A dual-frequency cylindrical antenna structure and antenna

Abstract

This invention relates to a dual-band cylindrical antenna structure and antenna, belonging to the field of antenna devices. The dual-band cylindrical antenna structure provided by this invention includes: a cylindrical resonant cavity with mirror-symmetrical sidewalls composed of metal conductors; a dielectric pillar made of a dielectric material with a loss below a set threshold disposed on the upper bottom surface of the cylindrical resonant cavity; a low-frequency resonant antenna structure disposed between the dielectric pillar and the lower bottom surface of the cylindrical resonant cavity; the low-frequency resonant antenna structure being electrically connected to a coaxial transmission line; and a high-frequency resonant antenna structure disposed on the lower bottom surface of the cylindrical resonant cavity, the high-frequency resonant antenna structure including two parallel metal sheets arranged along the axial direction of the cylindrical resonant cavity. The dual-band cylindrical antenna structure supports WiFi band signal transmission and exhibits good radiation directivity, radiation gain, and noise characteristics in the WiFi band. The antenna formed by the paired dual-band cylindrical antenna structures has good signal isolation performance.

Description

Technical Field

[0001] This invention relates to the field of antenna devices, and more particularly to a dual-frequency cylindrical antenna structure and antenna. Background Technology

[0002] Electronic devices with wireless communication capabilities typically use external antennas. During operation, external antennas often encounter the following problems: 1. External antennas are easily affected by the device's metal structure, altering their electromagnetic radiation characteristics and causing poor signal quality; 2. When multiple external antennas work together, mutual interference may occur, especially during the use and movement of electronic devices, causing antenna swaying. During antenna swaying, the antenna lacks stable radiation characteristics, resulting in mutual interference. Therefore, antenna design requires targeted structural design to reduce interference from the device's metal structure, improve signal isolation between different external antennas, and avoid mutual interference. Summary of the Invention

[0003] In order to solve the above-mentioned technical problems, or at least partially solve the above-mentioned technical problems, the present invention provides a dual-frequency cylindrical antenna structure and antenna.

[0004] In a first aspect, the present invention provides a dual-frequency cylindrical antenna structure, comprising:

[0005] A cylindrical resonant cavity, wherein the cylindrical resonant cavity has a structure with mirror-symmetrical sidewalls composed of metal conductors;

[0006] And, a dielectric pillar disposed on the bottom surface of the cylindrical resonant cavity, the dielectric pillar being a cylindrical structure made of a dielectric material with a loss below a set threshold;

[0007] A low-frequency resonant antenna structure is disposed between the dielectric pillar and the lower bottom surface of the cylindrical resonant cavity. The low-frequency resonant antenna structure is a cylinder formed by a metal conductor and is electrically connected to a coaxial transmission line.

[0008] A high-frequency resonant antenna structure is disposed on the bottom surface of the cylindrical resonant cavity, the high-frequency resonant antenna structure comprising two metal plates arranged parallel to each other along the axial direction of the cylindrical resonant cavity.

[0009] Furthermore, the cylindrical resonant cavity, the low-frequency resonant antenna structure, and the dielectric pillar are coaxially arranged.

[0010] Furthermore, the sidewalls of the cylindrical resonant cavity can be either arc-shaped sidewalls or grid-like sidewalls formed by metal pillars arranged periodically in a circular arc.

[0011] Furthermore, the coaxial transmission line is connected to the center of the lower bottom surface of the cylindrical resonant cavity, and the coaxial transmission line is connected to the coaxial transmission connector.

[0012] Furthermore, the bottom surface of the cylindrical resonant cavity is connected to a spring bracket, the spring bracket is connected to the coaxial transmission connector, the spring bracket is coaxially arranged with the cylindrical resonant cavity, and the coaxial transmission line is arranged along the central axis of the spring bracket.

[0013] Furthermore, the coaxial transmission line is connected to the bottom surface of the cylindrical resonant cavity and the coaxial transmission connector respectively via two rotating coaxial terminals.

[0014] Furthermore, the hollowed-out portion of the cylindrical resonant cavity sidewall is covered with a dielectric material whose loss is below a set threshold, so as to seal the sidewall of the cylindrical resonant cavity.

[0015] Furthermore, two metal plates from the high-frequency resonant antenna structure are arranged along the intersection line of the symmetry plane of the sidewall of the cylindrical resonant cavity and the bottom surface of the cylindrical resonant cavity, and the metal plates are positioned away from the sidewall.

[0016] Furthermore, the height of the metal sheet relatively close to the low-frequency resonant antenna structure is higher than the height of the other metal sheet.

[0017] Secondly, the present invention provides an antenna, characterized in that the antenna includes at least one pair of dual-frequency cylindrical antenna structures, the paired dual-frequency cylindrical antenna structures are non-coaxial and arranged in a mirror-symmetric manner, the paired dual-frequency cylindrical antenna structures are spaced apart by a predetermined distance, and the paired dual-frequency cylindrical antenna structures form an angle of 90° in the main radiation direction.

[0018] The technical solutions provided in the embodiments of the present invention have the following advantages compared with the prior art:

[0019] The antenna device described in this invention includes a cylindrical resonant cavity, a low-frequency resonant antenna structure disposed within the cylindrical resonant cavity, and a high-frequency resonant antenna structure. It supports the transmission and reception of wireless signals at different frequencies: 2.4GHz, 5.1GHz, and 5.8GHz, meeting the design requirements of current mainstream WiFi frequency bands.

[0020] The operating electric field distribution of the dual-frequency cylindrical antenna structure was tested under 2.4GHz, 5.1GHz, and 5.8GHz signals. It was found that the operating electric field of the dual-frequency cylindrical antenna structure is mainly formed by the low-frequency resonant antenna structure 2. Under 5.1GHz and 5.8GHz signals, the operating electric field of the dual-frequency cylindrical antenna structure is mainly formed by the high-frequency resonant antenna structure 4, which is suitable for the transmission and reception of low-frequency and high-frequency signals of current mainstream WiFi.

[0021] The radiation direction and radiation gain of the dual-frequency cylindrical antenna structure were tested at 2.4 GHz, 5.1 GHz, and 5.8 GHz. The results showed that the radiation direction of the dual-frequency cylindrical antenna structure is mainly oriented towards the hollowed-out sidewall of the cylindrical resonant cavity, exhibiting good directivity. The radiation gain was 3.07 dBi at 2.4 GHz, 3.15 dBi at 5.1 GHz, and 2.99 dBi at 5.8 GHz, demonstrating good radiation gain performance.

[0022] The S-parameters of the dual-frequency cylindrical antenna structure were tested under different frequency signal conditions. The results showed that the S11 of the dual-frequency cylindrical antenna structure was less than -10dB in the 2.35GHz-2.56GHz and 5.09GHz-5.83GHz signal ranges, indicating good noise performance.

[0023] The antenna, formed by the paired dual-band cylindrical antenna structure, supports dual-band WiFi signal transmission and has good signal isolation performance. Attached Figure Description

[0024] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of a dual-frequency cylindrical antenna structure provided in an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of the main body of a dual-frequency cylindrical antenna structure provided in an embodiment of the present invention;

[0028] Figure 3 This is a cross-sectional view of the main body of a dual-frequency cylindrical antenna structure provided in an embodiment of the present invention;

[0029] Figure 4 A schematic diagram of a spring support and coaxial transmission connector for a dual-frequency cylindrical antenna structure provided in an embodiment of the present invention;

[0030] Figure 5 A schematic diagram of the main body of another dual-frequency cylindrical antenna structure provided in an embodiment of the present invention;

[0031] Figure 6 This is a schematic diagram of the working electric field distribution of a dual-frequency cylindrical antenna structure provided in Embodiment 1 of the present invention;

[0032] Figure 7 This is a schematic diagram of the radiation direction test results of a dual-frequency cylindrical antenna structure provided in Embodiment 1 of the present invention;

[0033] Figure 8 This is a schematic diagram of the S-parameter test results of a dual-frequency cylindrical antenna structure provided in Embodiment 1 of the present invention;

[0034] Figure 9 This is a schematic diagram of the antenna provided in Embodiment 3 of the present invention;

[0035] Figure 10 This is a schematic diagram of the S-parameter test results of the antenna provided in Embodiment 3 of the present invention.

[0036] The labels and their meanings in the diagram are as follows:

[0037] 1. Cylindrical resonant cavity; 11. Arc-shaped sidewall; 12. Grid-shaped sidewall; 2. Low-frequency resonant antenna structure; 3. Dielectric pillar; 4. High-frequency resonant antenna structure; 5. Coaxial transmission line; 6. Spring support; 7. Coaxial transmission connector; 8. Arc-shaped dielectric material with loss below a set threshold. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] 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 apparatus 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 apparatus. 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 apparatus that includes said element.

[0040] Example 1

[0041] See Figure 1 As shown, an embodiment of the present invention provides a dual-frequency cylindrical antenna structure, including: a cylindrical resonant cavity 1, see reference. Figure 2 and Figure 3 As shown, in this embodiment, the cylindrical resonant cavity 1 includes: a circular upper bottom surface and a circular lower bottom surface, and an arc-shaped sidewall 11 connecting the upper and lower bottom surfaces. The upper bottom surface, the lower bottom surface, and the arc-shaped sidewall 11 are composed of metal conductors, and the arc-shaped sidewall 11 itself has a mirror-symmetrical structure. In a specific design, the cylindrical diameter of the cylindrical resonant cavity 1 is 1.5 cm, and the height of the antenna cylinder is 3.3 cm.

[0042] See Figure 4 As shown, a coaxial transmission line 5 is disposed in the middle of the lower bottom surface of the cylindrical resonant cavity 1, and the coaxial transmission line 5 is connected to a coaxial transmission connector 7. In a preferred embodiment, a spring bracket 6 is connected to the lower bottom surface of the cylindrical resonant cavity 1, and the spring bracket 6 is connected to the coaxial transmission connector 7. The spring bracket 6 is coaxially disposed with the cylindrical resonant cavity 1, and the coaxial transmission line 5 is disposed along the central axis of the spring bracket 6.

[0043] In a preferred embodiment, the coaxial transmission line 5 is connected to the lower surface of the cylindrical resonant cavity 1 and the coaxial transmission connector 7 via two rotating coaxial terminals. The coaxial transmission connector 7 is a connector used in the prior art as an interface for connecting radio frequency ports. The rotating coaxial terminals allow the dual-band cylindrical antenna structure to swing within a certain angle range, avoiding torsional damage to the main body of the dual-band cylindrical antenna structure.

[0044] A dielectric pillar 3 is disposed on the inner side of the upper bottom surface of the cylindrical resonant cavity 1. The dielectric pillar 3 is a cylindrical structure made of a dielectric material with a loss lower than a set threshold; the loss of the dielectric material used in the dielectric pillar 3 is lower than 10^-2. A low-frequency resonant antenna structure 2 is disposed between the dielectric pillar 3 and the lower bottom surface of the cylindrical resonant cavity 1. The low-frequency resonant antenna structure 2 is a cylinder formed of a metal conductor. The cylindrical resonant cavity 1, the low-frequency resonant antenna structure 2, and the dielectric pillar 3 are coaxially arranged. The low-frequency resonant antenna structure is connected to the coaxial transmission line 5 disposed at the lower bottom surface of the cylindrical resonant cavity 1.

[0045] A high-frequency resonant antenna structure 4 is further disposed on the lower bottom surface of the cylindrical resonant cavity 1. The high-frequency resonant antenna structure 4 includes two metal plates arranged parallel to each other along the axial direction of the cylindrical resonant cavity 1. In specific implementation, the two metal plates of the high-frequency resonant antenna structure 4 are arranged on the intersection line of the symmetry plane of the sidewall of the cylindrical resonant cavity 1 and the lower bottom surface of the cylindrical resonant cavity 1, and the metal plates are located away from the sidewall. The height of the metal plate relatively closer to the low-frequency resonant antenna structure 2 is higher than the height of the other metal plate.

[0046] As a preferred embodiment, see [reference] Figure 3 As shown, the hollowed-out portion of the sidewall of the cylindrical resonant cavity 1 is covered with a dielectric material arc surface 8 whose loss is lower than a set threshold, thereby sealing the sidewall of the cylindrical resonant cavity 1. This dielectric material arc surface, with its loss lower than the set threshold, protects the low-frequency resonant antenna structure 2 and the high-frequency resonant antenna structure 4 inside the metal cylinder of the antenna while simultaneously increasing the antenna gain.

[0047] To illustrate the effectiveness of the dual-band cylindrical antenna structure described in this invention, the operating electric field distribution of the dual-band cylindrical antenna structure was tested under 2.4GHz, 5.1GHz, and 5.8GHz signals. The 2.4GHz, 5.1GHz, and 5.8GHz signals used are consistent with current mainstream WiFi frequency band designs. Figure 6 As shown, under 2.4GHz signal conditions, the operating electric field of the dual-frequency cylindrical antenna structure is mainly formed by the low-frequency resonant antenna structure 2. Under 5.1GHz and 5.8GHz signal conditions, the operating electric field of the dual-frequency cylindrical antenna structure is mainly formed by the high-frequency resonant antenna structure 4. Therefore, this dual-frequency cylindrical antenna structure is suitable for transmitting and receiving both low-frequency and high-frequency signals in current mainstream WiFi networks.

[0048] To illustrate the effectiveness of the dual-frequency cylindrical antenna structure described in this invention, the radiation direction and radiation gain of the dual-frequency cylindrical antenna structure were tested under 2.4 GHz, 5.1 GHz, and 5.8 GHz signal conditions. Figure 7As shown, the radiation direction of the dual-band cylindrical antenna structure is mainly oriented towards the hollowed-out sidewall of the cylindrical resonant cavity, exhibiting good directivity. The radiation gain is 3.07 dBi at 2.4 GHz, 3.15 dBi at 5.1 GHz, and 2.99 dBi at 5.8 GHz. Therefore, this dual-band cylindrical antenna structure demonstrates good radiation gain performance in the WiFi band.

[0049] To illustrate the effectiveness of the dual-frequency cylindrical antenna structure described in this invention, the S-parameters of the dual-frequency cylindrical antenna structure were tested under different frequency signal conditions. For example... Figure 9 As shown, in the 2.35GHz-2.56GHz signal range and the 5.09GHz-5.83GHz signal range, the noise level of the dual-band cylindrical antenna structure S11 is less than -10dB. Therefore, the dual-band cylindrical antenna structure has good noise characteristics in the WIFI band.

[0050] Example 2

[0051] See Figure 5 As shown, this embodiment of the invention provides a dual-band cylindrical antenna structure, including a cylindrical resonant cavity 1. In this embodiment, the cylindrical resonant cavity 1 includes a circular upper and lower bottom surface, and a grid-like sidewall 12 connecting the upper and lower bottom surfaces. The grid-like sidewall 12 includes a plurality of metal pillars arranged periodically in a circular arc, and the metal pillars are arranged in a mirror-symmetrical structure. The grid-like sidewall 12 formed by the metal pillars arranged periodically in a circular arc has the same effect as the arc-shaped sidewall 11. In a specific design, the cylindrical diameter of the cylindrical resonant cavity 1 is 1.5 cm, and the height of the antenna cylinder is 3.3 cm.

[0052] Similarly, a coaxial transmission line 5 is disposed at the center of the lower bottom surface of the cylindrical resonant cavity 1, and the coaxial transmission line 5 is connected to the coaxial transmission connector 7. In a preferred embodiment, a spring bracket 6 is connected to the lower bottom surface of the cylindrical resonant cavity 1, and the spring bracket 6 is connected to the coaxial transmission connector 7. The spring bracket 6 is coaxially arranged with the cylindrical resonant cavity 1, and the coaxial transmission line 5 is arranged along the central axis of the spring bracket 6. The coaxial transmission line 5 is connected to the lower bottom surface of the cylindrical resonant cavity 1 and the coaxial transmission connector 7 respectively through two rotating coaxial terminals.

[0053] A dielectric pillar 3 is disposed on the inner side of the upper bottom surface of the cylindrical resonant cavity 1. The dielectric pillar 3 is a cylindrical structure made of dielectric material with a loss lower than a set threshold. For the working environment, the dielectric material used in the dielectric pillar 3 has a loss of less than 10^-2. A low-frequency resonant antenna structure 2 is disposed between the dielectric pillar 3 and the lower bottom surface of the cylindrical resonant cavity 1. The low-frequency resonant antenna structure 2 is a cylinder formed of metal conductor. The cylindrical resonant cavity 1, the low-frequency resonant antenna structure 2, and the dielectric pillar 3 are coaxially arranged. The low-frequency resonant antenna structure is connected to the coaxial transmission line 5 disposed at the lower bottom surface of the cylindrical resonant cavity 1.

[0054] A high-frequency resonant antenna structure 4 is further disposed on the lower bottom surface of the cylindrical resonant cavity 1. The high-frequency resonant antenna structure 4 includes two metal plates arranged parallel to each other along the axial direction of the cylindrical resonant cavity 1. In specific implementation, the two metal plates of the high-frequency resonant antenna structure 4 are arranged on the intersection line of the symmetry plane of the sidewall of the cylindrical resonant cavity 1 and the lower bottom surface of the cylindrical resonant cavity 1, and the metal plates are located away from the sidewall. The height of the metal plate relatively closer to the low-frequency resonant antenna structure 2 is higher than the height of the other metal plate.

[0055] Example 3

[0056] See Figure 6 As shown, this invention provides an antenna comprising at least one pair of dual-frequency cylindrical antenna structures. The paired dual-frequency cylindrical antenna structures are non-coaxial and arranged in a mirror-symmetrical manner. A predetermined distance is spaced between the paired dual-frequency cylindrical antenna structures, and the angle between the paired dual-frequency cylindrical antenna structures in the main radiation direction is 90°. In one specific embodiment, the predetermined distance between the paired dual-frequency cylindrical antenna structures is 8 cm. Because the dual-frequency cylindrical antenna structure has good directional characteristics in its radiation direction, setting the angle between the paired dual-frequency cylindrical antenna structures in the main radiation direction at 90° can effectively avoid interference between signals. To illustrate the effect of the antenna, the S-parameters of the antenna are tested, such as... Figure 10 As shown, the two antennas achieve dual-band performance in the 2.4GHz and 5G frequency bands, and the isolation between the two antennas in the operating frequency band can reach more than 20dB.

[0057] The antenna device described in this invention includes a cylindrical resonant cavity, a low-frequency resonant antenna structure disposed within the cylindrical resonant cavity, and a high-frequency resonant antenna structure. It supports the transmission and reception of wireless signals at different frequencies: 2.4GHz, 5.1GHz, and 5.8GHz, meeting the design requirements of current mainstream WiFi frequency bands.

[0058] The operating electric field distribution of the dual-frequency cylindrical antenna structure was tested under 2.4GHz, 5.1GHz, and 5.8GHz signals. It was found that the operating electric field of the dual-frequency cylindrical antenna structure is mainly formed by the low-frequency resonant antenna structure 2. Under 5.1GHz and 5.8GHz signals, the operating electric field of the dual-frequency cylindrical antenna structure is mainly formed by the high-frequency resonant antenna structure 4, which is suitable for the transmission and reception of low-frequency and high-frequency signals of current mainstream WiFi.

[0059] The radiation direction and radiation gain of the dual-frequency cylindrical antenna structure were tested at 2.4 GHz, 5.1 GHz, and 5.8 GHz. The results showed that the radiation direction of the dual-frequency cylindrical antenna structure is mainly oriented towards the hollowed-out sidewall of the cylindrical resonant cavity, exhibiting good directivity. The radiation gain was 3.07 dBi at 2.4 GHz, 3.15 dBi at 5.1 GHz, and 2.99 dBi at 5.8 GHz, demonstrating good radiation gain performance.

[0060] The S-parameters of the dual-frequency cylindrical antenna structure were tested under different signal frequencies. The results showed that the S11 of the dual-frequency cylindrical antenna structure was less than -10dB in the 2.35GHz-2.56GHz and 5.09GHz-5.83GHz signal ranges, indicating good noise performance.

[0061] Due to the excellent radiation directionality, radiation gain, and noise performance of the dual-band cylindrical antenna structure in the WiFi band, the antenna formed by the paired dual-band cylindrical antenna structures supports WiFi signal transmission in both frequency domains and has good signal isolation performance.

[0062] In the embodiments provided by this invention, it should be understood that the disclosed structures can be implemented in other ways. For example, the structural embodiments described above are merely illustrative. For instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interfaces, structures, or units, and may be electrical, mechanical, or other forms.

[0063] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0064] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A dual frequency cylindrical antenna structure, characterized by Suitable for transmitting and receiving low-frequency 2.4GHz, high-frequency 5.1GHz and 5.8GHz signals, including: A cylindrical resonant cavity (1) is a mirror-symmetric structure with sidewalls composed of metal conductors. The cylindrical resonant cavity (1) has a circular upper and lower bottom surface and an arc-shaped sidewall connecting the upper and lower bottom surfaces. The upper bottom surface, the lower bottom surface and the sidewall are composed of metal conductors, and the sidewall itself has a mirror-symmetric structure. And, a dielectric pillar (3) is disposed on the bottom surface of the cylindrical resonant cavity (1), the dielectric pillar (3) being a cylindrical structure made of dielectric material with a loss lower than a set threshold; A low-frequency resonant antenna structure (2) is disposed between the dielectric pillar (3) and the bottom surface of the cylindrical resonant cavity (1). The low-frequency resonant antenna structure (2) is a cylinder formed by a metal conductor. The low-frequency resonant antenna structure (2) is electrically connected to the coaxial transmission line (5). The high-frequency resonant antenna structure (4) is disposed on the bottom surface of the cylindrical resonant cavity (1). The high-frequency resonant antenna structure (4) includes two metal plates arranged along the axial direction of the cylindrical resonant cavity (1) and parallel to each other. The two metal plates in the high-frequency resonant antenna structure (4) are arranged on the intersection line of the symmetry plane of the side wall and the bottom surface, and the metal plates are located away from the side wall. The height of the metal plate that is relatively close to the low-frequency resonant antenna structure (2) is higher than the height of the other metal plate. The coaxial transmission line (5) is connected to the middle of the bottom surface of the cylindrical resonant cavity (1), and the coaxial transmission line (5) is connected to the coaxial transmission connector (7).

2. A dual-frequency cylindrical antenna structure according to claim 1, characterized in that The cylindrical resonant cavity (1), the low-frequency resonant antenna structure (2), and the dielectric pillar (3) are arranged coaxially.

3. A dual-frequency cylindrical antenna structure according to claim 1, characterized in that The sidewalls of the cylindrical resonant cavity (1) can be either arc-shaped sidewalls or grid-shaped sidewalls formed by metal pillars arranged periodically in a circular arc.

4. The dual-frequency cylindrical antenna structure of claim 1, wherein, The coaxial transmission line (5) is connected to the middle of the bottom surface of the cylindrical resonant cavity (1), and the coaxial transmission line (5) is connected to the coaxial transmission connector (7).

5. A dual-frequency cylindrical antenna structure according to claim 4, characterized in that The bottom surface of the cylindrical resonant cavity (1) is connected to the spring bracket (6), the spring bracket (6) is connected to the coaxial transmission connector (7), the spring bracket (6) is coaxially arranged with the cylindrical resonant cavity (1), and the coaxial transmission line (5) is arranged along the central axis of the spring bracket (6).

6. A dual-frequency cylindrical antenna structure according to claim 5, characterized in that The coaxial transmission line (5) is connected to the bottom surface of the cylindrical resonant cavity (1) and the coaxial transmission connector (7) respectively through two rotating coaxial terminals.

7. The dual-frequency cylindrical antenna structure according to claim 1, characterized in that, The hollowed-out portion of the sidewall of the cylindrical resonant cavity (1) is covered with a dielectric material whose loss is lower than a set threshold, so as to seal the sidewall of the cylindrical resonant cavity (1).

8. An antenna, characterized in that, The antenna includes at least one pair of dual-frequency cylindrical antenna structures as described in any one of claims 1-7. The paired dual-frequency cylindrical antenna structures are non-coaxial and arranged in a mirror-symmetric manner. The paired dual-frequency cylindrical antenna structures are spaced apart by a predetermined distance, and the angle between the paired dual-frequency cylindrical antenna structures in the main radiation direction is 90°.

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