Antenna assembly

Abstract

The invention discloses an antenna assembly, and relates to the technical field of Internet of Things. The antenna assembly comprises an antenna and a reflecting plate, the reflecting plate is provided with a reflecting surface, the antenna and the reflecting plate are arranged at an interval, the antenna and the reflecting surface are oppositely arranged, and the reflecting surface is used for adjusting an antenna pattern of the antenna. According to the embodiment of the invention, the antenna pattern is adjusted by arranging the reflecting plate with the reflecting surface, an antenna does not need to be customized for each scene, the cost is saved, and the implementation difficulty is low.

Description

Technical Field

[0001] This application relates to the field of Internet of Things (IoT) technology, and more particularly to an antenna assembly. Background Technology

[0002] The new passive IoT technology has advantages such as low cost, zero power consumption, easy deployment, and high density. It can be used in indoor deep coverage scenarios such as asset management and supermarket retail, as well as outdoor wide coverage scenarios such as smart grids and production logistics.

[0003] Unlike related mobile communication systems, passive IoT does not aim for continuous, seamless coverage of the target area. Instead, it prioritizes ensuring a strong connection between the exciter and the passive tags, providing sufficient energy to the tags for excitation, and simultaneously receiving data reported by the tags to read the information they carry. Therefore, the antenna setup for passive IoT systems targets the distribution of passive tags, rather than continuous coverage of the entire area. In areas where passive tags are not distributed, coverage should be minimized to ensure efficient use of signal energy. Based on this, flexible antenna deployment is necessary according to the distribution of passive tags.

[0004] However, since the deployment scenarios of passive IoT vary in size and the distribution areas of passive tags are also different, the antenna radiation pattern requirements are also different. Therefore, related technologies require antennas to be customized according to each project scenario, which is costly and difficult. Summary of the Invention

[0005] This application provides an antenna assembly to at least address the problem in related technologies that requires high costs and difficulties in customizing antennas for each project scenario.

[0006] In a first aspect, embodiments of this application provide an antenna assembly, including: an antenna and a reflector, the reflector having a reflective surface, the antenna being spaced apart from the reflector and the antenna being disposed opposite to the reflective surface, the reflective surface being used to adjust the antenna pattern of the antenna.

[0007] In this embodiment, the antenna assembly includes an antenna and a reflector. The reflector has a reflective surface, and the antenna and reflector are spaced apart and positioned opposite each other. The reflective surface is used to adjust the antenna pattern. This embodiment adjusts the antenna pattern by using a reflector with a reflective surface, eliminating the need to customize an antenna for each scenario, thus saving costs and reducing implementation difficulty. Attached Figure Description

[0008] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments of this application and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the antenna assembly provided in an embodiment of this application; Figure 2 This is a schematic diagram of a reflector provided in an embodiment of this application; Figure 3 This is a schematic diagram of another reflector provided in an embodiment of this application; Figure 4 This is a schematic diagram showing the horizontal / vertical angle between the antenna and the first focal point of the reflector, as provided in an embodiment of this application. Figure 5 This is a schematic diagram showing the horizontal / vertical angle between the antenna and the second focal point of the reflector, as provided in an embodiment of this application. Figure 6 This is a schematic diagram of the XZ axis section of a reflector provided in an embodiment of this application; Figure 7 This is a schematic diagram of another reflector's XZ axis section provided in an embodiment of this application; Figure 8 This is a schematic diagram of yet another reflector provided in an embodiment of this application; Figure 9 This is a schematic diagram of the angle between the antenna and the horizontal plane of the reflector provided in an embodiment of this application; Figure 10 This is a schematic diagram of the angle between the antenna and the vertical plane of the reflector provided in an embodiment of this application; Figure 11 This is a schematic diagram of the XZ axis section of another reflector provided in the embodiments of this application; Figure 12 This is a schematic diagram of the structure of a reflector provided in an embodiment of this application. Detailed Implementation

[0009] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0010] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0011] In passive IoT, antennas are typically deployed in limited areas such as rooftops and walls. To ensure good coverage of the target area, the antenna beamwidth should ensure that the main lobe of the antenna beam is within the target area. The beamwidth should not be too small to avoid the main lobe covering the ground in non-target areas; nor should it be too large to avoid excessive dispersion of antenna energy and interference from other areas.

[0012] Because the deployment scenarios of passive IoT vary in size and the distribution areas of passive tags are also different, the antenna radiation pattern requirements are also different. Therefore, the relevant technologies require customized antennas for each project scenario, which is costly and difficult.

[0013] In some instances, pattern-reconfigurable antennas control the radiation pattern by changing the antenna structure in real time while keeping other antenna characteristics constant. However, this type of antenna is more complex to design and significantly increases its cost.

[0014] Therefore, this application provides an antenna assembly that makes the antenna pattern variable by adding a reflector. The reflector is relatively mature in manufacturing process, easy to implement, and relatively simple to install.

[0015] The following is in conjunction with the appendix Figures 1 to 12 The present application provides a detailed description of an antenna assembly through specific embodiments and application scenarios.

[0016] like Figure 1 The diagram shown is a structural schematic of an antenna assembly provided in an embodiment of this application. Figure 1 As shown, the antenna assembly may include an antenna and a reflector. The reflector has a reflective surface, the antenna is spaced apart from the reflector, and the antenna is positioned opposite the reflective surface. The reflective surface is used to adjust the antenna pattern of the antenna.

[0017] The antenna and reflector can be detachable, allowing for the replacement of different reflectors depending on the scenario. Specifically, it can be as follows: Figure 1 As shown, a bracket is set up, and the antenna is set inside the bracket. The antenna is mounted on the bracket, and the antenna assembly is installed on the mounting surface of the installation position through the bracket.

[0018] In one example, the reflector can be replaced to meet the requirements based on at least one of the antenna's adjusted beamwidth and reflection direction.

[0019] In this embodiment, the antenna assembly includes an antenna and a reflector. The reflector has a reflective surface, and the antenna and reflector are spaced apart and positioned opposite each other. The reflective surface is used to adjust the antenna pattern. This embodiment adjusts the antenna pattern by using a reflector with a reflective surface, eliminating the need to customize an antenna for each scenario, thus saving costs and reducing implementation difficulty.

[0020] Since the antenna assembly in this embodiment does not require modification of the original antenna, but only changes the original antenna's beamwidth, beam direction, and other antenna pattern characteristics by adding a reflector, the antenna pattern characteristics are altered. By installing a reflector at the front end of the passive IoT antenna, the wireless signal, after being transmitted by the antenna, is reflected by the reflector. The reflector's ability to converge or diffuse the beam reconstructs the antenna pattern, thus changing its coverage area. Simultaneously, by matching the beamwidth to the coverage target, the coverage quality is enhanced.

[0021] As described above, the reflector has the function of reconstructing the antenna pattern, that is, it can adjust the antenna beamwidth and beam direction. Therefore, the shape of the reflector can be one leaf of a hyperboloid or a paraboloid. Different surfaces can be selected depending on the scenario, as long as the main lobe after antenna beam reflection can cover the target area. This embodiment does not impose any limitations based on the actual application.

[0022] In a shelf-type coverage scenario, the coverage area is the shelf itself. In this case, it's necessary to ensure the antenna's main lobe covers the vertical surface of the shelf, requiring adjustment of the antenna's beamwidth to fit the shelf spacing. The reflector surface of the reflector can be a hyperboloid, with the antenna placed at either its first or second focal point. The first focal point is the focus of the hyperboloid, and the second focal point is the point where the backward extensions of the emitted beam converge after reflection from the hyperboloid when the antenna is at the hyperboloid's focal point. Specifically, when the antenna is placed at the first focal point (referred to as the concave-side focal point in this application), as... Figure 2 As shown, the backward extensions of the reflected wave converge at the second focal point (referred to as the convex focal point in this application). At this point, the antenna beamwidth decreases. This is suitable for scenarios where the target coverage area is narrow but the original antenna beamwidth is large. When the antenna is placed at the convex focal point of a curved surface, as... Figure 3 As shown, the backward extension of the reflected wave from the hyperboloid reflector converges at the concave focal point, which increases the antenna beamwidth. This is suitable for scenarios where the target coverage area is wide but the original antenna beamwidth is small.

[0023] In one instance, the reflecting surface comprises any portion of a two-sheet hyperboloid.

[0024] In this embodiment, the hyperboloid can be a two-leaf hyperboloid, where any part refers to one leaf of the two-leaf hyperboloid. The reflective surface of the two-leaf hyperboloid shape allows adjustment of the antenna beam direction and beam width, achieving antenna pattern adjustment without changing the antenna itself.

[0025] In one example, the equation of the hyperboloid of the reflector is as follows:

[0026] in:

[0027] As mentioned above, in practical applications, the antenna is placed at the convex or concave focal point of the hyperboloid. To facilitate the placement of the reflector, the focal positions in the horizontal and vertical directions are set to be the same, i.e., a=b. The equation of the hyperboloid of the reflector then becomes:

[0028] In one example, to avoid the influence of antenna size on hyperboloid reflection, while keeping the antenna reflector as small as possible, the distance from the focal point of the reflector to the reflector is greater than or equal to the boundary distance between the near and far fields of the electromagnetic wave.

[0029] Furthermore, when the antenna is located in the concave direction of the hyperboloid reflector, then:

[0030] Where: D is the maximum size of the passive IoT antenna; λ is the electromagnetic wave wavelength.

[0031] When the antenna is located on the convex side of the hyperboloid reflector, then:

[0032] Since passive IoT antennas do not directly cover the target area, the reflector must be able to reflect more than 90% of the antenna's electromagnetic radiation energy back to the target area. Assuming the antenna's horizontal half-power angle is α and its vertical half-power angle is β, then the antenna's horizontal angle h on the reflector is greater than or equal to 2α, and its vertical angle v is greater than or equal to 2β. Figure 4 and 5 The diagrams shown are schematics illustrating the horizontal / vertical angles between the antenna and the first and second focal points of the reflector.

[0033] In one possible embodiment of this application, when the antenna beamwidth is reduced, the concave side of the hyperboloid is the reflecting surface, and the antenna is located at the first focal point of the reflecting surface, which is the focal point of the hyperboloid; when the antenna beamwidth is increased, the convex side of the hyperboloid is the reflecting surface, and the antenna is located at the second focal point of the reflecting surface, which is the point where the backward extensions of the emitted beam converge after reflection by the hyperboloid when the antenna is at the focal point of the hyperboloid.

[0034] In one example, specifically a scenario where the beamwidth is reduced, the antenna is positioned on the concave side of the reflector, i.e., at the first focal point. The horizontal beamwidth is adjusted as follows: Let the antenna's horizontal half-power angle be α, and the target value of the adjusted half-power angle after reflection be γ. For example... Figure 6 The diagram shown is a schematic diagram of the XZ axis section of the reflector. Figure 6In the diagram, A represents the position of the antenna, L represents the distance from the antenna to the reflector, and (z, x) represents the coordinates of the edge of the XZ axis tangent plane of the reflector.

[0035] The coordinates of the edge of the XZ axis tangent plane of the reflector have the following relationship:

[0036] The eccentricity of the XZ axis section of the reflector is K.

[0037] The distance from the antenna to the reflector is L, and satisfies... .

[0038] The focal length of the XZ axis tangent curve is F, and it satisfies... .

[0039] Then we have: , ,

[0040] From the triangular relationship, we can know that:

[0041]

[0042] From the above two equations, the value of x at the edge point of the XZ axis plane of the reflector can be obtained as follows:

[0043]

[0044] At this moment, the value of y at the vertical edge point of the reflector is:

[0045] The antenna vertical beamwidth is adjusted as follows:

[0046] If the vertical beamwidth is adjusted, a similar result can be obtained. The embodiments in this application will not be described in detail, as they are similar to the reasoning process described above.

[0047] In one example, specifically a scenario where the beamwidth is increased, the antenna is positioned on the convex side of the reflector, i.e., at the second focal point. The horizontal beamwidth is adjusted as shown below. Let the antenna's horizontal half-power angle be α, and the target value of the adjusted half-power angle after reflection be γ. For example... Figure 7 The diagram shown is a schematic diagram of the XZ axis section of the reflector. Figure 7 In the diagram, A represents the position of the antenna, L represents the distance from the antenna to the reflector, and (z, x) represents the coordinates of the edge of the XZ axis tangent plane of the reflector.

[0048] The coordinates of the edge of the XZ axis tangent plane of the reflector have the following relationship:

[0049] The eccentricity of the XZ axis section of the reflector is K.

[0050] The distance from the antenna to the reflector is L, and satisfies... .

[0051] The focal length of the XZ axis tangent curve is F, and it satisfies... .

[0052] Then we have: , ,

[0053] From the triangular relationship, we can know that:

[0054]

[0055] From the above two equations, the value of x at the edge point of the XZ axis plane of the reflector can be obtained as follows:

[0056]

[0057] At this moment, the value of y at the vertical edge point of the reflector is:

[0058] The antenna vertical beamwidth is adjusted as follows:

[0059] If the vertical beamwidth is adjusted, a similar result can be obtained. The embodiments in this application will not be described in detail, as they are similar to the reasoning process described above.

[0060] In one specific embodiment, taking a 900MHz system as an example: The maximum size of the 900MHz passive IoT antenna is 0.25 meters, with a horizontal half-power angle of 45° and a vertical half-power angle of 45°. The distance between the antenna and the reflector is 0.5 meters.

[0061] Assuming the horizontal half-power angle is adjusted to 30°, the antenna needs to be placed on the concave side of the reflector. The eccentricity of the reflector in the XZ axis tangent plane is K=8. The radius of the reflector's bottom surface along the X-axis is 0.42 meters, the radius of its bottom surface along the Y-axis is 0.42 meters, and its surface area is approximately 0.7 square meters.

[0062] Assuming the horizontal half-power angle is adjusted to 55 degrees, the antenna needs to be placed on the convex side of the reflector. The eccentricity of the reflector in the XZ axis tangent plane is K=3. The radius of the reflector's bottom surface along the X-axis is 0.44 meters, the radius of its bottom surface along the Y-axis is 0.44 meters, and its surface area is approximately 0.88 square meters.

[0063] In stacked coverage scenarios, the coverage area is the stacked goods area. In this case, it's necessary to ensure the antenna's main lobe covers the stacked area plane. This requires adjusting the antenna's beamwidth to adapt to the coverage requirements of the stacked area plane. In this case, a parabolic reflector shape is chosen. When the antenna is placed at the focal point of this parabolic reflector, the reflected waves will be parallel. This results in uniform antenna beam coverage, good coverage quality, better control over the coverage area, and avoidance of inter-cell signal interference. Figure 8 As shown.

[0064] In one example, the equation of the parabolic surface of the reflector is as follows:

[0065] Where p is a constant.

[0066] In one example, to avoid the problem of rapid attenuation of electromagnetic waves in the far field with increasing distance, the focal point of the reflector is larger than the boundary between the near and far fields of the electromagnetic waves. To ensure that the size of the reflector is minimized, i.e.:

[0067] Where: p / 2 is the distance from the focal point to the reflecting surface; D is the maximum size of the indoor coverage antenna; λ is the electromagnetic wave wavelength, which means that if it is a multi-frequency source, the highest frequency wavelength is taken.

[0068] Since indoor base station antennas do not directly cover the target area, the reflector must be able to reflect more than 90% of the antenna's electromagnetic radiation energy back to the target area. Assuming the horizontal half-power angle of the indoor base station antenna is α and the vertical half-power angle is β, then at a focal distance L from the reflector, its horizontal angle h is greater than or equal to 2α, and its vertical angle v is greater than or equal to 2β. Figure 9 and 10 The diagrams shown are schematics of the angles between the antenna and the horizontal plane and the vertical plane of the reflector.

[0069] like Figure 11 The diagram shown is a schematic diagram of the XZ axis section of the reflector. Figure 11 The distance from the antenna to the reflector is L, and the coordinates of the edge of the XZ axis tangent plane of the reflector are (z, x).

[0070] The coordinates of the edge of the XZ axis tangent plane of the reflector have the following relationship:

[0071] From the triangular relationship, we can know that:

[0072] From the above two equations, the value of x at the edge point of the XZ axis plane of the reflector can be obtained as follows:

[0073] Similarly, the value of y at the edge point of the YZ axis plane of the reflector is:

[0074] At higher frequencies, the coordinates of the reflector's focal point are much larger than the coordinates of the antenna's placement. Therefore, the parabolic reflector can be approximated as a plane, with an area approximately equal to 2x * 2y, or 4x * y.

[0075] In one specific embodiment, taking 900MHz as an example, the maximum size D of the indoor antenna is 0.3m, the horizontal half-power angle is 75 degrees, and the vertical half-power angle is 65 degrees. The x-axis bottom radius of the reflector is 0.21 meters, the y-axis bottom radius is 0.16 meters, and the surface area is approximately 0.14 square meters.

[0076] In one instance, the hyperboloid reflector's size is relatively similar whether the beamwidth of the antenna pattern is increased or decreased. Therefore, different coverage scenarios can be adapted by replacing the reflector.

[0077] The antenna and reflector can be integrated into a single unit, with the reflector being a detachable component. Different antenna pattern reconstruction schemes can be achieved by installing different reflectors. This allows for large-scale, standardized production of the device, avoiding customization for specific scenarios and reducing costs.

[0078] In one possible embodiment of this application, the shape of the planar projection of the reflector is rectangular.

[0079] In this embodiment, due to the unique coverage scenario of passive IoT, it is neither possible nor necessary to use a traditional hexagonal cellular structure to achieve continuous planar coverage. Therefore, the shape of the cell coverage can be chosen as a rectangle, which offers higher coverage strength. Since the planar projection of the reflector is rectangular, the radiation pattern of the antenna reflected wave will tend towards a rectangle, achieving not only continuous coverage but also easier interference coordination. Figure 12 As shown.

[0080] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0081] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal (which may be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0082] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. An antenna assembly, characterized in that, include: An antenna and a reflector, the reflector having a reflective surface, the antenna being spaced apart from the reflector and positioned opposite to the reflective surface, the reflective surface being used to adjust the antenna pattern of the antenna.

2. The antenna assembly according to claim 1, characterized in that, The reflecting surface includes any portion of a bisheet hyperboloid.

3. The antenna assembly according to claim 2, characterized in that, The distance from the focal point of the reflecting surface to the reflecting surface is greater than or equal to the boundary distance between the near field and far field of the electromagnetic wave of the antenna.

4. The antenna assembly according to claim 2, characterized in that, When the antenna beamwidth of the antenna is reduced, the concave side of the double-leaf hyperboloid is a reflecting surface, and the antenna is disposed at the first focal point of the reflecting surface, the first focal point being the focal point of the double-leaf hyperboloid; When the antenna beamwidth of the antenna is increased, the convex side of the double-leaf hyperboloid is a reflecting surface, and the antenna is located at the second focal point of the reflecting surface. The second focal point is the point where the backward extensions of the emitted beam converge after being reflected by the double-leaf hyperboloid when the antenna is at the focal point of the double-leaf hyperboloid.

5. The antenna assembly according to claim 4, characterized in that, When adjusting the antenna beamwidth, the vertical beamwidth of the antenna is adjusted as follows: Where α is the antenna's horizontal half-power angle; β is the antenna's vertical half-power angle; and γ is the target value of the antenna beam's adjusted half-power angle after reflection.

6. The antenna assembly according to claim 4, characterized in that, Replace the reflector according to the adjusted beamwidth or reflection direction of the antenna.

7. The antenna assembly according to claim 1, characterized in that, The reflective surface has a parabolic shape.

8. The antenna assembly according to claim 7, characterized in that, The antenna is positioned at the focal point of the reflective surface.

9. The antenna assembly according to claim 7, characterized in that, The distance from the focal point of the reflecting surface to the reflecting surface is greater than or equal to the boundary distance between the near field and far field of the electromagnetic wave of the antenna.

10. The antenna assembly according to claim 1, characterized in that, The shape of the planar projection of the reflector is rectangular.

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