Magnetic antenna for very low frequency electromagnetic detection and communication and applications thereof

Abstract

The application relates to the technical field of magnetic antennas, in particular to a magnetic antenna for ELF / VLF electromagnetic detection and communication and application thereof, which comprises a ring-shaped frame, permanent magnets and coils, multiple permanent magnets are uniformly arranged in the ring-shaped frame to form a permanent magnet array, the permanent magnet array is a ring-shaped Halbach array, and a spacing is left between every two adjacent permanent magnets in the permanent magnet array, and the magnetization directions of every two adjacent permanent magnets along the ring direction of the ring-shaped frame are arranged at a preset interval angle; the coils are arranged around each permanent magnet, all the coils are connected in parallel and then connected with an external power supply through a shunt, and the shunt is used for adjusting the current size and phase fed into the coils so as to adjust the radiation range of the magnetic antenna. The application introduces the concept of the Halbach array into the ELF / VLF magnetic antenna, maximally improves the antenna radiation efficiency under the condition of limited volume, and improves the practical application feasibility of the ELF magnetic antenna.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of magnetic antennas, and particularly relates to a magnetic antenna for ELF / VLF electromagnetic detection and communication and application thereof. BACKGROUND

[0002] Low-frequency magnetic antennas play a key role in many important fields, such as underwater vehicle communication, oil pipeline detection and positioning, medical diagnosis and non-destructive testing. In these applications, ELF / VLF electromagnetic waves have the characteristics of strong penetration and small attenuation, which make them show unique advantages in certain environments. For example, in underwater vehicle communication, ELF / VLF electromagnetic waves can penetrate hundreds of meters of seawater, providing a reliable communication means for underwater vehicles; in oil pipeline detection and positioning, ELF / VLF electromagnetic waves have good penetration ability and propagation distance, which helps to carry out non-contact pipeline detection and detection on the ground or underground, especially in complex soil or rock environments. Low-frequency magnetic antennas can generate an electromagnetic field near the oil pipeline, and by detecting the electromagnetic field changes of the oil pipeline, the position and direction of the oil pipeline can be determined.

[0003] Existing magnetic antennas mainly include coil antennas, capacitive antennas and permanent magnet arrays. These magnetic antennas usually need a large area of antenna array to work effectively. For example, coil antennas are usually made of multiple turns of wire, which are relatively large in size, and in order to generate a strong enough electromagnetic field, a large current is usually required. Capacitive antennas require larger parallel plates or metal conductors to form an effective electric field region. As for the permanent magnet array, although the structure is relatively compact, the strength of the magnetic field generated is limited, and the adjustment flexibility is insufficient. The common shortcomings of these devices are that their volume and weight are relatively large, especially when applied to mobile devices or portable devices, which significantly increases the overall weight and volume of the system. In addition, due to the low radiation efficiency, these devices consume a large amount of power, but the strength and coverage of the electromagnetic field generated are still limited, making it difficult to meet the needs of some applications. Therefore, under the same power input, traditional devices often fail to achieve the desired radiation effect, limiting their application range in practice.

[0004] In recent years, with advancements in novel magnetic field design technologies, several optimized schemes have significantly improved the performance of magnetic antennas. For example, the Hellbeck array design can achieve higher magnetic field strength within a small volume by rationally distributing the magnetic field, while effectively suppressing unnecessary interference from the surrounding environment, thereby improving the stability and reliability of the device. Compared to traditional antennas, this array has a clear advantage in space-constrained applications. Moreover, its applications are mainly focused on generating static magnetic fields, such as in magnetic levitation systems, particle accelerators, and high-efficiency motors. In these scenarios, the array improves system performance by optimizing the magnetic field distribution, demonstrating excellent efficiency. However, research and applications in generating dynamic electromagnetic fields are still in their early stages. Currently, the generation of dynamic electromagnetic fields typically relies on traditional coil or capacitor antenna technologies. While these technologies are mature, they cannot meet specific performance requirements in certain aspects.

[0005] Therefore, there is a need to provide a magnetic antenna for extreme / very low frequency electromagnetic detection and communication and its application to solve the above problems. Summary of the Invention

[0006] To address the current problem that the generation of dynamic electromagnetic fields typically relies on traditional coil or capacitor antenna technologies, which, while mature, cannot meet specific performance requirements, this invention provides a magnetic antenna for extreme / very low frequency electromagnetic detection and communication, and its applications, to solve existing problems.

[0007] The first aspect of this invention provides a magnetic antenna for extremely low / very low frequency electromagnetic detection and communication, employing the following technical solution, including:

[0008] Ring frame;

[0009] Multiple permanent magnets are evenly distributed within a ring frame to form a permanent magnet array. The permanent magnet array is a ring-shaped Helbeck array, with a gap between adjacent permanent magnets. The permanent magnet array includes: four first permanent magnets, four second permanent magnets, and eight third permanent magnets. The four first permanent magnets are evenly distributed within the ring frame, with their magnetization direction radially inward along the ring frame. Second permanent magnets are positioned between every two first permanent magnets, with their magnetization direction radially outward along the ring frame. Third permanent magnets are positioned between adjacent first and second permanent magnets, with their magnetization direction tangential to the ring frame. The magnetization direction of one of two adjacent third permanent magnets is clockwise tangential to the ring frame, and the magnetization direction of the other third permanent magnet is counterclockwise tangential to the ring frame.

[0010] And the coil, around each permanent magnet is provided, and all the coils are connected in parallel after the shunt and the external power supply, the shunt is used for adjusting the current size and phase of the coil, so as to adjust the radiation range of the magnetic antenna.

[0011] The further technical scheme of the present application is that the annular frame is made of polycarbonate, nylon or polypropylene material.

[0012] The further technical scheme of the present application is that the permanent magnet is a neodymium iron boron magnet.

[0013] The further technical scheme of the present application is that the annular frame comprises an upper annular shell and a lower annular shell, and the upper annular shell and the lower annular shell are connected through a buckle type structure.

[0014] The further technical scheme of the present application is that the permanent magnet and the coil thereon form a radiation unit, and mounting grooves corresponding to the radiation unit are formed on the upper annular shell and the lower annular shell.

[0015] The further technical scheme of the present application is that the external power supply is an external power supply with adjustable output frequency, and the output frequency is 0.1 Hz to 1 kHz.

[0016] The second aspect of the present application provides an embodiment of a method for applying a magnetic antenna for ELF / VLF electromagnetic detection and communication to cross-medium communication, the magnetic antenna provided in the first aspect of the present application is carried on a water platform, and a magnetic receiver is carried on an underwater platform, and the water platform transmits the output command through the magnetic field signal radiated by the magnetic antenna to the magnetic receiver of the underwater platform.

[0017] The third aspect of the present application provides an embodiment of a method for applying a magnetic antenna for ELF / VLF electromagnetic detection and communication to cross-medium communication, the magnetic antenna provided in the first aspect of the present application is carried on an underwater platform, and a magnetic receiver is carried on a water platform, and the underwater platform transmits the output command through the magnetic field signal radiated by the magnetic antenna to the magnetic receiver of the water platform.

[0018] The fourth aspect of the present application provides an embodiment of a method for applying a magnetic antenna for ELF / VLF electromagnetic detection and communication to seabed buried object detection, the magnetic antenna provided in the first aspect of the present application is carried on an underwater vehicle, and a magnetic receiver is carried on the underwater vehicle, the electromagnetic wave generated by the magnetic antenna radiates on the seabed buried object to excite a secondary field, and the magnetic receiver receives the response secondary field signal to analyze and identify the seabed buried object.

[0019] The fifth aspect of the present application provides an embodiment of a method for applying a magnetic antenna for ELF / VLF electromagnetic detection and communication to pipeline detection, wherein the magnetic antenna provided by the first aspect of the present application is mounted on a detection pipe, and when the detection pipe is inserted into a rescue well pipeline, the electromagnetic wave generated by the magnetic antenna meets the inner wall of the rescue well pipeline to generate an induced electromagnetic field, and the sensor in the detection pipe receives the induced electromagnetic field to determine the orientation and distance of the oil pipe in the accident well according to the change of the induced electromagnetic field.

[0020] The present application has the following advantages:

[0021] 1. The permanent magnets of the magnetic antenna are arranged in a ring-shaped Halbach array, and coils are arranged on the permanent magnets. The permanent magnets and the coils thereon form radiation units. All the coils are connected to an external power source through a shunt. The shunt is used to accurately control the current size and phase of the coils in each radiation unit. The unique magnetic field characteristics of the array are used to achieve stronger electromagnetic radiation efficiency in the ELF range. The array optimizes the arrangement of permanent magnets and the distribution of magnetic fields, so that the magnetic field outside the permanent magnet array is effectively enhanced, while the magnetic field inside the permanent magnet array is weakened, thereby improving the performance and compactness of the entire system, and improving the concentration and directivity of electromagnetic radiation. Even in the low frequency band, a strong electromagnetic radiation field can be effectively generated. The array is suitable for various ELF electromagnetic radiation application scenarios, such as oil and gas pipeline detection, long-distance communication, and magnetic field detection. That is, the present application introduces the concept of Halbach array into the ELF / VLF magnetic antenna to maximize the radiation efficiency of the antenna in a limited volume, thereby improving the practical application feasibility of the ELF magnetic antenna.

[0022] 2. In the feeding scheme of the magnetic antenna, an independent feeding line structure is designed, that is, the coils are connected to an external power source through a shunt. The shunt effectively introduces the current output by the external power source into each coil and controls the current size and phase of the coil to ensure the stability and consistency of the electromagnetic radiation of each radiation unit. The arrangement of the feeding line fully considers the structural characteristics of the special magnet array to ensure the balanced current distribution between the coils and achieve higher electromagnetic radiation conversion and transmission efficiency. This design significantly improves the radiation performance of the system in the ELF range.

[0023] 3. A ring-shaped frame is arranged outside the permanent magnet array. The ring-shaped frame is made of high-strength and low-conductivity engineering plastic (polycarbonate, nylon or polypropylene material). Neodymium-iron-boron magnets are used as the permanent magnet material. The structure and winding method of the coils optimize the output of the magnetic field. Through a series of designs, the performance of the magnetic antenna is improved, and the magnetic antenna has excellent heat resistance and mechanical stability. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to make the technical solutions in the embodiments of the present application or the prior art clearer, the accompanying drawings needed in the embodiments or prior art description will be briefly introduced. Obviously, the accompanying drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative effort based on these drawings.

[0025] Figure 1 Structure diagram of a magnetic antenna for ELF / VLF electromagnetic detection and communication according to the present application;

[0026] Figure 2 Magnetization direction diagram of a permanent magnet array of a magnetic antenna according to an embodiment of the present application;

[0027] Figure 3 Radiation diagram of a magnetic antenna designed according to a permanent magnet array shown in Figure 2

[0028] Figure 4 Radiation unit diagram formed by winding a coil on a permanent magnet according to an embodiment of the present application;

[0029] Figure 5 Magnetization direction diagram of a permanent magnet array according to the prior art;

[0030] Figure 6 Magnetic field value measurement line diagram of a magnetic antenna corresponding to a permanent magnet array of Figure 5 and a permanent magnet array of Figure 2 at 10 m;

[0031] Figure 7 Magnetic field simulation comparison diagram of a magnetic antenna corresponding to a permanent magnet array of Figure 5 and a permanent magnet array of Figure 2 at 10 m measurement line;

[0032] Figure 8 Schematic diagram of the magnetic antenna applied to air-to-sea cross-medium communication according to an embodiment of the present application;

[0033] Figure 9 Schematic diagram of the magnetic antenna applied to sea-to-air cross-medium communication according to an embodiment of the present application;

[0034] Figure 10 Schematic diagram of the magnetic antenna applied to submarine buried object detection according to an embodiment of the present application;

[0035] Figure 11 Schematic diagram of the magnetic antenna applied to active oil pipe detection according to an embodiment of the present application.

[0036] In the figure: 1, annular frame; 2, radiation unit. DETAILED DESCRIPTION​

[0037] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0038] An embodiment of the present application is a magnetic antenna for ELF / VLF electromagnetic detection and communication. The purpose of the embodiment is to provide a magnetic antenna that can achieve flexible control of dynamic magnetic fields within a certain range, thereby meeting the needs of different scenarios, and can generate a high-intensity, stable ELF electromagnetic field in all directions, reducing magnetic field leakage. To achieve the above technical purpose, as shown in Figure 1 The embodiment specifically includes: a ring-shaped frame 1, coils, and a plurality of permanent magnets; the plurality of permanent magnets are uniformly arranged in the ring-shaped frame 1 to form a Halbach permanent magnet array, and there is a spacing between every two adjacent permanent magnets in the permanent magnet array, and the magnetization directions of every two adjacent permanent magnets along the ring direction of the ring-shaped frame 1 are arranged at a preset interval angle; the coils are arranged on each permanent magnet, and all the coils are connected in parallel to a shunt and then connected to an external power supply, and the size and phase of the coil current are precisely controlled through the shunt, thereby controlling the radiation range of the magnetic antenna.

[0039] For example, as shown in Figure 2 In one specific embodiment, the interval angle in the Halbach permanent magnet array is 90°, and the specific permanent magnet array includes: four first permanent magnets, four second permanent magnets, and eight third permanent magnets; wherein the four first permanent magnets are uniformly arranged in the ring-shaped frame 1, and the magnetization direction of the first permanent magnet is inward along the radial direction of the ring-shaped frame 1; the second permanent magnet is arranged between every two first permanent magnets, and the magnetization direction of the four second permanent magnets is outward along the radial direction of the ring-shaped frame 1; the third permanent magnet is arranged between the adjacent first permanent magnet and the second permanent magnet, and the magnetization direction of the third permanent magnet is along the tangent direction of the ring-shaped frame 1, and the magnetization direction of one of the two adjacent third permanent magnets is the clockwise tangential direction of the ring-shaped frame 1, and the magnetization direction of the other third permanent magnet is the counterclockwise tangential direction of the ring-shaped frame 1; wherein in the embodiment, the size of each permanent magnet depends on the total diameter of the ring-shaped permanent magnet array, the number of permanent magnets, and the required magnetic field strength. In the embodiment, the diameter of the permanent magnet array is designed to be 0.5 m, and the length, width, and height of each permanent magnet are all 0.02 m × 0.02 m × 0.02 m; as shown in Figure 4As shown, the coils are wound with high-purity copper wire, which has low resistance, high conductivity, and good thermal stability. The choice of copper wire diameter depends on the current magnitude and resistance requirements. Each permanent magnet's coil is wound independently, tightly against the permanent magnet surface, and optimized according to the permanent magnet size, coil length, and number of turns. All coils are connected in parallel, and each coil is simultaneously connected in parallel to a shunt. The shunt enables precise control of the coil current and phase, i.e., as shown... Figure 3 As shown, by optimizing the magnetization direction of the permanent magnet, the magnetization direction of the permanent magnet exhibits a bottom-right-top-left pattern after being energized. The permanent magnet is then arranged in a circle around the annular frame 1 according to the bottom-right-top-left pattern, making the magnetic field distribution more concentrated and uniform, and achieving a stronger magnetic field radiation effect in the specified area.

[0040] It should be noted that, with Figure 2 The topmost permanent magnet is the first permanent magnet. Following a clockwise order, the first permanent magnet is the first permanent magnet, with its magnetization direction radially inward from the ring frame 1. The second permanent magnet is the third permanent magnet, with its magnetization direction tangential to the ring frame 1 in a clockwise direction. The third permanent magnet is the second permanent magnet, with its magnetization direction radially outward from the ring frame 1. The fourth magnet is also the third permanent magnet, and all four magnets are tangential to the ring frame 1 in a counter-clockwise direction. This process continues, with every four permanent magnets forming a cycle, ultimately creating a complete array of 16 permanent magnets. This design not only generates a high-strength and uniformly distributed magnetic field but also avoids excessive magnetic field leakage, thereby improving system efficiency. Neodymium iron boron (NdFeB) magnets are used as the permanent magnet material. This is a high-performance rare-earth permanent magnet material with extremely high magnetic energy product (energy density), capable of generating a strong magnetic field at room temperature. The application of neodymium iron boron magnets provides the entire system with a powerful magnetic field output capability, while their miniaturization characteristics meet the requirements of compact equipment design.

[0041] For example, in one specific embodiment, to enhance structural stability and provide protection for the permanent magnet array, the annular frame 1 of this embodiment is made of high-strength, low-conductivity engineering plastic material, such as polycarbonate (PC), nylon, or polypropylene (PP). The annular frame 1 includes an upper annular shell and a lower annular shell, which are connected by a snap-fit ​​structure. This design makes the device detachable, facilitating maintenance or component replacement when needed. This structural design not only effectively improves the overall stability of the device but also provides reliable protection during operation, ensuring that the permanent magnets and coils operate normally in high-temperature environments, while also facilitating operation and maintenance; secondly, as Figure 4As shown, the permanent magnets and the coils thereon form the radiating elements 2, and mounting grooves corresponding to the radiating elements 2 are formed on the upper and lower annular shells, and the radiating elements 2 are mounted in the annular frame 1 through the mounting grooves to ensure that they are firmly fixed in the frame and avoid loosening or displacement.

[0042] In this embodiment, polycarbonate is used as the material of the annular frame 1 because the material of the annular frame 1 needs to have good heat resistance, and the polycarbonate has the best heat resistance among the three materials, because a certain amount of heat may be generated inside the magnetic antenna during operation. The wall thickness of the annular frame 1 is designed to be 10 mm, which can ensure sufficient mechanical strength and will not significantly increase the weight of the device.

[0043] For example, in a specific embodiment, to meet the needs of different application scenarios, the external power supply is an external power supply with adjustable output frequency, and the output frequency is 0.1 Hz to 1 kHz.

[0044] The following describes this embodiment in combination with specific simulation data:

[0045] As shown in Figure 5 , the magnetization direction of the conventional antenna is usually radial outward, and the magnetization direction of each permanent magnet is arranged radially outward, and these permanent magnets are arranged in an array to form a ring-shaped array composed of 16 permanent magnets, and therefore the permanent magnet array of the magnetic antenna of the present application is different from the existing permanent magnet array, as shown in Figure 2 , the magnetization direction of the conventional antenna is usually radial outward, and the magnetization direction of each permanent magnet is arranged radially outward, and these permanent magnets are arranged in an array to form a ring-shaped array composed of 16 permanent magnets, and therefore the permanent magnet array of the magnetic antenna of the present application is different from the existing permanent magnet array, as shown in Figure 6 , the red measurement lines of the two kinds of magnetic antenna of the permanent magnet array are located at 10 meters, aiming to measure and compare the magnetic field values generated by the two kinds of magnetic antenna at this distance. Through this measurement, the simulation comparison chart of the magnetic field size of the two different designed permanent magnet arrays of the magnetic antenna at the 10-meter measurement line under the same environmental conditions is shown in Figure 7 . In this experiment, the magnetic antenna was simulated at an excitation frequency of 10 Hz, and the magnetic field strength at 10 meters was measured. The simulation results show that the magnetic field peak value of the magnetic antenna based on the permanent magnet array of the present application at 10 meters is 4 nT, and the minimum value is 1.5 nT, while the magnetic field value of the existing permanent magnet array under the same conditions is very small, almost 0 nT. This comparison result directly shows that the magnetic antenna with the proposed permanent magnet array arrangement structure can generate a stronger magnetic field at the same distance. This design makes the strength and distribution of the magnetic field have significant advantages, especially at a farther distance, the magnetic field decays slowly and can cover a wider range; and the magnetic antenna based on the special magnetic field arrangement structure not only outperforms the conventional design in terms of magnetic field strength, but also performs better in terms of propagation distance.

[0046] An embodiment of the application of a magnetic antenna for ELF / VLF electromagnetic detection and communication in the application method of cross-medium communication is shown in the figure. Figure 8 The magnetic antenna of the embodiment is mounted on a water platform (aircraft or ship), and a magnetic receiver is mounted on an underwater platform (underwater UUV), and the water platform transmits the output command through the magnetic field signal radiated by the magnetic antenna to the magnetic receiver of the underwater platform.

[0047] An embodiment of the application of a magnetic antenna for ELF / VLF electromagnetic detection and communication in the application method of cross-medium communication is shown in the figure. Figure 9 The magnetic antenna of the embodiment is mounted on an underwater platform (underwater UUV), and a magnetic receiver is mounted on a water platform (aircraft or ship), and the underwater platform transmits the output command through the magnetic field signal radiated by the magnetic antenna to the magnetic receiver of the underwater platform.

[0048] An embodiment of the application of a magnetic antenna for ELF / VLF electromagnetic detection and communication in the application method of cross-medium communication is shown in the figure. Figure 10 The magnetic antenna of the embodiment is mounted on an underwater vehicle (underwater UUV), and a magnetic receiver is mounted on the underwater vehicle (underwater UUV), and the electromagnetic wave generated by the magnetic antenna is radiated on the seabed buried object to excite a secondary field, and the magnetic receiver receives the response secondary field signal to analyze and identify the seabed buried object.

[0049] An embodiment of the application of a magnetic antenna for ELF / VLF electromagnetic detection and communication in the application method of cross-medium communication is shown in the figure. Figure 11 The magnetic antenna of the embodiment is mounted on a pipe probe, and an external power supply generates a current input to the magnetic antenna through a cable, and when the pipe probe is inserted into the rescue well pipe, the electromagnetic wave generated by the magnetic antenna encounters the oil pipe wall in the accident well to produce an induced electromagnetic field, and the sensor in the pipe probe receives the secondary induced electromagnetic field generated by the oil pipe in the accident well to determine the orientation and distance of the oil pipe in the accident well; it should be noted that the low-frequency electromagnetic wave emitted by the magnetic antenna can penetrate most non-conductive media, and the oil pipe is usually made of metal material and has high conductivity, and the low-frequency electromagnetic wave will produce an induced magnetic field around the oil pipe when it encounters the oil pipe during propagation.

[0050] The above only describes the preferred embodiments of the application, and is not intended to limit the application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the application shall be included in the protection scope of the application.

Claims

1. A magnetic antenna for ELF / VLF electromagnetic detection and communication, characterized in that, The magnetic antenna comprises: a ring-shaped frame; a plurality of permanent magnets, which are arranged in the ring-shaped frame to form a permanent magnet array, the permanent magnet array is a ring-shaped Halbach array, and a spacing is left between every two adjacent permanent magnets in the permanent magnet array, wherein the permanent magnet array comprises four first permanent magnets, four second permanent magnets, and eight third permanent magnets; the four first permanent magnets are arranged in the ring-shaped frame, and the magnetization direction of the first permanent magnet is inward along the radial direction of the ring-shaped frame; the second permanent magnet is arranged between every two first permanent magnets, and the magnetization direction of the four second permanent magnets is outward along the radial direction of the ring-shaped frame; the third permanent magnet is arranged between the adjacent first permanent magnet and the second permanent magnet, and the magnetization direction of the third permanent magnet is along the tangential direction of the ring-shaped frame, the magnetization direction of one of the two adjacent third permanent magnets is the clockwise tangential direction of the ring-shaped frame, and the magnetization direction of the other third permanent magnet is the counterclockwise tangential direction of the ring-shaped frame; and a coil, which is arranged around each permanent magnet, and all the coils are connected in parallel to a shunt and an external power supply, the shunt is used to adjust the current size and phase fed to the coil, so as to adjust the radiation range of the magnetic antenna.

2. A magnetic antenna for ELF / VLF electromagnetic detection and communication according to claim 1, characterized in that, The ring-shaped frame is made of polycarbonate, nylon, or polypropylene material.

3. A magnetic antenna for ELF / VLF electromagnetic detection and communication according to claim 1, characterized in that, The permanent magnet is a neodymium-iron-boron magnet.

4. A magnetic antenna for ELF / VLF electromagnetic detection and communication according to claim 1, characterized in that, The ring-shaped frame comprises an upper ring-shaped shell and a lower ring-shaped shell, and the upper ring-shaped shell and the lower ring-shaped shell are connected through a buckle type structure.

5. A magnetic antenna for ELF / VLF electromagnetic detection and communication according to claim 4, characterized in that, The permanent magnet and the coil thereon form a radiation unit, and a mounting groove corresponding to the radiation unit is formed on the upper ring-shaped shell and the lower ring-shaped shell.

6. A magnetic antenna for ELF / VLF electromagnetic detection and communication according to claim 1, characterized in that, The external power supply is an external power supply with adjustable output frequency, and the output frequency is 0.1 Hz to 1 kHz.

7. A method for application of a magnetic antenna for ELF / VLF electromagnetic detection and communication across a medium, characterized by, The magnetic antenna according to any one of claims 1-6 is carried on a water platform, and a magnetic receiver is carried on an underwater platform, the water platform transmits the output command through the magnetic field signal radiated by the magnetic antenna to the magnetic receiver of the underwater platform.

8. A method for application of a magnetic antenna for ELF / VLF electromagnetic detection and communication across a medium, characterized by, The magnetic antenna according to any one of claims 1-6 is carried on an underwater platform, and a magnetic receiver is carried on a water platform, the underwater platform transmits the output command through the magnetic field signal radiated by the magnetic antenna to the magnetic receiver of the water platform.

9. A method of application of a magnetic antenna for very low frequency electromagnetic detection and communication to detection of sea bottom burial objects, characterized in that, The magnetic antenna according to any one of claims 1-6 is carried on an underwater vehicle, and a magnetic receiver is carried on the underwater vehicle, the electromagnetic wave generated by the magnetic antenna radiates on a seabed buried object through seawater and a buried medium to excite a secondary field, and the magnetic receiver receives the response secondary field signal to analyze and identify the seabed buried object.

10. A method of using a magnetic antenna for ELF / VLF electromagnetic detection and communication for pipeline detection, characterized in that, The magnetic antenna according to any one of claims 1-6 is carried on a probe pipe, when the probe pipe is inserted into a rescue well pipe, the electromagnetic wave generated by the magnetic antenna meets the inner wall of the rescue well pipe to generate an induced electromagnetic field, a sensor in the probe pipe receives the induced electromagnetic field, and the position and distance of the oil pipe in the accident well are determined according to the change of the induced electromagnetic field.

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