Array type mechanical antenna based on magnetoelectric composite material and beam control method thereof

Abstract

The application provides an array type mechanical antenna based on a magnetoelectric composite material and a beam control method thereof, and is applied to the technical field of antennas. The array structure and the posture adjusting driving assembly connected with the array structure are arranged, the control unit is used to acquire target position information and generate a pointing coordinate, the posture adjusting driving assembly is controlled according to the pointing coordinate to adjust the physical posture of the array structure, and the main lobe of the radiation beam of the array structure is directed to the target position, so that the miniaturization, low power consumption and efficient cross-medium communication of the antenna are realized. The problems of the large size, high power consumption, fixed beam pointing, poor dynamic adaptation capability and weak single antenna radiation intensity of the traditional ultra-low frequency antenna are solved, and the advantages of realizing the miniaturization, low power consumption and efficient cross-medium communication of the antenna are achieved.

Description

Technical Field

[0001] This application relates to the field of antenna technology, and in particular to array-type mechanical antennas based on magnetoelectric composite materials and their beam control methods. Background Technology

[0002] Cross-domain communication is a core link in multi-domain collaborative operations involving sea, air, space, and submarine, playing a crucial role in the military field. Simultaneously, in the civilian sector, it is also an important support for promoting marine monitoring, low-altitude economic development, and the construction of marine networks, possessing both strategic and economic value. Achieving efficient and stable cross-media communication, especially between underwater and air, has always been a major technical challenge in this field.

[0003] The key to achieving cross-domain communication lies in overcoming the transmission limitations of different media (especially complex media such as seawater). Ultra-low frequency (ULF) electromagnetic waves, due to their low attenuation in different media, can propagate over longer distances in seawater, making them a preferred technology for cross-domain and cross-media communication. However, the application of ULF electromagnetic waves faces inherent technical bottlenecks: because antenna size is inversely proportional to operating frequency, the antenna size required for ULF signal transmission is typically extremely large; without changing the antenna size, the input power needs to be significantly increased. This directly leads to numerous practical problems in actual applications, such as large land requirements, high initial investment costs, and inconvenience in laying cables in complex scenarios, severely restricting the large-scale implementation and widespread application of cross-domain communication technology.

[0004] Therefore, existing technologies urgently need to be improved to address the aforementioned problems. Summary of the Invention

[0005] In view of the shortcomings of the prior art, this application provides an array-type mechanical antenna based on magnetoelectric composite materials and its beam control method, which is applied to the field of antenna technology and has the advantages of realizing antenna miniaturization, low power consumption and efficient cross-medium communication.

[0006] In a first aspect, an array-type mechanical antenna based on magnetoelectric composite materials includes at least:

[0007] The array structure is composed of multiple magnetoelectric composite radiation units arranged at a preset interval and connected by signals. Each of the magnetoelectric composite radiation units includes a magnetostrictive layer and a piezoelectric layer stacked on top of each other.

[0008] An attitude adjustment drive component is mechanically connected to the array structure and is used to drive the array structure to rotate in space to change the physical orientation of the array structure.

[0009] The control unit is used to acquire target position information and generate pointing coordinates, and control the attitude adjustment drive component to adjust the physical attitude of the array structure according to the pointing coordinates, so that the main lobe of the radiation beam of the array structure points to the target position.

[0010] Furthermore, the magnetoelectric composite radiation unit also includes:

[0011] An interface coupling layer is disposed between the magnetostrictive layer and the piezoelectric layer, for transmitting the mechanical stress generated by the piezoelectric layer under alternating electric field excitation through the inverse piezoelectric effect to the magnetostrictive layer, so as to generate an alternating magnetic field through the inverse magnetostrictive effect; wherein, the magnetostrictive layer is made of terbium-dysprosium-iron rare earth giant magnetostrictive alloy material, and the piezoelectric layer is made of lead zirconate titanate piezoelectric ceramic sheet material.

[0012] Furthermore, the magnetoelectric composite radiation unit adopts an LT-type magnetoelectric coupling working mode. The magnetization direction of the magnetostrictive layer is parallel to the interlayer interface plane between the magnetostrictive layer and the piezoelectric layer, and is also parallel to the length axis of the magnetostrictive layer. The polarization direction of the piezoelectric layer is perpendicular to the interlayer interface plane and is parallel to the thickness axis of the piezoelectric layer. The magnetization direction and the polarization direction are orthogonal to each other.

[0013] Furthermore, multiple identical magnetoelectric composite radiation units are arranged according to a preset geometric topology. The signal connection includes: connecting the electrode leads of multiple identical magnetoelectric composite radiation units in parallel with the same polarity and connecting them to the same excitation source, so as to realize the superposition of in-phase radiation fields of multiple magnetoelectric composite radiation units in the far field of space.

[0014] Furthermore, the magnetoelectric composite radiation unit adopts an MPM-type three-layer sandwich structure, wherein P is a piezoelectric layer, which serves as the middle layer, and M is a magnetostrictive layer. The two magnetostrictive layers are symmetrically stacked on the upper and lower surfaces of the piezoelectric layer, respectively.

[0015] Furthermore, the attitude adjustment driving component includes:

[0016] A two-axis mechanical turntable, wherein the array structure is fixedly installed on the loading end of the two-axis mechanical turntable;

[0017] The drive motor assembly is connected to the two-axis mechanical turntable and is used to adjust the azimuth and pitch angles of the array structure according to the pointing coordinates.

[0018] Secondly, a beam control method for an array-type mechanical antenna based on magnetoelectric composite materials is provided. This method is applied to a control unit to control an attitude adjustment drive assembly to adjust the physical attitude of the array structure. The method includes the following steps:

[0019] S1: Obtain the target location information of the communication target, and calculate the pointing coordinates of the array structure based on the target location information;

[0020] S2: Obtain the current feedback angle of the attitude adjustment drive component, and calculate the angle deviation value between the pointing coordinate and the current feedback angle;

[0021] S3: Generate a driving command based on the angle deviation value and send it to the attitude adjustment driving component to drive the array structure to rotate until the angle deviation value is within the preset error threshold range.

[0022] Furthermore, in step S1, the target location information is acquired through a target detection sensor.

[0023] Furthermore, step S1 includes:

[0024] S11: Obtain the spatial geographical location of the array structure;

[0025] S12: Based on the target location information and the spatial geographical location of the array structure, calculate the target azimuth and target elevation angle with the array structure as the origin. The pointing coordinates include the target azimuth and target elevation angle.

[0026] Furthermore, step S3 includes:

[0027] S31: Acquire the continuous azimuth information of the communication target in real time, and calculate the relative motion vector of the communication target relative to the array structure based on the continuous azimuth information;

[0028] S32: Generate a driving command based on the angle deviation value and send it to the attitude adjustment driving component, and obtain the system response delay of the attitude adjustment driving component from receiving the driving command to completing the action;

[0029] S33: Combining the relative motion vector and the system response delay, calculate the predicted azimuth information of the communication target after the system response delay;

[0030] S34: Feedforward compensation is performed on the pointing coordinates based on the predicted azimuth information to offset the influence of the mechanical lag of the attitude adjustment drive component on the beam alignment accuracy.

[0031] Beneficial Effects: The array-type mechanical antenna based on magnetoelectric composite materials and its beam control method proposed in this application, by setting up an array structure and an attitude adjustment drive component connected to the array structure, and by using a control unit to obtain target position information and generate pointing coordinates, and controlling the attitude adjustment drive component to adjust the physical attitude of the array structure according to the pointing coordinates, so that the main lobe of the radiation beam of the array structure points to the target position, realizes the miniaturization, low power consumption and efficient cross-medium communication of the antenna, and solves the problems of large size, high power consumption, fixed beam pointing, poor dynamic adaptation capability and weak single antenna radiation intensity of traditional ultra-low frequency antennas. It has the advantages of realizing the miniaturization, low power consumption and efficient cross-medium communication of the antenna. Attached Figure Description

[0032] Figure 1 This is a simulation model of the magnetoelectric composite radiation unit proposed in this application.

[0033] Figure 2 This is the near-field radiation pattern of the magnetic field of the mechanical antenna proposed in this application.

[0034] Figure 3 The magnetic near-field radiation pattern after the mechanical antenna attitude change provided in this application.

[0035] Figure 4 This is a simulation model of the mechanical antennas connected in parallel as provided in this application.

[0036] Figure 5 The magnetic near-field radiation pattern of the mechanical antennas connected in parallel according to this application.

[0037] Figure 6 A graph showing the relationship between the magnetic near-field radiation intensity and the spacing between the magnetoelectric composite radiation units provided in this application.

[0038] Labeling explanation: 1. Magnetostrictive layer; 2. Piezoelectric layer. Detailed Implementation

[0039] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. The components of the embodiments of this application described and marked in the accompanying drawings can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0040] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this application, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0041] In the current field of communication technology, especially in communication scenarios involving communication across different physical media, such as information exchange between underwater and air, there are significant technical challenges. Traditional communication methods, such as acoustic communication, suffer from severe energy reflection and loss at the water-air interface due to the huge difference in acoustic impedance, greatly limiting communication distance and quality. Ultra-low frequency (ULF) electromagnetic waves, due to their low attenuation in conductive media such as seawater, are considered an ideal carrier for long-distance cross-medium communication. However, the development of ULF communication technology has long been constrained by a fundamental physical law: the physical size of an antenna is inversely proportional to its operating frequency. This means that to efficiently radiate ULF signals, traditional antennas need to be extremely large, leading to high costs, huge footprint requirements, and difficulties in application on mobile platforms or in complex environments, severely hindering the widespread adoption of this technology.

[0042] To overcome this bottleneck, researchers in this field have begun developing novel antenna technologies that do not rely on the traditional alternating current-excited electromagnetic resonance principle. Among these, mechanical antennas based on magnetoelectric composite materials offer a novel solution to the technical problem of traditional antennas being unable to simultaneously achieve miniaturization and high radiation efficiency in the low-frequency band. These antennas utilize the electromechanical and magnetomechanical coupling effects within the magnetoelectric composite material to convert electrical energy into mechanical vibrations, which are then used to generate electromagnetic radiation. This overcomes the limitation of traditional antennas requiring half-wavelength electromagnetic resonance and solves the technical problems of the strong binding between the operating frequency and physical size of traditional antennas, as well as the inability to simultaneously achieve miniaturization and high radiation efficiency in the low-frequency band. However, existing single magnetoelectric composite mechanical antennas often suffer from limited radiated power and short operating distance. Furthermore, their radiated beams typically have a fixed directionality and cannot be dynamically adjusted according to changes in the location of the communication target. This severely limits their adaptability in mobile communication or scenarios requiring the establishment of links with multiple targets.

[0043] To address the above problems, this application proposes an array-type mechanical antenna based on magnetoelectric composite materials, comprising at least:

[0044] The array structure consists of multiple magnetoelectric composite radiation units arranged at a preset interval and connected by signals. Each magnetoelectric composite radiation unit includes a magnetostrictive layer 1 and a piezoelectric layer 2 stacked on top of each other.

[0045] The attitude adjustment drive component is mechanically connected to the array structure and is used to drive the array structure to rotate in space to change the physical orientation of the array structure.

[0046] The control unit is used to acquire target position information and generate pointing coordinates. Based on the pointing coordinates, it controls the attitude adjustment drive component to adjust the physical attitude of the array structure so that the main lobe of the array structure's radiation beam points to the target position.

[0047] Please refer to Figures 1 to 3 The working principle of this antenna can be understood as a complete, coordinated process. First, the entire process is initiated by the control unit. As the core of information processing and decision-making, the control unit can be implemented using a high-performance digital signal processor, a field-programmable gate array (FPGA), or an embedded microcontroller. The primary task of the control unit is to acquire the location information of the communication target. This information can come from various sources, such as precise geographic coordinates received through a global navigation satellite system, or azimuth and distance data provided by radar, photoelectric detection equipment, etc. After acquiring the raw target location information, the algorithm module inside the control unit performs coordinate calculations, combining the carrier attitude data to convert it into pointing coordinates in the antenna's own coordinate system, typically expressed as two parameters: azimuth and elevation angles.

[0048] Once the pointing coordinates are calculated, the control unit sends a drive command to the attitude adjustment drive component. The attitude adjustment drive component is the actuator that adjusts the physical pointing of the antenna. Upon receiving the command, the attitude adjustment drive component drives the antenna array structure it supports to perform a precise spatial attitude rotation. This rotation is not arbitrary but is controlled by a closed-loop control system to ensure that the deviation between the final attitude of the array structure and the calculated pointing coordinates is controlled within a preset error threshold range.

[0049] After the array structure is adjusted to the target pointing orientation, the antenna's excitation source begins operation, feeding a low-frequency alternating excitation electrical signal to the array structure. The array structure is the radiation core of the entire antenna, composed of multiple magnetoelectric composite radiating units. These units work together to efficiently convert the input electrical energy into outwardly radiated ultra-low frequency electromagnetic waves. Because these units are arranged in space according to a predetermined symmetrical geometric relationship and are excited by equal-amplitude and in-phase signals, the electromagnetic waves radiated by each unit will superimpose in-phase field strength in the target direction in space, forming constructive interference. This superposition effect forms a main lobe of a radiation beam with concentrated energy and excellent directivity. Through the aforementioned mechanical attitude adjustment process, the direction of this main lobe is precisely aligned with the communication target. In this way, most of the radiated energy is effectively projected towards the target direction, effectively improving the efficiency of signal transmission and communication distance, while also reducing interference to non-target directions.

[0050] By assembling multiple radiating elements and combining them with mechanical beam pointing adjustment, the technical solution of this application effectively solves the problem of insufficient radiation intensity of a single antenna. Furthermore, by dynamically adjusting the physical attitude, it overcomes the defect of fixed beam pointing of traditional mechanical antennas, giving the antenna unprecedented flexibility and adaptability to dynamic targets.

[0051] Furthermore, to gain a deeper understanding of the energy conversion mechanism within each magnetoelectric composite radiation unit, its specific structure and operation are crucial. In a preferred embodiment, the magnetoelectric composite radiation unit further includes:

[0052] An interface coupling layer is disposed between the magnetostrictive layer 1 and the piezoelectric layer 2. It is used to transfer the mechanical stress generated by the inverse piezoelectric effect in the piezoelectric layer 2 under the excitation of the alternating electric field to the magnetostrictive layer 1, so as to generate an alternating magnetic field through the inverse magnetostrictive effect. The magnetostrictive layer 1 is made of terbium-dysprosium-iron rare earth giant magnetostrictive alloy material, and the piezoelectric layer 2 is made of lead zirconate titanate piezoelectric ceramic sheet material.

[0053] The core function of the interface coupling layer is to efficiently and losslessly transfer the mechanical deformation generated by the piezoelectric layer 2 under electric field excitation to the magnetostrictive layer 1, thereby generating an alternating magnetic field through the inverse magnetostrictive effect. Simultaneously, to maximize energy conversion efficiency, the material constituting the magnetostrictive layer 1 is preferably made of a terbium-dysprosium-iron rare-earth giant magnetostrictive alloy, commonly known as a Terfenol-D sheet, while the piezoelectric layer 2 is made of lead zirconate titanate piezoelectric ceramic sheet material, i.e., a PZT sheet.

[0054] Lead zirconate titanate piezoelectric ceramics, especially the PZT-5H model, possess a very high piezoelectric strain constant, meaning they can generate greater mechanical deformation under the same electric field strength. In other applications, other piezoelectric materials such as barium titanate or lithium niobate can also be considered to meet different operating temperature or cost requirements. When an alternating electric field is applied, the piezoelectric layer 2 undergoes periodic expansion, contraction, or bending due to the inverse piezoelectric effect.

[0055] This minute mechanical deformation must be completely transferred to the magnetostrictive layer 1. The interface coupling layer plays a crucial bridging role here. This coupling layer is not a simple adhesive, but a specially selected and treated structural epoxy resin. This resin needs to have high shear strength and high Young's modulus to ensure that its own deformation is minimal when transferring stress, thereby minimizing energy loss at the interface. During construction, processes such as vacuum infusion or pressure curing are required to ensure that the coupling layer is free of bubbles and defects, forming a strong and dense bond with the piezoelectric layer 2 and the magnetostrictive layer 1. The interface coupling layer plays a crucial mechanical bridging role in the magnetoelectric energy conversion link. The mechanical strain generated by the piezoelectric layer 2 must be completely transferred to the magnetostrictive layer 1 through this layer. To maximize energy transfer efficiency, a modified epoxy resin with ultra-high shear strength and extremely low viscoelasticity is selected for the interface coupling layer. After curing, this resin can form a near-molecular-level tight interface bond with the piezoelectric and magnetostrictive layers on both sides, ensuring that no stress relaxation or interface slip occurs under high-frequency vibration environments. Through a vacuum pressure composite process, the thickness of this layer is precisely controlled between 5 and 15 micrometers. This micrometer-level thickness design not only compensates for microscopic irregularities on the material surface but also significantly reduces sound wave reflection losses at interfaces between different media.

[0056] When mechanical deformation is transferred to magnetostrictive layer 1 through the interface coupling layer, the mechanomagnetic energy conversion process begins. The choice of material for magnetostrictive layer 1 is also crucial. For example, terbium-dysprosium-iron rare-earth giant magnetostrictive alloys, commercially known as Terfenol-D, are used. This material exhibits an extremely large magnetostrictive coefficient and inverse magnetostrictive effect at room temperature. That is, when subjected to periodic alternating mechanical stress, the easy magnetization direction of its internal magnetic domains deflects synchronously, causing the macroscopic magnetization intensity of the material to change linearly with the frequency of the alternating stress. According to Maxwell's electromagnetic theory, the alternating magnetic field synchronously excites the alternating electric field, and the two mutually excite each other to form ultra-low frequency electromagnetic waves that can propagate into space. For applications requiring low cost and high shock resistance, other magnetostrictive materials with high magnetoelastic effects, such as iron-gallium alloys (Galfenol), can also be used for the magnetostrictive layer.

[0057] By matching and selecting materials for the magnetostrictive layer, the piezoelectric layer, and the interface coupling layer, as well as optimizing the design of the stacked structure and array topology, the entire link of efficient conversion from electrical energy to mechanical energy to alternating magnetic energy, and finally to spatial radiated electromagnetic waves, can be effectively guaranteed, significantly improving the antenna's magnetoelectric coupling efficiency, radiation efficiency, and equivalent radiated power.

[0058] To further optimize the magnetoelectric coupling effect within the magnetoelectric composite radiation unit, the polarization and magnetization directions of its different functional layers have been specially designed. Specifically, the magnetoelectric composite radiation unit adopts an LT-type magnetoelectric coupling operating mode. The magnetization direction of the magnetostrictive layer is parallel to the interlayer interface plane between the magnetostrictive and piezoelectric layers, and also parallel to the length axis of the magnetostrictive layer. The polarization direction of the piezoelectric layer is perpendicular to the interlayer interface plane and parallel to the thickness axis of the piezoelectric layer. The magnetization and polarization directions are orthogonal to each other.

[0059] The advantage of using the LT-type magnetoelectric coupling working mode is that, firstly, during the material preparation stage, the piezoelectric ceramic layer undergoes a polarization process. This involves applying a strong DC electric field at a high temperature slightly below its Curie temperature, maintaining the temperature, and then cooling the electric field to room temperature. This causes the internal electric dipoles to align along the electric field direction, i.e., the thickness direction. Thus, the piezoelectric layer 2 possesses piezoelectric activity along its thickness direction. Similarly, during the preparation of the magnetostrictive layer 1, a directional solidification process is used to align the easily magnetized grains in a strong magnetic field, aligning their easily magnetized directions along the length of the material. When the antenna operates, a DC bias magnetic field applied along the length direction causes the magnetic domains (equivalent to tiny magnetic needles) inside the magnetostrictive layer to deflect synchronously along the length direction, ensuring that the magnetization orientations of both magnetostrictive layers are completely consistent.

[0060] In practical operation, an excitation electrical signal is applied to the upper and lower surfaces of piezoelectric layer 2, forming an alternating electric field along the thickness direction. Since the remanent polarization direction of piezoelectric layer 2 matches the driving direction of the alternating electric field, this represents the optimal T-mode excitation (lateral thickness direction excitation) for the inverse piezoelectric effect. According to the tensor characteristics of the inverse piezoelectric effect, the alternating electric field along the thickness direction causes the piezoelectric layer 2 to undergo the largest amplitude alternating stretching deformation along its length. The magnetostrictive layer can be tightly coupled to the upper and lower surfaces of the piezoelectric layer along its length via an interface coupling layer. The stretching deformation of piezoelectric layer 2 synchronously drives the magnetostrictive layer 1 to also undergo stretching deformation along its length at the same frequency. This length direction happens to be the preset magnetization direction of the magnetostrictive layer 1, i.e., the L-mode. When the magnetostrictive material is stretched or compressed along its magnetization direction, its internal magnetic domains undergo the most significant reversible deflection, resulting in the largest amplitude alternating magnetization intensity change along its length, ultimately radiating electromagnetic waves of the same frequency outwards. This LT-type magnetoelectric coupling mode, through orthogonal orientation configuration, fully utilizes the anisotropic physical properties of the two materials to couple the three core components of electric field excitation, mechanical deformation transmission, and magnetic field response in the optimal orientation, thereby maximizing the magnetoelectric conversion efficiency and antenna radiation performance.

[0061] Having clarified the efficient working mechanism of a single magnetoelectric composite radiating element, this scheme addresses the technical challenges of limited radiated power and short effective range of a single element by constructing a high-power array antenna through multi-element arraying. That is:

[0062] Multiple identical magnetoelectric composite radiation units are arranged according to a preset geometric topology. Each magnetoelectric composite radiation unit is electrically connected through a feed network. The electrode leads of all magnetoelectric composite radiation units are connected in parallel with the same polarity and connected to the same excitation source. All parallel magnetoelectric composite radiation units are identical units with completely consistent structure, size, polarization direction, and magnetization orientation. The electrical length of the feed lines is matched to ensure that all units receive excitation signals of the same frequency and phase. Finally, the in-phase radiation fields of multiple radiation units in the far field of space are superimposed.

[0063] The arrangement of the preset geometric topology has a direct impact on the array's performance. For example, multiple magnetoelectric composite radiation units can be arranged into a one-dimensional linear array; or arranged in the same plane to form a two-dimensional surface array, such as a rectangular array or a circular array. The spacing between adjacent units in the array, i.e., the preset spacing, is a core key parameter in array design. Its value directly determines the key characteristics of the array's radiation pattern, including the width of the main lobe, the level of the side lobes, and the possible appearance of grating lobes.

[0064] Please refer to Figures 4 to 6 In one specific embodiment, simulation analysis revealed that for a linear array consisting of three elements, the combined radiated field strength in a specific direction reaches its maximum when the spacing between the elements is set to 5 cm. This means that under the constraints of a fixed operating frequency and complete suppression of grating lobes, there exists an optimal spacing that maximizes the radiation gain in the array normal direction and optimizes the energy concentration of the main lobe. Through parallel in-phase excitation with the same polarity and optimized geometric arrangement, the array antenna can form a main beam that is much narrower and has a much higher directional gain than a single radiating element through the spatial constructive interference of the radiation fields of multiple elements, effectively improving the effective communication distance and anti-interference capability of the antenna.

[0065] In one specific implementation, the magnetoelectric composite radiation units are arranged in space according to a square planar topology. In this arrangement, four magnetoelectric composite radiation units are located at the four vertices of a square with sides of 5 cm. To achieve low-loss, in-phase feeding connections of equal electrical length for each unit, the positive electrode of each magnetoelectric composite radiation unit is converged to a central metal distribution terminal block via a fine shielded wire of equal electrical length. The negative electrode is uniformly connected to a non-magnetic metal base plate of the array structure. This metal base plate is equipotentially connected to the ground of the excitation source, ultimately forming a parallel feeding loop with the same polarity and common ground. When an external high-power alternating signal source outputs a sinusoidal alternating voltage signal with the same mechanical resonant frequency as the magnetoelectric composite radiation unit, the excitation signal is synchronously and equally distributed to the four magnetoelectric composite radiation units through the metal distribution terminal block, achieving in-phase and frequency-in-phase excitation of all units.

[0066] Due to the high symmetry of the array's geometric topology and the equipotential characteristics of parallel circuits with the same polarity, the piezoelectric layers 2 within the four units simultaneously generate alternating mechanical deformations with the same frequency, phase, and amplitude. This synchronized deformation further induces the magnetostrictive layers 1 of each unit to generate alternating magnetic field fluctuations with the same frequency and phase as the excitation signal. In the far-field region at a certain distance from the array structure, the alternating magnetic fields radiated by each unit coherently superimpose in space, forming a directional radiation beam in the direction perpendicular to the array plane's normal. Under ideal lossless conditions, the field strength amplitude of this beam is nearly four times higher than that of a single unit, and the radiated power density is nearly sixteen times higher. This matrix-type topology not only significantly enhances the directional radiation capability in the array's normal direction and improves the antenna gain, but also improves the overall mechanical stiffness of the array through a symmetrical spatial support structure. This allows the antenna array to maintain a stable geometric shape during high-speed rotation, avoiding beam distortion and performance degradation caused by structural deformation.

[0067] The feeding connection method for each of the magnetoelectric composite radiation units is as follows: the electrode leads of multiple magnetoelectric composite radiation units are connected in parallel with the same polarity and then connected to the same alternating excitation signal source to achieve the superposition of the spatial far-field in-phase radiation fields of multiple magnetoelectric composite radiation units. Specifically, each magnetoelectric composite radiation unit has two electrodes on its piezoelectric layer 2, usually located on its upper and lower surfaces. The positive electrodes of all units are connected together by wires, and all negative electrodes are connected together. Then, the combined positive and negative buses are connected to the output terminal of the alternating excitation signal source, and the negative electrodes of all units are uniformly connected to the non-magnetic metal common ground plate of the array. The common ground plate is equipotentially connected to the ground terminal of the excitation source. This feeding method can ensure that the alternating voltage output by the excitation source is applied to each radiation unit synchronously and in phase, minimizing the phase deviation caused by the difference in the electrical length of the feed lines, and ensuring that the mechanical vibration of all units is highly synchronized on the time axis. Under ideal lossless and non-magnetic coupling conditions between units, the amplitude of the array's far-field synthesized magnetic field intensity is linearly positively correlated with the increase of the number of units, laying the foundation for the in-phase superposition of spatial radiation fields.

[0068] Furthermore, the magnetoelectric composite radiation unit adopts an MPM-type three-layer sandwich structure, in which P is the piezoelectric layer 2, the voltage layer is the middle layer, and M is the magnetostrictive layer 1. The two magnetostrictive layers 1 are symmetrically stacked on the upper and lower surfaces of the piezoelectric layer 2, respectively.

[0069] In the specific manufacturing process, a piezoelectric ceramic sheet that has undergone thickness-direction polarization treatment is first prepared. A modified epoxy interface coupling agent is then uniformly coated onto its two main surfaces. Two magnetostrictive material sheets are then coaxially aligned with the piezoelectric ceramic sheet and attached to the upper and lower surfaces of the piezoelectric sheet, respectively. Finally, a vacuum hot-pressing curing process is used to integrally form the magnetoelectric composite radiation unit with a symmetrical sandwich stack structure (MPM). This symmetrical stack structure has significant performance advantages: when the middle piezoelectric layer 2 undergoes expansion and contraction under the action of an alternating electric field, the stress generated is synchronously and uniformly transferred to the magnetostrictive materials in the upper and lower layers, driving the two magnetostrictive layers 1 to synchronously generate an inverse magnetostrictive effect. Compared to a double-layer structure with a magnetostrictive layer 1 on only one side, the MPM structure can more fully utilize the mechanical energy generated by the piezoelectric layer 2, effectively doubling the effective volume of the radiation source. Therefore, under the same excitation conditions, it can generate a stronger alternating magnetic field, significantly improving the radiation efficiency and output power of a single radiation unit. Meanwhile, this symmetrical structure can effectively suppress structural bending deformation caused by unilateral stress, ensuring a purer in-plane stretching vibration mode of the unit, which helps to form a stable far-field radiation field. Specifically, the magnetostrictive layer 1 and piezoelectric layer 2 have thicknesses of 0.5 mm, a length of 155 mm, a length of 80 mm, and widths of 20 mm respectively.

[0070] To achieve precise adjustment of the physical attitude of the array structure, the specific configuration of the attitude adjustment drive component is also crucial. This attitude adjustment drive component includes:

[0071] A two-axis mechanical turntable, with an array structure fixedly installed at the loading end of the two-axis mechanical turntable;

[0072] The drive motor unit is connected to the two-axis mechanical turntable and is used to adjust the azimuth and pitch angles of the array structure according to the pointing coordinates.

[0073] The attitude adjustment drive assembly can be implemented through the following embodiment: Specifically, the two-axis mechanical turntable consists of a horizontally rotating azimuth axis and a vertically swinging pitch axis. The array structure is mounted on the frame of the pitch axis. The drive motor assembly consists of two high-precision AC servo motors, connected to the azimuth and pitch axes respectively via precision reducers. Each servo motor is equipped with a high-resolution photoelectric encoder for real-time detection of the motor's rotation angle. The target pointing coordinates, including the target azimuth and pitch angles, are sent from the control unit to the servo driver. The controller inside the servo driver uses a PID algorithm to compare the target angle with the actual angle fed back by the encoder, adjusting the current supplied to the motor in real time to precisely control the motor's rotation, driving the array structure to move quickly and smoothly to the specified posture. Simultaneously, it combines feedforward compensation commands to optimize the drive signal and improve dynamic tracking performance.

[0074] By using the different types of attitude control drive components mentioned above, a trade-off can be struck between cost, accuracy, load capacity, and dynamic performance to provide reliable physical pointing capability for array-type mechanical antennas, based on the needs of actual applications.

[0075] This application also provides a beam control method for an array-type mechanical antenna based on magnetoelectric composite materials. This method is applied to a control unit to control an attitude adjustment drive assembly to adjust the physical attitude of the array structure. The method includes the following steps:

[0076] S1: Obtain the target location information of the communication target, and calculate the pointing coordinates of the array structure based on the target location information;

[0077] S2: Obtain the current feedback angle of the attitude adjustment drive component and calculate the angle deviation between the pointing coordinate and the current feedback angle;

[0078] S3: Generate driving commands based on the angle deviation value and send them to the attitude adjustment driving component to drive the array structure to rotate until the angle deviation value is within the preset error threshold range.

[0079] This method is a typical closed-loop servo control process. Its core idea is to accurately eliminate the error between the target pointing and the actual pointing through continuous feedback and correction.

[0080] In step S1, the target location information can come from various sources. For example, for a fixed ground station, the target location might be pre-stored satellite ephemeris data; for a mobile platform, the target location might be GNSS coordinates from a cooperating node received via a high-speed wireless data link. After receiving this raw location data, the control unit runs a coordinate transformation algorithm. For example, it combines the target's geographic coordinates (longitude, latitude, altitude) or spatial rectangular coordinates (X, Y, Z) with the antenna's own geographic location and attitude information, performs carrier attitude compensation, and then converts them into azimuth and elevation angles in a spherical coordinate system with the antenna phase center as the origin. These two angle values ​​constitute the pointing coordinates required to drive the attitude adjustment drive component.

[0081] In step S2, the motor in the attitude adjustment drive assembly is typically equipped with a position feedback sensor, such as the aforementioned photoelectric encoder or rotary transformer. These sensors can measure the azimuth and pitch angles of the mechanical turntable in real time and accurately, and send these angle values ​​back to the control unit as the current feedback angles. After receiving the feedback angles, the control unit will simultaneously compare them with the target pointing coordinates calculated in the previous step, and calculate the angle deviation values ​​in the azimuth and pitch angles respectively. This deviation value intuitively reflects the degree and direction of the antenna's current pointing away from the target.

[0082] In step S3, a control law algorithm, such as a classic proportional-integral-derivative (PID) controller, runs internally within the control unit. This algorithm calculates the control commands required for the servo drive based on the magnitude and trend of the current angle deviation. For example, if the deviation is large, the controller outputs a large drive signal to make the motor rotate rapidly to quickly reduce the error; as the deviation gradually decreases, the drive signal also decreases accordingly to prevent overshoot and oscillation. This drive command is sent to the motor of the attitude adjustment drive component via the servo driver, and the motor drives the array structure to rotate towards the target direction. This process of obtaining feedback, calculating deviation, generating commands, and executing drives is repeated cyclically with a fixed high-frequency control cycle. Each cycle reduces the angle deviation slightly until the final deviation is controlled within a preset error threshold range, such as ±0.1 degrees. At this point, it can be considered that the main lobe of the antenna beam is precisely aligned with the target, thus achieving a stable and reliable communication connection.

[0083] In step S1, the target location information is acquired through a target detection sensor.

[0084] Specifically, by using a target detection sensor to collect target position information in real time at a fixed high frequency period, the deviation between the calculated pointing coordinates and the actual target position can be effectively reduced, significantly reducing beam pointing deviation caused by information delay and measurement error, thereby improving the ability of the array-type mechanical antenna to track and align communication targets in complex dynamic environments.

[0085] Furthermore, step S1 includes:

[0086] S11: Obtain the spatial geographical location of the array structure;

[0087] S12: Based on the target location information and the spatial geographical location of the array structure, calculate the target azimuth and elevation angles with the array structure as the origin. The pointing coordinates include the target azimuth and elevation angles.

[0088] Obtaining the spatial geographic location of the array structure refers to acquiring its specific coordinates on Earth through a positioning system or pre-defined information. The target azimuth and elevation angles can be calculated using a geographic coordinate system transformation algorithm. For example, the geographic coordinates (longitude, latitude, altitude) of the array structure's phase center and the target location can first be converted to a geocentric rectangular coordinate system (ECEF). Then, a local coordinate system (e.g., a north-south coordinate system) is established with the array structure's phase center as the origin. The target's coordinates in the geocentric rectangular coordinate system are then transformed to this local coordinate system. Finally, based on the target coordinates in the local coordinate system, the target's azimuth and elevation angles are calculated according to a pre-defined angle definition.

[0089] This explicit calculation method solves the problems of unclear calculation logic and lack of unified standards for target location information and spatial geographical location of array structure. It eliminates the problem of insufficient accuracy in pointing coordinate calculation caused by ambiguity in the calculation method, improves the accuracy of the target azimuth and elevation angle calculation from the source, and ultimately significantly improves the alignment accuracy and dynamic tracking stability of the antenna beam.

[0090] In practical applications, especially when the communication target is in high-speed motion, the mechanical inertia and response delay of the attitude adjustment drive component become a significant problem. There is always a time lag between the control unit issuing the command and the mechanical structure completing its rotation. During this lag, the moving target has already left its original position, causing the antenna to be pointed at the target's past position, thus generating tracking errors. To solve this problem, the steps for driving the array structure to rotate have been optimized. Further, step S3 includes:

[0091] S31: Acquire continuous azimuth information of the communication target in real time, and calculate the relative motion vector of the communication target relative to the array structure based on the continuous azimuth information;

[0092] S32: Generate a driving command based on the angle deviation value and send it to the attitude adjustment driving component, and obtain the system response delay of the attitude adjustment driving component from receiving the driving command to completing the action;

[0093] S33: Combining the relative motion vector and the system response delay, calculate the predicted azimuth information of the communication target after the system response delay;

[0094] S34: Feedforward compensation is performed on the pointing coordinates based on the predicted azimuth information to offset the impact of the mechanical lag of the attitude adjustment drive component on the beam alignment accuracy.

[0095] First, the control unit continuously records the target's position at fixed time intervals, forming a time series t. By performing a second-order backward difference operation on this position sequence, the target's velocity and acceleration in the antenna coordinate system, i.e., the relative motion vector, can be estimated. Second, while generating drive commands based on the angle deviation value and sending them to the attitude adjustment drive component, the system response delay of the attitude adjustment drive component from receiving the drive command to completing the action is acquired, which is used for subsequent feedforward compensation logic. The system response delay refers to the total time elapsed from the moment the control unit generates the control algorithm result and issues the drive command until the array structure physically moves to the predetermined position and stabilizes. This delay is a fixed system parameter that can be obtained through pre-calibration or online identification, mainly including the calculation delay of the control unit, the communication transmission delay, and the response delay of the motor and mechanical structure.

[0096] The system response delay can be calculated by starting a high-precision microsecond timer inside the control unit to record the timestamp of the drive command. When the error tolerance judgment condition is met, the timestamp is recorded again. The difference between these two timestamps, after multiple measurements and averaging, can be used as the fixed delay parameter in the feedforward compensation logic.

[0097] Next, combining the calculated relative motion vector and the acquired system response delay, the predicted azimuth information of the communication target after the system response delay is calculated. This calculation adopts the classic uniform angular kinematics extrapolation model, which is applicable under the premise that the relative angular acceleration of the target can be ignored within the time window of the system response delay. The extrapolation formula is: the predicted azimuth angle is equal to the current azimuth angle plus the product of the azimuth rate and the system response delay, and the predicted pitch angle is equal to the current pitch angle plus the product of the pitch rate and the system response delay.

[0098] The calculation result provides the future location of the communication target when the antenna completes its adjustment, which can be used to generate drive commands in advance to offset tracking errors caused by system response delays. If the target's angular acceleration is not negligible, a second-order angular acceleration extrapolation term can be added to the uniform velocity term to further improve prediction accuracy.

[0099] Finally, feedforward compensation is applied to the original pointing coordinates based on the predicted azimuth information. That is, the control unit no longer uses only the current target azimuth as the driving command, but instead uses the predicted future azimuth as the new pointing coordinates, which are then sent to the attitude adjustment drive component after being combined with PID feedback closed-loop control. In this way, the antenna is commanded to point at the predicted target azimuth with a feedforward lead. After the system response delay and when the antenna finally moves to the target attitude, the moving communication target also arrives at the predicted azimuth almost synchronously, thus achieving high-precision dynamic alignment. This feedforward compensation mechanism can effectively suppress the impact of inherent system response lag on beam alignment accuracy and significantly improve the dynamic tracking performance for high-speed moving targets.

[0100] As a specific implementation method, the feedforward compensation logic exhibits excellent dynamic tracking accuracy when tracking high-speed maneuvering targets. When the communication target exhibits irregular motion trajectories such as non-uniform speed and high maneuverability, the control unit obtains continuous azimuth information of the communication target through high-frequency sampling that matches the target's maneuver bandwidth. The sampled data is first preprocessed by moving average filtering and outlier removal, and then the relative motion vector of the target with respect to the array structure is calculated using a second-order backward difference algorithm. This vector includes the angular velocity and angular acceleration of the target in the azimuth and pitch dimensions, which can be used for second-order uniform acceleration kinematic extrapolation prediction to achieve high-precision feedforward compensation tracking of high-speed maneuvering targets.

[0101] To calculate the feedforward compensation, the control unit calls upon the internally stored system response delay parameter, which is pre-measured experimentally to be 100 milliseconds. Based on the current angular velocity and angular acceleration, the control unit calculates the expected change in angular displacement of the target within the next 100 milliseconds. For example, if the target is moving upward and to the right at an angular velocity of 10 degrees per second, the control unit calculates the predicted azimuth information 100 milliseconds later, adding a one-degree lead to the current azimuth. Subsequently, the generated drive command is no longer based solely on the target's current position, but rather aligned with this predicted lead position. When the attitude adjustment drive component completes its rotation after the 100-millisecond system response delay, the physical pointing of the array structure can be precisely aligned with the new target's position. This motion prediction-based feedforward compensation mechanism effectively suppresses tracking errors caused by the slow response of the mechanical system, enabling the main lobe of the radiation beam to stably track and continuously align with the high-speed moving target, ensuring the continuity and stability of the communication signal.

[0102] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. An array-type mechanical antenna based on magnetoelectric composite materials, characterized in that, At least including: The array structure is composed of multiple magnetoelectric composite radiation units arranged at a preset interval and connected by signals. Each of the magnetoelectric composite radiation units includes a magnetostrictive layer and a piezoelectric layer stacked on top of each other. An attitude adjustment drive component is mechanically connected to the array structure and is used to drive the array structure to rotate in space to change the physical orientation of the array structure. The control unit is used to acquire target position information and generate pointing coordinates, and control the attitude adjustment drive component to adjust the physical attitude of the array structure according to the pointing coordinates, so that the main lobe of the radiation beam of the array structure points to the target position.

2. The array-type mechanical antenna based on magnetoelectric composite material according to claim 1, characterized in that, The magnetoelectric composite radiation unit also includes: An interface coupling layer is disposed between the magnetostrictive layer and the piezoelectric layer, for transferring the mechanical stress generated by the piezoelectric layer through the inverse piezoelectric effect under the excitation of an alternating electric field to the magnetostrictive layer, so as to generate an alternating magnetic field through the inverse magnetostrictive effect; wherein, the magnetostrictive layer is made of terbium-dysprosium-iron rare earth giant magnetostrictive alloy material, and the piezoelectric layer is made of lead zirconate titanate piezoelectric ceramic sheet material.

3. The array-type mechanical antenna based on magnetoelectric composite material according to claim 2, characterized in that, The magnetoelectric composite radiation unit adopts an LT-type magnetoelectric coupling working mode. The magnetization direction of the magnetostrictive layer is parallel to the interlayer interface plane between the magnetostrictive layer and the piezoelectric layer, and is also parallel to the length axis of the magnetostrictive layer. The polarization direction of the piezoelectric layer is perpendicular to the interlayer interface plane and is parallel to the thickness axis of the piezoelectric layer. The magnetization direction and the polarization direction are orthogonal to each other.

4. The array-type mechanical antenna based on magnetoelectric composite material according to claim 1, characterized in that, Multiple identical magnetoelectric composite radiation units are arranged according to a preset geometric topology. The signal connection includes: connecting the electrode leads of multiple identical magnetoelectric composite radiation units in parallel with the same polarity and connecting them to the same excitation source, so as to realize the superposition of the in-phase radiation fields of multiple magnetoelectric composite radiation units in the far field of space.

5. An array-type mechanical antenna based on magnetoelectric composite material according to claim 4, characterized in that, The magnetoelectric composite radiation unit adopts an MPM-type three-layer sandwich structure, wherein P is a piezoelectric layer, which serves as the middle layer, and M is a magnetostrictive layer. The two magnetostrictive layers are symmetrically stacked on the upper and lower surfaces of the piezoelectric layer, respectively.

6. The array-type mechanical antenna based on magnetoelectric composite material according to claim 1, characterized in that, The attitude adjustment drive component includes: A two-axis mechanical turntable, wherein the array structure is fixedly installed on the loading end of the two-axis mechanical turntable; The drive motor assembly is connected to the two-axis mechanical turntable and is used to adjust the azimuth and pitch angles of the array structure according to the pointing coordinates.

7. A beam control method for an array-type mechanical antenna based on magnetoelectric composite materials, characterized in that, This method is applied to a control unit to control the attitude adjustment drive component to adjust the physical attitude of the array structure. The method includes the following steps: S1: Obtain the target location information of the communication target, and calculate the pointing coordinates of the array structure based on the target location information; S2: Obtain the current feedback angle of the attitude adjustment drive component, and calculate the angle deviation value between the pointing coordinate and the current feedback angle; S3: Generate a driving command based on the angle deviation value and send it to the attitude adjustment driving component to drive the array structure to rotate until the angle deviation value is within the preset error threshold range.

8. The beam control method for an array-type mechanical antenna based on magnetoelectric composite materials according to claim 7, characterized in that, In step S1, the target location information is acquired by a target detection sensor.

9. A beam control method for an array-type mechanical antenna based on magnetoelectric composite materials according to claim 8, characterized in that, Step S1 includes: S11: Obtain the spatial geographical location of the array structure; S12: Based on the target location information and the spatial geographical location of the array structure, calculate the target azimuth and target elevation angle with the array structure as the origin. The pointing coordinates include the target azimuth and target elevation angle.

10. A beam control method for an array-type mechanical antenna based on magnetoelectric composite materials according to claim 7, characterized in that, Step S3 includes: S31: Acquire the continuous azimuth information of the communication target in real time, and calculate the relative motion vector of the communication target relative to the array structure based on the continuous azimuth information; S32: Generate a driving command based on the angle deviation value and send it to the attitude adjustment driving component, and obtain the system response delay of the attitude adjustment driving component from receiving the driving command to completing the action; S33: Combining the relative motion vector and the system response delay, calculate the predicted azimuth information of the communication target after the system response delay; S34: Feedforward compensation is performed on the pointing coordinates based on the predicted azimuth information to offset the influence of the mechanical lag of the attitude adjustment drive component on the beam alignment accuracy.

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