Mechanical antenna based on high-temperature superconducting

Abstract

The mechanical antenna comprises a vibration reduction chassis and a Dewar holder which is arranged above the vibration reduction chassis and can adjust the height, a Dewar is arranged above the Dewar holder, and a superconducting coil is arranged in the Dewar; a servo motor is arranged on the vibration reduction chassis, a magnetic conductive rotor is arranged on an output shaft of the servo motor, the magnetic conductive rotor penetrates through the Dewar pan-tilt and extends into the Dewar, and the superconducting coil is arranged outside the magnetic conductive rotor in a sleeving mode. The upper radiation limit of a traditional mechanical antenna is broken through, the radiation performance of an existing mechanical antenna is improved, and the technical problem that a magnetic field of a permanent magnet of an existing rotating magnet type mechanical antenna is difficult to improve or a superconducting magnetic rotor is difficult to rotate is solved; meanwhile, the radiation frequency is controlled by flexibly changing the number of the magnetic conductive blades, the problem that the rotation speed of the motor limits the radiation frequency is solved, the proper material of the magnetic conductive rotor is determined, and the performance of the antenna is further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of low-frequency mechanical antennas, and particularly to a mechanical antenna based on high-temperature superconductivity. Background Art

[0002] Ultra-low frequency (SLF, 30 - 300 Hz) electromagnetic waves are widely used in submarine communication and geological exploration fields due to their characteristics of long propagation distance and strong anti-electromagnetic pulse ability. However, most of the currently applied low-frequency transmitting antennas adopt electrically small antennas (ESAs), which mainly rely on near-field coupling for energy transmission. Since the electrically small antenna has a small size, its radiation resistance is low and its reactance is large, resulting in most of the input energy being consumed as heat rather than effective radiation, thus having the defect of low radiation efficiency.

[0003] To address the problem of low radiation efficiency of low-frequency antennas, the Defense Advanced Research Projects Agency (DARPA) of the United States proposed the concept of "mechanical antenna", which uses a rotating permanent magnet or piezoelectric material to excite electromagnetic waves and has higher radiation efficiency compared to traditional electrically small antennas. The currently studied types of low-frequency mechanical antennas mainly include rotating permanent magnet mechanical antennas and piezoelectric mechanical antennas. For example, research by the University of Wisconsin in the United States has shown that a mechanical antenna made of neodymium iron boron (NdFeB) magnets can generate an effective magnetic field within a range of 0.3 m, but its modulation method is prone to cause a decrease in bandwidth and radiation efficiency. On the other hand, Beijing University of Posts and Telecommunications proposed a piezoelectric mechanical antenna based on the electrostrictive effect. Although this solution can effectively reduce the antenna size and achieve long-distance communication, due to the influence of material properties, it has strict requirements for environmental temperature, which limits its practical application.

[0004] In recent years, the development of superconducting technology has provided a new solution for low-frequency antennas. Superconducting coils can generate extremely high magnetic field intensities in a low-temperature environment and achieve more efficient electromagnetic wave excitation. However, there are still certain technical bottlenecks in existing superconducting antennas. There are two major problems with directly rotating a superconducting magnet: one is that the superconducting magnet rotates while the cryostat remains stationary. At this time, the superconducting magnet is driven by an external motor through a connecting device, and this connecting device becomes a heat conduction channel, significantly deteriorating the heat insulation ability of the cryostat. If the motor is implanted into the cryostat, the volume of the cryostat will increase greatly, and it is also difficult to handle motor failures in a timely manner; the other is that the superconducting magnet rotates together with the cryostat, which requires a high-power motor, and real-time current regulation of the superconducting magnet is also difficult to achieve. Whether the cryostat rotates or not, it is very difficult to rotate the superconducting magnet in liquid nitrogen. From the perspective of engineering applications, the existing design schemes of superconducting magnet mechanical antennas are extremely complex technically and may be accompanied by coupled physical effects (such as eddy current induction of the cryostat, etc.), and do not have practical application significance. Summary of the Invention

[0005] The object of the present invention is to provide a mechanical antenna based on high-temperature superconductivity, aiming to solve the following technical problems existing in the prior art: First, when the superconducting magnet rotates while the dewar is stationary, the external motor drives the superconducting magnet through the connecting device, resulting in the connecting device becoming a heat conduction channel, thus significantly reducing the heat preservation ability of the dewar and increasing the risk of quenching of the superconducting magnet; Second, the traditional high-temperature superconducting mechanical antenna cannot flexibly adjust the magnetic field amplitude, there are certain limitations, and it cannot meet the diverse application requirements.

[0006] The present invention replaces the rotation of the superconducting magnet by the rotation of the magnetic conduction blades, which not only avoids the risk of quenching the superconducting magnet, but also ensures the normal generation of the alternating magnetic field, and is also conducive to realizing frequency modulation. Secondly, the superconducting magnet (coil) is always in the energized state during operation, and the current can be accurately regulated to change the magnetic field amplitude in real time.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A mechanical antenna based on high-temperature superconductivity, including a vibration reduction chassis, a dewar cloud platform arranged above the vibration reduction chassis and capable of adjusting the height, a dewar is arranged above the dewar cloud platform, and a superconducting coil is arranged in the dewar;

[0009] A servo motor is arranged on the vibration reduction chassis, a magnetic conduction rotor is arranged on the output shaft of the servo motor, one end of the magnetic conduction rotor away from the servo motor passes through the dewar cloud platform and extends into the dewar, and the superconducting coil is sleeved outside the magnetic conduction rotor, and ultra-low electromagnetic wave radiation is realized by rotating the magnetic conduction rotor.

[0010] In some embodiments, a dewar cover is detachably connected or hinged to the dewar, which can slow down the evaporation rate of liquid nitrogen in the dewar.

[0011] In some embodiments, a cursor is arranged on the dewar cover, and the cursor extends downward into the dewar for measuring the liquid level of liquid nitrogen.

[0012] In some embodiments, a braided belt is arranged on the dewar cover, one end of the braided belt is connected to the superconducting coil, and the other end is connected to the superconducting power supply, so that the current of the superconducting coil can be accurately regulated, and thus the magnetic field amplitude can be changed in real time.

[0013] In some embodiments, a sealing ring is arranged at the connection between the braided belt and the dewar cover, and a handle is arranged on the upper end surface of the dewar cover.

[0014] In some embodiments, a cylindrical hole is arranged in the dewar, the superconducting coil is sleeved outside the cylindrical hole, and one end of the magnetic conduction rotor away from the servo motor is arranged in the cylindrical hole to achieve the best magnetic focusing effect. When the magnetic conduction rotor rotates, it will disturb the constant magnetic field, and thus generate electromagnetic radiation.

[0015] In some embodiments, heat-insulating layers are provided on the outer wall and inner wall of the cylindrical hole and the Dewar, and the heat-insulating layers can effectively slow down the evaporation rate of liquid nitrogen.

[0016] In some embodiments, the magnetic rotor includes magnetic blades. The lower end of the magnetic blade is connected to the servo motor, and a magnetic cylinder is provided at the upper end. The magnetic blade is located below the Dewar gimbal.

[0017] In some embodiments, the number of the magnetic blades can be set according to specific application requirements. For example, the number is 2 - 8.

[0018] In some embodiments, a screw is provided on the Dewar gimbal, and the other end of the screw is rotatably connected to the vibration damping chassis.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention breaks through the radiation limit of traditional mechanical antennas, improves the radiation performance of existing mechanical antennas, controls the radiation frequency by flexibly changing the number of magnetic blades, and solves the problem that the radiation frequency is limited by the motor speed. At the same time, the current flowing into the superconducting coil can be accurately regulated by the superconducting power supply to change the amplitude of the magnetic field in real time, improving the convenience of the antenna system. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic diagram of the overall structure of the present invention;

[0022] Figure 2 is a schematic diagram of the structure of the Dewar of the present invention;

[0023] Figure 3 is a schematic diagram of the circuit connection of the present invention;

[0024] Figure 4 is a schematic diagram of the structure of the magnetic rotor of the present invention (2 blades);

[0025] Figure 5 is a schematic diagram of the structure of the magnetic rotor of the present invention (3 blades);

[0026] Figure 6 is a schematic diagram of the structure of the magnetic rotor of the present invention (4 blades).

[0027] As shown in the figure:

[0028] 1, vibration damping chassis; 2, servo motor; 3, magnetic rotor; 4, Dewar gimbal; 5, Dewar; 6, superconducting coil; 7, cursor; 8, Dewar cover; 9, braided tape; 10, sealing ring; 11, cylindrical hole; 12, screw; 13, handle; 31, magnetic cylinder; 32, magnetic blade; 51, heat-insulating layer; 52, bump. DETAILED DESCRIPTION OF THE INVENTION

[0029] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work belong to the scope of protection of the present invention.

[0030] Please refer to Figures 1-6 , a mechanical antenna based on high-temperature superconductivity, including a rectangular vibration reduction chassis 1. There is a rectangular open Dewar cloud platform 4 above the vibration reduction chassis 1. Nuts are installed at the four corners of the Dewar cloud platform 4, and screws 12 matching the nuts are installed inside the nuts. The other end of the screw 12 is rotatably connected to the vibration reduction chassis 1. For example, bearings can be provided on the vibration reduction chassis 1, and the screw 12 is installed on the bearings, so that the height of the Dewar cloud platform 4 can be adjusted by rotating the screw 12.

[0031] The upper end surface of the Dewar cloud platform 4 is provided with a Dewar 5. A cylindrical hole 11 is provided at the central position inside the Dewar 5. The height of the cylindrical hole 11 is the same as the height of the side wall of the Dewar 5. The superconducting coil 6 is sleeved outside the cylindrical hole 11. Liquid nitrogen is filled in the space between the outside of the cylindrical hole 11 and the inner wall of the Dewar 5, and the superconducting coil 6 is immersed in the liquid nitrogen. The superconducting coil 6 is a double-pancake coil wound by second-generation high-temperature superconducting tapes (with 65 turns and a diameter of 140 mm).

[0032] Both the inside and outside of the cylindrical hole 11 and the inside and outside walls of the Dewar 5 are wrapped with a heat-insulating layer 51, which can slow down the evaporation rate of liquid nitrogen to a certain extent. Protrusions 52 are provided on the outer wall of the Dewar 5, and through holes are provided on the protrusions 52. The Dewar 5 is fixed to the Dewar cloud platform 4 through bolts.

[0033] A Dewar cover 8 is provided on the upper end surface of the Dewar 5. The Dewar cover 8 is connected to the Dewar 5 in a detachable connection or hinged form. A cursor 7 is installed on the Dewar cover 8 for measuring the liquid level of liquid nitrogen, which is convenient for adding liquid nitrogen in time during use. The cursor 7 extends into the liquid nitrogen of the Dewar 5. The cursor 7 is a liquid level gauge, and its model is FRD-807Z.

[0034] The superconducting coil 6 is connected to a superconducting power supply through a copper braid 9 passing through the Dewar cover 8. A sealing ring 10 is provided at the place where the braid 9 passes through the Dewar cover 8. A handle 13 is provided on the upper end surface of the Dewar cover 8, which is convenient for extracting or rotating the Dewar cover 8.

[0035] Both the Dewar cover 8 and the Dewar 5 are made of non-metallic materials, such as made of ABS plastic, and the vibration reduction chassis 1 and the Dewar cloud platform 4 are both epoxy resin boards.

[0036] A servo motor 2 is installed on the vibration reduction chassis 1, directly below the Dewar cloud platform 4. The magnetic rotor 3 includes magnetic guide vanes 32. One end of the magnetic guide vane 32 is connected to the servo motor 2 through a coupling, and the other end is fixedly connected to one end of a magnetic guide cylinder 31. The end of the magnetic guide cylinder 31 far from the servo motor 2 passes through the Dewar cloud platform 4 and extends into the cylindrical hole 11 of the Dewar 5, and the magnetic guide vane 32 is located below the Dewar cloud platform 4.

[0037] As Figures 3-6 shown, in some specific embodiments, the number of the magnetic guide vanes 32 can be set to multiple pieces according to actual needs, for example, set to 2 - 8 pieces. By flexibly changing the number of the magnetic guide vanes 32, the radiation frequency can be controlled, solving the problem that the radiation frequency is limited by the rotation speed of the servo motor 2. When the number of the magnetic guide vanes 32 is 2 pieces, the 2 magnetic guide vanes 32 are arranged at 180°; when the number of the magnetic guide vanes 32 is 3 pieces, the included angle between the 3 magnetic guide vanes 32 is 120°; when the number of the magnetic guide vanes 32 is 4 pieces, the included angle between the 4 magnetic guide vanes 32 is 90°. The servo motor 2 is a programmable stepper motor, with the model number SM2P0908. The servo motor 2 is controlled to operate through a motor control system, and the motor control system is a two-axis stepper motor PLC controller, with the model number SM2P. By encoding the PLC controller, the speed and direction of the servo motor 2 can be controlled. By making the servo motor 2 rotate forward or reverse a set number of turns at a specified speed, FSK modulation can be achieved.

[0038] The magnetic guide cylinder 31 passes through the Dewar cloud platform 4 and extends into the cylindrical hole 11 in the Dewar 5 to achieve the best magnetic focusing effect.

[0039] The working principle of the present invention is as follows:

[0040] When a constant current is passed through the superconducting coil 6, a stable static magnetic field will be generated around it. Under the focusing action of the magnetic guide cylinder 31, multiple pairs of magnetic dipoles will be induced in the metal magnetic guide vanes 32. The servo motor 2 drives the magnetic guide vanes 32 to rotate through the coupling, and then electromagnetic waves of the same frequency will be continuously radiated.

[0041] Based on the architecture of traditional low-frequency mechanical antennas, the present invention uses a superconducting coil instead of a permanent magnet as the field source, and innovatively adopts the mode of a rotating magnetic rotor to generate radiation. The superconducting coil is not directly in contact with the magnetic rotor, avoiding the problem that mechanical energy is converted into heat energy, resulting in the quench of the superconducting part. Through data analysis processing, it can be intuitively observed that the radiation intensity changes with distance and current magnitude, and shows general laws, proving the feasibility of the scheme of using superconducting materials instead of traditional permanent magnet materials. Since the maximum magnetic field intensity provided by the superconducting material as the field source is theoretically stronger than that of the permanent magnet, the feasibility of the present invention lays a foundation for further improving the radiation intensity of low-frequency antennas.

[0042] Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A mechanical antenna based on high temperature superconductivity, characterized in that: It comprises a vibration reduction chassis (1), a dewar platform (4) arranged above the vibration reduction chassis (1) and capable of adjusting the height, a dewar (5) being arranged above the dewar platform (4), and a superconducting coil (6) being arranged inside the dewar (5); A servo motor (2) is provided on the vibration reduction chassis (1), a magnetic rotor (3) is provided on the output shaft of the servo motor (2), an end of the magnetic rotor (3) away from the servo motor (2) passes through a dewar platform (4) and extends into a dewar (5), and the superconducting coil (6) is sleeved outside the magnetic rotor (3), and electromagnetic wave radiation is achieved by rotating the magnetic rotor (3).

2. A mechanical antenna based on high temperature superconductivity according to claim 1, characterized in that: The dewar (5) is provided with a dewar cover (8) which is detachably connected or hinged.

3. A mechanical antenna based on high temperature superconductivity according to claim 2, characterized in that: The dewar cover (8) is provided with a cursor (7), and the cursor (7) extends downward to the interior of the dewar (5).

4. The high temperature superconducting mechanical antenna according to claim 2, characterized in that: A braided belt (9) is provided on the dewar cover (8), and the braided belt (9) is connected to the superconducting coil.

5. A mechanical antenna based on high temperature superconductivity according to claim 4, characterized in that: A sealing ring (10) is provided at the connection between the braided belt (9) and the Dewar cover (8), and a handle (13) is provided on the upper end surface of the Dewar cover (8).

6. The high temperature superconducting mechanical antenna according to claim 1, characterized in that: The dewar (5) is provided with a cylindrical hole (11), the superconducting coil (6) is sleeved outside the cylindrical hole (11), and the end of the magnetic rotor (3) away from the servo motor (2) is arranged in the cylindrical hole (11).

7. A high temperature superconducting mechanical antenna according to claim 6, characterized in that: The outer wall and the inner wall of the cylindrical hole (11) and the dewar (5) are both provided with a heat-insulating layer (51).

8. The high temperature superconducting mechanical antenna according to claim 1, characterized in that: The magnetic conductive rotor (3) comprises a magnetic conductive blade (32), the lower end of the magnetic conductive blade (32) is connected to the servo motor (2), the upper end is provided with a magnetic conductive cylinder (31), and the magnetic conductive blade (32) is located below the Dewar platform (4).

9. The high temperature superconducting mechanical antenna according to claim 8, characterized in that: The number of the magnetic conductive blades (32) is 2-8.

10. A high temperature superconducting mechanical antenna according to any one of claims 1 to 9, characterized in that: The Dewar platform (4) is provided with a screw rod (12), and the other end of the screw rod (12) is rotatably connected to the vibration reduction chassis (1).

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