A lever-type low-frequency magnetoelectric antenna

Abstract

The present invention discloses a lever-type low-frequency magnetoelectric antenna, belonging to the technical field of antennas, which includes a first mounting bracket and a second mounting bracket. A piezoelectric stack is provided between the two mounting brackets, and the piezoelectric stack can be telescopic in the energized state. A rotating shaft is further provided on the second mounting bracket, and an electromagnet is provided on the rotating shaft. The electromagnet is arranged in a magnetic induction coil. One end of the piezoelectric stack facing the second mounting bracket is connected to the side wall of the electromagnet, and there is a distance between the connection point of the piezoelectric stack and the electromagnet and the rotation point of the electromagnet. The lever-type low-frequency magnetoelectric antenna in this application can generate a magnetic induction intensity of 106.2 nT within a distance of 1 m, and successfully realizes amplitude shift keying communication with an information rate of 100 bps. 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.

Description

Technical Field

[0001] The present invention belongs to the technical field of antennas, and particularly 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 achieve electromagnetic wave transmission and reception. It has the characteristics of miniaturization, high radiation efficiency, good frequency characteristics, and strong anti-interference ability. Compared with traditional antennas, a magnetoelectric antenna can overcome size limitations and use strain to operate at the resonance frequency of sound waves. The size of a traditional electric antenna is usually dozens of kilometers, while the size of a magnetoelectric antenna is usually dozens of centimeters, and their sizes are not in the same order of magnitude.

[0003] Existing mechanical antennas are mainly rotary mechanical antennas and vibrating mechanical antennas. Most 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 generate greater inertia during mechanical movement, which brings greater difficulties to the regulation of mechanical antennas 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 requirements of the prior art, the present invention provides a lever-type low-frequency magnetoelectric antenna to solve the problem that existing mechanical antennas cannot balance the output field strength and information transmission rate.

[0005] To achieve the above object, the present invention provides a lever-type low-frequency magnetoelectric antenna, which includes:

[0006] A first mounting bracket and a second mounting bracket, with a piezoelectric stack 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 is connected to the second mounting bracket, and the piezoelectric stack can be telescopic when powered on;

[0007] A rotating shaft is further provided on the second mounting bracket, and an electromagnet is provided on the rotating shaft. The electromagnet is arranged in a 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 swinging plane of the electromagnet;

[0008] One end of the piezoelectric stack facing the second mounting bracket is connected to the side wall of the electromagnet, and there is a spacing between the connection point of the piezoelectric stack and the electromagnet and the rotation point of the electromagnet;

[0009] The electromagnet generates a magnetic field under the action of the magnetic induction coil and swings along the rotating shaft under the telescopic action of the piezoelectric stack to generate a changing magnetic field in two directions in the swinging plane, thereby realizing signal transmission.

[0010] As a further improvement of the present invention, the piezoelectric stack includes piezoelectric telescopic sheets, and interdigital electrodes are arranged inside the piezoelectric telescopic sheets. After the interdigital electrodes are electrified, the piezoelectric telescopic sheets expand and contract along the arrangement direction of the difference electrodes.

[0011] As a further improvement of the present invention, the interdigital electrodes are embedded in the piezoelectric telescopic sheets in pairs, a gap is left between the two interdigital electrodes, and comb-shaped extension parts extend out towards each other between the two interdigital electrodes. The extension parts of each interdigital electrode do not contact the other interdigital electrode;

[0012] And the two interdigital electrodes extend out of the piezoelectric telescopic sheets towards one end of the first mounting bracket, and leads are respectively connected to the two interdigital electrodes.

[0013] As a further improvement of the present invention, the first mounting bracket includes a first mounting seat, a first support rod is arranged vertically on the first mounting seat, a clamping rod is arranged on the first support rod facing the piezoelectric stack, the clamping rod includes two oppositely arranged clamping pieces, and the end of the piezoelectric stack is located between the two clamping pieces. A tightening screw is arranged on one of the clamping pieces.

[0014] As a further improvement of the present invention, the second mounting bracket includes a second mounting seat and a third mounting seat. Mounting holes are respectively arranged on the second mounting seat and the third mounting seat. The rotating shaft is arranged in the mounting holes, and rotating bearings are respectively arranged on the second mounting seat and the third mounting seat. The two ends of the rotating shaft are respectively sleeved in the two rotating bearings;

[0015] A plugging hole is radially arranged on the rotating shaft, and the electromagnet is plugged in the plugging hole.

[0016] As a further improvement of the present invention, the electromagnet is made of an iron-gallium alloy.

[0017] 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 in two directions in the swinging plane of the electromagnet.

[0018] As a further improvement of the present invention, the calculation method of the magnetic moment of the electromagnet is:

[0019] + (Formula 1)

[0020] Wherein, 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, zis the magnetic charge amplitude along the second direction, f is the signal frequency, t is the time, is the direction vector in the first direction; is the direction vector in the second direction.

[0021] As a further improvement of the present invention, the magnetic moment of the electromagnet is calculated as follows:

[0022] = (Formula 2)

[0023] wherein, the L is the distance from the axis of rotation to one end of the magnetic pole of the electromagnet, d is the telescopic length of the piezoelectric stack, l is the distance from the connection point of the piezoelectric stack and the electromagnet to the axis of rotation.

[0024] The above improved technical features can be combined with each other as long as they do not conflict with each other.

[0025] Generally speaking, compared with the prior art, the beneficial effects of the above technical solutions conceived by the present invention include:

[0026] (1) For the lever-type low-frequency magnetoelectric antenna of the present invention, the telescopic movement of the piezoelectric stack drives the rotation of the electromagnet. The electromagnet forms a lever structure with the axis of rotation as the fulcrum. The deflection amount of the electromagnet is amplified by using the lever structure, thereby increasing the magnetic moment and generating a stronger magnetic induction intensity. Secondly, the rotation form of the piezoelectric stack driving the electromagnet is different from that of the traditional rotary mechanical antenna. Its deflection angle is limited by the telescopic amplitude of the piezoelectric stack. The overall rotational inertia of the electromagnet is smaller than that of the rotary mechanical antenna, making its rotation controllable and the swing amplitude inertia smaller. The magnetic field fluctuation generated by it has a higher correlation with the telescopic frequency of the piezoelectric stack and has better information loading ability. For the lever-type low-frequency magnetoelectric antenna in this application, its operating frequency and quality factor can reach 339~356Hz and 37.67~39.56 respectively; this lever-type low-frequency magnetoelectric antenna can generate a magnetic induction intensity of 106.2nT within a distance of 1m and successfully achieve amplitude shift keying communication with an information rate of 100bps. This 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.

[0027] (2) The lever-type low-frequency magnetoelectric antenna of the present invention selects a piezoelectric stack, and then embeds interdigital electrodes in the piezoelectric stack. A voltage signal is applied to the piezoelectric stack through the interdigital electrodes. After the piezoelectric stack senses the change in the electric field, it expands and contracts. Then, the piezoelectric stack drives the electromagnet to swing. The electromagnet generates a magnetic field under the action of the magnetic induction coil, and the deflection of the electromagnet causes a change in the magnetic field, and electromagnetic waves are excited in the surrounding space to achieve signal transmission. In the lever-type low-frequency magnetoelectric antenna of the present application, due to its lever structure, the electromagnet swings in a plane during actual movement, forming a superposition of vibrations in two orthogonal directions, increasing the output field strength and omnidirectionality of the magnetoelectric antenna. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a schematic diagram of the overall structure of the lever-type low-frequency magnetoelectric antenna in the embodiment of the present invention;

[0029] Figure 2 is a schematic diagram of the structure of the piezoelectric stack in the embodiment of the present invention;

[0030] Figure 3 is a schematic diagram of an equivalent magnetic dipole model in the embodiment of the present invention;

[0031] Figure 4 is a graph of the amplitude-frequency response characteristics of the lever-type low-frequency magnetoelectric antenna in the embodiment of the present invention;

[0032] Figure 5 is a working schematic diagram of the lever-type low-frequency magnetoelectric antenna in the embodiment of the present invention;

[0033] Figure 6 is the original waveform diagram and oscilloscope received waveform diagram of the amplitude shift keying signal in the embodiment of the present invention.

[0034] In all the drawings, the same reference numerals represent the same technical features, specifically:

[0035] 1. First mounting bracket; 2. Second mounting bracket; 3. Piezoelectric stack; 4. Rotating shaft; 5. Electromagnet;

[0036] 301. Piezoelectric stack; 302. Interdigital electrode. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0037] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to 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 used 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.

[0038] In the description of the present invention, it should be understood that, unless otherwise specified, the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0039] In addition, unless otherwise specified, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0040] In the present invention, unless otherwise clearly defined and limited, the terms "mounted", "connected", "coupled", "fixed", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] In the present invention, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0042] Embodiment:

[0043] Please refer to Figures 1 - 6, in the preferred embodiment of the present invention, the lever - type low - frequency magnetoelectric antenna includes a first mounting bracket 1 and a second mounting bracket 2. A piezoelectric stack 3 is provided 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 telescopic in the energized state. Secondly, a rotating shaft 4 is further provided on the second mounting bracket 2, and an electromagnet 5 is provided on the rotating shaft 4, and the electromagnet 5 is arranged inside a magnetic induction coil. The two ends of the magnetic poles generated by the electromagnet 5 under the action of the magnetic induction coil are coplanar with the swinging plane of the electromagnet 5. And, one end of the piezoelectric stack 3 facing the second mounting bracket 2 is connected to the side wall of the electromagnet 5, and there is a distance 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 telescopic action of the piezoelectric stack 3 to generate a changing magnetic field in two directions within the swinging plane to achieve signal transmission.

[0044] In the lever - type low - frequency magnetoelectric antenna of the present application, the telescopic movement of the piezoelectric stack 3 drives the rotation of the electromagnet 5. The electromagnet 5 forms a lever structure with the rotating shaft 4 as the fulcrum. The deflection amount of the electromagnet 5 is amplified by using the lever structure, thereby increasing the magnetic moment and generating a stronger magnetic induction intensity. Secondly, the rotation form of the piezoelectric stack 3 driving the electromagnet 5 is different from that of the traditional rotary mechanical antenna. Its deflection angle is limited by the telescopic amplitude of the piezoelectric stack 3. The overall rotational inertia of the electromagnet 5 is smaller than that of the rotary mechanical antenna, making its rotation controllable and the swinging amplitude inertia smaller. The magnetic field fluctuation generated by it has a higher correlation with the telescopic frequency of the piezoelectric stack 3 and has better information transmission ability.

[0045] Specifically, the electromagnet 5 in the present application needs to rotate within a plane. To avoid the contact and interference between the electromagnet 5 and the placement plane during rotation, the first mounting bracket 1 and the second mounting bracket 2 are provided in the present application to raise 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, etc. Secondly, the swinging of the electromagnet 5 within the plane 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 also stronger. The signal receiving device can capture the signal change at more angles, making the lever - type low - frequency magnetoelectric antenna have higher energy transmission efficiency.

[0046] Further, as Figure 2As shown, as an alternative embodiment of the present invention, the piezoelectric stack 3 in the present application includes a piezoelectric stack 301, and interdigital electrodes 302 are provided inside the piezoelectric stack 301. After the interdigital electrodes 302 are energized, the piezoelectric stack 301 can expand and contract along the arrangement direction (the first direction) of the interdigital electrodes 302. Specifically, the piezoelectric stack 301 in the present application has a high piezoelectric constant and a high electromechanical coupling coefficient, and can generate 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 interdigital electrodes 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 interdigital electrodes 302 are located, and the piezoelectric stack 301 will expand and contract correspondingly under the action of the electric field formed by the interdigital electrodes 302.

[0047] Optionally, the piezoelectric stack 301 in the present application is one or more of piezoelectric ceramics, piezoelectric crystals or piezoelectric polymers. The piezoelectric stack 301 can be selected from lead zirconate titanate, barium titanate, quartz crystal, lithium niobate, polyvinylidene fluoride copolymer or polylactic acid-based piezoelectric polymer.

[0048] Further, as an alternative embodiment of the present invention, the interdigital electrodes 302 in the present application are embedded in the piezoelectric stack 301 in pairs, and there is a gap between the two interdigital electrodes 302. Comb-shaped extensions extend outwards from the two interdigital electrodes 302 towards each other, and the extensions of each interdigital electrode 302 do not contact the other interdigital electrode 302. Secondly, one end of the two interdigital electrodes 302 facing the first mounting bracket 1 extends out of the piezoelectric stack 301, and the two interdigital electrodes 302 are respectively connected with leads. The form in which the interdigital electrodes 302 are arranged along the setting direction of the piezoelectric stack 301 can ensure the consistency between the signal generated by the interdigital electrodes 302 and the expansion and contraction amplitude of the piezoelectric stack 301, and the leads are used for the input of an external signal source.

[0049] Further, the first mounting bracket 1 in the present application includes a first mounting base, a first support rod is provided vertically on the first mounting base, and a clamping rod is provided on the first support rod facing the piezoelectric stack 3. The clamping rod includes two oppositely arranged clamping pieces. The end of the piezoelectric stack 3 is located between the two clamping pieces, and a tightening screw is provided on one of the clamping pieces. 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 base 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 pieces and the tightening screw facilitates clamping the piezoelectric stack 3 and enables the clamping force between the clamping rod and the piezoelectric stack 3 to be adjustable, which is convenient for fixing and taking and placing the piezoelectric stack 3.

[0050] Further, the second mounting bracket 2 in the present application includes a second mounting base and a third mounting base, and mounting holes are respectively provided between the second mounting base and the third mounting base. The rotating shaft 4 is inserted through the mounting holes, and rotating bearings are respectively provided between the second mounting base and the third mounting base. Both ends of the rotating shaft 4 are respectively sleeved in the two rotating bearings; secondly, the rotating shaft 4 is provided with a plug hole in the radial direction, and the electromagnet 5 is inserted into the plug 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 base and the third mounting base are arranged side by side, the rotating shaft 4 is erected between them, and the rotating shaft 4 can rotate stably through the two rotating bearings, so that the electromagnet 5 swings stably under the telescopic action of the piezoelectric stack 3. Preferably, the rotating bearing is a ball bearing.

[0051] Optionally, both the first mounting bracket 1 and the second mounting bracket 2 in the present application are placed on a plane. The first mounting bracket 1 can swing or move slightly on the plane to adapt to the telescopic displacement of the piezoelectric stack 3.

[0052] Optionally, the electromagnet 5 in the present application is made of an iron-gallium alloy, and the magnetic induction coil in the present application is a Helmholtz coil. Although a conventional permanent magnet also has a magnetic field and forms 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 fluctuation generated by it in the swinging state is relatively small, ultimately resulting in a low signal intensity received by the signal receiving device and affecting the signal transmission quality. Therefore, the present application selects the form of cooperation between the electromagnet 5 and the magnetic induction coil, and arranges the magnetic pole direction in the swinging plane, so that the magnetic field fluctuation generated when the electromagnet 5 swings is larger, in order to improve the signal transmission quality.

[0053] 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 in two directions of the electromagnet 5 in the swinging plane. According to electromagnetic theory, the value of the time-varying electromagnetic field generated by a 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 values of the time-varying electromagnetic fields generated by the two can be obtained, so as to obtain the difference between the present application and the traditional antenna.

[0054] Specifically, the magnetic moment of a typical sheet-like membrane electrode assembly is set as m 0 , Q representing the equivalent magnetic moment, and its expression is as follows:

[0055] (Formula 3)

[0056] where d represents the magnetic charge amplitude, f represents the signal frequency, t represents the time, represents the direction vector.

[0057] As Figure 3 shown, Figure 3 in (a) is the deflection magnetic dipole sub-model diagram of the lever-type low-frequency magnetoelectric antenna, Figure 3 in (b) is the orthogonal magnetic dipole model diagram of the lever-type low-frequency magnetoelectric antenna. According to 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:

[0058] + (Formula 1)

[0059] where, 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 magnetic charge amplitude along the second direction, f is the signal frequency, t is the 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 from the signal input end to the lever-type low-frequency magnetoelectric antenna.

[0060] Specifically, in this application, the first direction is preferably the telescopic direction of the piezoelectric stack, and the second direction in this application is preferably the direction perpendicular to the telescopic direction of the piezoelectric stack 3 in the swinging plane of the electromagnet 5.

[0061] Furthermore, based on the above Formula 1, the specific calculation method of the magnetic moment generated by the electromagnet 5 in this application is:

[0062] = (Formula 2)

[0063] where, L is the distance from the center of the rotation axis 4 to one end of the magnetic pole of the electromagnet 5, d is the telescopic length of the piezoelectric stack 3, l is the distance from the connection point of the piezoelectric stack 3 and the electromagnet 5 to the center of the rotation axis 4.

[0064] Through the above Formula 1 and Formula 2, the magnetic moment parameters of the lever-type low-frequency magnetoelectric antenna in this application can be reflected. Compared with the antenna structure under the conventional one-dimensional amplitude, it can be clearly seen that the magnetic moment of the lever-type low-frequency magnetoelectric antenna in this application is greater than that of the conventional antenna structure, and its swinging inertia is smaller than that of the mechanical rotating antenna, and it has a more accurate signal transmission ability.

[0065] For the lever - type low - frequency magnetoelectric antenna designed in this application, under the condition of the same input power, different l (the distance from the connection point of the piezoelectric stack 3 and the electromagnet 5 to the axis of the rotating shaft 4) of the lever - type low - frequency magnetoelectric antenna's amplitude - frequency response characteristics are obtained. The results are as Figure 4 shown. It can be seen that the magnetic induction intensities under different l 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 - 3dB bandwidth remains unchanged. The bandwidth remains unchanged while the resonant frequency decreases, indicating an increase in the relative bandwidth. And 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.

[0066] Furthermore, this application uses amplitude - shift keying signals to demonstrate the communication of the lever - type low - frequency magnetoelectric antenna in the ultra - low - frequency band. Specifically, as Figure 5 shown, the amplitude - shift keying signal is generated by a 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 stack 301 through the two leads of the interdigital electrode 302. The piezoelectric stack 301 expands and contracts correspondingly 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 a giant magneto - impedance sensor at a distance of 1 m and displayed on an oscilloscope. The original waveform of the amplitude - shift keying signal and the waveform received by the oscilloscope are respectively as Figure 6 shown in (a) and (b) in. It can be seen that the signal waveform envelope generated by the lever - type low - frequency magnetoelectric antenna in this application is very clear, and this lever - type low - frequency magnetoelectric antenna can achieve the transmission of amplitude - shift keying signals at a communication rate of 100 bps.

[0067] The lever - type low - frequency magnetoelectric antenna in this application can significantly improve the magnetic induction intensity and efficiency of the antenna. And in the actual measurement of the amplitude - frequency effect characteristics, the resonant frequency and Q - value range of this lever - type low - frequency magnetoelectric antenna are 339 - 356 Hz and 37.67 - 39.56 respectively. Its maximum magnetic induction intensity is 106.2 nT within a range of 1 m, and it can achieve the modulation of amplitude - shift keying signals at 100 bps.

[0068] Those skilled in the art can easily understand that the above - mentioned are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle 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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