Ultra-wideband omnidirectional unmanned aerial vehicle antenna

Abstract

The working frequency band of the ultra-wideband omnidirectional unmanned aerial vehicle antenna can cover 400-560MHz, and the ultra-wideband omnidirectional unmanned aerial vehicle antenna comprises a radiation structure, a grounding plate, a feed structure and an air dielectric layer, the upper-layer metal patch comprises four water-drop-shaped patches and a circular patch; the shape of the grounding plate is the same as that of the upper-layer metal patch, but the size is slightly larger. By using the radiation patch with a gradual change structure, impedance conversion from a feeding point to a free space is realized, the performance of the antenna changes slowly along with the frequency, the bandwidth of the antenna is improved, meanwhile, the feeding point is distributed at the two independent patches, the isolation of the antenna can be improved, the metal feeder loaded with a 50-ohm resistor is introduced, and the bandwidth of the antenna is improved. According to the antenna, the current path and distribution on the patch are changed, the resonance efficiency of the antenna is reduced, the requirements of large bandwidth and high gain are effectively met with fewer materials, the feed mode of two ports is set to be in-phase equal-amplitude feed, the distortion of an antenna pattern is prevented, and the omnidirectional performance of the antenna is ensured.

Description

Technical Field

[0001] The present invention belongs to the field of antenna technology, and in particular relates to an ultra-wideband omnidirectional UAV antenna, whose operating frequency band can cover 400MHz-560MHz. Background Art

[0002] The 400-560MHz frequency band is a lower frequency band with good propagation characteristics. It can penetrate buildings and obstacles and is suitable for wireless communication scenarios that require wide coverage and deep penetration. Patch antennas and whip antennas are generally used to achieve coverage of 400-560MHz.

[0003] The design of low-frequency band antennas is often affected by the trade-off between physical size and electrical performance. In order to achieve high bandwidth, the antenna needs to have a wide impedance bandwidth and resonance bandwidth. Therefore, the physical size of low-frequency band antennas is relatively large, and they are limited by physical parameters such as wavelength, making it particularly difficult to achieve high bandwidth while maintaining the antenna size.

[0004] Through searching, for example, CN202021080953.0 discloses a 400M whip-shaped broadband suction cup antenna. Although it improves the fixation of the antenna, it usually has poor heat dissipation effect due to structural reasons during use, and it is too large in size and not easy to conform. For example, CN20150628217.1 discloses a 433MHz miniaturized omnidirectional microstrip antenna. Although it avoids the disadvantages of high return loss and low antenna radiation efficiency, it still has the problem of low bandwidth, and the working frequency band is only between 430.1919-436MHz; for example, CNCN201611061947.9 discloses a four-leaf clover-shaped broadband circularly polarized planar antenna. Although it has the characteristics of large bandwidth, the radiation pattern is not omnidirectional.

[0005] Therefore, at least how to improve the large size, small bandwidth, low gain of patch antennas and the difficulty of conforming to the whip antenna is a technical problem that those skilled in the art need to solve. Summary of the invention

[0006] The purpose of the present invention is to provide an ultra-wideband omnidirectional UAV antenna with the advantages of small size, large bandwidth, high gain and easy conformality in view of the problems of the prior art.

[0007] To this end, the present invention provides an ultra-wideband omnidirectional UAV antenna, the operating frequency band of which can cover 400MHz-560MHz, including a radiation structure, a ground plate, a feeding structure and an air dielectric layer; wherein: The radiating structure includes an upper metal patch; The ground plate is located below the radiation structure; The air dielectric layer is distributed between the upper metal patch and the ground plane; The feeding structure penetrates through the air dielectric layer and includes a plurality of metal feeding lines.

[0008] Wherein: the upper metal patch includes four teardrop-shaped patches and a circular patch; The four teardrop-shaped patches are symmetrically distributed about the center; the tips of the four teardrop-shaped patches are connected to the circular patch; the symmetry centers of the four teardrop-shaped patches overlap with the center of the circular patch; The ground plate has the same shape as the upper metal patch, but is larger in size than the upper metal patch; The size of the ground plate is 1.2-1.3 times larger than that of the upper metal patch, preferably 1.2221 times; The four teardrop-shaped patches of the upper metal patch correspond to the four teardrop-shaped patches of the ground plate one by one, and each teardrop-shaped patch of the upper metal patch is connected to the corresponding teardrop-shaped patch of the ground plate through a metal feeder; Two metal short-circuit posts are respectively provided between two adjacent teardrop-shaped patches of the upper metal patch and the corresponding teardrop-shaped patches of the ground plate; The distance between the upper metal patch and the ground plane is 1 / 15-1 / 16 of the wavelength of the central operating frequency, preferably 1 / 15.6; The distance between the upper metal patch and the ground plane is 7-8 times, preferably 8 times, the circular patch radius of the upper metal patch; The two metal feed lines on the two teardrop-shaped patches without metal short-circuit posts are fed with the same phase and amplitude; The two metal feed lines on the two teardrop-shaped patches with metal short-circuit posts are not fed, and the metal feed lines are loaded with 50Ω resistors to improve current distribution and reduce the resonant frequency of the antenna; On a teardrop-shaped patch provided with a metal short-circuit post, a metal feeder and two metal short-circuit posts are arranged from outside to inside along the central axis of the teardrop-shaped patch; On a teardrop-shaped patch provided with a metal short-circuit post, the distance between two metal short-circuit posts is 1 / 124-1 / 125 of the center operating frequency, preferably 1 / 124.8, and the distance between the metal feeder on the current teardrop-shaped patch and the nearest metal short-circuit post is 1 / 1247-1 / 1249 of the center operating frequency, preferably 1 / 1248; The teardrop-shaped patch of the upper metal patch gradually widens and then gradually narrows from the inside to the outside, and the end of the patch is arc-shaped. The gradual change from the inside to the outside can make the impedance matching smoother, and the arc at the end can prevent the antenna's radiation pattern from being distorted; preferably, its length is 1 / 4 of the wavelength corresponding to the center operating frequency, the widest part is 1 / 6-1 / 7 of the wavelength corresponding to the center operating frequency, preferably 1 / 6.6, and the angle of the tip opening is 50°; Furthermore, the patches connected by the two metal feed lines for feeding are orthogonal to each other; Furthermore, the patches connected by the two non-power-feeding metal feed lines are orthogonal to each other; It can be seen from the technical solution provided by the above invention that compared with the prior art, the present invention provides a 400-560MHz ultra-wideband conformal UAV antenna. By using a radiating patch with a gradient structure, it is possible to achieve impedance transformation from the feeding point to the free space, so that the antenna performance changes slowly with frequency, thereby improving the bandwidth of the antenna. At the same time, the tail of the radiating patch adopts an arc design to reduce the distortion of the radiation pattern, and introduces a metal feed line loaded with a 50Ω resistor to change the current path and distribution on the patch and reduce the resonance efficiency of the antenna, so as to effectively achieve the requirements of large bandwidth and high gain with less material. The feeding mode of the two ports is set to in-phase and equal-amplitude feeding to prevent the distortion of the antenna radiation pattern and ensure the omnidirectionality of the antenna. The upper and lower ground plates of the antenna are metal thin plates, which are easy to conform. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 A top view of a 400MHz-560MHz ultra-wideband omnidirectional UAV antenna provided by the present invention; Figure 2 A perspective view of a 400MHz-560MHz ultra-wideband omnidirectional UAV antenna provided by the present invention; Figure 3 The S11 parameter diagram obtained by simulating a 400MHz-560MHz ultra-wideband omnidirectional UAV antenna provided by the present invention; Figure 4 a is a 400MHz-560MHz ultra-wideband omnidirectional UAV antenna provided by the present invention, and the E-plane (i.e., electric plane, i.e., the directional plane parallel to the electric field direction) radiation pattern of the antenna obtained by simulation; Figure 4 b is a 400MHz-560MHz ultra-wideband omnidirectional UAV antenna provided by the present invention, and the H-plane (i.e., magnetic plane, i.e., the directional plane parallel to the magnetic field direction) radiation pattern of the antenna obtained by simulation; Among them: 1. upper metal patch; 1-1. first teardrop-shaped patch; 1-2. second teardrop-shaped patch; 1-3. third teardrop-shaped patch; 1-4. fourth teardrop-shaped patch; 1-5. first circular patch; 2. lower ground plane; 2-1. fifth teardrop-shaped patch; 2-2. sixth teardrop-shaped patch; 2-3. seventh teardrop-shaped patch; 2-4. eighth teardrop-shaped patch; 2-5. second circular patch; 3. first metal feeder; 4. second metal feeder; 5. third metal feeder; 6. fourth metal feeder; 7. first metal short-circuit column; 8. second metal short-circuit column; 9. third metal short-circuit column; 10. fourth metal short-circuit column. DETAILED DESCRIPTION

[0010] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0011] In the description of the present invention, it should be understood that the terms "center", "upper", "lower", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0012] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0013] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0014] See also Figure 1 to Figure 2The present invention provides an ultra-wideband omnidirectional UAV antenna, whose operating frequency band can cover 400MHz to 560MHz. The antenna specifically includes a radiation structure, a ground plate, a feeding structure and an air dielectric layer; wherein, The radiation structure includes an upper metal patch 1; the upper metal patch 1 includes a first water drop-shaped patch 1-1, a second water drop-shaped patch 1-2, a third water drop-shaped patch 1-3, a fourth water drop-shaped patch 1-4, and a first circular patch 1-5 located in the same XOY plane; the tips of the first water drop-shaped patch 1-1, the second water drop-shaped patch 1-2, the third water drop-shaped patch 1-3, and the fourth water drop-shaped patch 1-4 are connected to the first circular patch 1-5; the first water drop-shaped patch 1-1, the second water drop-shaped patch 1-2, the third water drop-shaped patch 1-3, and the fourth water drop-shaped patch 1-4 are centrally symmetrically arranged about the center of the first circular patch 1-5; the first water drop-shaped patch 1-1, the second water drop-shaped patch 1-2, the third water drop-shaped patch 1-3, and the fourth water drop-shaped patch 1-4 are the same in size and shape, and there is a distance between them.

[0015] The ground plate is located below the radiation structure, and has the same shape as the upper metal patch 1, but a larger size than the upper metal patch 1. In this embodiment, the size of the ground plate is 1.2221 times larger than that of the upper metal patch 1, and the upper metal patch 1 and the ground plate are both metal thin plates; The grounding plate specifically includes a fifth water drop-shaped patch 2-1, a sixth water drop-shaped patch 2-2, a seventh water drop-shaped patch 2-3, an eighth water drop-shaped patch 2-4, and a second circular patch 2-5 of the same size and shape; the tips of the fifth water drop-shaped patch 2-1, the sixth water drop-shaped patch 2-2, the seventh water drop-shaped patch 2-3, and the eighth water drop-shaped patch 2-4 are connected to the second circular patch 2-5; the fifth water drop-shaped patch 2-1, the sixth water drop-shaped patch 2-2, the seventh water drop-shaped patch 2-3, and the eighth water drop-shaped patch 2-4 are centrally symmetrically arranged about the center of the second circular patch 2-5; there is a spacing between the fifth water drop-shaped patch 2-1, the sixth water drop-shaped patch 2-2, the seventh water drop-shaped patch 2-3, and the eighth water drop-shaped patch 2-4.

[0016] The fifth water drop-shaped patch 2-1, the sixth water drop-shaped patch 2-2, the seventh water drop-shaped patch 2-3, the eighth water drop-shaped patch 2-4, and the second circular patch 2-5 are respectively located directly below the first water drop-shaped patch 1-1, the second water drop-shaped patch 1-2, the third water drop-shaped patch 1-3, the fourth water drop-shaped patch 1-4, and the first circular patch 1-5.

[0017] The air dielectric layer is distributed between the upper metal patch 1 and the ground plane; The feeding structure penetrates the air dielectric layer, is connected to the upper metal patch 1 and the ground plane, and specifically includes a first metal feed line 3 , a second metal feed line 4 , a third metal feed line 5 , and a fourth metal feed line 6 .

[0018] The two ends of the first metal feed line 3 are respectively connected to the first water drop-shaped patch 1-1 and the fifth water drop-shaped patch 2-1; the two ends of the second metal feed line 4 are respectively connected to the second water drop-shaped patch 1-2 and the sixth water drop-shaped patch 2-2; the two ends of the third metal feed line 5 are respectively connected to the third water drop-shaped patch 1-3 and the seventh water drop-shaped patch 2-3; the two ends of the fourth metal feed line 6 are respectively connected to the fourth water drop-shaped patch 1-4 and the eighth water drop-shaped patch 2-4; the first water drop-shaped patch 1-1 and the second water drop-shaped patch 1-2 are orthogonal to each other, and the third water drop-shaped patch 1-3 and the fourth water drop-shaped patch 1-4 are orthogonal to each other; A first metal short-circuit column 7 and a second metal short-circuit column 8 are provided between the third water drop-shaped patch 1-3 and the seventh water drop-shaped patch 2-3; a third metal short-circuit column 9 and a fourth metal short-circuit column 10 are also provided between the fourth water drop-shaped patch 1-4 and the eighth water drop-shaped patch 2-4; Taking the center of the first circular patch 1-5 as the starting point, the third metal feed line 5, the first metal short-circuit column 7, and the second metal short-circuit column 8 are arranged in a straight line from the outside to the inside; the distance between the first metal short-circuit column 7 and the second metal short-circuit column 8 is 1 / 124.8 of the center operating frequency, and the distance between the third metal feed line 5 and the first metal short-circuit column 7 is 1 / 1248 of the center operating frequency; Taking the center of the first circular patch 1-5 as the starting point, the fourth metal feed line 6, the third metal short-circuit column 9, and the fourth metal short-circuit column 10 are arranged in a straight line from the outside to the inside; the distance between the third metal short-circuit column 9 and the fourth metal short-circuit column 10 is 1 / 124.8 of the center operating frequency, and the distance between the fourth metal feed line 6 and the third metal short-circuit column 9 is 1 / 1248 of the center operating frequency; In this embodiment, the radius of the first circular patch 1-5 is 5 mm; In this embodiment, the distance between the upper metal patch 1 and the ground plane is 1 / 15.6 of the wavelength of the central operating frequency, which is 8 times the radius of the first circular patch 1-5, that is, 40 mm, and the magnification is 1.2221; It should be noted that, for the antenna of the present invention, when the antenna is working, the first metal feed line 3 and the second metal feed line 4 feed the upper metal patch 1 in the same phase and with the same amplitude through the coaxial line; the third metal feed line 5 and the fourth metal feed line 6 do not feed, and a certain impedance value is preset, and the preset impedance value is 50Ω; The first water drop-shaped patch 1-1 to the fourth water drop-shaped patch 1-4 of the upper metal patch 1 have the same shape and size, and their edges are represented by the following function: Where x is the maximum width of the teardrop-shaped patch, and y is the length of the teardrop-shaped patch.

[0019] The shapes of the first teardrop-shaped patch 1-1 to the fourth teardrop-shaped patch 1-4 of the upper metal patch 1 all tend to gradually widen and then gradually narrow from the inside to the outside, and the end of the patch is arc-shaped, gradually changing from the inside to the outside, and the gradual trend is from small to large and then to small, which can make the impedance matching smoother, so as to improve the current distribution, increase the current path, and enhance the antenna impedance bandwidth, so that the radiation pattern has omnidirectional radiation characteristics; preferably, its length is 1 / 4 of the wavelength corresponding to the center operating frequency, the widest point is 1 / 6.6 of the wavelength corresponding to the center operating frequency, and the angle of the tip opening is 50°.

[0020] In this embodiment, by adding a first metal short-circuit column 7, a second metal short-circuit column 8, a third metal short-circuit column 9, a fourth metal short-circuit column 10 and a third metal feed line 5 and a fourth metal feed line 6 loaded with 50Ω between the upper metal patch 1 and the ground plate, the current distribution on the radiation structure is changed to achieve miniaturization of the antenna and reduce the resonant frequency of the antenna; In this embodiment, the dielectric substrate of the antenna selects the simplest air dielectric layer, eliminating the influence of the general dielectric substrate on the antenna performance, and in the antenna design process of the present invention, the height of the metal feed line is selected to be 40 mm on the basis of maintaining the antenna gain performance; In the present invention, Figure 3 , Figure 4 a. Figure 4 b shows the various radiation properties of the bionic antenna of the present invention. The 400-560MHz ultra-wideband omnidirectional drone antenna designed by the present invention has an impedance matching bandwidth of 400MHz~560MHz, a relative bandwidth of 33%, and maintains a relatively stable gain within this frequency band. The radiation pattern meets the characteristics of an omnidirectional antenna.

[0021] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. An ultra-wideband omnidirectional drone antenna, with an operating frequency band covering 400MHz-560MHz, including: Radiating structure; A ground plate, which is located below the radiation structure; An air dielectric layer, which is distributed between the upper metal patch and the ground plane; A feeding structure, which penetrates the air dielectric layer; The feeding structure includes a plurality of metal feed lines; The radiation structure comprises an upper metal patch, and the upper metal patch comprises four teardrop-shaped patches and a circular patch; the four teardrop-shaped patches are symmetrically distributed about the center; the tips of the four teardrop-shaped patches are connected to the circular patch; the symmetry centers of the four teardrop-shaped patches overlap with the center of the circular patch; The ground plate has the same shape as the upper metal patch, but is larger in size than the upper metal patch; The four teardrop-shaped patches of the upper metal patch correspond to the four teardrop-shaped patches of the ground plate one by one, and each teardrop-shaped patch of the upper metal patch is connected to the corresponding teardrop-shaped patch of the ground plate through a metal feeder; Two metal short-circuit posts are respectively provided between two adjacent teardrop-shaped patches of the upper metal patch and the corresponding teardrop-shaped patches of the ground plate; The two metal feed lines on the two teardrop-shaped patches without metal short-circuit posts are fed with the same phase and amplitude; The two metal feed lines on the two teardrop-shaped patches provided with metal short-circuit posts do not feed power, and both of the metal feed lines are loaded with resistors.

2. The ultra-wideband omnidirectional UAV antenna according to claim 1, characterized in that: The size of the ground plate is 1.2-1.3 times larger than that of the upper metal patch.

3. The ultra-wideband omnidirectional UAV antenna according to claim 1, characterized in that: The distance between the upper metal patch and the ground plane is 1 / 15-1 / 16 of the wavelength of the central operating frequency.

4. The ultra-wideband omnidirectional UAV antenna according to claim 1, characterized in that: The distance between the upper metal patch and the ground plate is 7-8 times the circular patch radius of the upper metal patch.

5. The ultra-wideband omnidirectional UAV antenna according to claim 1, characterized in that: The resistance value of the metal feed line loaded with resistance is 50Ω.

6. The ultra-wideband omnidirectional UAV antenna according to claim 1, characterized in that: On a teardrop-shaped patch provided with a metal short-circuit column, a metal feeder and two metal short-circuit columns are arranged from outside to inside along the central axis of the teardrop-shaped patch.

7. The ultra-wideband omnidirectional UAV antenna according to claim 6, characterized in that: On a teardrop-shaped patch provided with metal short-circuit posts, the distance between two metal short-circuit posts is 1 / 124-1 / 125 of the center operating frequency, and the distance between the metal feeder on the current teardrop-shaped patch and the nearest metal short-circuit post is 1 / 1247-1 / 1249 of the center operating frequency.

8. The ultra-wideband omnidirectional UAV antenna according to claim 1, characterized in that: The teardrop-shaped patch of the upper metal patch shows a trend of gradually becoming wider and then narrowing from the inside to the outside, and the end of the patch is in an arc shape.

9. The ultra-wideband omnidirectional UAV antenna according to claim 8, characterized in that: The teardrop-shaped patch length of the upper metal patch is 1 / 4 of the wavelength corresponding to the central operating frequency, the widest part is 1 / 6-1 / 7 of the wavelength corresponding to the central operating frequency, and the angle of the tip opening is 50°.

10. The ultra-wideband omnidirectional UAV antenna according to claim 1, characterized in that: The patches connected by the two metal feed lines for feeding are orthogonal to each other; the patches connected by the two metal feed lines for not feeding are orthogonal to each other.

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