AMC antenna device in a wound configuration.

[0014] Figure 4 This is shown immediately after the AMC antenna is removed from the holding structure during deployment. Figure 1 A perspective view of the AMC antenna device.

[0015] Figure 5 yes Figure 1 A cross-sectional view of a portion of the AMC antenna device, illustrating the various structures of the AMC antenna device in its retracted state during retraction.

[0016] Figure 6 It is included Figure 1 A plan view of an example flexible printed circuit board (PCB) within an AMC antenna device.

[0017] Figure 7 It is along Figure 6 The cross-sectional view taken from line 7-7 illustrates an example of a layered structure of a flexible PCB.

[0018] Figure 8 It is along Figure 1 The cross-sectional view taken from line 8-8 depicts the interlayer structure of an example AMC antenna device.

[0019] Figure 9 This indicates a connection to Figure 1 A schematic diagram of the antenna feed line, an example of an antenna element in an AMC antenna device.

[0020] Figure 10 yes Figure 1 A perspective view of the central portion of the upper part of an AMC antenna, illustrating the portion of the antenna feed line.

[0021] Figure 11 It is along Figure 10 The cross-sectional view taken from line 11-11 depicts an example integration of the antenna feed line within the AMC antenna.

[0022] Figure 12A yes Figure 1 A partial end view of an AMC antenna, illustrating an example latch in the retracted state of the AMC antenna.

[0023] Figure 12B yes Figure 1 A partial end view of the AMC antenna, illustrating an instance latch in a locked state during the operation of the AMC antenna after being unfolded.

[0024] Figure 13 This is a flowchart depicting the operation of an example method for deploying an AMC antenna on an unmanned vehicle according to an embodiment. Detailed Implementation

[0025] The following description, with reference to the accompanying drawings, is provided to aid in a comprehensive understanding of certain exemplary embodiments of the technology disclosed herein for illustrative purposes. The description contains various specific details to aid those skilled in the art in understanding the technology, but these details are to be considered illustrative only. For the purposes of simplicity and clarity, this description may be omitted where descriptions containing well-known functions and constructions might obscure the understanding of those skilled in the art.

[0026] Figure 1 This is a perspective view of an example artificial magnetic conductor (AMC) antenna device 100 in an operational configuration according to an embodiment. The AMC antenna device 100 may include an AMC antenna 10 and a holding structure 20 for holding the AMC antenna 10 during retraction. (It should be noted that the AMC antenna 100 may sometimes be referred to interchangeably herein as an AMC antenna device.) Figure 1 The AMC antenna 10 described below is in a configuration following removal from the retaining structure 20 and after the operation of changing its structure from a contracted configuration to an expanded operating configuration.

[0027] Figure 2 It is shown Figure 1 A cross-sectional perspective view of a portion of an example structure of an AMC antenna device. Also refer to... Figure 1 and 2 The AMC antenna 10 may include a ground plane 105, an antenna element layer 130 having at least one antenna element 135, and an antenna feed line (e.g., Figure 11 The 300, for clarity, is from... Figure 1 and 2 (omitted). The ground plane 105 may include: a base layer 110 having a conductive substrate surface; a frequency selective surface (FSS) layer 120; and a plurality of flexible conductors 115 electrically connecting the FSS layer 120 to the conductive substrate surface. The conductors 115 may include a conductive material such as metal. The conductors 115 may be in any of a variety of possible forms. For example, the conductors 115 may be wires, posts, springs, traces, etc.

[0028] The ground plane 105, with its textured surface configuration exhibiting conductive characteristics, can be understood as a "high-impedance surface" within a given frequency band, where the surface wave modes differ significantly from those on a smooth metallic surface. (It should be noted that the term "frequency-selective surface (FSS)" emphasizes the frequency-sensitive nature of the high-impedance surface.) The ground plane 105 can also be understood as an "in-phase reflector" that suppresses surface waves. The textured structure of the ground plane 105 allows the AMC antenna 10 to be manufactured substantially thinner than conventional ground plane antennas, i.e., non-AMC antennas with radiating elements spaced λ / 4 above the ground plane.

[0029] The AMC antenna 10 further includes a latching mechanism L (e.g., including individual latches L1 to L2) between the substrate layer 110 and the FSS layer 120. N When the AMC antenna 10 is deployed from its retracted configuration, the latching mechanism L is configured to change from an unlocked state to a locked state. Figure 1 and 2 In the locked state described herein, the base layer 110 and the FSS layer 120 are fixedly separated by a predetermined distance. The AMC antenna 10 further includes an inflatable airbag system, which, for example, has a first airbag 103a (“first airbag portion”) and a second airbag 103b (“second airbag portion”) between the base layer 110 and the FSS layer 120. As further described below, when the inflatable airbag system deflates and the latching mechanism L unlocks, the FSS layer 120 can contract against the base layer 110, resulting in a very thin structure for the AMC antenna 10. This allows the AMC antenna 10 to be rolled up in a coiled configuration within the holding structure 20. When the AMC antenna 10 is removed from the holding structure 20 on the surface 285 of a carrier (e.g., an orbiting satellite), the airbag system receives a gas input to set the AMC antenna 10 in its operating configuration. For this purpose, the airbag system inflates to generate a force sufficient to change the latching mechanism L from the unlocked state to the locked state, thereby properly separating the FSS layer 120 from the base layer 110 by a desired predetermined distance.

[0030] Multiple flexible printed circuit boards (PCBs) 107 can be individually disposed between the substrate layer 110 and the FSS layer 120, wherein each PCB 107 includes a set of flexible conductors 115. For example... Figure 2 As explained below, when the latching mechanism is in the locked state, each PCB 107 can be oriented substantially orthogonal to the substrate layer 110 and the FSS layer 120. Figure 5 As described, when the latching mechanism L is unlocked, each PCB 107 can at least partially retract relative to the substrate layer 110 and the FSS layer 120. In this state, the main surface of each PCB 107 can be tilted toward the substrate layer 110, thereby closing the air gap between the substrate layer 110 and the FSS layer 120 to provide a compact configuration for retraction. It should be noted here that in other embodiments, the flexible conductor 115 is disposed as a separate conductor between the FSS layer 120 and the substrate layer 110, and is not embedded within the PCB 107 (PCB 107 omitted).

[0031] FSS layer 120 includes a plurality of conductive patches 121_1 to 121_n separated from each other by narrow isolation areas (“streets”) 123. Each conductive patch 121 may contain a layer printed on, for example, a polyimide film (e.g., The conductive surface on the thin dielectric sheet is used, and the isolation region 123 can be a region of the dielectric sheet without printed conductors. Therefore, the conductive patches 121_1 to 121_n and the dielectric sheet (and in some cases, additional dielectric sheets on the opposite side of the printed conductors) can collectively form a continuous sheet or sandwich structure. The width of the isolation region 123 is smaller than the area of ​​the conductive patch 121, thereby creating capacitance between adjacent conductive patches 121 that contribute to the formation of a high-impedance surface. Each conductor 115 can be oriented in the z (vertical) direction and electrically connect one of the conductive patches 121 to the conductive substrate surface of the substrate layer 110, such that a "bed of nails" structure (with dielectric reinforcement of the PCB 107) is provided between the substrate layer 110 and the FSS layer 120. Each of the substrate layer 110, the FSS layer 120, and the antenna element layer 130 can be a flexible sheet structure with a main surface oriented in the xy plane.

[0032] The AMC phenomenon is achievable by appropriately designing the number, geometry, and layout of the conductive patches 121; at least one antenna element of the antenna layer 130; the length of the conductor 115; and the spacing between the antenna element layer 130 and the FSS 120. As mentioned, the AMC phenomenon enables the AMC antenna 10 to be significantly thinner than conventional antennas with radiating elements spaced λ / 4 above the ground plane. For example, the AMC phenomenon allows for efficient antenna performance where the spacing between the antenna element layer 130 and the substrate surface 119 is << λ / 4, for example, in the range of λ / 40 to λ / 10. This efficiency can be achieved due to the in-phase reflection and suppression of surface waves. Therefore, despite the close spacing between the layers, constructive interference occurs between the signal radiated directly into free space by the antenna element layer 130 and the same signal that initially propagates toward the ground plane 105 and is then reflected from the ground plane 105.

[0033] exist Figure 1 In this embodiment, the example antenna element 135 is illustrated as a crossed dipole, comprising a first dipole element 132 and a second dipole element 134 orthogonal to the first dipole element 132. Other types of antenna elements can be substituted, such as a single dipole, a loop antenna, a microstrip patch element array, etc. The crossed dipole 135 can be printed on a dielectric sheet illustrated in a hexagonal shape, the hexagonal shape occupying a certain proportion of... Figure 1Each of the FSS layer 120 and the substrate layer 110 has a smaller surface area. In other examples, the antenna element layer 130 extends in the xy plane along with each of the FSS layer 120 and the substrate layer 110. An example configuration of the ground plane 105 may include multiple dielectric or metal ribs 117, each longitudinally oriented in the y or x direction, to increase structural support at the bottom end of the conductor 115. For example, the ribs 117 may be arranged in a lattice pattern comprising rows of multiple ribs (e.g., along...). Figure 2 (oriented along the x-axis or substantially parallel to the x-axis) and columns of multiple ribs (e.g., along...) Figure 2 (Oriented along or substantially parallel to the y-axis). As another example, such as Figure 2 As described herein, each rib 117 can substantially extend the length of the basement layer 110 (e.g., along...). Figure 2 (Oriented along or substantially parallel to the y-axis). As another example, substrate 110 may include one or more continuous ribs 117. As yet another example, substrate 110 may not include ribs 117. Conductive patches 121_1 to 121_n may each be arranged in a lattice and have the same geometry, such as all rectangles or all squares as depicted, or alternatively, all hexagons, all circles, or other suitable shapes. In some embodiments, conductive patches 121_1 to 121_n may also be configured to have the same or substantially the same dimensions (e.g., within manufacturing tolerances). Each conductive patch 121 may be electrically connected to a corresponding conductor 115 via a connection 128 in its central location.

[0034] Figure 3 This is a perspective view showing the holding structure 20 of the AMC antenna device 100 that holds the AMC antenna 10 in a wound configuration during retraction. Figure 1 and 2 All components of the AMC antenna 10 described herein can be held coiled within the holding structure 20. Additionally, other components of the AMC antenna 10 described below, such as the antenna feed and balun, can be stored coiled within the holding structure 20. The balun can be hardwired to an RF front-end located outside the holding structure 20 via a flexible cable having sections that are coiled within the holding structure 20 and unfold when the AMC antenna 10 is removed from the holding structure 20.

[0035] Figure 4 It is a perspective view depicting the AMC antenna immediately after it is removed from the holding structure 20 during deployment. Figure 4The view also illustrates an example arrangement of the AMC antenna 10 relative to the retaining structure 20 before insertion. Under these conditions, airbags 103a and 103b deflate, allowing the FSS layer 120 to retract against the base layer 110 (the latching mechanism L unlocks and can lie flat between the FSS layer 120 and the base layer 110 during the deflation of the airbag system). The resulting flattened structure of the AMC antenna 10 allows the AMC antenna to be easily inserted and wound within the retaining structure 20 during initial retraction, and then unwound during deployment for removal. Airbag 103a may include a gas insertion port 102a coupled to a gas line 104a. Airbag 103b may include a gas insertion port 102b coupled to a gas line 104b. After removal from the retaining structure 20, gas can be inserted into each of the gas lines 104a and 104b to inflate airbags 103a and 103b to an inflated state, for example... Figure 1 As illustrated herein, at least one of the additional airbag portions of the airbag system may be housed within the AMC antenna 10, for example, as a rectangular airbag arranged longitudinally between peripheral portions 110a and 120a. The additional airbag may have its own insertion port and gas line, or may be coupled to each of airbags 103a and 103b to provide a continuous airbag system arranged along three sides of the AMC antenna 10. In the latter case, only one port and gas line (e.g., 102a and 104a) may be included in the airbag system. The illustrated airbag system is an example. The airbag system may have different configurations and arrangements of airbags.

[0036] Continue to refer to Figures 1 to 4 The latching mechanism L is illustrated as comprising a plurality of latches L1 to L2 distributed along the relatively peripheral portion of the AMC antenna 10. N (For example, as depicted, N = 6). For example, the FSS layer 120 may include first to fourth rectangular peripheral portions (strips) 120a, 120b, 120c, and 120d, which, when the airbag system inflates, respectively cover the corresponding peripheral portions 110a, 110b, 110c, and 110d. First set of latches L1, L2, and L... N The latches can be distributed between peripheral portions 110b and 120b, and the second set of latches L3, L4, and L5 can be distributed between peripheral portions 110a and 120a. Airbag 103a is disposed between peripheral portions 110c and 120c; airbag 103b is disposed between peripheral portions 120d and 110d. In other embodiments, one or more additional latches may be disposed adjacent to airbag 103a between peripheral portions 110c and 120c, and one or more additional latches may be disposed adjacent to airbag 103b between peripheral portions 110d and 120d.

[0037] In this embodiment, the retaining structure 20 is a generally cylindrical structure having a first opposing end wall 216 and a second opposing end wall 218, a main shaft 225 between the end walls 216 and 218, and a support rod 228 coupling the end walls 216 and 218 to each other. Each of the end walls 216, 218 may have a helical groove 214 on its inner surface 212 to facilitate guiding and retaining the AMC antenna 10 in a rolled-up configuration. At least the opposing edge portions of the ground plane 105 remain rolled up within the pair of helical grooves 214 during retraction. If the antenna layer 130 is configured to extend co-exist with the ground plane 105, the opposing edge portions of the antenna layer 130 may also be retained within the helical grooves 214.

[0038] The main shaft 225 may have a mechanical link 272 (schematically shown) extending to the peripheral portion 110a of the base layer 110. To initially hold the AMC antenna 10 within the holding structure 20, the AMC antenna 10 can be positioned as follows: Figure 4 In the contracted state shown, conductor 115 bends and FSS layer 120 contracts toward substrate layer 110, such that the thickness of at least the edge portion of the contracted structure is thinner than the width of groove 214. It should be noted that in the contracted state, FSS layer 120 can contract toward substrate layer 110 in the +x direction, causing FSS layer 120 to shift relative to substrate layer 110. Because the two layers are shifted in the contracted state, the peripheral portion 110a of substrate layer 110 is no longer covered by the corresponding peripheral portion 120a of FSS layer 120.

[0039] The main shaft 225 can be rotated (e.g., clockwise) to pull the AMC antenna 10 into the retaining structure 210. As an example, a manual crank (not shown) or an actuator 275 with a connecting rod 273 can be coupled to the end 219 of the main shaft 225 to apply a rotational force to pull the AMC antenna 10 into the retaining structure 210. Once the AMC antenna 10 is thus retained, the AMC antenna assembly 100 can be transported to a carrier, such as an orbiting satellite, prior to launch and secured to the carrier's surface 285. Because the retaining structure 20 is more robust to environmental conditions and movement than the AMC antenna 10 itself (if otherwise mounted on surface 285 without protection), securing the retaining structure 20 to surface 285 before deploying the AMC antenna 10 increases the probability of successful deployment. As another example, surface 285 is a planetary surface or the surface of an artificial structure on a planet. In this configuration, the holding structure 20, in which the AMC antenna 10 is fixed, can be transported by a drone and landed on the surface 285 for subsequent unmanned deployment.

[0040] To deploy the AMC antenna 10 from the holding structure 20, the main shaft 225 can be rotated (e.g., counterclockwise) by the actuator 275, thereby allowing the AMC antenna 10 to slide out in a plate-like configuration when in a retracted state in the +x direction. Alternatively or additionally, another actuator 260 arranged on the surface 285 can automatically pull the AMC antenna 10 out from the holding structure 20. For this purpose, the AMC antenna 10 can have an opening 129 in the peripheral portion 120b through which the link 262 of the actuator 260 can be attached to the AMC antenna 10. It should be noted that the actuator 260 and / or the actuator 275 can be a robotic arm fixed to the surface 285.

[0041] Figure 5 This is a cross-sectional view of a portion of the AMC antenna 10, illustrating the various structures of the AMC antenna in its retracted state. As can be seen, in the retracted state, each PCB 107 is tilted relative to the FSS layer 120 and the substrate layer 110, such that in the cross-sectional view, each PCB 107 forms an acute angle with the substrate layer 110. Each conductor 115 may include a lower end 116b and an upper end 116a, discussed below.

[0042] Figure 6 This is a plan view of example flexible PCB 107. Figure 7 It is along Figure 6 The cross-sectional view taken by line 7-7 illustrates an example layered structure of the flexible PCB 107. The PCB 107 may have a generally rectangular outline. Each PCB 107 may have a set of conductors 115 embedded therein and extending laterally from edge to edge. Each conductor 115 may include an upper end 116a and a lower end 116b, each in the form of a rectangular or square tab. The conductors 115 may be sandwiched between a first dielectric film 111 and a second dielectric film 112 (e.g., ...). Between (or FR4).

[0043] Figure 8 It is along Figure 1 The cross-sectional view taken by line 8-8 depicts an example interlayer structure of the AMC antenna 10 during operation (deployment). Figure 8 An example connection structure is depicted for a single conductor 115 on the PCB 107 located below the antenna element layer 130; the same connection structure can be applied to all conductors 115 of the AMC antenna 10 located below the antenna element layer 130. For those conductors 115 outside the area of ​​the antenna element layer 130, the upper structure can be different (discussed below). (It should also be noted that in...) Figure 8In other cross-sectional views herein, features following those described may be omitted for clarity. The substrate 110 may include a conductive substrate surface 119, which is adhered to or printed onto the bottom surface of the flexible dielectric sheet 144 for structural integrity and to facilitate electrical and mechanical connections to the conductor 115. Dielectric ribs 117 may be adhered to the top surface of the dielectric sheet 144 and support the connection between the conductor 115 and the substrate surface 119. Plated vias 158 may have been formed through the ribs 117 and the substrate 110. The bottom end 116b of the conductor 115 may have been inserted into the via 158 and electrically connected to the conductive substrate surface 119, wherein a conductive adhesive 157, such as molten and cooled solder, surrounds the end 116b within the via 158.

[0044] FSS layer 120 may include conductive patches 121_1 to 121_n sandwiched between lower dielectric sheet 154 and upper dielectric sheet 164. Alternatively, FSS layer 120 may be constructed using a single dielectric sheet 154 or 164 having conductive patches 121 printed thereon. Mechanical and electrical connections 128 between the upper portion of conductor 115 and FSS layer 120 may include plated vias 168, an upper end 116a, and conductive adhesive 167 within vias 168. Figure 8 A single connection 128 is depicted between conductor 115 and a given conductive patch 121_j, the conductive patch being separated from adjacent conductive patches 121_(j-1) and 121_(j+1) by corresponding isolation regions 123. After the conductive patch 121 is deposited on the upper surface of dielectric sheet 154, dielectric sheet 164 containing isolation regions 123 may have been formed by layering dielectric material on top of conductive patch 121. However, if dielectric sheet 164 is omitted, isolation region 123 may be an air gap or dielectric filler. Each of dielectric sheets 144, 154, 164, and 174 may be, for example... The polyimide film.

[0045] Electrical connections 128 penetrating the AMC antenna 10 can each be positioned at a fixed distance above the dielectric sheet 144 (with the latching mechanism L in a locked state). In this manner, the FSS layer 120 is supported, with its lower surface uniformly spaced at a fixed distance from the substrate layer 110. An air gap 191 can exist in the region surrounding the conductor 115.

[0046] Antenna element layer 130 may include at least one antenna element 132 printed on top of dielectric layer 174. An example mechanical connection between antenna element layer 130 and FSS layer 120 may include a rigid extension 176 of the upper end 116a of conductor 115 extending above the upper surface of dielectric sheet 164, an electroplated blind via 178 in the lower surface of dielectric sheet 174, and a conductive adhesive 177, such as solder. The upper end of extension 176 may have been inserted into via 178 and adhered to dielectric sheet 174 by melting and cooling adhesive 177. All or most of conductor 115 located below antenna element layer 130 may similarly include extensions 176 adhered to dielectric sheet 174 in this manner. Therefore, antenna element layer 130 may be entirely supported by conductor 115 and uniformly spaced a short distance from the upper surface of FSS layer 120. It should be noted that if as in Figure 1 In one example, if antenna layer 130 is centered only relative to FSS layer 120, then the extensions 176 of conductors 115 located outside the area of ​​antenna layer 130 can be omitted. These peripheral conductors 115 can all be designed to have the same or substantially the same length (e.g., within manufacturing tolerances), and their tips can be flush with the upper surface of dielectric sheet 164. Similarly, each of the conductors 115 located below antenna layer 130 can be designed identically or substantially identically, with extensions 176 of the same or substantially the same length (e.g., within manufacturing tolerances). Due to the aforementioned mechanical connection between FSS layer 120 and antenna element layer 130, a narrow air gap 171 may exist between layers 120 and 130. In an alternative configuration, the extensions 176 on conductors 115 are omitted throughout the AMC antenna 100; dielectric sheets 164 and 174 are melted or formed as a single dielectric sheet; and there is no air gap 171 between FSS layer 120 and antenna element layer 130.

[0047] Figure 9This is a schematic diagram illustrating an example antenna feed 300 that can be connected to antenna element 135 of AMC antenna 10. Antenna feed 300 may include a pair of baluns 350; a first flexible coaxial cable 310 having a first end connected to the baluns 350 and having an outer conductor 313 and an inner conductor 311; a second flexible coaxial cable 320 having a first end connected to the baluns 350 and having an outer conductor 323 and an inner conductor 321; and first interconnects 317, second interconnects 319, third interconnects 327, and fourth interconnects 329, respectively. A first dipole element 132 includes dipole arms 132a and 132b; a second dipole element 134 includes dipole arms 134a and 134b. The second end of the first coaxial cable 310 is connected to the first dipole element 132, wherein interconnect 317 connects the outer conductor 313 to dipole arm 132a and interconnect 319 connects the inner conductor 311 to dipole arm 132b. The second end of the second coaxial cable 310 is connected to the second dipole element 134, wherein interconnect 327 connects the outer conductor 323 to dipole arm 134a and interconnect 329 connects the inner conductor 321 to dipole arm 134b.

[0048] Figure 10 This is a perspective view depicting the central portion of an example of the upper part of the AMC antenna 10, illustrating a portion of the example antenna feed line 300. The central portion of the cross dipole antenna element 135 may cover the intersection area of ​​the concentrated adjacent conductive patches 121_i, 121_(i+1), 121_(i+2), and 121_(i+3). By removing the corner parts of each of the conductive patches 121_i to 121_(i+3), an opening 375 in the FSS layer 120 can be formed in the concentrated area. Another opening 385 may have been formed in the concentrated area of ​​the antenna element layer 130. Coaxial cables 310 and 320 may extend vertically (in the z-direction) between the antenna element layer 130 and the substrate layer 110 during the deployed state of the AMC antenna 10. During the retracted state, the coaxial cables may be retracted between the antenna element layer 130 and the substrate layer 110.

[0049] The second ends of coaxial cables 310 and 320 may penetrate opening 375 and at least partially penetrate opening 385. Interconnectors 317 and 327 may each be embodied as wire connections. Alternatively, interconnectors 317 and 327 may take the form of funnel-shaped metal segments integrated with conductive extensions. The funnel-shaped metal segments are soldered or otherwise electrically connected to the respective external conductors 313 or 323, and the conductive extensions are soldered or otherwise electrically connected to the input points of dipole arms 132a or 134a. Interconnectors 319 and 329 may be direct solder connections to the input points of dipole arms 132b and 134b, respectively.

[0050] Figure 11 It is along Figure 10 The cross-sectional view taken by line 11-11 depicts an example integration of the antenna feed line 300 within the AMC antenna 10. This view shows that the balun 350 can be positioned adjacent to the lower surface of the AMC antenna 10, and the lower ends of the coaxial cables 310 and 320 can penetrate the opening 365 in the substrate layer 100 and connect to the balun 350. The coaxial cables 310 and 320 can extend vertically side by side, with their upper ends penetrating the opening 375 in the FSS layer 120 and the opening 385 in the dielectric sheet 174 of the antenna layer 130 to facilitate electrical connection with the cross-dipole antenna element 135. In the retracted state, the coaxial cables 310 and 320 can be contracted similarly to conductor 115 ( Figure 5 (The contraction state described in the text).

[0051] Figure 12A This is a partial end view of the AMC antenna 10, illustrating an example latch Li in the retracted / unlocked state of the AMC antenna 10. Figure 12B This is an end view of the same portion of the AMC antenna 10 in its locked operation state after deployment. The latches L1 to L2 of the AMC antenna 10 are shown. N Any of the components can have a latch Li structure, which may include an upper rod 405, a lower rod 403, and a central latch coupler 401 coupling the upper rod 405 and the lower rod 403. The upper support 407 can be attached to the FSS layer 120 and forms a movable joint with the upper portion of the upper rod 405. The lower support 409 can be attached to the base layer 110 and forms a movable joint with the lower rod 403. Therefore, in the unlocked state, the upper rod 405 forms an acute angle with the FSS layer 120, and the lower rod 403 forms an acute angle with the base layer 110, such that the FSS layer 120 and the base layer 110 are closely spaced to optimize the retraction of the AMC antenna 10. In the locked state, the upper rod 405 and the lower rod 403 are vertically aligned, thereby providing a fixed predetermined interval between the base layer 110 and the FSS layer 120.

[0052] Figure 13 This is a flowchart depicting the operation of an example method 1300 for deploying an AMC antenna 10 on an unmanned vehicle according to an embodiment. By method 1300, the AMC antenna 10 is first stored in its retracted state in a holding structure, such as the holding structure 20 described above (S1310). The holding structure can then be transported to the unmanned vehicle along with the AMC antenna 10 stored therein (S1320). As previously mentioned, some examples of unmanned vehicles (e.g., vehicles containing surface 285) include orbiting satellites, planetary surfaces, or artificial structures on planetary surfaces.

[0053] The AMC antenna can then be deployed (S1330) by removing it from the holding structure using the actuators described above (e.g., 275 and / or 260) and fully inflating the airbag system (e.g., airbags 103a and 103b) to change the latching mechanism (e.g., “L”) from the unlocked state to the locked state. Due to the latching, the FSS layer 120 becomes appropriately spaced from the substrate layer 110, and the AMC antenna 10 is configured for operation, e.g., in Figure 1 In the configuration shown above.

[0054] With the AMC antenna in an operational configuration, a robotic arm or similar device (e.g., an actuator 260 with linkage 262) can secure the AMC antenna to the surface 285 of the carrier. In an embodiment, the balun 350 is hardwired, for example, to the RF front end of the communication system via a flexible cable (not shown), having sections that are wound within the holding structure 20 during retraction and are not wound when the AMC antenna 10 is removed. If the balun 350 is not so hardwired, a robotic arm or similar device can electrically connect the balun 350 to the RF front end. In either case, once the RF front end connection to the balun 350 is secured, active communication of the signal by the AMC antenna can be initiated.

[0055] While the techniques described herein have been specifically shown and described with reference to exemplary embodiments thereof, those skilled in the art will understand that various changes in form and detail may be made therein without departing from the spirit and scope of the claimed subject matter as defined by the appended claims and their equivalents.

Claims

1. An artificial magnetic conductor (AMC) antenna device (100), comprising: Ground plane (105), the ground plane comprising: A substrate layer (110) includes a conductive substrate surface (119). A frequency selective surface (FSS) layer (120) above the substrate layer, the FSS layer comprising a plurality of conductive patches (121) separated from each other; and Multiple flexible conductors (115), each flexible conductor electrically connecting one of the conductive patches to the surface of the conductive substrate; A flexible antenna element layer (130) above the FSS layer, the flexible antenna element layer including at least one antenna element (135). A latching mechanism (L) between the substrate layer and the FSS layer is configured to transition from an unlocked state to a locked state, wherein in the locked state, the conductive substrate surface is fixedly separated from the FSS layer by a predetermined distance; and An inflatable airbag system (103a, 103b) is located between the base layer and the FSS layer. The inflatable airbag system is configured to receive a gas input during the deployment of the AMC antenna device and to inflate to generate a force sufficient to change the latching mechanism from the unlocked state to the locked state.

2. The AMC antenna device (100) according to claim 1, wherein the inflatable airbag system comprises: The first inflatable airbag portion (103a) extends longitudinally between the first peripheral portion of the base layer (110c) and the first peripheral portion of the FSS layer (120c); as well as The second inflatable airbag portion (103b) extends longitudinally between the second peripheral portion of the base layer (110d) and the second peripheral portion of the FSS layer (120d). The second peripheral portion of the base layer is opposite to the first peripheral portion of the base layer, and the second peripheral portion of the FSS layer is opposite to the first peripheral portion of the FSS layer.

3. The AMC antenna device (100) according to claim 1 or 2, further comprising a retaining structure (20) configured to retain (i) the antenna element layer, (ii) the ground plane of the FSS layer having contracted toward the substrate surface, and (iii) the inflatable airbag system when the AMC antenna device is retracted.

4. The AMC antenna device (100) according to claim 3, further comprising at least one actuator (275, 260) configured to remove the antenna element layer, the ground plane and the inflatable airbag system from the retaining structure.

5. The AMC antenna device (100) according to claim 4, wherein the retaining structure holds the antenna element layer, the ground plane and the inflatable airbag system in a wound state.

6. The AMC antenna device (100) according to claim 5, wherein the retaining structure is a cylindrical structure including a pair of helical grooves (214) in corresponding opposite ends (216, 218), wherein the opposite edge portions of the ground plane are held wound within the pair of helical grooves.

7. The AMC antenna device (100) according to claim 1, wherein: The FSS layer includes a first dielectric sheet (154) and the plurality of conductive patches are printed conductive patches on the first dielectric sheet; and The at least one antenna element is at least one printed conductive element (132, 134) on the second dielectric sheet (174). Each of the first and second dielectric sheets is flexible.

8. The AMC antenna device (100) according to claim 1, further comprising a flexible antenna feed (310, 320) having a first end electrically connected to the at least one antenna element, an opposite end below the substrate layer, and a central portion extending between the substrate surface and the at least one antenna element through at least one opening (375) in the FSS layer.

9. The AMC antenna device (100) of claim 8, further comprising a balun (350) disposed beneath the substrate and connected to the opposite end of the antenna feed.

10. The AMC antenna device (100) according to claim 1, wherein the at least one antenna element comprises at least one cross dipole antenna element (135).

11. The AMC antenna device (100) according to claim 1, wherein the substrate layer further comprises a flexible dielectric substrate (144), and the conductive substrate surface is a printed conductive material on the flexible dielectric substrate.

12. The AMC antenna device (100) of claim 1, further comprising a plurality of flexible printed circuit boards (PCBs) (107), each flexible PCB being disposed between the substrate layer and the FSS layer and each comprising a group of a plurality of flexible conductors (115), wherein each of the flexible PCBs is oriented substantially orthogonally to the substrate layer and the FSS layer when the latching mechanism is in the locked state, and is oriented non-orthogonally to adjacent portions of each of the substrate layer and the FSS layer when the latching mechanism is unlocked.

13. The AMC antenna device (100) according to claim 1, wherein the latching mechanism comprises a plurality of latches (L1 to L2) distributed between at least two peripheral portions of the FSS layers (120a, 120b) and at least two corresponding peripheral portions of the substrate layers (110a, 110b). N ).

14. A method (1300) for retracting and deploying an artificial magnetic conductor (AMC) antenna (10) on an unmanned vehicle (285), the method comprising: The AMC antenna is retracted in a retaining structure (S1310), wherein the AMC antenna includes: (i) an antenna element layer; (ii) a ground plane including a frequency selective surface (FSS) layer and a base layer below the FSS layer and including a conductive substrate surface; (iii) a latching mechanism between the base layer and the FSS layer; and (iv) an inflatable airbag system between the base layer and the FSS layer. During the deployment of the AMC antenna: Remove the AMC antenna from the holding structure using an actuator (S1330); and The inflatable airbag is inflated to generate a force sufficient to change the latching mechanism from an unlocked state to a locked state (S1330), wherein in the locked state, the conductive substrate surface is fixedly separated from the FSS by a predetermined distance.

15. The method (1300) according to claim 14, wherein the unmanned vehicle is an orbiting satellite.

16. The method (1300) of claim 14 or 15, wherein the retaining structure holds the AMC antenna in a wound state, and the actuator causes the AMC antenna to unfold from the retaining structure in a plate-like shape.

17. The method (1300) of claim 14 or 15, wherein the AMC antenna further comprises a flexible antenna feed (132, 134) stored in the retaining structure in a coiled shape, the flexible antenna feed being unwound during the removal of the AMC antenna.

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