A waveguide slot antenna communication system

Abstract

This invention discloses a slotted antenna communication system, belonging to the field of antenna and microwave technology. The system includes: a far-end signal source; a far-end surface wave mode coupler, employing a self-balancing magnetic dipole antenna, used to transmit the source signal to a single conductor via non-contact wireless coupling to excite surface waves; a single conductor as the transmission medium; a near-end surface wave mode coupler, also employing a self-balancing magnetic dipole antenna, used to extract the surface wave energy from the single conductor surface into a radio frequency signal via non-contact wireless coupling; and a repeater antenna, a helical antenna, fed to the near-end surface wave mode coupler with their central axes collinear and aligned, used to convert the radio frequency signal into a free-space wave for outward transmission. The spacing of the non-contact wireless coupling is adapted and adjusted according to the diameter of the long conductor. This invention achieves efficient surface wave excitation and directional repeatering without damaging existing pipeline structures in industrial settings, effectively reducing path loss.

Description

Technical Field

[0001] This invention belongs to the field of antenna and microwave technology, and specifically relates to a slotted antenna communication system. Background Technology

[0002] As 5G technology is gradually commercialized and evolves into 6G technology, the demand for high-speed, reliable, and low-latency wireless communication for the industrial internet is becoming increasingly urgent.

[0003] Traditional wireless communication, which relies entirely on free-space radiation, struggles to guarantee link stability in industrial settings (such as elevator shafts and mines) due to obstruction by metal equipment and multipath interference. To address this, existing technologies have proposed surface wave communication systems that utilize readily available long, straight, cylindrical metal structures (such as hollow pipes or metal rails) as the electromagnetic wave transmission medium. However, existing surface wave communication systems face the following significant technical bottlenecks in practical industrial applications: First, existing surface wave excitation and coupling devices (such as traditional coaxial feed structures or dielectric horn waveguides) often rely on physical electrical contact with the conductor or require cutting and modification of the cable structure, which is unacceptable in industrial sites with strict safety standards (such as power grids and mine pipelines). Even if a partially non-contact waveguide structure is used, there are stringent requirements on the diameter and material of the conductor, resulting in large equipment size that is difficult to flexibly adapt to existing pipelines of varying thicknesses on site.

[0004] Secondly, industrial confined spaces (such as narrow tunnels or shafts) often have highly asymmetrical spatial geometry. Traditional terminal relay antennas have weak beam control capabilities and usually adopt omnidirectional radiation. This results in a large amount of spatial radio frequency energy converted from surface waves being dissipated on the tunnel walls, making it impossible to achieve efficient and directional coverage for mobile users in specific work areas.

[0005] In summary, designing a novel communication system that can achieve non-contact, high-efficiency surface wave excitation of single conductors of different sizes without damaging existing physical infrastructure, and can also perform efficient directional forwarding based on the characteristics of confined spaces, has become a pressing technical challenge in the field of industrial internet communication. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide a slotted antenna communication system that solves the problems in the prior art.

[0007] The objective of this invention can be achieved through the following technical solutions: A slotted antenna communication system includes: A remote surface wave mode coupler is used to wirelessly couple a source signal to a single conductor to excite surface waves. A single conductor serves as the transmission medium for the surface waves; A near-end surface wave mode coupler is used to extract the surface wave energy of the single conductor surface into a radio frequency signal via wireless coupling. And a repeater antenna, which is fed to the near-end surface wave mode coupler, for converting the derived radio frequency signal into a free space wave for transmission; The near-end surface wave mode coupler is collinearly aligned with the central axis of the transponder antenna.

[0008] Furthermore, the length of the single conductor is greater than or equal to 10 times the operating wavelength of the source signal transmitted in the single conductor.

[0009] Furthermore, the arrangement between the distal surface wave mode coupler and the single conductor, as well as between the proximal surface wave mode coupler and the single conductor, is non-contact.

[0010] Furthermore, both the far-end surface wave mode coupler and the near-end surface wave mode coupler employ a self-balancing magnetic dipole antenna or an electric dipole antenna fed by a ring balancer.

[0011] Furthermore, the relay antenna is a helical antenna or a high-gain linearly polarized antenna.

[0012] Furthermore, a signal forwarding device for a slotted antenna communication system includes: a near-end surface wave mode coupler, which is a self-balancing magnetic dipole antenna; The repeater antenna is a helical antenna; The self-balancing magnetic dipole antenna is fed to the spiral antenna, and the central axis of the self-balancing magnetic dipole antenna coincides with that of the spiral antenna. The self-balancing magnetic dipole antenna is configured to be positioned close to the single conductor for extracting surface wave energy from the surface of the single conductor via wireless coupling.

[0013] Furthermore, the self-balancing magnetic dipole antenna is configured to have an adjustable rotation angle around the axis of the single conductor.

[0014] Furthermore, the self-balancing magnetic dipole antenna is configured to have an adjustable deployment position relative to the single conductor along its extension direction.

[0015] Furthermore, the single conductor is an enameled wire with a diameter of 0.8 mm.

[0016] Furthermore, the coupling distance between the self-balancing magnetic dipole antenna and the enameled wire is 5 mm.

[0017] The beneficial effects of this invention are: 1. This invention constructs a hybrid wireless communication system combining wired surface wave transmission and free-space wireless transmission by combining a single conductor, a surface wave mode coupler, and a repeater antenna. This mechanism utilizes a single conductor as the guiding medium for electromagnetic wave transmission, enabling high-frequency signals to be transmitted as surface waves. This effectively reduces transmission path loss caused by environmental obstruction, improves deep fading, and enhances the signal-to-noise ratio at the receiver and the overall reliability of the link.

[0018] 2. This application employs non-contact wireless coupling at both the far and near ends. By configuring an adjustable non-contact wireless coupling distance, the system can flexibly utilize various long straight conductors (such as pipelines of different diameters) that are more than 10 times the working wavelength in existing industrial scenarios, achieving efficient excitation and access of surface waves without damaging or cutting the original cable structure, significantly reducing on-site construction difficulty and modification costs.

[0019] 3. The near-end surface wave mode coupler of the present invention is fed to a topology structure in which a highly directional helical antenna is collinearly aligned with its central axis. This combination and spatial arrangement of the coupling and relay antennas can efficiently convert the extracted surface wave energy into free space waves with specific beam direction at the near end, which helps to achieve more targeted local mobile user coverage in complex and confined spaces and improve the utilization rate of communication energy.

[0020] 4. By configuring the self-balancing magnetic dipole antenna with an adjustable rotation angle around the long conductor and a movable deployment position along the extension direction of the long conductor, the system can flexibly mount the repeater at any suitable node of the long conductor according to the actual channel conditions and user distribution on site. This design facilitates segmented signal amplification or multi-area cascaded coverage in industrial sites, giving the communication network strong scalability and adaptability. Attached Figure Description

[0021] 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.

[0022] Figure 1 This is a schematic diagram of the slotted antenna communication system of the present invention; Figure 2 The diagrams show a comparison of path loss generated by communication using the slotted antenna communication system of this invention and free space propagation, respectively. Figure 3 This is a comparison chart of the bit error rates generated by communication using the slotted antenna communication system of the present invention and free space propagation, respectively. Figure 4 This is a comparison diagram of the path loss generated by changing the coupling distance of the slotted antenna communication system of the present invention to 50mm and by communicating through free space propagation. Figure 5 This is a comparison diagram of the path loss generated by using a high-gain linearly polarized antenna as the relay antenna in the slotted antenna communication system of the present invention and by communicating through free space propagation. Figure 6 This is a comparison of the path loss generated by the present invention's slotted antenna communication system using a 120mm diameter conductor and coupling distances of 5mm and 50mm, and by communication via free space propagation. Figure 7 This is a comparison diagram of the path loss generated by using a high-gain linearly polarized antenna and a long conductor diameter of 120mm as the relay antenna of the slotted antenna communication system of the present invention, and by communicating through free space propagation. Figure 8 This is a comparison diagram of the path loss generated by an electric dipole antenna fed by a two-dimensional ring balancer instead of a surface wave coupler in the slotted antenna communication system of the present invention, and by communication through free space propagation. In the diagram: 1-Far-end surface wave mode coupler, 2-Near-end surface wave mode coupler, 3-Relay antenna, 4-Mobile user, 5-Single conductor. Detailed Implementation

[0023] 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, and 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.

[0024] Example 1 like Figure 1 As shown, a slotted antenna communication system includes a single conductor 5. A far-end surface wave mode coupler 1 and a near-end surface wave mode coupler 2 are respectively arranged around the far end and near end of the single conductor 5 and are wirelessly coupled to the single conductor. A repeater antenna 3 is connected below the near-end surface wave mode coupler 2, and a mobile user 4 is arranged around the repeater antenna 3. The communication process of the slotted antenna communication system is as follows: the far-end surface wave mode coupler 1 wirelessly couples with the single conductor 5 to generate surface waves. The surface waves are transmitted from the single conductor 5 to the near-end surface wave mode coupler 2, and then to the repeater antenna 3. The repeater antenna 3 transmits the signal to the mobile user 4 through wireless free space, thereby achieving stable communication. The effectiveness and reliability of the wireless communication system can be judged by the transmission path loss and bit error rate.

[0025] In this embodiment, both the far-end surface wave mode coupler 1 and the near-end surface wave mode coupler 2 use self-balancing magnetic dipole antennas (from: C. Shen, W.-J. Lu, and L. Zhu, “Planar self-balanced magnetic dipole antenna with wide beamwidth characteristic”). IEEE Trans. Antennas Propag. ( , vol. 67, no. 7, pp. 4860–4865, Jul. 2019.), the repeater antenna 3 uses a helical antenna, the mobile user 4 uses a monopole whip antenna, and the single conductor 5 uses international standard QA non-scraping, directly solderable enameled wire with a diameter of 0.8mm.

[0026] The length of the single conductor 5 should be much larger than the operating wavelength of the coupler, for example, more than 10 times the operating wavelength (in this embodiment, the length of the single conductor 5 is 9 meters, equivalent to 73 times the operating wavelength). According to Sommerfeld's surface wave theory, a surface wave is a traveling wave that propagates on the surface of a conductive metal. When a signal is transmitted through a single conductor that is not long enough, it will be reflected at the end, thus generating a standing wave mode. Experimental tests have shown that when the length of the single conductor exceeds 10 times the wavelength, the coupler can effectively excite surface wave modes on the single conductor.

[0027] A copper wire (single conductor 5) is placed in free space without direct contact with any antennas. Two self-balancing magnetic dipole antennas are placed around the far and near ends of the single conductor 5, respectively, with a coupling distance of 5 mm. A helical antenna (relay antenna 3) is placed below the near-end self-balancing magnetic dipole antenna (near-end surface wave mode coupler 2). The impedance of both the helical antenna (relay antenna 3) and the self-balancing dipole antenna (near-end surface wave mode coupler 2) in the same frequency band is set to 50 ohms. The two are connected through a dual-anode converter, so that the surface wave energy is effectively transferred to the helical antenna through the self-balancing dipole antenna. A monopole whip antenna (mobile user 4) is placed around the receiving relay antenna 3, with a relay distance of 15 cm.

[0028] The central axes of the self-balancing magnetic dipole antenna (coupler 1) and the receiving / relay antenna (coupler 2 and relay antenna 3) are both perpendicular to the central axis of the single conductor 5, and the single conductor 5 is always kept straight and parallel to the ground. The two self-balancing magnetic dipole antennas (couplers 1 and 2) are wirelessly coupled to copper wires at the far end and near end of the single conductor 5, respectively. The monopole whip antenna (mobile user 4) receives the signal transmitted by the relay antenna 3 through free space.

[0029] In other embodiments, the surface wave coupler can also be an electric dipole antenna, the relay antenna can be any other high-gain antenna, and the single conductor 5 can be a long conductor of any diameter. The wireless coupling distance between the surface wave coupler and the single conductor 5 can be adjusted according to the diameter of the single conductor 5. The far-end surface wave coupler 1 and the near-end surface wave coupler 2 can be positioned around the single conductor 5 at any rotation angle. The near-end surface wave coupler 2 can move to any position around the single conductor 5. The transmission distance between the far-end surface wave coupler 1 and the near-end surface wave coupler 2 using wired surface wave transmission can be adjusted as needed. The relay antenna 3 is connected to the near-end surface wave coupler 2 to relay the far-end signal and cover the mobile user 4 as needed. The mobile user 4 can be freely positioned at different locations around the relay antenna. The maximum transmission distance between the mobile user 4 and the relay antenna 3 can be adjusted according to the transmission power of the far-end signal source and the wireless coupling distance between the far-end surface wave coupler 2 and the single conductor 5.

[0030] Example 2 In this embodiment, the path loss and bit error rate are calculated by actually measuring the transmission loss of the slotted antenna communication system (Embodiment 1) and free space propagation. The process is as follows: S collected based on vector network analysis 21 The data (including amplitude and phase data) and the path loss calculation formula are shown in (1).

[0031] (1) in, This represents the average path loss value. M Indicates the number of samples taken over a single transmission distance. N f This indicates the number of frequency points in a single sampling. H m ( f , d ) indicates the first m Frequency response in the next sample n Indicates the first m In the second sampling n One frequency point.

[0032] Based on the measured data, the CIF path loss model formula can be obtained, as shown in equation (2). Based on equation (2) and the transmit power of the vector network analyzer (0 dBm in this example), the signal-to-noise ratio can be determined, and thus the bit error rate under different modulation schemes can be determined (from: C. Shen, W.-J. Lu, and L. Zhu, “Planar self-balanced magnetic dipole antenna with wide beamwidth characteristic,” IEEE Transactions. Antennas Propag. (See, vol. 67, no. 7, pp. 4860–4865, Jul. 2019.), this embodiment uses QPSK modulation, and its bit error rate results are as follows. Figure 3 As shown.

[0033] (2) Among them, PL CIF ( d ) indicates a distance of d The path loss data measured at that time, PL( f 0, d 0) is the reference distance d Path loss at 0 (in this embodiment) d 0 is 1 meter). n This is the path loss factor. X σ The mean is μ The variance is σ The shadow effect.

[0034] The transmission path loss of a slotted antenna communication system and free-space propagation at a transmission distance of 6 meters is as follows: Figure 2 As shown, the black and red solid lines represent the path loss generated by the slotted antenna communication system and free space propagation, respectively. According to experimental data, in the frequency band of 2.35~2.5GHz, the average path loss of free space propagation is about 18dB higher than that of the slotted antenna communication system.

[0035] Bit error rate results for slotted antenna communication systems and free-space propagation are as follows: Figure 3 As shown, the black and red solid lines represent the bit error rates of the slotted antenna communication system and free-space propagation, respectively. Figure 3 As a result, under the same transmission distance conditions, the bit error rate of the slotted antenna communication system is lower than that of free space propagation. Comparison of experimental data shows that, compared to free space propagation, using a slotted antenna communication system can significantly reduce path loss and bit error rate.

[0036] Example 3 Based on Example 1, the coupling distance of the surface wave coupler was changed to 50mm, and the experiment was conducted again. The experimental results were processed using the method described in Example 2 to obtain the path loss under this condition, and compared with free propagation. Figure 4 As shown in the figure. According to experimental data, within the frequency band of 2.35~2.5GHz, the average path loss of free space propagation is about 4.39dB higher than that of the slotted antenna communication system under the same conditions.

[0037] Based on the results of Examples 1, 2 and 3, it can be found that as the coupling distance of the surface wave coupler increases, the path loss will increase to a certain extent, but it is still lower than the transmission loss of free space propagation, proving that the slotted antenna communication system can communicate effectively under different coupling distance conditions.

[0038] Example 4 Based on Example 1, the repeater antenna was changed to a high-gain linearly polarized antenna (from: WQ Jia, FY Ji, WJ Lu, CX Pan, et al. “Dual-resonant high-gain wideband Yagi-Udaantenna using full-wavelength sectorial dipoles,” IEEE Open J. Antennas and Propag. (2021, 2: 872-881.), with other conditions remaining unchanged, the experiment was conducted. The experimental results were processed in the manner described in Example 2 to obtain the path loss under these conditions, and compared with free propagation, as shown. Figure 5 As shown in the figure. According to experimental data, within the frequency band of 2.35~2.5GHz, the average path loss of free space propagation is about 13.2dB higher than that of the slotted antenna communication system under the same conditions.

[0039] Based on the results of Examples 1, 2, and 4, it can be found that using different high-gain antennas as the relay antenna in the slotted antenna communication system can significantly reduce the path loss of communication compared to free-space propagation. This proves that the relay antenna in this slotted antenna communication system can be any high-gain antenna.

[0040] Example 5 Based on Example 1, the diameter of the long single conductor was changed to 120mm, and the coupling distances were 5mm and 50mm respectively. The experiment was conducted again, and the results were processed using the method described in Example 2 to obtain the path loss under these conditions. This path loss was then compared with that of free propagation. Figure 6As shown in the figure. According to experimental data, within the frequency band of 2.35~2.5GHz, the average path loss of free-space propagation is approximately 8.7dB higher than that of the slotted antenna communication system using a 120mm diameter conductor and a 5mm coupling distance; and approximately 6.3dB higher than that of the slotted antenna communication system using a 120mm diameter conductor and a 50mm coupling distance. Based on the results of Examples 1, 2, and 5, it can be observed that the slotted antenna communication system can communicate under conditions of using long conductors of arbitrary diameters and different coupling distances. The larger the diameter of the long conductor, the greater the path loss; the greater the coupling distance, the greater the path loss. However, compared with free space propagation, it can still significantly reduce the path loss of communication, thus proving that the communication system can achieve effective communication under conditions of long conductors of different diameters and different coupling distances.

[0041] Example 6 Based on Example 4, the diameter of the long single conductor was changed to 120mm, while other conditions remained unchanged. Experiments were conducted, and the results were processed using the method described in Example 2 to obtain the path loss under these conditions. This path loss was then compared with that obtained through free propagation. Figure 7 As shown in the figure. According to experimental data, within the frequency band of 2.35~2.5GHz, the average path loss of free space propagation is about 8.6dB higher than that of the slotted antenna communication system under the same conditions.

[0042] Based on the results of Examples 1, 2, 4, 5 and 6, it can be further demonstrated that the slotted antenna communication system can effectively communicate under different conductor diameters, and the path loss increases with the increase of the conductor diameter, but the path loss is still significantly lower than that of free space propagation communication.

[0043] Example 7 Based on Example 1, the surface wave coupler was replaced with an electric dipole antenna fed by a ring balancing device (from patent application No. 202510385962.1, entitled "An Antenna Design Method for an Integrated Two-Dimensional Structure Balancing Device"). All other conditions remained unchanged, and experiments were conducted. The experimental results were processed using the method described in Example 2 to obtain the path loss under these conditions, which was then compared with free propagation. Figure 7 As shown in the figure. According to experimental data, within the frequency band of 2.35~2.5GHz, the average path loss of free space propagation is about 4.3dB higher than that of the slotted antenna communication system under the same conditions.

[0044] Based on the results of Examples 1, 2, and 7, it can be found that the surface wave coupler in the slotted antenna communication system can be a magnetic dipole antenna or an electric dipole antenna. The slotted antenna communication system composed of these two types of antennas can significantly reduce the path loss of communication compared with free space propagation.

[0045] In summary, this invention proposes a slotted antenna communication system that wirelessly connects a far-end surface wave mode coupler, a near-end surface wave mode coupler, and a repeater antenna to a single conductor, fully exciting surface wave modes and combining them with wireless communication to generate a wireless transmission channel. Because the surface wave propagation mechanism reduces path loss and mitigates multipath fading, a channel with nearly constant parameters is obtained. The surface wave mode coupler is wirelessly coupled to the single conductor, and the coupling distance can be adjusted according to the transmit power of the far-end surface wave mode coupler, allowing for on-demand access to the receiving repeater antenna and mobile users to cover different areas. Experimental results verify the effectiveness and reliability of this wireless communication system, thus demonstrating its broad application prospects in completely random industrial IoT channels.

[0046] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0047] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A slotted antenna communication system, characterized in that, include: A remote surface wave mode coupler is used to wirelessly couple a source signal to a single conductor to excite surface waves. A single conductor serves as the transmission medium for the surface waves; A near-end surface wave mode coupler is used to extract the surface wave energy of the single conductor surface into a radio frequency signal via wireless coupling. And a repeater antenna, which is fed to the near-end surface wave mode coupler, for converting the derived radio frequency signal into a free space wave for transmission; The near-end surface wave mode coupler is collinearly aligned with the central axis of the transponder antenna.

2. The slotted antenna communication system according to claim 1, characterized in that, The length of the single conductor is greater than or equal to 10 times the operating wavelength of the source signal transmitted in the single conductor.

3. The slotted antenna communication system according to claim 1, characterized in that, The distal surface wave mode coupler and the single conductor, as well as the near-end surface wave mode coupler and the single conductor, are arranged in a non-contact manner.

4. The slotted antenna communication system according to claim 1, characterized in that, Both the far-end surface wave mode coupler and the near-end surface wave mode coupler employ a self-balancing magnetic dipole antenna or an electric dipole antenna fed by a ring balancer.

5. A slotted antenna communication system according to claim 1, characterized in that, The relay antenna is a helical antenna or a high-gain linearly polarized antenna.

6. A signal forwarding device for a slotted antenna communication system, characterized in that, include: Near-end surface wave mode coupler, which is a self-balancing magnetic dipole antenna; The repeater antenna is a helical antenna. The self-balancing magnetic dipole antenna is fed to the spiral antenna, and the central axis of the self-balancing magnetic dipole antenna coincides with that of the spiral antenna. The self-balancing magnetic dipole antenna is configured to be positioned close to the single conductor for extracting surface wave energy from the surface of the single conductor via wireless coupling.

7. The signal forwarding device for a slotted antenna communication system according to claim 6, characterized in that, The self-balancing magnetic dipole antenna is configured to have an adjustable rotation angle around the axis of the single conductor.

8. The signal relay device according to claim 6, characterized in that, The self-balancing magnetic dipole antenna is configured to have an adjustable deployment position relative to the single conductor along its extension direction.

9. The signal relay device according to claim 6, characterized in that, The single conductor is an enameled wire with a diameter of 0.8 mm.

10. The signal relay device according to claim 9, characterized in that, The coupling distance between the self-balancing magnetic dipole antenna and the enameled wire is 5 mm.

Images