EP3316397B1

EP3316397B1 - Fixed multibeam stereoscopic helical antenna array and helical antenna flexible support device thereof

Info

Publication number: EP3316397B1
Application number: EP17769236.5A
Authority: EP
Inventors: Jianjun Zhang; Yuan Zhuang; Xiaodan WU; Weiliang LIU; Wenchao WEI; Hao Hu; Yi Huang; Xiaochuan SHUANG
Original assignee: Shanghai Spaceflight Institute of TT&C and Telecommunication
Current assignee: Shanghai Spaceflight Institute of TT&C and Telecommunication
Priority date: 2016-03-23
Filing date: 2017-01-18
Publication date: 2019-09-04
Anticipated expiration: 2037-01-18
Also published as: WO2017161959A1; EP3316397A1; EP3316397A4; CN105762483B; CN105762483A

Description

Technical Field

The present invention relates to a helical antenna array, and more particularly to a fixed multi-beam helical antenna stereoscopic array with a folding and unfolding function and a helical antenna flexible support device thereof.

Background Art

The helical antenna is an antenna widely used in the field of astronavigation. Compared with the microstrip antenna commonly used in the array antenna, the multi-turn axial mode single-wire helical antenna is significantly dominate in the directional diagram band width, circular polarization degree, directional pattern symmetry. Therefore, the number of array elements of the small-size antenna array can be greatly reduced when the array antenna gain is retained unchanged, with the single-wire helical antenna being an array element. In order to improve the gain, single-wire helical antenna usually has more turns, therefore having a greater height, a compression-release device can be used to greatly reduce the height of the antenna in the non-working state, and it is especially suitable for large-size applications at low-frequency.
In applications where the array antenna is required to realize a large angle of view with a fixed beam, the gain is reduced rapidly when scanning to a large angle in terms of a planar antenna array design. To increase the gain, it is necessary to increase the number of array elements to therefore cause the array beam to narrow. In this case, a greater number of wave positions are required to cover the required view angle range, resulting in a geometric growth in the number of the feeding networks. If the antenna array is designed as a stereoscopic structure, the physical direction of the array is changed, so that the antenna array operates in the absence of a scanning angle or a small scanning angle, then an excessive increase in the number of array elements can be avoided, and the scale of the feeding network can be reduced.
A single-wire helical antenna achieves a gain of no less than 10 dB in at least 10% of the bandwidth. For applications requiring a fixed multi-beam antenna with a gain coverage of 8 dB over a larger coverage (e.g. ±65°), it is suitable to employ a stereoscopic structure antenna array scheme with a single-wire helical antenna as the array element. The structure design of the stereoscopic array is carried out according to the specific gain coverage requirement, so that each pair of the antennas points to different azimuths, and the final beam coverage requirement is realized by arranging a series of different pointing antennas on the structure.
Document CN 104 836 011 A discloses a helical spatial antenna comprises a spiral antenna body 4, a protective cover 5 and an insulating plate 2 fixed on a base 1. Document US 3 836 979 A discloses a helical antenna configured to be mounted on a fixed point of a land. Document WO 2015/042968 A1 discloses a sector configuration system comprising a cylindrical antenna array for mobile communications. Document JP 3 649516 B2 discloses a helical antenna unit comprising a helical antenna comprising a plurality of loops, a plurality of parallel flexible support wires being uniformly distributed around the axis of the helical antenna to support said helical antenna, a plurality of pitch fine-adjustment devices by which the flexible support wires are connected to the plurality of loops of the helical antenna, each pitch fine-adjustment device comprising an adjustment block fixed to the helical antenna, the flexible support wire being provided through the adjustment block, and the adjustment block. None of these solutions allows an easy and accurate adjustment of the pitch of the helical antenna.

Summary of the Invention

It is an object of the present invention to provide a fixed multi-beam helical antenna stereoscopic array with a folding and unfolding function and a helical antenna flexible support device thereof, for solving the problem of the conventional planar helical antenna array that the gain decreases rapidly when scanning to a large angle, while increasing the number of the array elements leads to narrowing of the array beam.
It is a second object of the present invention to provide a fixed multi-beam helical antenna stereoscopic array with a folding and unfolding function and a helical antenna flexible support device thereof, for realizing a fixed multi-beam antenna with a wide coverage of field of view to meet the functional requirements of the antenna, and the folding and unfolding function of the antenna is introduced to achieve effective control over the size envelope and weight of the antenna, etc.
To achieve the above objects, the present invention provides a fixed multi-beam helical antenna stereoscopic array as defined in independent claim 1. In addition, optional features are set out by dependent claims 2-12. The embodiments that do not fall within the scope of the claims shall be treated as examples.
The invention has the following advantages and positive effects by adopting the above technical solution:

1) the invention realizes antenna beam pointing deflection by using the stereoscopic frustum structure, so as to realize a beam coverage in the airspace in a wider field of view, without using the phase-shifting feeding network and costs can be greatly saved as compared with the conventional phased-array antennas;
2) the invention realizes the high gain multi-beam coverage of the antenna by using the stereoscopic frustum structure, thus realizing the spatial segmentation in the case of ensuring full coverage of the wide area airspace and reducing the number of targets in a single beam, which greatly reduces the processing capacity of a single channel and improves the detection probability as compared with the conventional antennas;
3) the invention reduces the mutual coupling between the antenna units by using the beam isolation plate, which can greatly reduce the size of the stereoscopic frustum structure as compared with the way of simply isolating the space; the isolation plate is provided with weight reducing holes, which can reduce the weight under the premise of not affecting the electrical performance;
4) the present invention utilizes the restoring force of the helical antenna itself and the unidirectional support characteristic of the flexible wire to realize the control over the pitch and rigidity of the helical antenna so as to realize the flexible support of the helical antenna. Compared with the hard support device of conventional helical antenna, the design structure greatly reduces the weight of the helical antenna device, and can achieve helical compression release, which greatly reduces installation space of the helical antenna;
5) the single-wire helical antenna used in the present invention can achieve an 8 dB gain coverage within a ±25° beam within 12% of the bandwidth, and is superior to the conventional microstrip antenna array scheme from electrical performance, cost and weight.
6) the device of the invention has the advantages of simple structure, convenient assembly and high promotion value.

Brief Description of the Drawings

FIG. 1 is a schematic structural view of a frustum structure of a fixed multi-beam helical antenna stereoscopic array of the present invention in a 7-beam application;
FIG. 2 is a schematic structural view of a fixed multi-beam helical antenna stereoscopic array of the present invention in a 7-beam application in an unfolding state;
FIG. 3 is a schematic structural view of a fixed multi-beam helical antenna stereoscopic array in a 7-beam application in a folding state;
FIG. 4 is a beam coverage simulation diagram of a fixed multi-beam helical antenna stereoscopic array of the present invention in a 7-beam application in which the contour line is an 8 dB gain and the operating frequency is f₁;
FIG. 5 is a beam coverage simulation diagram of a fixed multi-beam helical antenna stereoscopic array of the present invention in a 7-beam application in which the contour is an 8 dB gain and the operating frequency is f₂, f₁≈1.1f₂;
FIG. 6 is a schematic structural view of a helical antenna flexible support device according to the present invention;
FIG. 7 is a schematic diagram showing the connection between the flexible support wire and the helical antenna in the present invention.

Detailed Description of the Invention

The technical solution in the embodiments of the present invention will be described and discussed clearly and completely in conjunction with the accompanying drawings. It is obvious that what is described herein is merely part of but not all the examples of the present invention, based on the embodiments of the present invention, all the other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present invention. In order to facilitate understanding of the embodiments of the present invention, the following description will be given by way of embodiments as example with reference to the accompanying drawings, and the embodiments are not to be construed as limiting the embodiments of the present invention.
As shown in FIGs. 1 and 2, the present embodiment provides a multi-beam helical antenna stereoscopic array, comprising a frustum structure 10 and a plurality of helical antenna units 20. Wherein the frustum structure 10 comprises a top surface 11 and a plurality of side surfaces 12, the upper ends of side surface 12 are connected to the edges of the top surface 11, and the side edges of the side surfaces 12 are connected to the side edges of the adjacent side surfaces 12. The helical antenna units 20 are respectively provided on the top surface 11 and the side surfaces 12, and the helical antenna units 20 are respectively fixedly mounted on the top surface and the side surfaces. The frustum structure 10 formed by the top surface 11 and the side surfaces 12 is a primary structure for supporting the respective helical antenna units 20, and since the respective angles between the respective faces of the frustum structure 20 themselves are different from each other, the antenna beams of the helical antenna units on the top surface and the side surfaces are pointing at different directions. Thus, the multi-beam helical antenna stereoscopic array realizes antenna beam of the helical antenna units pointing deflection by using the stereoscopic frustum structure, so as to realize a beam coverage in the airspace in a wider angle of view, without using the phase-shifting feeding network and costs can be greatly saved as compared with the conventional phased-array antennas.
In a further preferred embodiment, the above top surface 11 is provided as a regular polygon. Referring to FIG. 1, the top surface 11 in this embodiment is a regular hexagon. Correspondingly, the side surfaces 12 are provided as isosceles trapezoids, an upper end of the side surfaces 12 is connected to the edge of one side of the top surface 11, and the side edges of the side surfaces 12 are connected to the side edges of the adjacent side surfaces. In this way, the top surface 11 of the regular hexagon is matched with the side surfaces 12 of six isosceles trapezoids to form a frustum structure having, and the frustum structure is overall stable with six side ridges and six upper ridges and can stably support each helical antenna unit. Of course, in other preferred embodiments, the top surface is not limited to regular hexagon, and may be provided with other polygons such as a regular quadrilateral, pentagon, heptagon, octagon and the like as needed. The top surface of such regular polygons can match the side surfaces of the isosceles trapezoids to form a uniform frustum structure with the same side edges, so that the antenna beams of the helical antenna units on the respective side surfaces have a same uniform pointing deflection with respect to the helical antenna units of the top surface. And the pointing deflection between the antenna beams of the helical antenna units on the respective side surfaces is the same, and uniform beam coverage of the airspace in the wider view field can be achieved.
Wherein the diameter of the circumscribed circle of the top surface of the regular polygon is set to any value between 0.7 times, 0.8 times, or 0.7 to 0.8 times the antenna operating wavelength of the helical antenna unit. It is preferably 0.75 times the antenna operating wavelength of the helical antenna unit. The top surface of this size allows the pointing deflection between the antenna beams of the helical antenna units on the respective side surfaces with respect to the helical antenna units on the top surface to fit the beam coverage of the respective helical antenna units so that the beams of the respective antenna units are uniformly expanded to cover a larger view angle within airspace.
In another preferred embodiment, the above-mentioned frustum structure 10 further comprises a bottom surface with the same regular polygon as the top surface, but the area of the bottom surface is larger than the top surface, and the respective edge of the bottom surface are respectively connected to the bottom edge of the respective side surfaces. The bottom surface matches the side surfaces and the top surface to form an internal space of the frustum structure so that the internal space of the frustum structure can be installed with various measurement and control stand-alone devices with low noise and so on. Therefore, the frustum structure with a bottom surface can be sealed as needed to control the internal working environment of the frustum structure, wherein, each face of the frustum structure is made from a low-density metal material to meet the rigidity and strength requirements of the frustum structure.
In a preferred embodiment of the present invention, the adjacent two side surfaces are connected by a side bracket 14, the side surfaces 12 are connected to the top surface 11 by the upper bracket 13, and the lower bracket 15 is provided on the lower parts of the side surface, and the upper bracket 13, the side bracket 14 and the lower bracket 15 form the support bracket of the frustum structure 10. The frustum structure is a primary support structure of the antenna stereoscopic array, and the rigidity and strength requirements can be further satisfied by providing the support bracket. Wherein the upper bracket 13 is a regular polygonal structure that matches the top surface 11. Correspondingly, the lower bracket 15 is also a regular polygonal structure. The upper bracket 13, the side bracket 14 and the lower bracket 15 are fixedly connected by fasteners. The upper bracket 13, the side bracket 14 and the lower bracket 15 serve to connect and fix the top surface and the side surfaces, and serve to connect and fix the side surfaces to the side surfaces. And in an embodiment including the bottom surface, the lower bracket 15 is a regular polygonal structure which matches the bottom surface, and the lower bracket 15 also functions to connect and fix the side surfaces and the bottom surface. The setting of the brackets between the faces provides better fixed molding of the frustum structure and a good support and fixation of the helical antenna units on the respective faces. And in the different embodiments, changing sizes of the upper bracket 13, the side bracket 14 and the lower bracket 15, and changing the corresponding sizes of the top and side surfaces connected, can realize the purpose of changing the respective positions and angles of the respective faces of the stereoscopic array formed by the frustum structure may, thereby to adjust the angles of the beams of the helical antenna units on the respective faces, so that the antenna array is more suitable for a variety of performance requirements.
Further, see FIG. 2, the helical antenna units of the multi-beam helical antenna stereoscopic array provided in the present invention further include a dielectric plate 22, in addition to the helical antenna 21 and a plurality of parallel flexible support wires 23. The bottom of the helical antenna 21 is mounted on the dielectric plate 22, wherein the dielectric plate 22 is made from an insulating material, and the helical antenna can be directly mounted on the frustum structure made from the above-mentioned metal material by the dielectric plate 22. Each of the helical antenna units of the entire antenna array is mounted on the top and side surfaces of the frustum structure of the multi-beam helical antenna stereoscopic array by the insulating dielectric plate, respectively. The helical antenna unit of the present embodiment supports and fixes the helical antenna by fitting of the flexible support wires and the dielectric plate. The helical antenna unit has a simple structure, a light weight, and is easy to operate and has a high promotion value as compared with the helical antenna support device of the prior art.
In another preferred embodiment of the helical antenna unit, a pitch fine-adjustment device 24 is also provided, a plurality of flexible support wires 23 are uniformly arranged around the helical antenna 21, and each of the flexible support wires 23 is axially arranged along the helical antenna 21, and the support wires 23 are connected to loops of the helical antenna 21 by a pitch fine-adjustment device 24. The flexible support wires herein are also made from an insulating material.
Referring to FIG. 3, the flexible support wires only provide tension, so that each helical antenna of the helical antenna unit can be easily compressed below or lower than the beam isolation plate, thereby reducing the antenna collapsing envelope. When the helical antenna unit is in the absence of external constraints, the helical antenna achieves incomplete unfolding in the interaction of its own restoring force and tension of the flexible support wires. The helical antenna pitch fine-adjustment is achieved further by the pitch fine-adjustment device between the flexible support wires and helical antenna, in order to effectively control the rigidity and pitch of the helical antenna.
The helical antenna unit has a folding and unfolding function, simple structure and light weight, and it can adjust the pitch and rigidity of the helical antenna. Compared with the conventional helical antenna hard support device, the support structure of the antenna greatly reduces the weight of the helical antenna device, and can achieve the helical compression release, thus greatly reducing the installation space of the helical antenna.
Wherein the bottom of the helical antenna 21 is mounted on the dielectric plate 22 by a plurality of dielectric bases 25 and the plurality of dielectric bases 25 are uniformly distributed in the circumferential direction, and the dielectric bases 25 herein are also made from an insulating material. The dielectric bases can be provided to ensure the stability of the helical antenna fixed on the dielectric plate, and since each part of a turn of the bottom of the helical antenna is not on the same horizontal plane, the plurality of the dielectric bases in the invention are of non-equal heights, and the height of the dielectric base is determined by the height of the helical antenna provided thereon away from the dielectric plate. While the dielectric bases and the dielectric plate made from the insulating material do not affect the normal operation of the helical antenna.
Referring again to FIG. 2, in another preferred embodiment of the present invention, the edge of the top surface (i.e., on the ridge where the top surface is connected to the side surface) and the side edge where every two adjacent side surfaces 12 are connected (i.e., on the ridge where the edges of every two adjacent side surfaces are connected) are respectively provided thereon with beam isolation plates 30, and the beam isolation plates 30 in this embodiment are metal plates or metal meshes. Wherein the upper beam isolation plate 31 is fixedly connected to the ridge where the top surface and the side surfaces are connected, and the side beam isolation plates 32 is fixedly connected to the ridge where every two adjacent side surfaces are connected. Each of the beam isolation plates 30 is fixed to the frustum structure by fasteners, and the upper beam isolation plate and the side beam isolation plate are also tightly fixed by fasteners so that each of the beam isolation plates is tightly connected to each other as a whole. In an embodiment in which the frustum structure is formed with the support frame being composed of an upper bracket, a side bracket and a lower bracket, the ridge of the frustum structure is composed of an upper bracket and side brackets, and the beam isolation plates 30 are fixed to the upper bracket and side brackets. When the angle between the respective faces of the frustum structure in the different embodiments is changed, the beam isolation plate also changes with the inclination angle of the ridge of the frustum structure to accommodate the beam isolation of the helical antennas of different angles. The multi-beam helical antenna stereoscopic array can effectively reduce the mutual coupling between the antenna units by using the beam isolation plate, and can greatly reduce the size of the stereoscopic frustum structure as compared with the way of simply isolating the space.
Wherein the height of the beam isolation plate 30 is set to 0.3 to 0.4 times the operating wavelength of the antenna of the helical antenna unit, and the height thereof is preferably set to 0.375 times the operating wavelength of the antenna.
Further, the above-described beam isolation plate 30 is slantingly mounted on each of the above-mentioned ridges, and the mounting angle thereof equally divide the space between two faces of the frustum structure 10 where the ridges are located. It is important to note that the ridges herein do not include the part of the frustum structure connected to the bottom surface or the lower bracket, that is, the edges of the bottom of the frustum structure do not need to be provided with isolation devices.
The beam isolation plates 30 are provided with weight reducing holes when they are provided as metal plates, wherein the weight reducing holes have a diameter of not more than 0.1 times the antenna operating wavelength of the helical antenna units 20; the beam isolation plates 30 have a plurality of metal mesh holes when they are metal meshes, wherein the metal mesh holes have a diameter of not more than 0.1 times the antenna operating wavelength of the helical antenna units 20. The weight can be reduced under the premise of not affecting the electrical performance if the beam isolation plate is provided with weight reducing apertures or the beam isolation plate is provided as a metal mesh having metal mesh holes.
FIG. 4 is a beam coverage simulation diagram of a fixed multi-beam helical antenna stereoscopic array of the present invention in a 7-beam application in which the contour is an 8 dB gain and the operating frequency is f₁; FIG. 5 is a beam coverage simulation diagram of a fixed multi-beam helical antenna stereoscopic array of the present invention in a 7-beam application in which the contour is an 8 dB gain and the operating frequency is f₂, f₁≈1.1^∗f₂. It can be seen that the antenna stereoscopic array provided by the invention has a large beam coverage and the overlapping area between the beams is smaller and the antenna works better. The single-wire helical antenna used in the present invention can achieve an 8 dB gain coverage within ±25° within the beam within 12% of the bandwidth, and is superior to the conventional microstrip antenna array scheme from electrical performance, cost and weight.
The present invention provides a fixed multi-beam helical antenna stereoscopic array having a folding and unfolding function which can be used to simultaneously receive multichannel signals from a large angle of view. Compared with the conventional scheme of realizing multi-beam antenna through phased array technology, it not only has the advantages of low cost, light weight, but also has the folding and unfolding function. In addition, the antenna stereoscopic array realizes a beam coverage of a wider angle of view in the airspace, and has extremely high application promotion value.
Referring to FIGs. 6-7, the present invention also provides a helical antenna flexible support device which can be used as a helical antenna unit of the fixed multi-beam helical antenna as described above, or as a helical antenna flexible support device alone. The device consists of a dielectric plate 22, a plurality of dielectric bases 25, a plurality of flexible support wire 23, and the like. The helical antenna support device of the present invention has simple structure and light weight, and it can adjust the pitch and rigidity of the helical antenna.
Specifically, the bottom of the helical antenna 21 is fixed to the dielectric plates 22 by a plurality of dielectric bases 25, and the plurality of dielectric bases 25 are uniformly distributed in the circumferential direction to ensure the stability of the fixation to the helical antenna 21, since each part of a turn of the bottom of the helical antenna is not on the same horizontal plane, the plurality of the dielectric bases 25 in the invention are of non-equal heights, and the height of the dielectric bases 25 are determined by the height of the helical antenna 21 thereon away from the dielectric plate 22. Wherein, the dielectric plate 22 and the dielectric bases 25 are all made from an insulating material so as to prevent the dielectric plate 22 and the dielectric bases 25 from affecting the normal operation of the helical antenna 21.
In the present embodiment, the bottom of the helical antenna 21 is mounted to the dielectric plate 22 by three dielectric bases 25; of course, the number of the dielectric bases 25 provided may be four, five, etc., and may be set depending on the specific circumstance but is not limited herein.
In the present embodiment, the plurality of flexible support wires 23 are circumferentially arranged around the helical antenna 21, each flexible support wire 23 is axially arranged, and the flexible support wires 23 can be provided in a number according to the specific circumstance, as shown in FIG. 6, three flexible support wires 23 are provided, and five or six of and the like may be provided, and there is no limitation here. The flexible support wires 23 serve to axially support the helical antenna 21.
Further, the flexible support wires 23 are comprised of insulated wires of high strength.
In the present embodiment, each of the flexible support wires 23 is connected to each loop of the helical antennas 21 by the pitch fine-adjustment device 24, so that each loop of the helical antennas 21 are axially movable by the pitch fine-adjustment device 24 with respect to the flexible support wires 23 to adjust the space (i.e., the pitch of the helical antenna 21) between the each loop of the helical antennas 21, thus precisely controlling the pitch of the helical antenna 21.
Further, the pitch of the helical antenna 21 in the natural state is larger than the required pitch (i.e., the pitch of the helical antenna 21 after it is mounted to the support device); the pitch of the helical antenna 21 is constrained to the required pitch by the flexible support wires 23 so as to ensure that the helical antenna 21 is always in a non-fully released state, at which time the helical antenna 21 itself has a certain restoring force; the rigidity of the helical antenna 21 is controlled under the interactions of the restoring force of the helical antenna 21 and the restraining force of the flexible support wires 23 thereto.
Further, the design or strength selection of the dielectric bases 25 and the flexible support wires 23 need to be capable of withstanding the shock released by the compression moment of the helical antenna 21.
In the present embodiment, in connection with FIGs. 6 and 7, the pitch fine-adjustment device 24 includes an adjustment block 241 fixed on the helical antenna 21, the flexible support wires 23 are fitted through the adjustment block 241, and the adjustment block 241 axially moves along the flexible support wires 23 to achieve fine-adjustment of pitch; When the pitch is adjusted, the adjustment block 241 and the flexible support wire 23 are fixed by dispensing with an insulating glue. Of course, the specific structure of the pitch fine-adjustment device 24 is not limited to the above, but may be adjusted depending on the specific circumstance.
In the present embodiment, a radio frequency connector joint 26 (hereinafter referred to as SMA) is connected to the end of the bottom of the helical antenna 21, and one end of the SMA joint is connected to the transceiver to realize transceiving control over the helical antenna signals. And the other end is fixed to the end of the helical antenna 21 by welding or by means of an adapter. The dielectric plate 22 is further fixed to an adapter plate 27 to mechanically fix of the helical antenna platform. The shape of the adapter plate 27 is determined by the external mounting platform of the helical antenna device, and is not limited thereto. For example, when the helical antenna flexible support device is mounted as a helical antenna unit in the above-described fixed multi-beam helical antenna stereoscopic array, the top surface and side surfaces of different shapes of the frustum structure can be used as the above-described adapter plate 27.
The present invention also provides a helical antenna flexible support device which can be used as a helical antenna unit of the fixed multi-beam helical antenna as described above, or as a helical antenna flexible support device alone. Specifically, the device includes a helical antenna and parallel flexible support wires, the plurality of flexible support wires arranged in parallel are uniformly distributed around the helical antenna, and the flexible support wires are axially arranged along the helical antenna to support the helical antenna. The device (which can also be regarded as a helical antenna unit) supports and fixes the helical antenna by providing a plurality of flexible support wires arranged in parallel, so that the helical antenna has the folding and unfolding function, which is very suitable for adjusting the space occupied by the helical antenna to satisfy it for different occasions. Wherein, the device, as an extension of the helical antenna flexible support device as shown in FIG. 6, may be used alone or the device may be worked as a helical antenna unit of the fixed multi-beam helical antenna stereoscopic array as shown in FIG. 2. In other preferred embodiments, each part structure of the device as shown in FIG. 6 may also be used in any combination where the function and the operational effect do not conflict.
In a preferred embodiment, the helical antenna flexible support device further comprises a dielectric plate on which the bottom of the helical antenna is mounted and the dielectric plate is made from an insulating material. The dielectric plate may be provided as a separate dielectric plate structure to be mounted on an insulating surface of a frustum structure of a fixed multi-beam helical antenna stereoscopic array or other structure on which a helical antenna needs to be mounted, or on the insulating surface of the frustum structure of the fixed multi-beam helical antenna stereoscopic array.
Further, the helical antenna flexible support device further comprises a dielectric base, the bottom of the helical antenna is mounted on the dielectric plate via a number of dielectric bases, and the dielectric bases are circumferentially distributed and made from an insulating material. Since each part of a turn of the bottom of the helical antenna 21 is not on the same horizontal plane, the plurality of the dielectric bases 5 in the invention are of non-equal heights, and the height of the dielectric base is determined by the height of the helical antenna there on away from the dielectric plate 3.
In another preferred embodiment, there is further provided a pitch fine-adjustment device, the flexible support wires are connected to each loop of the helical antenna by a pitch fine-adjustment device. The flexible support wires and the helical antenna are connected by the pitch fine-adjustment device, the present invention utilizes the restoring force of the helical antenna itself and the unidirectional support characteristic of the flexible wire to realize the control over the pitch and rigidity of the helical antenna so as to realize the flexible support of the helical antenna. Compared with the conventional helical antenna hard support device, the design structure greatly reduces the weight of the helical antenna device, and can achieve helical compression release, which greatly reduces installation space of the helical antenna;
In sum, the helical antenna flexible support device of the present embodiment, on one hand, supports and fixes the helical antenna by fitting of the flexible support wires and the dielectric plate. The helical antenna support device has a simple structure, a light weight, and is easy to operate and has a high promotion value as compared with the helical antenna support device of the prior art. On the other hand, the flexible support wires and the helical antenna are connected by the pitch fine-adjustment device, the present invention utilizes the restoring force characteristic of the helical antenna itself and the unidirectional support characteristic of the flexible wire to realize the control over the pitch and rigidity of the helical antenna. Compared with the conventional helical antenna hard support device, the design structure greatly reduces the weight of the helical antenna device, and can achieve helical compression release, which greatly reduces installation space of the helical antenna.

Claims

A fixed multi-beam helical antenna stereoscopic array, said array comprising a plurality of helical antenna units (20), each helical antenna unit (20) comprising:
- a helical antenna (21) comprising a plurality of loops,

- a plurality of parallel flexible support wires (23) being uniformly distributed around the axis of the helical antenna (21) to support said helical antenna (21), said flexible support device further comprising a plurality of pitch fine-adjustment devices (24) by which the flexible support wires (23) are connected to the plurality of loops of the helical antenna (21), each pitch fine-adjustment device (24) comprising an adjustment block (241) fixed to the helical antenna (21), the flexible support wire (23) being provided through the adjustment block (241), and the adjustment block (241) being axially movable along the flexible support wire (23) to achieve fine-adjustment of pitch, the array further comprising a frustum structure (10), said frustum structure (10) comprising a top surface (11) and a plurality of side surfaces (12), upper ends of said side surfaces (12) being connected to edges of the top surface (11), a side edge of a side surface (12) being connected to a side edge of the adjacent side surface (12), wherein the helical antenna units (20) are respectively provided on the top surface (11) and the side surfaces (12), the bottom of the helical antenna (21) of each helical antenna unit (20) being respectively mounted on the top surface (11) or on the side surfaces (12).
The array according to claim 1, wherein each helical antenna unit (20) further comprises a dielectric plate (22) on which the bottom of each helical antenna (21) is mounted, said dielectric plate (22) being made from an insulating material.
The array according to claim 2, wherein each helical antenna unit (20) further comprises a plurality of dielectric bases (25), the bottom of peach helical antenna (21) being mounted on the dielectric plate (22) via one or more of said dielectric bases (25), and the dielectric bases (25) being circumferentially distributed and made from an insulating material.
The array according to claim 3, wherein the bottom of each helical antenna (21) is fixed to the dielectric plate (22) by three dielectric bases (25) of non-equal heights.
The array according to any of claims 1 to 4, wherein each helical antenna (21) is mounted to the dielectric plate (22) and the plurality of flexible support wires (23), each helical antenna (21) configured to be in a non-fully released state.
The array according to any of claims 1 to 5, wherein reach helical antenna unit (20) further comprises an adapter and an adapter plate (27), wherein an end of the bottom of each helical antenna (21) is connected with the adapter, and the dielectric plate (22) is fixed to the adapter plate (27).
The array according to any of the preceding claims, wherein the top surface (11) is in the shape of a regular polygon, and the side surfaces (12) are in the shape of isosceles trapezoids, wherein the upper ends of the side surfaces (12) are respectively connected to the edges of the top surface (11), and the side edge of the side surface (12) is connected to the side edge of the adjacent side surface (12).
The array according to claim 7, wherein the circumscribed circle of the top surface (11) has a diameter of about 0.7 to 0.8 times the antenna operating wavelength of the helical antenna unit (20).
The array according to any of the preceding claims, further comprising a bottom surface having a shape of a regular polygon that is the same as the top surface (11), the area of the bottom surface being larger than that of the top surface (11), and each edge of the bottom surface being respectively connected to bottom edges of the side surfaces (12).
The array according to any of the preceding claims, wherein each of the two adjacent side surfaces (12) are connected by a side bracket (14), and wherein the side surfaces (12) are connected to the top surface (11) by upper brackets (13), wherein lower brackets (15) are provided on the lower parts of the side surfaces (12), and wherein a support frame of the frustum structure (10) is composed of the upper brackets (13), the side brackets (14) and the lower brackets (15).
The array according to any of the preceding claims, wherein beam isolation plates (30) are respectively provided on a ridge where the top surface (11) is connected with the side surfaces (12), and on a ridge where every two adjacent side surfaces (12) are connected, said beam isolation plates (30) being metal plates or metal meshes.
The array according to claim 11, wherein the beam isolation plate (30) has a height of 0.3 to 0.4 times the antenna operating wavelength of the helical antenna unit (20).