A magnetoelectric antenna and a tuning method thereof based on an equivalent circuit model

Abstract

The application discloses a magneto-electric antenna and a tuning method thereof based on an equivalent circuit model. The magneto-electric antenna comprises a magneto-electric antenna body and a load. The load is arranged at the end of the magneto-electric antenna body. The upper cutoff frequency, the lower cutoff frequency and the bandwidth of the magneto-electric antenna are adjusted by adjusting the total mass of the load and the total elastic coefficient of the magneto-electric antenna body, so that the upper cutoff frequency, the lower cutoff frequency and the bandwidth of the magneto-electric antenna reach target values. The total mass of the load and the total elastic coefficient of the magneto-electric antenna body can be accurately calculated through a calculation formula by establishing an RLC series resonance equivalent circuit model of the magneto-electric antenna. The application can realize accurate tuning of the magneto-electric antenna.

Description

Technical Field

[0001] This invention belongs to the field of low-frequency communication, and more specifically, relates to a magnetoelectric antenna and its tuning method based on an equivalent circuit model. Background Technology

[0002] Magnetoelectric antennas are a new type of low-frequency mechanical antenna that directly generates electromagnetic signals based on vibrating magnetic dipoles. They have great development potential in fields such as shore-to-submarine, underwater, and underground communications.

[0003] In existing technologies, magnetoelectric antennas are generally finished products with non-adjustable resonant frequencies, which are determined after manufacturing. The working principle of magnetoelectric antennas differs from that of electric antennas, and the impedance matching tuning methods used for electric antennas in the electrical field are not applicable to magnetoelectric antennas. Therefore, how to accurately tune a magnetoelectric antenna without altering its radiating structure is a pressing problem that needs to be solved. Summary of the Invention

[0004] In view of the above-mentioned defects or improvement needs of the prior art, the present invention provides a magnetoelectric antenna and a tuning method based on an equivalent circuit model, which can achieve precise tuning of the magnetoelectric antenna.

[0005] To achieve the above objectives, according to one aspect of the present invention, a method for tuning a magnetoelectric antenna based on an equivalent circuit model is provided. The magnetoelectric antenna includes a magnetoelectric antenna body and a load, wherein the load is disposed at the end of the magnetoelectric antenna body. The upper cutoff frequency, lower cutoff frequency, and bandwidth of the magnetoelectric antenna are adjusted by adjusting the total mass of the load and the total elastic coefficient of the magnetoelectric antenna body, so that the upper cutoff frequency, lower cutoff frequency, and bandwidth of the magnetoelectric antenna reach target values. After adjustment, the total mass of the load and the total elastic coefficient of the magnetoelectric antenna body satisfy the following:

[0006]

[0007]

[0008] Where M is the total mass of the load after adjustment, K is the total elastic coefficient of the magnetoelectric antenna body after adjustment, and f H ' is the target value of the upper cutoff frequency, f L ' is the target value of the lower cutoff frequency, B' is the target value of the bandwidth, and R is the damping of the magnetoelectric antenna.

[0009] Furthermore, the total mass of the load is adjusted by adding mass to the load, where the mass of the load itself is m1, and the mass added to the load is m2, and m1 and m2 satisfy:

[0010]

[0011] Furthermore, the overall elastic coefficient of the magnetoelectric antenna body is adjusted by connecting an elastic material in parallel to the antenna body. The elastic coefficient of the magnetoelectric antenna body itself is k1, and the elastic coefficient of the elastic material is k2. k1 and k2 satisfy the following:

[0012]

[0013] Furthermore, the elastic material is an elastic keel sheet.

[0014] Furthermore, the overall elastic coefficient of the magnetoelectric antenna body is adjusted by bonding multiple antenna layers.

[0015] Furthermore, the magnetoelectric antenna body includes a sealed gas cavity, an electrostrictive part, a mechanical vibration conduction part, and a piezomagnetic part arranged sequentially along a preset direction. The total elasticity coefficient of the magnetoelectric antenna body is adjusted by changing the air pressure inside the sealed gas cavity.

[0016] Furthermore, by dynamically adjusting the mass of the load and the elastic coefficient of the magnetoelectric antenna body, the resonant frequency of the magnetoelectric antenna is always kept at the frequency required for frequency modulation.

[0017] According to a second aspect of the present invention, a magnetoelectric antenna is provided, the magnetoelectric antenna including a magnetoelectric antenna body and a load, the load being disposed at an end of the magnetoelectric antenna body, the upper cutoff frequency, lower cutoff frequency, and bandwidth of the magnetoelectric antenna being adjusted by adjusting the total mass of the load and the total elastic coefficient of the magnetoelectric antenna body, such that the upper cutoff frequency, lower cutoff frequency, and bandwidth of the magnetoelectric antenna reach target values, and the total mass of the load and the total elastic coefficient of the magnetoelectric antenna body satisfy the following after adjustment:

[0018]

[0019] Where M is the total mass of the load after adjustment, K is the total elastic coefficient of the magnetoelectric antenna body after adjustment, and f H ' is the target value of the upper cutoff frequency, f L ' is the target value of the lower cutoff frequency, B' is the target value of the bandwidth, and R is the damping of the magnetoelectric antenna.

[0020] Furthermore, the magnetoelectric antenna body includes a sealed gas cavity, an electrostrictive part, a mechanical vibration conduction part, and a piezomagnetic part arranged sequentially along a preset direction. The total elasticity coefficient of the magnetoelectric antenna body is adjusted by changing the air pressure inside the sealed gas cavity.

[0021] Furthermore, a fixing base for fixing the magnetoelectric antenna body is provided at the other end of the sealed gas cavity opposite to the electrostrictive part.

[0022] Overall, compared with the prior art, the above-described technical solutions conceived in this invention can achieve dynamic tuning of magnetoelectric antennas after production finalization, which is beneficial for optimizing antennas that deviate from the predetermined operating frequency and has a wide range of application value. For example, for magnetoelectric antennas using frequency modulation, the antenna resonant frequency can be adjusted synchronously and dynamically during transmission, so that the antenna always works at the resonant frequency point. For magnetoelectric antennas with long-distance communication and large-scale array requirements, dynamic tuning technology can tune different antenna array elements to the same operating frequency point, thereby improving the radiation efficiency of the array. Attached Figure Description

[0023] Figure 1 This is the equivalent vibration model of the magnetoelectric antenna in this embodiment of the invention;

[0024] Figure 2 This is the equivalent circuit model of the magnetoelectric antenna in this embodiment of the invention;

[0025] Figure 3 This is the equivalent circuit model of the magnetoelectric antenna with added load in an embodiment of the present invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the 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 merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0027] In this embodiment of the invention, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, apparatus, product or device that includes a series of steps or modules is not necessarily limited to those steps or modules that are explicitly listed, but may include other steps or modules that are not explicitly listed or that are inherent to such process, method, product or device.

[0028] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0029] This invention provides a magnetoelectric antenna and its tuning method based on an equivalent circuit model, which will be described below.

[0030] An embodiment of the present invention provides a tuning method for a magnetoelectric antenna based on an equivalent circuit model. First, an equivalent circuit model of RLC series resonance is established through the vibration model of the magnetoelectric antenna. The elastic coefficient, load, and damping of the magnetoelectric antenna are respectively equivalent to physical quantities in the circuit to achieve the purpose of precise tuning.

[0031] A magnetoelectric antenna includes a magnetoelectric antenna body and a load. The magnetoelectric antenna body is the part of the magnetoelectric antenna excluding the load. The load is located at the end of the magnetoelectric antenna body. The vibration model of the magnetoelectric antenna is as follows: Figure 1 As shown.

[0032] Based on this vibration model, the formula for calculating the resonant frequency of an ideal lightweight magnetoelectric antenna can be derived:

[0033]

[0034] Where m is the load mass of the ideal lightweight magnetoelectric antenna, and k is the elastic coefficient of the ideal lightweight magnetoelectric antenna. Based on equation (1), the qualitative tuning of the ideal lightweight magnetoelectric antenna can be completed. For example, increasing the load lowers the frequency; increasing the elastic coefficient raises the resonant frequency. Equation (1) is based on an ideal linear lightweight spring and cannot be directly applied to calculate the multi-order resonant frequencies of actual mechanical antennas.

[0035] However, based on equation (1), an equivalent circuit model of the magnetoelectric antenna can be further established. Equation (1) can be further rewritten as equation (2).

[0036]

[0037] Because the energy in the vibration system of the magnetoelectric antenna is consumed only by the antenna vibration, the vibration model of the magnetoelectric antenna is equivalent to a series resonant circuit. Since the total elastic coefficient is the sum of the elastic coefficients of the two when the magnetoelectric antenna is connected in parallel with the elastic keel, in equation (2), k... -1 It can be compared to a capacitor in a circuit; because the load of the magnetoelectric antenna is directly superimposed in series when it increases, m can be compared to an inductor in a circuit; the damping of the antenna itself is compared to the equivalent resistance; the amplitude is compared to the current amplitude in a circuit.

[0038] Figure 2 This is the equivalent circuit model of a magnetoelectric antenna.

[0039] Based on the equivalent circuit model, the resonant frequency f(2) and lower cutoff frequency f of the magnetoelectric antenna can be obtained. L (3) Upper cutoff frequency f H (4) and the formula for calculating bandwidth B(5).

[0040]

[0041] Where R is the damping of the magnetoelectric antenna, L = m, C = k -1 .

[0042] The upper cutoff frequency, lower cutoff frequency, and bandwidth of the magnetoelectric antenna are adjusted by regulating the total mass of the load and the total elastic coefficient of the magnetoelectric antenna body, so that the upper cutoff frequency, lower cutoff frequency, and bandwidth of the magnetoelectric antenna reach the target values.

[0043] After adjustment, the total mass of the load and the total elastic modulus of the magnetoelectric antenna body satisfy the following:

[0044]

[0045] Where M is the total mass of the load after adjustment, K is the total elastic coefficient of the magnetoelectric antenna body after adjustment, and f H ' is the target value of the upper cutoff frequency, f L ' is the target value of the lower cutoff frequency, and B' is the target value of the bandwidth.

[0046] Without altering the structure of the magnetoelectric antenna radiator, there are several options for adjusting the total mass of the load or the total elastic coefficient of the magnetoelectric antenna body.

[0047] For example, the total mass of a load can be changed by adding mass to the load.

[0048] Figure 3 The equivalent circuit model of the magnetoelectric antenna with added load is given, where R1 is the equivalent resistance of the magnetoelectric antenna, L1 is the equivalent inductance of the magnetoelectric antenna, k1 is the elastic coefficient of the magnetoelectric antenna itself, m1 is the mass of the load itself, m2 is the mass of the object added to the load (e.g., a weight), and L2 is the equivalent inductance of the object added to the load. Figure 3 middle, satisfy:

[0049]

[0050]

[0051] For example, the overall elastic coefficient of the magnetoelectric antenna body can be adjusted by connecting elastic materials such as elastic keel plates in parallel to the magnetoelectric antenna body.

[0052] k2 is the elastic coefficient of the parallel elastic materials.

[0053] satisfy:

[0054]

[0055] For example, the overall elastic coefficient of the magnetoelectric antenna body can be adjusted by bonding multiple antennas together, that is, by connecting multiple magnetoelectric antenna bodies in parallel.

[0056] Of course, the total mass of the load and the total elastic coefficient of the magnetoelectric antenna body can also be adjusted simultaneously. M = m1 + m2, K = k1 + k2.

[0057] In another embodiment, the magnetoelectric antenna body includes a sealed gas cavity, an electrostrictive part, a mechanical vibration conduction part, and a piezomagnetic part arranged sequentially along a preset direction. The elasticity coefficient of the magnetoelectric antenna body is adjusted by changing the air pressure inside the sealed gas cavity. The higher the air pressure, the higher the elasticity coefficient.

[0058] A sealed gas cavity is used to adjust the elastic coefficient of the magnetoelectric antenna body by changing the gas pressure inside the cavity. It also serves to reduce the mechanical energy loss of the mechanical antenna by totally reflecting the mechanical vibration waves generated by the electrostrictive part at the interface with the electrostrictive part. The electrostrictive part includes an electrostrictive material body and electrodes, used to convert electrical energy supplied by the electrodes into mechanical energy through the electrostrictive material body. A mechanical vibration conduction part is used to conduct the mechanical vibration waves from the electrostrictive part to the piezomagnetic part. The piezomagnetic part is used to convert the mechanical energy conducted through the mechanical vibration conduction part into magnetic energy.

[0059] The aforementioned magnetoelectric antenna tuning method based on the equivalent circuit model has broad application value. For example, for magnetoelectric antennas using frequency modulation, the antenna resonant frequency can be adjusted synchronously and dynamically during transmission, ensuring the antenna always operates at its resonant frequency. This is achieved by dynamically adjusting the mass of the load and the elastic coefficient of the magnetoelectric antenna body, ensuring the resonant frequency of the antenna remains at the frequency required for frequency modulation. Furthermore, for magnetoelectric antennas requiring long-distance communication and large-scale array deployment, dynamic tuning technology can tune different antenna elements to the same operating frequency, improving the array's radiation efficiency.

[0060] The simulation results are as follows:

[0061] Taking the PZT-5H / Metglas type magnetoelectric antenna with a length of 100mm, a width of 20mm, and a thickness of 0.5mm as an example, the elasticity coefficient can be measured to be 471720N / m.

[0062] Table 1. Meanings and values ​​of symbols in the text.

[0063]

[0064] Calculate the resonant frequencies when the weight load is 0.03Kg, 0.06Kg, 0.09Kg, and 0.12Kg respectively.

[0065] Table 2 Calculation results of natural frequencies under different mechanical load conditions

[0066]

[0067] By adding keel-type springs and bonding multiple antenna layers, the elastic coefficients of the antenna model were changed to 535000 N / m, 830000 N / m, 890000 N / m, 1000000 N / m, and 1500000 N / m. The resonant frequencies were calculated for each model with a load of 0.03 kg. The calculation results are shown in Table 3.

[0068] Table 3. Calculation results of natural frequencies under different elastic coefficients.

[0069]

[0070] The resonant frequencies of the test sample under different mechanical load conditions were obtained in the experiment. The test results are shown in Table 4.

[0071] Table 4. Test results of natural frequencies under different mechanical load conditions.

[0072]

[0073] The experimental results are consistent with the theoretical results. As the mechanical load increases, the resonant frequency of the mechanical antenna decreases. Under the current laboratory conditions, the frequency can be adjusted from -50% to 0Hz. By changing the mechanical load conditions, such as replacing the spring with one with one with a stronger tension or increasing the upper limit of the displacement of the fixed constraint module, the resonant frequency of the antenna can theoretically approach 0Hz. Under different mechanical load conditions, the bandwidth of the antenna vibration can remain stable.

[0074] The resonant frequencies of the test sample under different elastic coefficients are shown in Table 5.

[0075] Table 5. Test results of natural frequencies under different elastic coefficients.

[0076]

[0077]

[0078] Experimental results show that as the elasticity coefficient of the mechanical antenna increases, the resonant frequency rises accordingly, which is consistent with theoretical results. Under laboratory conditions, by adjusting the antenna elasticity coefficient, the resonant frequency can be adjusted by 0% to 75%, and the bandwidth can be expanded by 0% to 207%. By changing different elasticity coefficient conditions, such as replacing the keel with one with a larger elasticity coefficient or increasing the number of composite layers in the antenna, theoretically, the frequency offset range and bandwidth can be improved even more significantly.

[0079] Another embodiment of the magnetoelectric antenna of the present invention includes a magnetoelectric antenna body and a load. The load is disposed at the end of the magnetoelectric antenna body. The upper cutoff frequency, lower cutoff frequency, and bandwidth of the magnetoelectric antenna are adjusted by adjusting the total mass of the load and the total elastic coefficient of the magnetoelectric antenna body, so that the upper cutoff frequency, lower cutoff frequency, and bandwidth of the magnetoelectric antenna reach target values. After adjustment, the total mass of the load and the total elastic coefficient of the magnetoelectric antenna body satisfy the following:

[0080]

[0081] Where M is the total mass of the load after adjustment, K is the total elastic coefficient of the magnetoelectric antenna body after adjustment, and f H ' is the target value of the upper cutoff frequency, f L ' is the target value of the lower cutoff frequency, and B' is the target value of the bandwidth.

[0082] Furthermore, the magnetoelectric antenna body includes a sealed gas cavity, an electrostrictive part, a mechanical vibration conduction part, and a piezomagnetic part arranged sequentially along a preset direction. The total elasticity coefficient of the magnetoelectric antenna body is adjusted by changing the air pressure inside the sealed gas cavity.

[0083] Furthermore, the magnetoelectric antenna has a fixing base for fixing the magnetoelectric antenna body at the other end of the sealed gas cavity opposite to the electrostrictive part.

[0084] The principle and effect of the above-mentioned magnetoelectric antenna are the same as those of the above-mentioned magnetoelectric antenna tuning method, and will not be repeated here.

[0085] Those skilled in the art will readily understand that the above description is merely 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 within the scope of protection of the present invention.

Claims

1. A method for tuning a magnetoelectric antenna based on an equivalent circuit model, characterized in that, The magnetoelectric antenna includes a magnetoelectric antenna body and a load. The load is located at the end of the magnetoelectric antenna body. The upper cutoff frequency, lower cutoff frequency, and bandwidth of the magnetoelectric antenna are adjusted by adjusting the total mass of the load and by connecting an elastic material in parallel with the magnetoelectric antenna body to adjust the total elastic coefficient of the magnetoelectric antenna body. This ensures that the upper cutoff frequency, lower cutoff frequency, and bandwidth of the magnetoelectric antenna reach target values. After adjustment, the total mass of the load and the total elastic coefficient of the magnetoelectric antenna body satisfy the following: in, M To adjust the total mass of the afterload, K To adjust the overall elastic coefficient of the magnetoelectric antenna body, ' is the target value of the upper cutoff frequency. ' is the target value for the lower cutoff frequency. ' is the target value for the bandwidth, The damping of the magnetoelectric antenna is given.

2. The magnetoelectric antenna tuning method as described in claim 1, characterized in that, The total mass of the load is adjusted by adding mass to the load, the mass of the load itself being [missing information]. m 1. The mass added to the load is m 2, m 1. m 2. Satisfies: 。 3. The magnetoelectric antenna tuning method as described in claim 1, characterized in that, In the process of adjusting the overall elastic coefficient of the magnetoelectric antenna body by connecting an elastic material in parallel to the magnetoelectric antenna body, the elastic coefficient of the magnetoelectric antenna body itself is: The elastic modulus of the elastic material is , , satisfy: 。 4. The magnetoelectric antenna tuning method as described in claim 3, characterized in that, The elastic material is an elastic keel sheet.

5. The magnetoelectric antenna tuning method as described in claim 1, characterized in that, The method of adjusting the total elastic coefficient of the magnetoelectric antenna body by connecting elastic material in parallel to the magnetoelectric antenna body is replaced by adjusting the total elastic coefficient of the magnetoelectric antenna body by bonding multiple antenna layers.

6. The magnetoelectric antenna tuning method as described in claim 1, characterized in that, The magnetoelectric antenna body includes a sealed gas cavity, an electrostrictive part, a mechanical vibration conduction part, and a piezomagnetic part arranged sequentially along a preset direction. The method of adjusting the total elastic coefficient of the magnetoelectric antenna body by connecting an elastic material in parallel to the magnetoelectric antenna body is replaced by adjusting the total elastic coefficient of the magnetoelectric antenna body by changing the air pressure inside the sealed gas cavity.

7. The magnetoelectric antenna tuning method as described in claim 1, characterized in that, By dynamically adjusting the mass of the load and the elastic coefficient of the magnetoelectric antenna body, the resonant frequency of the magnetoelectric antenna is always kept at the frequency required for frequency modulation.

8. A magnetoelectric antenna, characterized in that, The magnetoelectric antenna includes a magnetoelectric antenna body and a load. The load is located at the end of the magnetoelectric antenna body. The upper cutoff frequency, lower cutoff frequency, and bandwidth of the magnetoelectric antenna are adjusted by adjusting the total mass of the load and by connecting an elastic material in parallel with the magnetoelectric antenna body to adjust the total elastic coefficient of the magnetoelectric antenna body. This ensures that the upper cutoff frequency, lower cutoff frequency, and bandwidth of the magnetoelectric antenna reach target values. After adjustment, the total mass of the load and the total elastic coefficient of the magnetoelectric antenna body satisfy the following: in, M To adjust the total mass of the afterload, K To adjust the overall elastic coefficient of the magnetoelectric antenna body, ' is the target value of the upper cutoff frequency. ' is the target value for the lower cutoff frequency. ' is the target value for the bandwidth, The damping of the magnetoelectric antenna is given.

9. The magnetoelectric antenna as described in claim 8, characterized in that, The magnetoelectric antenna body includes a sealed gas cavity, an electrostrictive part, a mechanical vibration conduction part, and a piezomagnetic part arranged sequentially along a preset direction. The method of adjusting the total elastic coefficient of the magnetoelectric antenna body by connecting an elastic material in parallel to the magnetoelectric antenna body is replaced by adjusting the total elastic coefficient of the magnetoelectric antenna body by changing the air pressure inside the sealed gas cavity.

10. The magnetoelectric antenna as described in claim 9, characterized in that, A fixing base for fixing the magnetoelectric antenna body is provided at the other end of the sealed gas cavity opposite to the electrostrictive part.

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