Circularly polarized antenna and communication system

Abstract

Provided in the present disclosure are a circularly polarized antenna and a communication system, which relate to the technical field of antennas. The circularly polarized antenna comprises a radiating plate, a substrate and a plurality of feed probes, wherein the radiating plate is provided with a plurality of slots, the slots extend through the radiating plate in the thickness direction of the radiating plate, and the slots are arranged in a circumferential array; the substrate is opposed to and spaced apart from the radiating plate, and the substrate is provided with a feed network; and the plurality of feed probes are located between the radiating plate and the substrate and are spaced apart from each other, and one end of each feed probe is electrically connected to the feed network, and the other end thereof is electrically connected to the radiating plate. The circularly polarized antenna has a high gain and a relatively small size.

Description

Circularly polarized antennas and communication systems Technical Field

[0001] The present disclosure relates to the field of antenna technology, and in particular to a circularly polarized antenna and a communication system. Background Art

[0002] Communication systems include antennas, which radiate or receive electromagnetic waves. Depending on their polarization, antennas include horizontally polarized antennas, vertically polarized antennas, circularly polarized antennas, and elliptically polarized antennas. Circularly polarized antennas are widely used due to their robustness against attenuation and multipath. However, conventional circularly polarized antennas cannot simultaneously meet the requirements of high gain and miniaturization.

[0003] Summary of the Invention

[0004] Embodiments of the present disclosure provide a circularly polarized antenna and a communication system having high gain and small size.

[0005] To achieve the above objectives, the embodiments of the present disclosure adopt the following technical solutions:

[0006] In one aspect, a circularly polarized antenna is provided, comprising:

[0007] A radiation plate, wherein the radiation plate is provided with a plurality of slits, the slits penetrating the radiation plate along the thickness direction of the radiation plate, and the plurality of slits are arranged in a circumferential array;

[0008] a substrate, the substrate being opposite to and spaced from the radiation plate, and the substrate being provided with a feeding network;

[0009] A plurality of feeding probes are located between the radiation plate and the substrate and are arranged at intervals, one end of the feeding probe is electrically connected to the feeding network, and the other end of the feeding probe is electrically connected to the radiation plate.

[0010] In some embodiments, the feeding probe and the radiation plate are an integrally formed structure.

[0011] In some embodiments, the feeding probe is in a long strip shape, and the area of ​​the feeding probe is smaller than or equal to the area of ​​the gap.

[0012] In some embodiments, the feeding probe is formed by bending material in the gap toward the substrate.

[0013] In some embodiments, the plurality of feeding probes are configured to support the radiating plate.

[0014] In some embodiments, the distance between the radiation plate and the substrate is less than or equal to λ*1 / 4, where λ is the center frequency wavelength of the circularly polarized antenna.

[0015] In some embodiments, an extending direction of the feeding probe forms an angle with a normal direction of the radiation plate.

[0016] In some embodiments, the multiple gaps include a first gap, a second gap, a third gap, and a fourth gap, the first gap and the second gap are arranged at intervals along a first direction, the third gap and the fourth gap are arranged at intervals along a second direction, and the first direction and the second direction are perpendicular to each other and parallel to the radiation plate.

[0017] In some embodiments, the radiation plate is shaped as a centrally symmetrical figure, and the geometric center of the radiation plate coincides with the center of the circular array.

[0018] In some embodiments, when the radiation plate is polygonal in shape, one diagonal line of the radiation plate is along the first direction, and another diagonal line of the radiation plate is along the second direction.

[0019] In some embodiments, the edges of the first slot, the second slot, the third slot, and the fourth slot adjacent to the center of the circular array are connected to the feeding probe.

[0020] In some embodiments, the feed network includes a first feed end, a second feed end, a third feed end, and a fourth feed end, wherein the first feed end is electrically connected to the edge of the first slot through the feed probe, the second feed end is electrically connected to the edge of the second slot through the feed probe, the third feed end is electrically connected to the edge of the third slot through the feed probe, and the fourth feed end is electrically connected to the edge of the fourth slot through the feed probe.

[0021] The first feeding terminal and the second feeding terminal are configured to output signals with opposite phases, and the third feeding terminal and the fourth feeding terminal are configured to output signals with opposite phases.

[0022] In some embodiments, the feed network includes a power splitter circuit, a first differential circuit, and a second differential circuit, the power splitter circuit includes a combining end, a first branch end, and a second branch end, the first differential circuit is electrically connected to the first branch end, the first feed end, and the second feed end, and the second differential circuit is electrically connected to the second branch end, the third feed end, and the fourth feed end.

[0023] In some embodiments, the feeding network is arranged on a side of the substrate away from the radiation board, and a reflective ground is further provided on a side of the substrate facing the radiation board. The reflective ground is provided with an avoidance hole, and the feeding probe passes through the avoidance hole to be electrically connected to the feeding network.

[0024] In some embodiments, the circularly polarized antenna further includes an antenna cover, which includes a cover body and a base plate, the base plate is sealed and connected to the cover body to form an installation cavity, and the radiation plate, the substrate and the feeding probe are located in the installation cavity.

[0025] On the other hand, a communication system is provided, comprising the circularly polarized antenna.

[0026] The circularly polarized antenna and communication system provided by the present disclosure include a radiating plate, a substrate, and multiple feeding probes. The radiating plate and substrate are arranged opposite and spaced apart, with the multiple feeding probes located between the radiating plate and the substrate. The substrate is provided with a feeding network, which is electrically connected to the radiating plate via the feeding probes. Due to the thin thickness of the radiating plate and the small number of layers of the circularly polarized antenna structure perpendicular to the radiating plate, the circularly polarized antenna has a small size while maintaining high gain. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0028] FIG1 is a front view of a circularly polarized antenna provided by an embodiment of the present disclosure;

[0029] FIG2 is a side view of a circularly polarized antenna provided in an embodiment of the present disclosure;

[0030] FIG3 is a rear view of a circularly polarized antenna provided in an embodiment of the present disclosure;

[0031] FIG4 is a schematic diagram of a radiating plate and a feeding probe in a circularly polarized antenna provided by an embodiment of the present disclosure;

[0032] FIG5 is a rear view of a radiating plate and a feeding probe in a circularly polarized antenna provided by a disclosed embodiment;

[0033] FIG6 is a side view of a radiating plate and a feeding probe in a circularly polarized antenna provided by the disclosed embodiment;

[0034] FIG7 is a cross-sectional view of a substrate in a circularly polarized antenna provided in an embodiment of the present disclosure;

[0035] FIG8 is a front view of a substrate in a circularly polarized antenna provided by an embodiment of the present disclosure;

[0036] FIG9 is a schematic diagram of a feeding network in a circularly polarized antenna provided by an embodiment of the present disclosure;

[0037] FIG10 is a front view of a radiating plate in a circularly polarized antenna provided by an embodiment of the present disclosure;

[0038] FIG11 is an exploded schematic diagram of a circularly polarized antenna provided in an embodiment of the present disclosure;

[0039] FIG12 is a front view of an installed circularly polarized antenna provided by an embodiment of the present disclosure;

[0040] FIG13 is a side view of an installed circularly polarized antenna provided by an embodiment of the present disclosure;

[0041] FIG14 is a rear view of an installed circularly polarized antenna provided by an embodiment of the present disclosure;

[0042] FIG15 is a graph showing a standing wave ratio characteristic of a circularly polarized antenna provided in an embodiment of the present disclosure;

[0043] FIG16 is a diagram showing the isolation characteristics of a circularly polarized antenna according to an embodiment of the present disclosure;

[0044] FIG17 is a cross-polarization ratio characteristic diagram of a circularly polarized antenna provided in an embodiment of the present disclosure;

[0045] FIG18 is a characteristic diagram of a power dividing circuit S11 in a circularly polarized antenna provided by an embodiment of the present disclosure;

[0046] FIG19 is a characteristic diagram of the power difference between a first branch terminal and a second branch terminal of a power dividing circuit in a circularly polarized antenna provided by an embodiment of the present disclosure;

[0047] FIG20 is a phase difference characteristic diagram between a first branch terminal and a second branch terminal in a power dividing circuit of a circularly polarized antenna provided by an embodiment of the present disclosure;

[0048] FIG21 is a diagram showing the overall standing wave ratio characteristics of a circularly polarized antenna provided by an embodiment of the present disclosure;

[0049] FIG22 is a diagram showing the axial ratio characteristics of a circularly polarized antenna according to an embodiment of the present disclosure;

[0050] FIG23 is a diagram showing the overall gain characteristics of a circularly polarized antenna according to an embodiment of the present disclosure. Specific embodiments

[0051] The following will be combined with the accompanying drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the embodiments described are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present disclosure.

[0052] In the embodiments of the present disclosure, words such as "first", "second", "third", and "fourth" are used to distinguish between identical or similar items with substantially the same functions and effects. This is only for the purpose of clearly describing the technical solutions of the embodiments of the present disclosure, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features.

[0053] In the embodiments of the present disclosure, “a plurality of” means two or more, and “at least one” means one or more, unless otherwise clearly and specifically defined.

[0054] In the embodiments of the present disclosure, the orientations or positional relationships indicated by terms such as “upper” and “lower” are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present disclosure and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present disclosure.

[0055] The multipath effect occurs when electromagnetic waves propagate along different paths, with each component arriving at the receiver at different times. These components, due to their phases, interfere with each other, distorting the original signal or causing errors. For example, if an electromagnetic wave propagates along two different paths that differ by half a wavelength, the two signals will cancel each other out when they reach their destination (with peaks and troughs coinciding).

[0056] When electromagnetic waves propagate through mine tunnels, they are prone to multipath effects. Taking coal mines as an example, coal mine tunnels are narrow, with numerous corners and branch tunnels. Furthermore, the tunnel walls are covered with a large amount of rough, irregular surfaces such as coal and rock. As electromagnetic waves propagate through these tunnels, they are constantly reflected and refracted, generating multipath effects that severely attenuate their propagation capabilities.

[0057] Among them, one of the reasons why the multipath effect causes serious attenuation of the electromagnetic wave propagation ability is that the polarization mode of the electromagnetic wave changes multiple times during the propagation process.

[0058] Currently, the most widely used plate-shaped directional antennas and rod-shaped omnidirectional antennas are both linearly polarized. These linearly polarized antennas are susceptible to multipath effects, resulting in poor wireless communication quality. Circularly polarized antennas, on the other hand, offer superior resistance to attenuation and multipath effects, and are therefore widely used in coal mines and other wells. However, conventional circularly polarized antennas either have high gain but are bulky, or are smaller and have low gain.

[0059] In view of this, the embodiments of the present disclosure provide a circularly polarized antenna that is compact in size while having a high gain. The circularly polarized antenna provided in the embodiments of the present disclosure can be used as a base station antenna, as a Wi-Fi antenna, and as a positioning antenna. When the circularly polarized antenna is used as a base station antenna, the circularly polarized antenna can be used in mines such as coal mines to achieve mobile communications in the mines; when the circularly polarized antenna is used as a Wi-Fi antenna, the circularly polarized antenna is used to achieve Wi-Fi communications; when the circularly polarized antenna is used as a positioning antenna, the circularly polarized antenna can be used in mines such as coal mines to determine the specific locations of personnel, equipment, etc. in the mines. Of course, the circularly polarized antenna provided in the embodiments of the present disclosure can also have other application scenarios, which are not listed here one by one.

[0060] The circularly polarized antenna provided by the present disclosure is described in detail below with reference to the accompanying drawings.

[0061] FIG1 is a front view of a circularly polarized antenna provided in an embodiment of the present disclosure, FIG2 is a side view of a circularly polarized antenna provided in an embodiment of the present disclosure, and FIG3 is a rear view of a circularly polarized antenna provided in an embodiment of the present disclosure.

[0062] As shown in Figures 1 to 3, the circularly polarized antenna 100 includes a radiating plate 41, a substrate 42, and a plurality of feeding probes 411. The radiating plate 41 and the substrate 42 are spaced apart from each other, with the plurality of feeding probes 411 located between the radiating plate 41 and the substrate 42. A feeding network 422 is provided on the substrate 42. One end of the feeding probes 411 is electrically connected to the feeding network 422, and the other end of the feeding probes 411 is electrically connected to the radiating plate 41. Electrical signals in the feeding network 422 can be transmitted to the radiating plate 41 through the feeding probes 411, thereby stimulating the radiating plate 41 to radiate electromagnetic waves into free space. Alternatively, the radiating plate 41 receives electromagnetic waves in free space and generates electrical signals, which are then transmitted to the feeding network 422 through the feeding probes 411.

[0063] Figure 4 is a schematic diagram of a radiating plate and a feeding probe in a circularly polarized antenna provided in an embodiment of the present disclosure, Figure 5 is a rear view of the radiating plate and the feeding probe in a circularly polarized antenna provided in an embodiment of the present disclosure, and Figure 6 is a side view of the radiating plate and the feeding probe in a circularly polarized antenna provided in an embodiment of the present disclosure. As shown in Figures 4 to 6, the radiating plate 41 is an overall plate-like structure, having a plate surface perpendicular to the thickness direction, and a slot 412 is provided on the plate surface. The slot 412 extends through the radiating plate 41 along the thickness direction of the radiating plate 41, that is, the slot 412 refers to a hollow area provided on the radiating plate 41.

[0064] In practical applications, the radiation plate 41 can be a metal plate, such as a copper plate, an aluminum plate, etc. The radiation plate 41 can also include a support plate and a metal plate, wherein the metal plate covers the surface of the support plate, and the support plate is used to support the metal plate to prevent the metal plate from bending and deformation.

[0065] The slot 412 can be in the form of an elongated strip, that is, the length of the slot 412 is much larger than the width. For example, as shown in FIG5 , when the slot 412 is rectangular, the length of the rectangle is much larger than the width of the rectangle, that is, the size of L1 is much larger than the size of W1. For another example, when the slot 412 is elliptical, the major axis of the ellipse is much larger than the minor axis of the ellipse. In addition to rectangles and ellipses, the slot 412 can also be in the form of a polygon or other irregular shapes, which are not listed here. The embodiments of the present disclosure do not limit the specific shape of the slot 412. In actual application, it can be flexibly set according to the specific use requirements of the circularly polarized antenna 100.

[0066] The radiation plate 41 is provided with a plurality of slits 412, which are arranged in a circular array. When the slits 412 are arranged in a circular array, the length direction of the slits 412 can extend along the radial direction of the circular array. For example, referring to Figure 5 , the dotted circle in Figure 5 represents the virtual circle on which the circular array is based, and the length dimension L1 of the slits 412 is along the radial direction of the virtual circle. Furthermore, the slits 412 can be spaced apart. For example, referring to Figure 5 , a gap is provided between adjacent slits 412 along the circumference of the virtual circle; and a gap is also provided between adjacent slits 412 along the radial direction of the virtual circle.

[0067] For example, with continued reference to FIG5 , the radiating plate 41 is provided with four slots 412 arranged in a cross shape. For example, the radiating plate 41 has a first direction X and a second direction Y, which are mutually perpendicular and parallel to the surface of the radiating plate 41. The radiating plate 41 includes first slots 412a and second slots 412b spaced apart along the first direction X, and also includes third slots 412c and fourth slots 412d spaced apart along the second direction Y. Because the first direction X and the second direction Y are perpendicular, the polarization directions of the first slots 412a and second slots 412b spaced apart along the first direction X are perpendicular to the polarization directions of the third slots 412c and fourth slots 412d spaced apart along the second direction Y, thereby achieving circular polarization of the antenna.

[0068] Of course, in addition to the above-mentioned slots 412 , the radiation plate 41 may also be provided with other hollow areas, for example, to improve the gain of the circularly polarized antenna 100 .

[0069] In practical applications, the size of the radiating plate 41 can be determined based on the operating frequency of the circularly polarized antenna 100. For example, if the operating frequency range of the circularly polarized antenna 100 is 2300 MHz to 2500 MHz, and the radiating plate 41 is square, the size of the radiating plate 41 can be 75 mm × 75 mm, that is, the size of the radiating plate 41 is 0.59λ × 0.59λ, where λ is the wavelength of the center frequency.

[0070] In some embodiments, the shape of the radiation plate 41 is a centrally symmetrical figure, and the geometric center of the radiation plate 41 coincides with the center of the circular array, so that the equivalent electrical lengths of the peripheries of the respective slots 412 are equal, which is beneficial for reducing the axial ratio characteristic.

[0071] Exemplarily, as shown in FIG5 , the radiation plate 41 is a square, and the center of the plurality of slits 412 arranged in a circular array is located at the geometric center of the square.

[0072] Of course, the radiation plate 41 can also be circular or polygonal such as triangular, hexagonal, octagonal, etc.

[0073] Furthermore, when the shape of the radiation plate 41 is polygonal, one diagonal line of the radiation plate 41 is along the first direction X, and the other diagonal line of the radiation plate 41 is along the second direction Y.

[0074] For example, with continued reference to FIG. 5 , when the radiation plate 41 is a square, one diagonal line of the square extends along the first direction X, and the other diagonal line of the square extends along the second direction Y.

[0075] For another example, as shown in FIG10 , when the radiation plate 41 is an octagon, one diagonal line of the octagon extends along the first direction X, and the other diagonal line of the octagon extends along the second direction Y.

[0076] When the shape of the radiation plate 41 is a polygon, the length of the polygon diagonal is the longest, and the first direction X and the second direction Y are both along the diagonal direction, so that the size of the radiation plate 41 is smaller when the equivalent electrical length of the dipole is constant, thereby reducing the size of the circularly polarized antenna 100.

[0077] Continuing with Figures 3 and 9 , the substrate 42 is provided with a feed network 422. The feed network 422 includes a combiner terminal 61 and multiple feed terminals, which are electrically connected to the radiating plate 41 via the feed probe 411. When the circularly polarized antenna 100 is used to radiate electromagnetic waves, the feed network 422 receives signals via the combiner terminal 61. After being processed by the feed network 422, the signals are transmitted to the feed probe 411 via the multiple feed terminals, thereby feeding the radiating plate 41. When the circularly polarized antenna 100 is used to receive electromagnetic waves, the operating process is reversed and will not be further described here.

[0078] The substrate 42 may further be provided with a reflective ground, which is spaced apart from and opposite to the radiation plate 41, so that the reflective ground can reflect electromagnetic waves toward the radiation plate 41. In practical applications, the reflective ground may be a metal plate or a metal film layer.

[0079] The substrate 42 is generally plate-shaped and is spaced apart from and opposite to the radiating plate 41. The substrate 42 is used to support and connect structures such as the feed network 422 and the reflective ground. For example, the substrate 42 has two side surfaces perpendicular to its thickness, with the feed network 422 disposed on one side and the reflective ground disposed on the other.

[0080] Figure 7 is a cross-sectional view of a substrate in a circularly polarized antenna according to an embodiment of the present disclosure. As shown in Figure 7, substrate 42 includes a base layer 42a, a first conductive layer 42b, and a second conductive layer 42c. The first conductive layer 42b is located on the side of the base layer 42a facing the radiating plate 41, while the second conductive layer 42c is located on the side of the base layer 42a facing away from the radiating plate 41. The first conductive layer 42b is reflectively disposed on the first conductive layer 42b, and the feed network 422 is disposed on the second conductive layer 42c.

[0081] In practical applications, the substrate 42 may be a printed circuit board (PCB), and the feeding network 422 and the reflective ground are respectively located on two different conductive film layers of the PCB.

[0082] In practical applications, the substrate 42 can be a polygon such as a square or rectangle, or it can be circular or irregular in shape. The disclosed embodiments do not limit the shape of the substrate 42. To reduce the size of the circularly polarized antenna 100, the substrate 42 can be slightly larger than the radiating plate 41, or equal to or slightly smaller than the radiating plate 41. The shape of the substrate 42 can be the same as or different from that of the radiating plate 41.

[0083] Figure 8 is a front view of a substrate in a circularly polarized antenna provided by an embodiment of the present disclosure. As shown in Figure 8, when a reflective ground is provided on the side of the substrate 42 facing the radiating plate 41 and a feed network 422 is provided on the side of the substrate 42 facing away from the radiating plate 41, the reflective ground can be provided with an escape hole 423. One end of the feed probe 411 passes through the escape hole 423 to electrically connect to the feed network 422, and the feed probe 411 does not contact the escape hole 423, thereby isolating the feed probe 411 from the reflective ground.

[0084] For example, when the substrate 42 is a printed circuit board, the avoidance hole 423 penetrates the substrate 42 along the thickness direction of the substrate 42, one end of the feeding probe 411 is inserted into the avoidance hole 423, and the portion of the feeding probe 411 exposed from the feeding network 422 side is welded to the feeding network 422, and the portion of the feeding probe 411 exposed from the reflection ground side is insulated from the reflection ground.

[0085] The distance between the radiating plate 41 and the substrate 42 can be less than or equal to λ*1 / 4, where λ is the center frequency wavelength of the circularly polarized antenna 100. Specifically, when reflectively disposed on the side of the substrate 42 facing the radiating plate 41, the distance between the radiating plate 41 and the substrate 42 is less than or equal to λ*1 / 4. Reducing the distance between the radiating plate 41 and the substrate 42 can reduce the size of the antenna, making it easier to miniaturize the circularly polarized antenna 100.

[0086] 1 to 3 , the circularly polarized antenna 100 may further include a connector 2 for electrically connecting the coaxial cable and the feed network 422, thereby enabling signals to be transmitted between the coaxial cable and the feed network 422. For example, the connector 2 is an SMA (Sub Miniature version A) connector.

[0087] The substrate 42 is relatively thick and has a certain structural strength, so the connector 2 can be fixed to the substrate 42, making the connector 2 more secure. In addition, since the feed network 422 is provided on the substrate 42, when the connector 2 is fixed to the substrate 42, the electrical connection between the connector 2 and the feed network 422 can be facilitated.

[0088] Exemplarily, when the connector 2 is an SMA connector, the threaded portion of the connector 2 is electrically connected to the reflective ground, and the core wire portion of the connector 2 is electrically connected to the feed network 422 .

[0089] In some embodiments, in addition to supporting and connecting the feed network 422 and the reflective ground, the substrate 42 can also support the radiating plate 41. For example, the substrate 42 and the radiating plate 41 are connected as an integral structure, so that the relative position between the substrate 42 and the radiating plate 41 is not easily changed, thereby preventing the performance of the circularly polarized antenna 100 from being affected by the relative position change between the substrate 42 and the radiating plate 41.

[0090] For example, a support structure is provided between the substrate 42 and the radiation plate 41 , and the substrate 42 and the radiation plate 41 are connected as an integral structure through the support structure. The support structure is used to support the radiation plate 41 to prevent the radiation plate 41 from warping or deformation.

[0091] For another example, multiple feeding probes 411 are configured to support the radiating plate 41. Specifically, the multiple feeding probes 411 support the radiating plate 41, so that the radiating plate 41 and the substrate 42 are positioned opposite and spaced apart. The feeding probes 411 both transmit signals and serve as structural members to support the radiating plate 41, reducing the number of parts in the circularly polarized antenna 100 and lowering costs.

[0092] A plurality of feeding probes 411 are located between the radiation plate 41 and the substrate 42 and arranged at intervals. One end of the feeding probe 411 is electrically connected to the feeding network 422 , and the other end is electrically connected to the radiation plate 41 .

[0093] The feeding probe 411 can be made of a conductive material (e.g., copper, aluminum, or other metal). One end of the feeding probe 411 is electrically connected to the feeding network 422, and the other end of the feeding probe 411 is electrically connected to the radiating plate 41, thereby enabling signal transmission between the radiating plate 41 and the feeding network 422. The feeding probe 411 is not limited to an elongated needle shape and can also have other shapes, such as a strip, cylinder, cone, frustum, prism, or pyramid, as long as it can achieve signal transmission between the radiating plate 41 and the feeding network 422.

[0094] A plurality of feeding probes 411 are provided between the radiation plate 41 and the substrate 42. The plurality of feeding probes 411 are arranged at intervals. The number of the feeding probes 411 can be two or four.

[0095] For example, when the number of feeding probes 411 is two, the multiple feeding probes 411 include a first feeding probe and a second feeding probe, the first feeding probe is used to feed current around the first slot 412a and the second slot 412b, and the second feeding probe is used to feed current around the third slot 412c and the fourth slot 412d.

[0096] For another example, when the number of feeding probes 411 is four, the multiple feeding probes 411 include a first feeding probe, a second feeding probe, a third feeding probe and a fourth feeding probe, the first feeding probe is used to feed current around the periphery of the first slot 412a, the second feeding probe is used to feed current around the periphery of the second slot 412b, the third feeding probe is used to feed current around the periphery of the third slot 412c, and the fourth feeding probe is used to feed current around the periphery of the fourth slot 412d.

[0097] The circularly polarized antenna 100 provided in an embodiment of the present disclosure includes a radiating plate 41, a substrate 42, and a plurality of feeding probes 411. The radiating plate 41 and the substrate 42 are arranged opposite each other and spaced apart, with the plurality of feeding probes 411 located between the radiating plate 41 and the substrate 42. The substrate 42 is provided with a feeding network 422, which is electrically connected to the radiating plate 41 via the feeding probes 411. Because the radiating plate 41 is relatively thin and the number of layers of the circularly polarized antenna 100 along a direction perpendicular to the radiating plate 41 is relatively small, the circularly polarized antenna 100 can achieve high gain while maintaining a compact size.

[0098] In some embodiments, the feed probe 411 and the radiating plate 41 may be integrally formed. The integrally formed structure herein refers to a structure formed as a whole by an integral molding process, as distinguished from a structure in which the feed probe 411 and the radiating plate 41 are connected as a whole by welding, bonding, clamping, threading, or the like.

[0099] For example, the feeding probe 411 and the radiation plate 41 are formed into an integral structure by a stamping process, or the feeding probe 411 and the radiation plate 41 are printed into an integral structure by a 3D printing process, or the feeding probe 411 and the radiation plate 41 are formed into an integral structure by electroplating on the surface of the support plate, etc.

[0100] The feed probe 411 and the radiating plate 41 are integrally formed, reducing the number of parts in the circularly polarized antenna 100 and simplifying assembly of the circularly polarized antenna 100. Furthermore, the integrally formed structure of the feed probe 411 and the radiating plate 41 secures their relative positions, preventing relative movement between the feed probe 411 and the radiating plate 41 and potentially affecting the performance of the circularly polarized antenna 100.

[0101] Furthermore, the feeding probe 411 can be elongated. Elongated means that the length of the feeding probe 411 is much greater than its width. For example, with continued reference to Figures 5 and 6 , the length L2 of the feeding probe 411 is much greater than its width W2. The area of ​​the feeding probe 411 can be less than or equal to the area of ​​the gap 412. For example, with continued reference to Figures 5 and 6 , the value of L2 × W2 is less than or equal to the value of L1 × W1.

[0102] Illustratively, L2 is less than or equal to L1, and W2 is less than or equal to W1.

[0103] Furthermore, the feed probe 411 is formed by bending the material within the gap 412 toward the substrate 42. The material within the gap 412 refers to the material located in the area where the gap 412 is located before the gap 412 is formed. For example, if the radiation plate 41 is a copper plate, the material within the gap 412 refers to the copper material located in the area where the gap 412 is located before the gap 412 is formed. Since the formation of the gap 412 in the radiation plate 41 requires the removal of part of the material of the radiation plate 41, the feed probe 411 is made of the material that needs to be removed, which reduces the amount of waste and saves costs. In addition, the radiation plate 41 is formed with multiple bending structures, which increases the structural rigidity of the radiation plate 41 and makes the radiation plate 41 less susceptible to bending and deformation.

[0104] 5 and 6 , the slot 412 is rectangular. When the slot 412 is formed, three sides of the rectangle are cut, and then the rectangular material surrounded by the three sides is bent along the other uncut side toward the substrate 42 to form the feeding probe 411.

[0105] In some embodiments, the extension direction of the feeding probe 411 forms an angle with the normal direction of the radiating plate 41, that is, the extension direction of the feeding probe 411 is not parallel to the normal direction of the radiating plate 41. The extension direction of the feeding probe 411 refers to the length direction of the feeding probe 411. For example, referring to FIG6 , the length direction of the feeding probe 411 is the direction of dimension L2 in the figure.

[0106] When the length L2 of the feeding probe 411 remains unchanged, an angle is formed between the extension direction of the feeding probe 411 and the normal direction of the radiating plate 41, which can reduce the distance between the radiating plate 41 and the substrate 42, thereby reducing the size of the circularly polarized antenna 100 and making it easier to miniaturize the circularly polarized antenna 100.

[0107] Exemplarily, the feeding probe 411 is tilted in a direction away from the center of the radiation plate 41 , from the direction of the radiation plate 41 toward the substrate 42 .

[0108] In some embodiments, the end of the feeding probe 411 facing the radiating plate 41 is connected to an edge of the slots 412 near the center of the circular array. For example, as shown in FIG5 , the end of the feeding probe 411 facing the radiating plate 41 is connected to an edge of the slots 412 near the center of the virtual circle. When the radiating plate 41 includes a first slot 412a, a second slot 412b, a third slot 412c, and a fourth slot 412d, the edges of the first slot 412a, the second slot 412b, the third slot 412c, and the fourth slot 412d near the center of the circular array are all connected to the feeding probe 411.

[0109] When the feeding probes 411 are used to support the radiation plate 41 , and the circularly polarized antenna 100 includes four feeding probes 411 , the radiation plate 41 is more firmly supported by the four feeding probes 411 and is less likely to shake.

[0110] When the circularly polarized antenna 100 includes four feeding probes 411 , all four feeding probes 411 may be used to transmit signals, or two of the four feeding probes 411 may be used to transmit signals.

[0111] FIG9 is a schematic diagram of a feed network in a circularly polarized antenna provided by an embodiment of the present disclosure. As shown in FIG9 , the feed network 422 may include a first feed terminal 66, a second feed terminal 67, a third feed terminal 68, and a fourth feed terminal 69. The first feed terminal 66 is electrically connected to the edge of the first slot 412 a via a first feed probe, the second feed terminal 67 is electrically connected to the edge of the second slot 412 b via a second feed probe, the third feed terminal 68 is electrically connected to the edge of the third slot 412 c via a third feed probe, and the fourth feed terminal 69 is electrically connected to the edge of the fourth slot 412 d via a fourth feed probe.

[0112] The first feed terminal 66 and the second feed terminal 67 are configured to output signals with opposite phases, i.e., the phases of the signals output by the first feed terminal 66 and the second feed terminal 67 differ by 180°. The third feed terminal 68 and the fourth feed terminal 69 are configured to output signals with opposite phases, i.e., the phases of the signals output by the third feed terminal 68 and the fourth feed terminal 69 differ by 180°.

[0113] The feeding network 422 implements four-point differential feeding through the first feeding terminal 66 , the second feeding terminal 67 , the third feeding terminal 68 and the fourth feeding terminal 69 , thereby improving polarization bluntness and facilitating reduction of the axial ratio characteristic.

[0114] 9 , the feed network 422 includes a power divider circuit 422a, a first differential circuit 64, and a second differential circuit 65. The power divider circuit 422a includes a combining terminal 61, a first branching terminal 62, and a second branching terminal 63. The combining terminal 61 is used to receive signals, and the first branching terminal 62 and the second branching terminal 63 are used to output signals. The signals output by the first branching terminal 62 and the second branching terminal 63 have a phase difference of 90°.

[0115] The first differential circuit 64 is electrically connected to the first shunt terminal 62 , the first feed terminal 66 and the second feed terminal 67 , and is configured to receive a signal from the first shunt terminal 62 and output signals with a phase difference of 180° through the first feed terminal 66 and the second feed terminal 67 .

[0116] The second differential circuit 65 is electrically connected to the second branch terminal 63 , the third feed terminal 68 and the fourth feed terminal 69 , and is configured to receive a signal from the second branch terminal 63 and output signals with a phase difference of 180° through the first feed terminal 66 and the second feed terminal 67 .

[0117] Figure 18 is a diagram showing the S11 characteristics of a power divider circuit in a circularly polarized antenna according to an embodiment of the present disclosure. As shown in Figure 18 , the power divider circuit has an excellent S11 characteristic below -23 dB across the entire operating frequency band.

[0118] Figure 19 is a graph showing the power difference between the first branch terminal 62 and the second branch terminal of a power divider circuit in a circularly polarized antenna according to an embodiment of the present disclosure. As shown in Figure 19, the power difference between the two branch terminals within the operating frequency band is less than 0.08 dB, indicating that the two branches share almost equal power.

[0119] Figure 20 shows the phase difference characteristics between the first branch terminal 62 and the second branch terminal in a power divider circuit of a circularly polarized antenna provided by an embodiment of the present disclosure. As shown in Figure 20 , the phase difference at the center frequency of power divider circuit 422a is approximately 270 degrees, and the phase difference is 90 degrees. The phase deviation at the low frequency (2.3 GHz) and high frequency (2.5 GHz) on both sides of the operating frequency is within ±5 degrees, which can be considered a small phase deviation.

[0120] It should be noted that in the feed network 422 shown in FIG9 , phase differences between the output signals of different lines are achieved by varying the lengths of the different lines. In practical applications, the structure of the feed network 422 is not limited to this, as long as it can implement four-point differential feeding. For example, the feed network 422 may include a phase shifter, such as a liquid crystal phase shifter, to control the phase difference of the signal.

[0121] Figure 11 is an exploded schematic diagram of a circularly polarized antenna provided by an embodiment of the present disclosure. As shown in Figure 11, the circularly polarized antenna 100 may further include a radome 1 having a mounting cavity defined therein. Components such as a radiating plate 41, a substrate 42, and a feed probe 411 are disposed within the mounting cavity, such that the radome 1 protects the components within the mounting cavity from damage by external forces.

[0122] The radome 1 is usually exposed in the use environment, so the radome 1 usually has certain flame retardancy, structural strength and corrosion resistance. For example, the radome 1 can be made of polycarbonate (PC for short).

[0123] To reduce the overall size of the circularly polarized antenna 100, the distance between the radome 1 and the radiating plate 41 can be set to be smaller. For example, the distance between the radome 1 and the radiating plate 41 can be set to λ*1 / 10. In practical applications, the distance between the radome 1 and the radiating plate 41 can be further reduced by selecting a material with a lower dielectric constant for the radome 1, thereby further reducing the size of the circularly polarized antenna 100.

[0124] Continuing with Figure 10 , the radome 1 may include a housing 11 and a base plate 12. The base plate 12 is hermetically connected to the housing 11, so that the housing 11 and the base plate 12 together form a mounting cavity. The base plate 12 is hermetically connected to the housing 11, thereby relatively sealing the mounting cavity and preventing dust and moisture from the operating environment of the circularly polarized antenna 100 from entering the mounting cavity and corroding the radiating plate 41, substrate 42, and feed probe 411. For example, the base plate 12 is bonded to the housing 11 using a curing adhesive.

[0125] For example, a through hole 121 is provided on the base plate 12. The end of the connector 2 extends from the mounting cavity through the through hole 121 to the outside of the radome 1, thereby electrically connecting the connector 2 to the coaxial line. In actual use, the connector 2 and the sidewall of the through hole 121 can also be sealed to enhance the airtightness of the mounting cavity.

[0126] Continuing with FIG11 , the substrate 42 can be secured to the radome 1 by screws 5. For example, a screw hole 421 is provided at each of the four corners of the substrate 42, and mounting holes are provided on the radome 1 at positions opposite the screw holes 421. The screws 5 are passed through the mounting holes and the screw holes 421 in sequence to secure the substrate 42 to the radome 1.

[0127] Figure 12 is a front view of an installed circularly polarized antenna according to an embodiment of the present disclosure, Figure 13 is a side view of an installed circularly polarized antenna according to an embodiment of the present disclosure, and Figure 14 is a rear view of an installed circularly polarized antenna according to an embodiment of the present disclosure. As shown in Figures 12 to 14 , the circularly polarized antenna 100 may further include a mounting bracket 3 , one end of which is connected to the radome 1 , and the other end of which is used to connect to a wall 200 , etc., to secure the circularly polarized antenna 100 .

[0128] Exemplarily, the mounting bracket 3 is L-shaped and is mounted on the radome 1 and the wall 200 by screws 5 .

[0129] Figure 15 is a graph showing the standing wave ratio (VSWR) characteristics of a circularly polarized antenna provided by an embodiment of the present disclosure. As shown in Figure 15, the circularly polarized antenna 100 exhibits a VSWR characteristic of less than 1.5 in the 2.24-2.58 GHz range, fully covering the mobile E-band (2.32-2.37 GHz) and Wi-Fi 2.4G (2.4-2.4835 GHz) bands, expanding the antenna's application range.

[0130] Figure 16 is a diagram showing the isolation characteristics of a circularly polarized antenna according to an embodiment of the present disclosure. As shown in Figure 16 , the circularly polarized antenna 100 has an isolation greater than 25 dB in the entire operating frequency band, indicating good isolation.

[0131] Figure 17 is a graph showing the cross-polarization ratio of a circularly polarized antenna according to an embodiment of the present disclosure. The cross-polarization ratio of the circularly polarized antenna 100, or the polarization purity of linear polarization, is shown in Figure 17 . The circularly polarized antenna 100 exhibits a cross-polarization ratio exceeding 31 dB within its operating frequency band, effectively establishing a low-bias circularly polarized antenna 100.

[0132] Figure 21 is a graph showing the VSWR characteristics of a circularly polarized antenna according to an embodiment of the present disclosure. As shown in Figure 21, the circularly polarized antenna 100 exhibits an excellent VSWR characteristic of less than 1.23 within the 2.2-2.6 GHz frequency band, demonstrating excellent port matching characteristics.

[0133] Figure 22 shows the axial ratio characteristics of a circularly polarized antenna according to an embodiment of the present disclosure. As shown in Figure 22, the circularly polarized antenna 100 exhibits an axial ratio of less than 3 dB within the 2.22-2.56 GHz frequency band and less than 1.1 dB within the 2.3-2.5 GHz operating frequency band. This indicates that the circularly polarized antenna 100 according to an embodiment of the present disclosure exhibits excellent circular polarization characteristics.

[0134] Figure 23 is a diagram showing the overall gain characteristics of a circularly polarized antenna provided by an embodiment of the present disclosure. As shown in Figure 23, the circularly polarized antenna 100 has a high gain characteristic of 8.48 to 8.82 dBi within the operating frequency band, providing strong support for long-distance communication in coal mines using the circularly polarized antenna 100.

[0135] The present disclosure also provides a communication system including the circularly polarized antenna 100. The communication system can be applied to a mobile E-band (2320-2370 MHz) communication system, a Wi-Fi 2.4G band (2.4-2.4835 GHz) communication system, or a UWB positioning system band (3700-4200 MHz) communication system.

[0136] The communication system provided by the embodiments of the present disclosure includes a circularly polarized antenna 100 comprising a radiating plate 41, a substrate 42, and multiple feeding probes 411. The radiating plate 41 and substrate 42 are arranged opposite each other and spaced apart, with the multiple feeding probes 411 located between the radiating plate 41 and the substrate 42. The substrate 42 is provided with a feeding network 422, which is electrically connected to the radiating plate 41 via the feeding probes 411. Because the radiating plate 41 is relatively thin and the number of layers in the circularly polarized antenna 100 perpendicular to the radiating plate 41 is relatively small, the circularly polarized antenna 100 can achieve high gain while maintaining a compact size.

[0137] The above description is merely a specific embodiment of the present disclosure, but the scope of protection of the present disclosure is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this disclosure should be included in the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure should be based on the scope of protection of the claims.

Claims

1. A circularly polarized antenna, characterized in that, Comprising: A radiation plate, the radiation plate being provided with a plurality of slits, the slits penetrating the radiation plate along the thickness direction of the radiation plate, and the plurality of slits being arranged in a circumferential array; A substrate, the substrate being opposite to and spaced apart from the radiation plate, and the substrate being provided with a feeding network; A plurality of feeding probes, the plurality of feeding probes being located between the radiation plate and the substrate and arranged at intervals, one end of the feeding probe being electrically connected to the feeding network and the other end being electrically connected to the radiation plate.

2. The circularly polarized antenna according to claim 1, wherein, The feeding probe and the radiation plate are of an integrally formed structure.

3. The circularly polarized antenna according to claim 2, wherein, The feeding probe is strip-shaped, and the area of the feeding probe is less than or equal to the area of the slit.

4. The circularly polarized antenna according to claim 3, wherein, The feeding probe is formed by bending the material within the slit towards the substrate.

5. The circularly polarized antenna according to claim 1, wherein, The plurality of feeding probes are configured to support the radiation plate.

6. The circularly polarized antenna according to claim 1, wherein, The distance between the radiation plate and the substrate is less than or equal to λ*1 / 4, where λ is the center frequency point wavelength of the circularly polarized antenna.

7. The circularly polarized antenna according to claim 6, wherein, There is an included angle between the extending direction of the feeding probe and the normal direction of the radiation plate.

8. The circularly polarized antenna according to any one of claims 1 to 7, wherein, The plurality of slits include a first slit, a second slit, a third slit, and a fourth slit. The first slit and the second slit are arranged at intervals along a first direction, the third slit and the fourth slit are arranged at intervals along a second direction, and the first direction and the second direction are perpendicular to each other and both parallel to the radiation plate.

9. The circularly polarized antenna according to claim 8, wherein, The shape of the radiation plate is a centrally symmetric figure, and the geometric center of the radiation plate coincides with the center of the circumferential array.

10. The circularly polarized antenna according to claim 9, wherein, When the shape of the radiation plate is a polygon, one diagonal of the radiation plate is along the first direction, and the other diagonal of the radiation plate is along the second direction.

11. The circularly polarized antenna according to claim 8, wherein, For the first slit, the second slit, the third slit, and the fourth slit, feeding probes are connected to the edges near the center of the circumferential array.

12. The circularly polarized antenna according to claim 11, wherein, The feeding network includes a first feeding end, a second feeding end, a third feeding end, and a fourth feeding end. The first feeding end is electrically connected to the edge of the first slit through the feeding probe, the second feeding end is electrically connected to the edge of the second slit through the feeding probe, the third feeding end is electrically connected to the edge of the third slit through the feeding probe, and the fourth feeding end is electrically connected to the edge of the fourth slit through the feeding probe. The first feeding end and the second feeding end are configured to output signals with opposite phases, and the third feeding end and the fourth feeding end are configured to output signals with opposite phases.

13. The circularly polarized antenna according to claim 12, wherein, The feeding network includes a power splitting circuit, a first differential circuit, and a second differential circuit. The power splitting circuit includes a combining end, a first splitting end, and a second splitting end. The first differential circuit is electrically connected to the first splitting end, the first feeding end, and the second feeding end. The second differential circuit is electrically connected to the second splitting end, the third feeding end, and the fourth feeding end.

14. The circularly polarized antenna according to claim 1, wherein, The feeding network is arranged on the side of the substrate away from the radiation plate. A reflective ground is further provided on the side of the substrate facing the radiation plate. The reflective ground is provided with avoidance holes, and the feeding probes pass through the avoidance holes and are electrically connected to the feeding network.

15. The circularly polarized antenna according to claim 1, wherein, The circularly polarized antenna further includes a radome, the radome includes a cover body and a bottom plate, the bottom plate is sealingly connected to the cover body to enclose an installation cavity, and the radiation plate, the substrate and the feeding probe are located in the installation cavity.

16. A communication system, characterized in that, Comprising the circularly polarized antenna according to any one of claims 1 to 15.

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