Omnidirectional circularly polarized antenna

Abstract

According to the omnidirectional circularly polarized antenna, the oscillator arms are of a spiral structure, so that under the condition that the heights of the antennas are the same, compared with linear oscillator arms, the oscillator arms are longer in current path and have good standing-wave ratio characteristics and gain characteristics; due to the fact that the multiple oscillator arms on the same layer are arranged in the circumferential array mode, and the spiral directions of the oscillator arms on different layers are opposite, the omnidirectional circularly-polarized antenna has the excellent omnidirectional performance and the stable radiation characteristic. Due to the arrangement of the short-circuit sleeve, the influence of induction current on the feed cable on an antenna radiation pattern can be effectively reduced, the original pattern can be preserved to the greatest extent, and the antenna has higher gain and more stable radiation performance; in general, the omni-directional circularly polarized antenna is not easily influenced by cable induction current, and shape preservation and distortion reduction can be performed on a directional diagram to the greatest extent while the characteristics of high gain and high axial ratio are maintained, so that the communication quality is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of communication antennas, in particular to an omnidirectional circularly polarized antenna. Background Art

[0002] With the continuous advancement of mobile communication technology, antennas have become an indispensable and critical component in modern smart devices. Antenna performance directly impacts device performance and user experience. With the rapid development of 5G communications, smart homes, smart industrial equipment, intelligent driving, and long-distance unmanned image transmission equipment are all heavily dependent on antenna systems. Excellent antenna design often determines a product's competitiveness, placing high demands on antenna design for smart devices.

[0003] Traditional, previous-generation image transmission antennas for smart terminals or drones often feature excellent radiation patterns and axial ratio performance when used alone. However, conventional smart terminals, image transmission antennas, or navigation antennas often integrate a long transmission cable to facilitate connection between the antenna and the device, increasing range and flexibility. Generally, the antenna's radiation performance is affected by induced currents in the cable, resulting in distortion of the radiation pattern, deterioration of radiation performance, and deterioration of axial ratio characteristics, which in turn affects communication quality and image transmission distance. Therefore, minimizing the impact of cables is an urgent task, posing a challenge to existing design approaches.

[0004] Traditional antennas suffer from a common problem: their radiation patterns are easily affected by induced currents in the long cables integrated at their lower ends, resulting in severe pattern distortion. When the cables are short and thin, the distortion is low, making this a minor issue in some scenarios. However, as the cables increase in length and diameter, the distortion worsens until the radiation pattern deteriorates completely, rendering communication impossible. The axial ratio becomes more pronounced, indicating a deterioration in circular polarization characteristics, which is unacceptable in system design. Furthermore, this design suffers from the problem of induced currents in the cables interfering with the antenna's standing waves, leading to poor matching. Therefore, a method to improve these shortcomings of traditional antennas is urgently needed. Utility Model Content

[0005] (1) Technical problems solved

[0006] To solve the above problems, the utility model provides an omnidirectional circularly polarized antenna, which is not easily affected by cable induced currents. While maintaining high gain and high axial ratio characteristics, it can maximally preserve the shape of the radiation pattern, reduce distortion, and thus improve the quality of communication.

[0007] (2) Technical solution

[0008] To achieve the above objectives, the present invention provides the following technical solutions:

[0009] An omnidirectional circularly polarized antenna, comprising:

[0010] A radome, wherein a feed substrate is provided inside the radome, the feed substrate having an upper layer and a lower layer, the lower layer of the feed substrate being provided with a feed cable for connecting to an external device, the feed cable having an extension extending out of the radome, the extension of the feed cable being provided with a short-circuit sleeve;

[0011] Two layers of feeder groups, the two layers of feeder groups being parallel to each other and respectively arranged on the upper and lower layers of the feed substrate, the feeder groups comprising a plurality of horizontal feeders arranged in a circumferential array, the horizontal feeders having first and second ends spaced apart from each other, the first ends of the plurality of horizontal feeders on the same layer being interconnected;

[0012] An array arm, wherein a plurality of the array arms are provided corresponding to the plurality of the horizontal feed lines, and the array arm is a spiral structure, and the array arm is provided on the outside of the feed substrate in a fitted state, with one end of the array arm connected to the horizontal feed line and the other end extending on the outside of the feed substrate;

[0013] The spiral directions of the plurality of array arms arranged on the same layer of the feed substrate are the same, and the spiral direction of the array arms arranged on the upper layer of the feed substrate is opposite to the spiral direction of the array arms arranged on the lower layer of the feed substrate.

[0014] Preferably, the feed substrate is a cylindrical hollow structure, the upper structure and the lower structure of the feed substrate are symmetrically designed, and a plurality of routing bosses are provided on the feed substrate corresponding to the plurality of array arms, and the plurality of routing bosses have gaps and are arranged in a circular axis array.

[0015] Preferably, the feed substrate is an ultra-thin flexible circuit board.

[0016] Preferably, the feeder cable is RG402 cable and has a length of 80 mm.

[0017] Preferably, the short-circuit sleeve is made of metal, one end of the short-circuit sleeve is short-circuited and welded to the feeder cable, and the other end is open-circuited.

[0018] Preferably, the width of the horizontal feed line gradually increases from the first end to the second end.

[0019] Preferably, the array arm arranged on the upper layer of the feed substrate extends along a right-handed thread direction, and the array arm arranged on the lower layer of the feed substrate extends along a left-handed thread direction.

[0020] Preferably, the feeder group and the array arm are both etched on the substrate by a laser engraving process.

[0021] (3) Beneficial effects

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] Since the two layers of feed line groups are parallel to each other and are respectively arranged on the upper layer and the lower layer of the feed substrate, a stacked structure can be formed, thereby effectively saving space and facilitating the miniaturization of the omnidirectional circularly polarized antenna.

[0024] Since the array arm in the present application is a spiral structure, when the antenna height is the same, compared with the traditional array arm which is a straight line from end to end, the current path of the array arm in the present application is longer and has more current paths, thereby ensuring that it has good standing wave ratio and gain characteristics; when the array arm length is the same, compared with the traditional design, the structure in the present application can greatly reduce the height of the antenna and achieve a low profile, which is conducive to the miniaturization of the omnidirectional circularly polarized antenna.

[0025] Since multiple array arms are provided corresponding to multiple horizontal feed lines, the multiple array arms on the same layer are arranged in a circular array. Since the multiple array arms arranged on the same layer of the feed substrate have the same spiral direction, the spiral direction of the array arm arranged on the upper layer of the feed substrate is opposite to the spiral direction of the array arm arranged on the lower layer of the feed substrate. Therefore, the omnidirectional circularly polarized antenna has excellent omnidirectionality and stable radiation characteristics.

[0026] Since a short-circuit sleeve is provided at the extending portion of the feeder cable, the feeder cable can be effectively protected from the influence of the induced current. Specifically, conventional cables usually have significant induced currents and lack any means of canceling and suppressing them, so parasitic radiation will be generated in the far field. This parasitic radiation is the fundamental factor causing distortion of the antenna pattern. Although the feeder cable in the present application has significant induced currents, thanks to the presence of the short-circuit sleeve, a reverse canceling current will be generated. Since the parasitic current is canceled by the generated reverse current, the far-field radiation is greatly reduced, thereby achieving a conformal effect on the pattern.

[0027] In general, the omnidirectional circularly polarized antenna in this application is not easily affected by cable induced currents. While maintaining high gain and high axial ratio characteristics, it can preserve the directional pattern to the greatest extent, reduce distortion, and thus improve the quality of communication. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0029] Figure 1 Shows a three-dimensional diagram of the omnidirectional circularly polarized antenna of the present invention;

[0030] Figure 2 Shown Figure 1 A three-dimensional image of the medium omnidirectional circularly polarized antenna from another angle;

[0031] Figure 3 Shown Figure 2 A three-dimensional image of the medium omnidirectional circularly polarized antenna with the radome removed;

[0032] Figure 4 Shown Figure 3 A magnified view of part A in FIG;

[0033] Figure 5 Shown Figure 1 A three-dimensional diagram of a vertical side of a medium omnidirectional circularly polarized antenna;

[0034] Figure 6 Shown Figure 1 A perspective view of another vertical side of the medium omnidirectional circularly polarized antenna;

[0035] Figure 7 Shown Figure 1 Top view of the medium omnidirectional circularly polarized antenna;

[0036] Figure 8 Shown Figure 1 Bottom view of the medium omnidirectional circularly polarized antenna;

[0037] Figure 9 Shown Figure 1 A sectional perspective view of a vertical section of the central radome;

[0038] Figure 10 Shown Figure 1 A sectional perspective view of a vertical section of the short-circuit sleeve;

[0039] Figure 11 Shows a schematic diagram of the current direction of a conventional design without a short-circuit sleeve and the present invention with a short-circuit sleeve;

[0040] Figure 12 Shows a schematic diagram of radiation characteristics of a conventional design without a short-circuit sleeve and the present invention with a short-circuit sleeve;

[0041] Figure 13 Shows a schematic diagram of the omnidirectional three-dimensional radiation direction of the utility model;

[0042] Figure 14 Shown is a schematic diagram of the standing wave ratio of the present utility model;

[0043] Figure 15 A schematic diagram of the axis ratio of the present invention is shown.

[0044] In the figure: 1. Antenna cover; 2. Feeder group; 21. Horizontal feeder; 211. First end; 212. Second end; 3. Array arm; 4. Feed substrate; 41. Upper layer; 42. Lower layer; 43. Routing boss; 5. Feeder cable; 51. Extension; 6. Short-circuit sleeve. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described 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 making creative efforts are within the scope of protection of the present invention.

[0046] See attached Figure 1 , Attachment Figure 3 And attached Figure 8 -Attached Figure 10 The embodiment of the utility model discloses an omnidirectional circularly polarized antenna, including an antenna cover 1, a two-layer feeder group 2, and an array arm 3. A feed substrate 4 is provided inside the antenna cover 1. The feed substrate 4 has an upper layer 41 and a lower layer 42. The lower layer 42 of the feeder substrate 4 is provided with a feeder cable 5 for connecting to an external device. The feeder cable 5 has an extension portion 51 extending out of the antenna cover 1. The extension portion 51 of the feeder cable 5 is provided with a short-circuit sleeve 6. The two-layer feeder group 2 is parallel to each other and is respectively provided on the upper layer 41 and the lower layer 42 of the feeder substrate 4. The feeder group 2 includes a plurality of horizontal feeders 21 arranged in a circular array. The horizontal feeder 21 has The first ends 211 and the second ends 212 are far away from each other, and the first ends 211 of the multiple horizontal feed lines 21 on the same layer are connected to each other; multiple array arms 3 are provided corresponding to the multiple horizontal feed lines 21, and the array arms 3 have a spiral structure. The array arms 3 are arranged on the outside of the feed substrate 4 in a fitted state, one end of the array arm 3 is connected to the horizontal feed line 21, and the other end extends on the outside of the feed substrate 4; wherein, the spiral direction of the multiple array arms 3 arranged on the same layer of the feed substrate 4 is the same, and the spiral direction of the array arms 3 arranged on the upper layer 41 of the feed substrate 4 is opposite to the spiral direction of the array arms 3 arranged on the lower layer 42 of the feed substrate 4.

[0047] See attached Figure 4 , Attachment Figure 7 and attached Figure 8 Based on the above scheme, since the two layers of feed line groups 2 are parallel to each other and are respectively arranged on the upper layer 41 and the lower layer 42 of the feed substrate 4, a stacked structure can be formed, thereby effectively saving space and facilitating the miniaturization of the omnidirectional circularly polarized antenna.

[0048] See attached Figure 5 and attached Figure 6Based on the above scheme, since the array arm 3 in the present application is a spiral structure, when the antenna height is the same, compared with the traditional array arm that is a straight line from end to end, the current path of the array arm 3 in the present application is longer and has more current paths, thereby ensuring that it has good standing wave ratio and gain characteristics; when the array arm length is the same, compared with the traditional design, the structure in the present application can greatly reduce the height of the antenna, achieve a low profile, and is conducive to the miniaturization of the omnidirectional circularly polarized antenna.

[0049] See attached Figure 12 and attached Figure 13 Based on the above scheme, since multiple array arms 3 are provided corresponding to multiple horizontal feed lines 21, the multiple array arms 3 on the same layer are arranged in a circular array. Since the multiple array arms 3 arranged on the same layer of the feed substrate 4 have the same spiral direction, the spiral direction of the array arms 3 arranged on the upper layer 41 of the feed substrate 4 is opposite to the spiral direction of the array arms 3 arranged on the lower layer 42 of the feed substrate 4. Therefore, the omnidirectional circularly polarized antenna has excellent omnidirectionality and stable radiation characteristics.

[0050] See attached Figure 2 And attached Figure 11 -Attached Figure 15 Based on the above solution, since the short-circuit sleeve 6 is provided on the extending portion 51 of the feeder cable 5, the feeder cable 5 can be effectively protected from the influence of the induced current. Specifically, conventional cables usually have significant induced currents and lack any means to suppress them. Therefore, parasitic radiation will be generated in the far field. This parasitic radiation is the fundamental factor causing distortion of the antenna pattern. Although the feeder cable 5 in the present application has significant induced currents, thanks to the presence of the short-circuit sleeve 6, a reverse cancellation current will be generated. Since the parasitic current is cancelled by the generated reverse current, the far-field radiation is greatly reduced, thereby achieving a conformal effect on the pattern.

[0051] In general, the omnidirectional circularly polarized antenna in this application is not easily affected by cable induced currents. While maintaining high gain and high axial ratio characteristics, it can preserve the directional pattern to the greatest extent, reduce distortion, and thus improve the quality of communication.

[0052] It should be noted that this application does not limit the head-to-tail line width ratio, tilt angle, length and other parameters of the array arm, which can be flexibly selected according to actual conditions. For example, adjusting the head-to-tail line width ratio of the array arm can control the working bandwidth, adjusting the tilt angle of the array arm can adjust and optimize the axial ratio characteristics without increasing the antenna height, and adjusting the length of the array arm can adjust the resonant frequency.

[0053] It should be noted that the length of the short-circuit sleeve 6 is not limited in this application, and the length of the short-circuit sleeve 6 can be reasonably adjusted according to actual conditions to better suppress the induced current on the feeder cable 5.

[0054] See attached Figure 3 Furthermore, the following design is implemented in this embodiment. Specifically, the feed substrate 4 is a cylindrical hollow structure. The upper layer 41 and the lower layer 42 of the feed substrate 4 are symmetrically designed. The feed substrate 4 is provided with a plurality of routing bosses 43 corresponding to the plurality of array arms 3. The plurality of routing bosses 43 have gaps and are arranged in a circular axis array.

[0055] Through the above-mentioned structural design, since the feed substrate 4 is provided with a hollow portion, the weight of the omnidirectional circularly polarized antenna can be further reduced. Since the feed substrate 4 is vertically symmetrical and has a circular array design in the horizontal direction, the structural distribution is relatively uniform, so the omnidirectional circularly polarized antenna can have excellent omnidirectionality. In addition, it has the advantages of being easy to process and more aesthetically pleasing.

[0056] It should be noted that the material and type of the feed substrate 4 are not limited in this application and can be flexibly selected according to actual needs. This embodiment introduces one of the designs. Specifically, the feed substrate 4 uses an ultra-thin flexible circuit board.

[0057] The above-described structural design enables the feed substrate 4, fabricated from an ultra-thin flexible circuit board, to have excellent power supply performance, meeting design requirements for smaller and higher-density installations. This also helps reduce assembly steps and enhances reliability. The feed substrate 4 can be freely bent, wound, and folded, and can withstand millions of dynamic bends without damaging the conductors. It can be arbitrarily arranged according to spatial layout requirements and freely moved and extended in three-dimensional space, thereby achieving integrated component assembly and conductor connection. Furthermore, the feed substrate 4 can significantly reduce the size and weight of electronic products, meeting the needs of the development of electronic products towards high density, miniaturization, and high reliability.

[0058] See attached Figure 1 It should be noted that the type and size of the feeder cable 5 are not limited in this application and can be flexibly selected according to actual needs. This embodiment introduces one of the designs. Specifically, the feeder cable 5 uses RG402 cable and has a length of 80 mm.

[0059] See attached Figure 1 and attached Figure 10 In order to make the short-circuit sleeve 6 meet the above functions, the following design is carried out in this embodiment. Specifically, the material of the short-circuit sleeve 6 is metal, one end of the short-circuit sleeve 6 is short-circuited and welded to the feeder cable 5, and the other end is open-circuited.

[0060] Through the design of the above structure, the influence of the induced current on the feed cable 5 on the antenna radiation pattern can be effectively reduced, and the original radiation pattern can be preserved to the greatest extent, solving the problem that the current products on the market are generally susceptible to cable interference, and have higher gain and more stable radiation performance.

[0061] See attached Figure 7 and attached Figure 8 It should be noted that the size and structure of the horizontal feeder 21 are not limited in this application and can be flexibly selected according to actual needs. This embodiment introduces one of the designs. Specifically, the width of the horizontal feeder 21 gradually increases from the first end 211 to the second end 212.

[0062] Through the design of the above structure, the horizontal feed line 21 adopts a gradient line width to achieve good matching. The gradient line is a common impedance matching line. The gradient line width can achieve continuous impedance change, which is more continuous than the quarter-wavelength impedance transformer. Generally speaking, a thin line width represents a high impedance, and a wide line width represents a low impedance characteristic. In this embodiment, the thin line at the feed point gradually changes to a thick line at the end of the array arm 3, realizing the conversion from high impedance to low impedance, thereby achieving impedance matching of the antenna.

[0063] See attached Figure 5 and attached Figure 6 It should be noted that the spiral direction of the array arm 3 is not limited in this application and can be flexibly selected according to actual needs. This embodiment introduces one design. Specifically, the array arm 3 arranged on the upper layer 41 of the feed substrate 4 extends along the right-handed thread direction, and the array arm 3 arranged on the lower layer 42 of the feed substrate 4 extends along the left-handed thread direction.

[0064] There are various ways to connect different components. This embodiment introduces one of them. Specifically, the feeder group 2 and the array arm 3 are both etched on the substrate by laser engraving technology.

[0065] The above-mentioned structural design greatly reduces design costs, eliminates the need for high-performance circuit boards or high-precision sheet metal parts in traditional antennas, and achieves low costs. Relying on mature laser engraving technology, it greatly improves production efficiency and ensures the consistency of mass production of products.

[0066] In summary, this omnidirectional circularly polarized antenna exhibits excellent standing wave ratio (SWR), high gain, axial ratio, and stable radiation characteristics. The introduction of the short-circuit sleeve (6) not only modifies the radiation pattern and axial ratio but also reduces the impact of cables on the antenna's standing waves. This omnidirectional circularly polarized antenna boasts a small size, low profile, light weight, and low price, making it ideal for integration with smart devices, achieving miniaturization and integration. Compared to traditional omnidirectional circularly polarized antennas, its radiation performance stability is significantly improved.

[0067] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0068] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of this application.

[0069] Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An omnidirectional circularly polarized antenna, characterized in that: include: A radome, wherein a feed substrate is provided inside the radome, the feed substrate having an upper layer and a lower layer, the lower layer of the feed substrate being provided with a feed cable for connecting to an external device, the feed cable having an extension extending out of the radome, the extension of the feed cable being provided with a short-circuit sleeve; Two layers of feeder groups, the two layers of feeder groups being parallel to each other and respectively arranged on the upper and lower layers of the feed substrate, the feeder groups comprising a plurality of horizontal feeders arranged in a circumferential array, the horizontal feeders having first and second ends spaced apart from each other, the first ends of the plurality of horizontal feeders on the same layer being interconnected; An array arm, wherein a plurality of the array arms are provided corresponding to the plurality of the horizontal feed lines, and the array arm is a spiral structure, and the array arm is provided on the outside of the feed substrate in a fitted state, with one end of the array arm connected to the horizontal feed line and the other end extending on the outside of the feed substrate; The spiral directions of the plurality of array arms arranged on the same layer of the feed substrate are the same, and the spiral direction of the array arms arranged on the upper layer of the feed substrate is opposite to the spiral direction of the array arms arranged on the lower layer of the feed substrate.

2. The omnidirectional circularly polarized antenna according to claim 1, wherein: The feed substrate is a cylindrical hollow structure, the upper structure and the lower structure of the feed substrate are symmetrically designed, and a plurality of routing bosses are provided on the feed substrate corresponding to the plurality of array arms. The plurality of routing bosses have gaps and are arranged in a circular axis array.

3. The omnidirectional circularly polarized antenna according to claim 1, wherein: The feed substrate is an ultra-thin flexible circuit board.

4. The omnidirectional circularly polarized antenna according to claim 1, wherein: The feeder cable is RG402 cable and has a length of 80 mm.

5. The omnidirectional circularly polarized antenna according to claim 1, wherein: The short-circuit sleeve is made of metal, one end of the short-circuit sleeve is short-circuited and welded to the feeder cable, and the other end is open-circuited.

6. The omnidirectional circularly polarized antenna according to claim 1, characterized in that: The width of the horizontal feed line gradually increases from the first end to the second end.

7. The omnidirectional circularly polarized antenna according to claim 1, characterized in that: The array arm arranged on the upper layer of the feed substrate extends along the right-handed thread direction, and the array arm arranged on the lower layer of the feed substrate extends along the left-handed thread direction.

8. The omnidirectional circularly polarized antenna according to any one of claims 1 to 7, characterized in that: The feeder group and the array arm are both etched on the substrate by a laser engraving process.

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