Lever-type low-frequency magnetoelectric antenna

Abstract

The invention discloses a lever-type low-frequency magnetoelectric antenna, which belongs to the technical field of antennas, and comprises a first mounting bracket and a second mounting bracket, a piezoelectric stack is arranged between the two mounting brackets, and the piezoelectric stack is telescopic in a power-on state; the second mounting support is further provided with a rotating shaft, the rotating shaft is provided with an electromagnet, the electromagnet is arranged in the magnetic induction coil, the end, facing the second mounting support, of the piezoelectric stack is connected to the side wall of the electromagnet, and a gap is reserved between the connecting point of the piezoelectric stack and the electromagnet and the rotating point of the electromagnet. The lever type low-frequency magnetoelectric antenna can generate the magnetic induction intensity of 106.2 nT within the distance of 1 m, amplitude-shift keying communication with the information rate of 100 bps is successfully achieved, and the lever type low-frequency magnetoelectric antenna integrally has the advantages of being large in output and high in information rate and has wide application prospects in the field of cross-medium high-speed information transmission.

Description

Technical Field

[0001] The invention belongs to the technical field of antennas, and in particular relates to a lever-type low-frequency magnetoelectric antenna. Background Art

[0002] A magnetoelectric antenna is an antenna that uses the magnetoelectric coupling effect to transmit and receive electromagnetic waves. It has the characteristics of miniaturization, high radiation efficiency, good frequency characteristics, and strong anti-interference ability. Compared with traditional antennas, magnetoelectric antennas can overcome size limitations and use strain to operate at the resonant frequency of sound waves. The size of traditional electric antennas is usually tens of kilometers, while the size of magnetoelectric antennas is usually tens of centimeters. The sizes of the two are not in the same order of magnitude.

[0003] Existing mechanical antennas are mainly rotating mechanical antennas and vibrating mechanical antennas. Most of the existing mechanical antennas increase the magnetic moment by increasing the size of the radiation module, thereby increasing the output field strength and transmission distance. However, the increase in the size of the radiation module will produce greater inertia during mechanical movement, which brings greater difficulties to the control of the mechanical antenna and cannot effectively improve the information transmission rate. Summary of the invention

[0004] In view of one or more of the above defects or improvement needs in the prior art, the present invention provides a lever-type low-frequency magnetoelectric antenna to solve the problem that the existing mechanical antenna cannot take into account both the output field strength and the information transmission rate.

[0005] To achieve the above object, the present invention provides a lever-type low-frequency magnetoelectric antenna, which comprises: A first mounting bracket and a second mounting bracket, a piezoelectric stack is provided between the first mounting bracket and the second mounting bracket, one end of the piezoelectric stack is connected to the first mounting bracket, and the other end of the piezoelectric stack is connected to the second mounting bracket, and the piezoelectric stack is retractable when powered on; The second mounting bracket is also provided with a rotating shaft, and an electromagnet is provided on the rotating shaft. The electromagnet is arranged in the magnetic induction coil, and the two ends of the magnetic poles generated by the electromagnet under the action of the magnetic induction coil are located in the swing plane of the electromagnet; One end of the piezoelectric stack facing the second mounting bracket is connected to the side wall of the electromagnet, and a distance is left between the connection point between the piezoelectric stack and the electromagnet and the rotation point of the electromagnet; The electromagnet generates a magnetic field under the action of the magnetic induction coil, and swings along the rotation axis under the expansion and contraction action of the piezoelectric stack to generate a changing magnetic field in two directions within the swinging plane to achieve signal transmission.

[0006] As a further improvement of the present invention, the piezoelectric stack comprises a piezoelectric expansion piece, wherein the piezoelectric expansion piece is provided with interdigital electrodes inside, and the piezoelectric expansion piece expands and contracts along the arrangement direction of the difference electrodes after the interdigital electrodes are energized.

[0007] As a further improvement of the present invention, the interdigital electrodes are embedded in the piezoelectric expansion sheet in pairs, a gap is left between the two interdigital electrodes, and comb-shaped extensions are respectively extended between the two interdigital electrodes, and the extension of each interdigital electrode does not contact the other interdigital electrode; The two interdigital electrodes extend out of the piezoelectric expansion sheet toward one end of the first mounting bracket, and the two interdigital electrodes are respectively connected with lead wires.

[0008] As a further improvement of the present invention, the first mounting bracket includes a first mounting seat, the first mounting seat is provided with a first support rod in the vertical direction, the first support rod is provided with a clamping rod toward the piezoelectric stack, the clamping rod includes two clamping plates arranged opposite to each other, the end of the piezoelectric stack is located between the two clamping plates, and one of the clamping plates is provided with a tightening screw.

[0009] As a further improvement of the present invention, the second mounting bracket includes a second mounting seat and a third mounting seat, the second mounting seat and the third mounting seat are respectively provided with mounting holes, the rotating shaft is inserted into the mounting holes, and the second mounting seat and the third mounting seat are respectively provided with rotating bearings, and the two ends of the rotating shaft are respectively sleeved in the two rotating bearings; The rotating shaft is provided with an inserting hole in the radial direction, and the electromagnet is inserted in the inserting hole.

[0010] As a further improvement of the present invention, the electromagnet is an iron-gallium alloy.

[0011] As a further improvement of the present invention, the time-varying electromagnetic field of the electromagnet is proportional to the magnetic moment, and the magnetic moment of the electromagnet is obtained by fitting the magnetic moments of the electromagnet in two directions in the swinging plane.

[0012] As a further improvement of the present invention, the magnetic moment of the electromagnet is calculated as follows: + (Formula 1) Among them, the m LMEA is the magnetic moment of the electromagnet, Q is the equivalent magnetic charge coefficient, D is the magnetic charge amplitude along the first direction, z is the charge amplitude along the second direction, f is the signal frequency, t For time, is the direction vector in the first direction; is the direction vector in the second direction.

[0013] As a further improvement of the present invention, the magnetic moment of the electromagnet is calculated as follows: = (Formula 2) Among them, the L is the distance from the axis of the rotating shaft to one end of the magnetic pole of the electromagnet, d is the telescopic length of the piezoelectric stack, l It is the distance from the connection point between the piezoelectric stack and the electromagnet to the axis of the rotating shaft.

[0014] The above-mentioned improved technical features can be combined with each other as long as they do not conflict with each other.

[0015] In general, compared with the prior art, the above technical solution conceived by the present invention has the following beneficial effects: (1) The lever-type low-frequency magnetoelectric antenna of the present invention drives the electromagnet to rotate by utilizing the telescopic movement of the piezoelectric stack. The electromagnet forms a lever structure with the rotation axis as the fulcrum. The lever structure amplifies the deflection amount of the electromagnet, thereby increasing the magnetic moment and generating a stronger magnetic induction intensity. Secondly, the piezoelectric stack drives the electromagnet to rotate in a manner different from that of a traditional rotary mechanical antenna. Its deflection angle is limited by the telescopic range of the piezoelectric stack. The overall rotational inertia of the electromagnet is smaller than that of a rotary mechanical antenna, making its rotation controllable and its swinging amplitude inertia smaller. The magnetic field fluctuations it generates are more highly correlated with the telescopic frequency of the piezoelectric stack and have better information loading capabilities. The lever-type low-frequency magnetoelectric antenna in the present application has an operating frequency and a quality factor of 339~356Hz and 37.67~39.56 respectively; the lever-type low-frequency magnetoelectric antenna can generate a magnetic induction intensity of 106.2nT within a distance of 1m, and successfully realizes amplitude shift keying communication with an information rate of 100bps. The lever-type magnetoelectric antenna as a whole has the advantages of large output and high information rate, and has broad application prospects in the field of cross-media high-speed information transmission.

[0016] (2) The lever-type low-frequency magnetoelectric antenna of the present invention uses a piezoelectric expansion piece, and then embeds a forked electrode in the piezoelectric expansion piece. A voltage signal is applied to the piezoelectric expansion piece through the forked electrode. The piezoelectric expansion piece senses the change in the electric field and expands and contracts. Then the piezoelectric expansion piece drives the electromagnet to swing. The electromagnet generates a magnetic field under the action of the magnetic induction coil, and the electromagnet deflects to cause the magnetic field to change, and excites electromagnetic waves in the surrounding space to achieve signal transmission. The lever-type low-frequency magnetoelectric antenna in the present application adopts a lever structure. The electromagnet swings in a plane during the actual movement, forming a superposition of vibrations in two orthogonal directions, which increases the output field strength and omnidirectionality of the magnetoelectric antenna. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the overall structure of the lever-type low-frequency magnetoelectric antenna in an embodiment of the present invention; Figure 2 is a schematic structural diagram of a piezoelectric stack in an embodiment of the present invention; Figure 3 is a schematic diagram of an equivalent magnetic dipole model in an embodiment of the present invention; Figure 4 is an amplitude-frequency response characteristic diagram of a lever-type low-frequency magnetoelectric antenna in an embodiment of the present invention; Figure 5 2 is a schematic diagram of the operation of the lever-type low-frequency magnetoelectric antenna in an embodiment of the present invention; Figure 6 It is the original waveform diagram of the amplitude shift keying signal and the waveform diagram received by the oscilloscope in the embodiment of the present invention.

[0018] In all the drawings, the same reference numerals represent the same technical features, specifically: 1. First mounting bracket; 2. Second mounting bracket; 3. Piezoelectric stack; 4. Rotating shaft; 5. Electromagnet; 301. Piezoelectric stretchable sheet; 302. Interdigital electrode. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0020] In the description of the present invention, it should be understood that, unless otherwise specified, terms such as “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0021] In addition, unless otherwise specified, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0022] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0024] Example: See also Figures 1 to 6 The lever-type low-frequency magnetoelectric antenna in the preferred embodiment of the present invention includes a first mounting bracket 1 and a second mounting bracket 2, a piezoelectric stack 3 is arranged between the first mounting bracket 1 and the second mounting bracket 2, one end of the piezoelectric stack 3 is connected to the first mounting bracket 1, and the other end is connected to the second mounting bracket 2, and the piezoelectric stack 3 can be extended and retracted when powered on; secondly, a rotating shaft 4 is also arranged on the second mounting bracket 2, an electromagnet 5 is arranged on the rotating shaft 4, and the electromagnet 5 is arranged in the magnetic induction coil, and the two ends of the magnetic poles generated by the electromagnet 5 under the action of the magnetic induction coil are coplanar with the swing plane of the electromagnet 5; and, the piezoelectric stack 3 in the present application is connected to the side wall of the electromagnet 5 at one end facing the second mounting bracket 2, and a distance is left between the connection point of the piezoelectric stack 3 and the electromagnet 5 and the rotation point of the electromagnet 5. The electromagnet 5 in the present application generates a magnetic field under the action of the magnetic induction coil, and swings along the rotating shaft 4 under the expansion and contraction of the piezoelectric stack 3 to generate a changing magnetic field in two directions in the swing plane to achieve signal transmission.

[0025] The lever-type low-frequency magnetoelectric antenna in the present application uses the telescopic movement of the piezoelectric stack 3 to drive the electromagnet 5 to rotate. The electromagnet 5 forms a lever structure with the rotating shaft 4 as a fulcrum. The lever structure is used to amplify the deflection of the electromagnet 5, thereby increasing the magnetic moment and generating a stronger magnetic induction intensity. Secondly, the rotation form of the electromagnet 5 driven by the piezoelectric stack 3 is different from that of the traditional rotary mechanical antenna. Its deflection angle is limited by the telescopic range of the piezoelectric stack 3. The overall rotational inertia of the electromagnet 5 is smaller than that of the rotary mechanical antenna, so that its rotation is controllable and the swing amplitude inertia is smaller. The magnetic field fluctuations it generates are more correlated with the telescopic frequency of the piezoelectric stack 3 and have better information transmission capabilities.

[0026] Specifically, the electromagnet 5 in the present application needs to rotate within the plane. In order to avoid contact and interference between the electromagnet 5 and the placement plane when rotating, the present application sets a first mounting bracket 1 and a second mounting bracket 2, so as to lift the rotating shaft 4 to a certain height, which is convenient for the rotation of the electromagnet 5 and the setting of the magnetic induction coil. Secondly, the swing of the electromagnet 5 in the plane in the present application can form a time-varying magnetic moment in two directions. Compared with the conventional single-direction magnetic moment, the electromagnetic field intensity generated by it is higher and the omnidirectionality is stronger. The signal receiving device can capture the signal changes at more angles, so that the lever-type low-frequency magnetoelectric antenna has a higher energy transmission efficiency.

[0027] Furthermore, if Figure 2 As shown, as an optional embodiment of the present invention, the piezoelectric stack 3 in the present application includes a piezoelectric expansion piece 301, and the piezoelectric expansion piece 301 is provided with a forked electrode 302 inside, and the piezoelectric expansion piece 301 can be expanded and contracted along the arrangement direction (first direction) of the forked electrode 302 after the forked electrode 302 is energized. Specifically, the piezoelectric expansion piece 301 in the present application has a high piezoelectric constant and electromechanical coupling coefficient, and can produce a large expansion and contraction deformation under the action of a small electric field to drive the electromagnet 5 to swing. When a voltage is applied to the forked electrode 302 in the present application, due to the action of the electric field, an electric field distribution will be formed in the area where the forked electrode 302 is located, and the piezoelectric expansion piece 301 will be expanded and contracted accordingly under the action of the electric field formed by the forked electrode 302.

[0028] Optionally, the piezoelectric expansion piece 301 in the present application is one or more of piezoelectric ceramics, piezoelectric crystals or piezoelectric polymers. The piezoelectric expansion piece 301 can be selected from lead zirconate titanate, barium titanate, quartz crystal, lithium niobate, polyvinylidene fluoride copolymer or polylactic acid-based piezoelectric polymer.

[0029] Further, as an optional embodiment of the present invention, the interdigital electrodes 302 in the present application are embedded in the piezoelectric expansion piece 301 in pairs, and a gap is left between the two interdigital electrodes 302, and a comb-shaped extension portion extends toward each other between the two interdigital electrodes 302, and the extension portion of each interdigital electrode 302 does not contact the other interdigital electrode 302. Secondly, the two interdigital electrodes 302 extend out of the piezoelectric expansion piece 301 toward one end of the first mounting bracket 1, and the two interdigital electrodes 302 are respectively connected to leads. The arrangement of the interdigital electrodes 302 along the setting direction of the piezoelectric expansion piece 301 can ensure the consistency between the signal generated by the interdigital electrodes 302 and the expansion amplitude of the piezoelectric expansion piece 301, and the leads are used for the input of an external signal source.

[0030] Furthermore, the first mounting bracket 1 in the present application includes a first mounting seat, the first mounting seat is provided with a first support rod in the vertical direction, and the first support rod is provided with a clamping rod toward the piezoelectric stack 3, the clamping rod includes two clamping plates arranged opposite to each other, the end of the piezoelectric stack 3 is located between the two clamping plates, and one of the clamping plates is provided with a tightening screw. The first mounting bracket 1 in the present application is mainly used to clamp the end of the piezoelectric stack 3, the combination of the first mounting seat and the first support rod is used to lift the end of the piezoelectric stack 3 to a certain height, the combination of the two clamping plates and the tightening screw is convenient for clamping the piezoelectric stack 3, and the clamping force between the clamping rod and the piezoelectric stack 3 is adjustable, so as to facilitate the fixing and placement of the piezoelectric stack 3.

[0031] Furthermore, the second mounting bracket 2 in the present application includes a second mounting seat and a third mounting seat, and mounting holes are respectively arranged between the second mounting seat and the third mounting seat, the rotating shaft 4 is inserted into the mounting holes, and rotating bearings are respectively arranged between the second mounting seat and the third mounting seat, and the two ends of the rotating shaft 4 are respectively sleeved in the two rotating bearings; secondly, the rotating shaft 4 is radially provided with a plug-in hole, and the electromagnet 5 is inserted in the plug-in hole. The second mounting bracket 2 in the present application is mainly used to form a rotating structure of the electromagnet 5, the second mounting seat and the third mounting seat are arranged side by side, the rotating shaft 4 is set between the two, and the rotating shaft 4 can be stably rotated through two rotating bearings, so that the electromagnet 5 can stably swing under the telescopic action of the piezoelectric stack 3. Preferably, the rotating bearing is a ball bearing.

[0032] Optionally, the first mounting bracket 1 and the second mounting bracket 2 in the present application are both placed on a plane, and the first mounting bracket 1 can be slightly swung or moved on the plane to accommodate the telescopic displacement of the piezoelectric stack 3 .

[0033] Optionally, the electromagnet 5 in the present application is an iron-gallium alloy, and the magnetic induction coil in the present application is a Helmholtz coil. Although conventional permanent magnets also have a magnetic field, and also form a variable magnetic field in a swinging state. However, the magnetic poles of the permanent magnet are arranged along the axial direction of the rotating shaft 4, and the magnetic field fluctuations generated in the swinging state are relatively small, which ultimately leads to a low signal strength received by the signal receiving device, affecting the signal transmission quality. Therefore, the present application selects the combination of the electromagnet 5 and the magnetic induction coil, and arranges the direction of the magnetic poles in the swinging plane, so that the magnetic field fluctuations generated when the electromagnet 5 swings are large, so as to improve the signal transmission quality.

[0034] Further, as an optional embodiment of the present invention, the time-varying electromagnetic field of the electromagnet 5 in the present application is proportional to the magnetic moment, and the magnetic moment of the electromagnet 5 is obtained by fitting the magnetic moments of the electromagnet 5 in two directions in the swinging plane. According to electromagnetic theory, the time-varying electromagnetic field value generated by the magnetoelectric antenna is proportional to the magnetic moment. Therefore, by comparing the magnetic moments of the traditional antenna structure and the lever-type low-frequency magnetoelectric antenna in the present application, the difference in the time-varying electromagnetic field value generated by the two can be obtained, thereby obtaining the difference between the present application and the traditional antenna.

[0035] Specifically, the magnetic moment of a typical sheet-shaped membrane electrode assembly is assumed to be m0, Q Represents the equivalent magnetic moment, and its expression is as follows: (Formula 3) in d represents the magnetic charge amplitude, f represents the signal frequency, t Represents time, Represents the direction vector.

[0036] like Figure 3 As shown, Figure 3 (a) is a diagram of the deflection magnetic dipole model of the lever-type low-frequency magnetoelectric antenna. Figure 3 (b) is an orthogonal magnetic dipole model diagram of a lever-type low-frequency magnetoelectric antenna. Based on the antenna structure under the above one-dimensional amplitude, the magnetic moment expression of the lever-type low-frequency magnetoelectric antenna in this application is derived as follows: + (Formula 1) Among them, m LMEA is the magnetic moment of the electromagnet, Q is the equivalent magnetic charge coefficient, D is the magnetic charge amplitude along the first direction, z is the charge amplitude along the second direction, f is the signal frequency, t For time, is the direction vector in the first direction; is the direction vector in the second direction. Here f Refers to the signal frequency input to the lever-type low-frequency magnetoelectric antenna at the signal input terminal.

[0037] Specifically, the first direction in the present application is preferably the telescopic direction of the piezoelectric stack, and the second direction in the present application is preferably the direction in the swinging plane of the electromagnet 5 that is perpendicular to the telescopic direction of the piezoelectric stack 3 .

[0038] Further, based on the above formula 1, the specific calculation method of the magnetic moment generated by the electromagnet 5 in the present application is: = (Formula 2) in, L is the distance from the axis of the rotating shaft 4 to one end of the magnetic pole of the electromagnet 5, d is the telescopic length of the piezoelectric stack 3, l It is the distance from the connection point between the piezoelectric stack 3 and the electromagnet 5 to the axis center of the rotating shaft 4.

[0039] Through the above formulas 1 and 2, the magnetic moment parameters of the lever-type low-frequency magnetoelectric antenna in the present application can be reflected. Compared with the antenna structure under conventional one-dimensional amplitude, it can be obviously seen that the magnetic moment of the lever-type low-frequency magnetoelectric antenna in the present application is greater than the magnetic moment of the conventional antenna structure, and its swing inertia is smaller than that of the mechanical rotating antenna, and it has more accurate signal transmission capability.

[0040] For the lever-type low-frequency magnetoelectric antenna designed in this application, different l The amplitude-frequency response characteristics of the lever-type low-frequency magnetoelectric antenna under the condition of (the distance from the connection point between the piezoelectric stack 3 and the electromagnet 5 to the axis of the rotating shaft 4) are shown in the figure. Figure 4 As shown, it can be seen that different l The magnetic induction intensities under the conditions are 4.3 nT, 5.2 nT, 6.9 nT, 10.6 nT, 21.5 nT, and 106.2 nT respectively. The above results show that l The smaller it is, the lower the resonant frequency of the lever-type low-frequency magnetoelectric antenna, the higher the magnetic induction intensity, the lower the quality factor, and the bandwidth remains unchanged at -3dB. The bandwidth remains unchanged and the resonant frequency decreases, indicating that the relative bandwidth increases. The lower the operating frequency of the antenna, the more difficult it is to expand the bandwidth, which is particularly important in the ultra-low frequency band.

[0041] Furthermore, the present application uses amplitude shift keying signals to demonstrate the communication of a lever-type low-frequency magnetoelectric antenna in an ultra-low frequency band. Specifically, Figure 5As shown, the amplitude shift keying signal is generated by the signal transmitter, and then forms a high-voltage AC excitation signal through a high-voltage amplifier; the high-voltage AC excitation signal is transmitted to the piezoelectric expansion piece 301 through the two leads of the interdigital electrode 302, and the piezoelectric expansion piece 301 correspondingly expands and contracts and drives the electromagnet 5 to swing. The electromagnet 5 generates a time-varying magnetic field signal under the action of the Helmholtz coil. The time-varying magnetic field signal is received by the giant magneto-impedance sensor at 1m and displayed on the oscilloscope. The original waveform of the amplitude shift keying signal and the waveform received by the oscilloscope are shown as follows: Figure 6 As shown in (a) and (b), it can be seen that the signal waveform envelope generated by the lever-type low-frequency magnetoelectric antenna in the present application is very clear, and the lever-type low-frequency magnetoelectric antenna can realize the transmission of amplitude shift keying signals at a communication rate of 100 bps.

[0042] The lever-type low-frequency magnetoelectric antenna in the present application can significantly improve the magnetic induction intensity and efficiency of the antenna. In the measurement of actual amplitude-frequency effect characteristics, the resonant frequency and Q value range of the lever-type low-frequency magnetoelectric antenna are 339~356Hz and 37.67~39.56 respectively, and its maximum magnetic induction intensity is 106.2nT at a range of 1m, which can realize modulation of 100bps amplitude shift keying signal.

[0043] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A lever-type low-frequency magnetoelectric antenna, characterized in that: include: A first mounting bracket and a second mounting bracket, a piezoelectric stack is provided between the first mounting bracket and the second mounting bracket, one end of the piezoelectric stack is connected to the first mounting bracket, and the other end of the piezoelectric stack is connected to the second mounting bracket, and the piezoelectric stack is retractable when powered on; The second mounting bracket is also provided with a rotating shaft, and an electromagnet is provided on the rotating shaft. The electromagnet is arranged in the magnetic induction coil, and the two ends of the magnetic poles generated by the electromagnet under the action of the magnetic induction coil are located in the swing plane of the electromagnet; One end of the piezoelectric stack facing the second mounting bracket is connected to the side wall of the electromagnet, and a distance is left between the connection point between the piezoelectric stack and the electromagnet and the rotation point of the electromagnet; The electromagnet generates a magnetic field under the action of the magnetic induction coil, and swings along the rotation axis under the expansion and contraction action of the piezoelectric stack to generate a changing magnetic field in two directions within the swinging plane to achieve signal transmission.

2. The lever-type low-frequency magnetoelectric antenna according to claim 1, characterized in that: The piezoelectric stack includes a piezoelectric expansion piece, wherein interdigital electrodes are arranged inside the piezoelectric expansion piece. When the interdigital electrodes are energized, the piezoelectric expansion piece expands and contracts along the arrangement direction of the interdigital electrodes.

3. The lever-type low-frequency magnetoelectric antenna according to claim 2, characterized in that: The interdigital electrodes are embedded in the piezoelectric expansion sheet in pairs, a gap is left between the two interdigital electrodes, and comb-shaped extensions are extended toward each other between the two interdigital electrodes, and the extension of each interdigital electrode does not contact the other interdigital electrode; The two interdigital electrodes extend out of the piezoelectric expansion sheet toward one end of the first mounting bracket, and the two interdigital electrodes are respectively connected with lead wires.

4. The lever-type low-frequency magnetoelectric antenna according to claim 1, characterized in that: The first mounting bracket includes a first mounting seat, the first mounting seat is provided with a first support rod in the vertical direction, the first support rod is provided with a clamping rod toward the piezoelectric stack, the clamping rod includes two clamping plates arranged opposite to each other, the end of the piezoelectric stack is located between the two clamping plates, and one of the clamping plates is provided with a tightening screw.

5. The lever-type low-frequency magnetoelectric antenna according to claim 1, characterized in that: The second mounting bracket comprises a second mounting seat and a third mounting seat, the second mounting seat and the third mounting seat are respectively provided with mounting holes, the rotating shaft is inserted into the mounting holes, and the second mounting seat and the third mounting seat are respectively provided with rotating bearings, and the two ends of the rotating shaft are respectively sleeved in the two rotating bearings; The rotating shaft is provided with an inserting hole in the radial direction, and the electromagnet is inserted in the inserting hole.

6. The lever-type low-frequency magnetoelectric antenna according to claim 1, characterized in that: The electromagnet is an iron-gallium alloy.

7. The lever-type low-frequency magnetoelectric antenna according to claim 1, characterized in that: The time-varying electromagnetic field of the electromagnet is proportional to the magnetic moment, and the magnetic moment of the electromagnet is obtained by fitting the magnetic moments of the electromagnet in two directions in the swinging plane.

8. The lever-type low-frequency magnetoelectric antenna according to claim 7, characterized in that: The magnetic moment of the electromagnet is calculated as follows: + (Formula 1) Among them, the m LMEA is the magnetic moment of the electromagnet, Q is the equivalent magnetic charge coefficient, D is the magnetic charge amplitude along the first direction, z is the charge amplitude along the second direction, f is the signal frequency, t For time, is the direction vector in the first direction; is the direction vector in the second direction.

9. The lever-type low-frequency magnetoelectric antenna according to claim 8, characterized in that: The magnetic moment of the electromagnet is calculated as follows: = (Formula 2) Among them, the L is the distance from the axis of the rotating shaft to one end of the magnetic pole of the electromagnet, d is the telescopic length of the piezoelectric stack, l It is the distance from the connection point between the piezoelectric stack and the electromagnet to the axis of the rotating shaft.

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