Chip-type receiving antenna simulation method and device based on finite-difference time-domain method

Abstract

The application discloses a chip type receiving antenna simulation method and device based on a time domain finite difference method, and the method comprises the following steps: establishing a differential equation group of multi-physical field coupling according to an electromagnetic field, a stress field and a sound field of the receiving antenna and converting the differential equation group into a solving equation group based on the time domain finite difference method; establishing a geometric structure model of the receiving antenna, and setting model parameters required for simulation, wherein the model parameters at least comprise geometric parameters, material parameters, grid parameters of the receiving antenna and an excitation frequency of a magnetic induction excitation source; iteratively calculating the solving equation group according to the model parameters until a preset simulation time length, and obtaining a simulation result based on sound wave excitation; obtaining a simulation resonance frequency of the receiving antenna according to the simulation result, adjusting the geometric parameters and the material parameters to make the simulation resonance frequency equal to the excitation frequency, and taking the geometric parameters as optimal geometric parameters and the material parameters as optimal material parameters. The application can solve the multi-physical field problem, is more efficient and occupies less storage resources.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, and in particular to a simulation method and apparatus for chip-type receiving antennas based on the finite-difference time-domain method. Background Technology

[0002] Wireless communication is a communication method that utilizes the property of electromagnetic waves to propagate in free space for information exchange. It is one of the fastest-growing and most widely used communication technologies in recent years. The most important component of wireless communication is the antenna, which is responsible for transmitting and receiving wireless signals. A chip antenna is a type of antenna that is directly mounted on the surface of a circuit board to perform the antenna function.

[0003] The basic idea of ​​the Finite-Difference Time-Domain (FDTD) method is to replace the first-order partial derivatives of the field quantity with respect to time and space with the central difference quotient. By recursively simulating the wave propagation process in the time domain, the field distribution can be obtained. Compared with the finite element method, the FDTD algorithm is more efficient and requires less storage resources, and it has wide applications in fields such as electromagnetic field numerical calculation and acoustic numerical calculation.

[0004] However, dedicated antenna simulation software cannot achieve coupled simulation of magnetoelastic-electric multiphysics fields. Currently, the relevant simulation methods based on the FDTD algorithm can only simulate the transmission of chip antennas, not the reception of chip antennas. Therefore, there is a need for an efficient simulation method and device for chip antennas that consumes less storage resources. Summary of the Invention

[0005] The purpose of this invention is to provide a simulation method and apparatus for chip-type receiving antennas based on the finite-difference time-domain method, so as to solve the technical problem that the existing technology cannot efficiently simulate chip-type receiving antennas.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] Simulation methods for chip-type receiving antennas based on the finite-difference time-domain method include:

[0008] A set of multi-physics coupled differential equations is established based on the electromagnetic field, stress field, and acoustic field of the receiving antenna, and the set of differential equations is transformed into a set of solution equations based on the finite difference method in the time domain.

[0009] Establish a geometric model of the receiving antenna, and set the model parameters required for simulation in the geometric model. The model parameters include at least the geometric parameters, material parameters, mesh parameters and excitation frequency of the magnetic induction excitation source of the receiving antenna. The mesh parameters are related to the internal bulk acoustic waves of the material used in the receiving antenna.

[0010] The system of equations is iteratively calculated based on the model parameters until the preset simulation duration, thereby obtaining the simulation results of the receiving antenna based on acoustic excitation.

[0011] The simulated resonant frequency of the receiving antenna is calculated based on the simulation results. The geometric parameters and material parameters are adjusted in the geometric structure model so that the simulated resonant frequency is equal to the excitation frequency. The geometric parameters are taken as the optimal geometric parameters and the material parameters are taken as the optimal material parameters.

[0012] Optionally, the geometric model includes:

[0013] A piezoelectric layer and a magnetostrictive layer disposed above and / or below the piezoelectric layer;

[0014] A positive electrode is provided at the upper end of the piezoelectric layer, and a negative electrode is provided at the lower end of the piezoelectric layer. Both the positive electrode and the negative electrode are connected to an oscilloscope to achieve voltage measurement.

[0015] Optionally, the system of differential equations is:

[0016]

[0017]

[0018]

[0019]

[0020]

[0021] Where E is the electric field vector, H is the magnetic field vector, D is the electric flux density vector, B is the magnetic flux density vector, r is the stress, P represents the piezoelectric layer material, M represents the magnetostrictive layer material, and T... M For the stress of the magnetostrictive layer material, e D e is the stress constant of the piezoelectric layer. B c is the stress constant of the magnetostrictive layer. D c is the mechanical stiffness constant of the piezoelectric layer. B ε is the mechanical stiffness constant of the magnetostrictive layer. S μ is the strain-free dielectric constant of the piezoelectric layer. Sσ is the strain-free permeability of the magnetostrictive layer, σ is the conductivity of the piezoelectric layer material, and v is the velocity vector. P Let v be the velocity vector in the piezoelectric layer material. M Let E be the velocity vector in the magnetostrictive layer material, z represent the z-direction in the Cartesian coordinate system, and E Z H represents the z-direction component of the electric field in the piezoelectric layer material. X denoted as the x-direction component of the magnetic field in the magnetostrictive layer material. This represents the derivative of a partial differential, where t is time.

[0022] Optionally, the solution system of equations based on the finite-difference time-domain method is as follows:

[0023]

[0024]

[0025]

[0026]

[0027]

[0028] Where Δt is the time step and Δz is the spatial step; n and i are the indices of the field quantity in the time and spatial dimensions, respectively; This represents the x-direction component of the magnetic field in a magnetostrictive layer material with spatial dimension index i and time dimension index n+1 / 2; B represents the velocity vector in the magnetostrictive layer material with spatial dimension index i+1 / 2 and time dimension index n; n+1 / 2 This represents the magnetic flux density vector with spatial dimension index n+1 / 2; This represents the stress vector in the magnetostrictive layer material with spatial dimension index i and time dimension index n+1 / 2; This represents the z-direction component of the magnetic field in a piezoelectric material with spatial dimension index i and time dimension index n+1 / 2. This represents the velocity vector in the piezoelectric layer material with spatial dimension index i+1 / 2 and time dimension index n; This represents the stress vector in a piezoelectric material with spatial dimension index i and time dimension index n+1 / 2. This represents the stress vector in a material with spatial dimension index i and time dimension index n+1 / 2. This represents the stress vector in a material with spatial dimension index i-1 and time dimension index n-1 / 2.

[0029] Optionally, it also includes:

[0030] The receiving efficiency of the receiving antenna is calculated based on the simulation results, and the receiving efficiency is:

[0031]

[0032] Among them, P rec P represents the signal power received by the receiving antenna, i.e., the power output to the load or RF front end. in Z0 is the signal power of the input antenna, Z0 is the wave impedance, μ0 is the free permeability, and B is the signal power of the input antenna. m U is the amplitude of the magnetic induction excitation source, σ is the conductivity of the piezoelectric layer material, h is the thickness of the piezoelectric layer or magnetostrictive layer, and U is the magnetic induction excitation source. z,m The voltage is set at a distance h for calculating the potential between piezoelectric layers.

[0033] Optionally, the process of iteratively calculating the system of equations based on the model parameters until the preset simulation duration further includes:

[0034] Initialize the field quantities by setting the magnetic field of the magnetostrictive layer, the electric field of the piezoelectric layer, the overall stress field, and the overall velocity field vector to zero vectors.

[0035] Set boundary conditions to set the stress field of the first boundary node and the second boundary node in the Z direction of the geometric mesh of the magnetostrictive layer and the air boundary to zero. The component of the first boundary node in the Z direction is 0, and the component of the second boundary node in the Z direction is the total thickness of the antenna.

[0036] Optionally, the process of iteratively calculating the system of equations based on the model parameters until the preset simulation duration further includes:

[0037] Set the spatial nodes for simulation calculations, and set the spatial step size and time step size for simulation based on preset stability conditions and the material parameters;

[0038] The preset stability condition is related to the internal bulk acoustic wave of the material used in the receiving antenna at the simulated resonant frequency.

[0039] Optionally, the spatial step size is:

[0040]

[0041] Where Δz is the spatial step size in the Z direction, and λ ac,min This is the minimum wavelength of the bulk acoustic wave in the material at the simulated resonant frequency.

[0042] Optionally, the time step is:

[0043]

[0044] Where Δt is the time step, vac,max To simulate the maximum sound velocity of bulk sound waves in a material at the resonant frequency.

[0045] This invention also provides a chip-type receiving antenna simulation device based on the finite-difference time-domain method, comprising:

[0046] The equation system construction module is used to establish a set of differential equations coupled with multi-physics fields based on the electromagnetic field, stress field and acoustic field of the receiving antenna, and to transform the set of differential equations into a set of solution equations based on the finite difference method in the time domain.

[0047] The model parameter setting module is used to establish the geometric structure model of the receiving antenna, and to set the model parameters required for simulation in the geometric structure model. The model parameters include at least the geometric parameters, material parameters, mesh parameters and excitation frequency of the magnetic induction excitation source of the receiving antenna. The mesh parameters are related to the internal bulk acoustic waves of the material used in the receiving antenna.

[0048] The simulation result acquisition module is used to iteratively calculate the solution system of equations based on the model parameters until the preset simulation time, so as to obtain the simulation results of the receiving antenna based on acoustic excitation.

[0049] The optimal parameter determination module is used to calculate the simulated resonant frequency of the receiving antenna based on the simulation results, adjust the geometric parameters and material parameters in the geometric structure model so that the simulated resonant frequency is equal to the excitation frequency, and use the geometric parameters as the optimal geometric parameters and the material parameters as the optimal material parameters.

[0050] In view of this, the beneficial effects of this invention are:

[0051] This invention establishes a set of multi-physics coupled differential equations based on the electromagnetic field, stress field, and acoustic field of the receiving antenna, enabling coupled simulation of magnetoelastic-electric multi-physics fields and solving the multi-physics problem of receiving antennas. The differential equations are then transformed into a set of solution equations based on the finite-difference time-domain method. Solving these equations using the model parameters allows for rapid acquisition of simulation results for the receiving antenna. Compared to traditional finite element simulation methods, the finite-difference time-domain method is more efficient and requires less storage resources. Based on the magneto-electric coupling effect and acoustic excitation, the size of the receiving antenna can reach the micrometer or even nanometer scale. Compared to traditional antennas, the size of the chip-type receiving antenna can be reduced by 3-5 orders of magnitude. The simulation results allow for further analysis of the receiving performance of the novel chip-type receiving antenna, providing technical support for its application. Attached Figure Description

[0052] Figure 1 This is a schematic flowchart of the method of the present invention;

[0053] Figure 2A schematic diagram of the geometric structure model established for this invention;

[0054] Figure 3 This is a flowchart illustrating an embodiment of the method of the present invention;

[0055] Figure 4 This is a schematic diagram of the structure of an embodiment of the device of the present invention. Detailed Implementation

[0056] This invention provides a method and apparatus for simulating chip-type receiving antennas based on the finite-difference time-domain method, in order to solve the technical problem that existing technologies cannot efficiently simulate chip-type receiving antennas.

[0057] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

[0058] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0059] The novel antenna involved in this invention is based on the magnetoelectric coupling effect and is excited by acoustic waves, thus its size can reach the micrometer or even nanometer scale. This type of novel antenna has become a research hotspot in the field of antenna miniaturization technology in recent years. Because it does not rely on current resonance but on the acoustic wave resonance of the bulk acoustic waves inside the elastic material, the size of the novel antenna can be reduced by 3-5 orders of magnitude compared to traditional antennas. The magnetoelectric coupling effect, simply put, is the effective conversion between a magnetic field and an electric field. This principle has wide applications in ferroelectric memories, microelectromechanical systems (MEMS, NEMS), implantable biomedical devices, and other fields.

[0060] The purpose of this invention is to meet the modeling requirements of acoustically excited receiving antennas based on novel principles, providing theoretical research tools for practical antenna device implementation and simulation calculation tools for material selection and parameter optimization. Compared to the finite element method, the time-domain differential finite element method is more efficient and requires less storage resources. Finite element simulation methods based on existing commercial software are not dedicated simulation methods for this type of novel antenna; dedicated antenna simulation software cannot achieve coupled simulation of magnetoelastic-electro-electronic multiphysics fields.

[0061] Furthermore, current novel antenna-related simulation methods based on the finite-difference time-domain method can only simulate antenna transmission. Therefore, this invention provides a chip-type receiving antenna simulation method and apparatus based on the finite-difference time-domain method. This is a novel simulation method and apparatus for receiving electromagnetic signals, which can solve multi-physics problems, is more efficient, and occupies less storage resources, providing certain technical guidance for the simulation and research of novel receiving antennas.

[0062] Please see Figure 1 This invention provides an embodiment of a chip-type receiving antenna simulation method based on the finite-difference time-domain method, including:

[0063] S100: Establish a set of differential equations for multi-physics coupling based on the electromagnetic field, stress field, and acoustic field of the receiving antenna, and transform the set of differential equations into a set of solution equations based on the finite difference method in the time domain.

[0064] S200: Establish a geometric model of the receiving antenna, and set the model parameters required for simulation in the geometric model. The model parameters include at least the geometric parameters, material parameters, mesh parameters, and excitation frequency of the magnetic induction excitation source of the receiving antenna. The mesh parameters are related to the internal bulk acoustic waves of the material used in the receiving antenna.

[0065] S300: Iteratively calculate the set of equations based on the model parameters until the preset simulation time, and obtain the simulation results of the receiving antenna based on acoustic excitation;

[0066] S400: Calculate the simulated resonant frequency of the receiving antenna based on the simulation results, adjust the geometric parameters and material parameters in the geometric structure model so that the simulated resonant frequency is equal to the excitation frequency, and use the geometric parameters as the optimal geometric parameters and the material parameters as the optimal material parameters.

[0067] The receiving antenna involved in this embodiment of the invention is a novel chip-based receiving antenna. In step S100, a set of differential equations with multi-physics coupling is established based on the electromagnetic field, stress field and acoustic field of the receiving antenna. For example, a set of differential equations with magnetic-elastic-electric coupling is established. The differential equations are replaced by the central second-order difference form, and the set of differential equations is transformed into a set of recursive solution equations based on the finite-difference time-domain method.

[0068] The simulation of the novel chip-based receiving antenna in this embodiment involves multiple physical fields, requiring the combined solution of multiple physical fields, including electromagnetic field, stress field, and acoustic field, by combining the equations of elasticity, Maxwell's equations, and constitutive equations of piezoelectric and magnetostrictive materials.

[0069] Specifically, Maxwell's equations are shown in equation (1):

[0070]

[0071] in, Let be the Nabla operator, E be the electric field vector, H be the magnetic field vector, D be the electric flux density vector, B be the magnetic flux density vector, and σ be the conductivity of the piezoelectric layer material. Let B be the derivative of its partial derivative with respect to time t. This represents the partial derivative of D with respect to time t.

[0072] Specifically, the equations of elasticity are shown in equation (2):

[0073]

[0074] Where r is stress, S is strain, u is displacement, c is stiffness coefficient, ρ is the mass density of the material, and ω is the natural angular frequency of the material. The calculation rules related to strain S are expressed as shown in equation (3):

[0075]

[0076] Specifically, the constitutive equations for piezoelectric materials are shown in equation (4):

[0077]

[0078] Specifically, the constitutive equations for magnetostrictive materials are shown in equation (5):

[0079]

[0080] Wherein, the subscripts P and M represent the materials of the piezoelectric layer and the magnetostrictive layer, respectively; E P T P SP and H represent the electric field, stress, and strain vectors of the piezoelectric layer material, respectively; M T M S M These are the electric field, stress, and strain vectors of the magnetostrictive layer material, respectively; e D e B These are the stress constants of the piezoelectric layer and the magnetostrictive layer, respectively; subscript D indicates parameters measured under constant electric flux density conditions, and subscript B indicates parameters measured under constant magnetic flux density conditions; c D c B These are the mechanical stiffness constants of the piezoelectric layer and the magnetostrictive layer, respectively; ε S μ S These are the unstrained dielectric constant of the piezoelectric layer and the unstrained magnetic permeability of the magnetostrictive layer, respectively.

[0081] By coupling equations (1), (2), (4) and (5), we obtain the magnetic-elastic-electric coupling equations, as shown in equations (6) to (10):

[0082]

[0083]

[0084]

[0085]

[0086]

[0087] Where v is the velocity vector of the material, v P With v M The velocity vectors in the piezoelectric layer and magnetostrictive layer materials, respectively; Z represents the z-direction in the Cartesian coordinate system, E Z H represents the z-direction component of the electric field in the piezoelectric layer material. x denoted as the x-direction component of the magnetic field in the magnetostrictive layer material.

[0088] It should be noted that Equation (10) is applicable to both piezoelectric and magnetostrictive layer materials. That is, the stress fields obtained by Equations (7) and (9) can be substituted into Equation (10) to calculate the velocity vectors of the piezoelectric and magnetostrictive layer materials respectively.

[0089] By replacing the differential equations (6)-(10) with the central second-order difference form, we obtain the solution equation system (11)-(15) based on the finite-difference time-domain method (FDTD):

[0090]

[0091]

[0092]

[0093]

[0094]

[0095] Where Δt is the time step and Δz is the spatial step; n and i are the indices of the field quantity in the time and spatial dimensions, respectively; This represents the x-direction component of the magnetic field in a magnetostrictive layer material with spatial dimension index i and time dimension index n+1 / 2; B represents the velocity vector in the magnetostrictive layer material with spatial dimension index i+1 / 2 and time dimension index n; n+1 / 2This represents the magnetic flux density vector with spatial dimension index n+1 / 2; This represents the stress vector in the magnetostrictive layer material with spatial dimension index i and time dimension index n+1 / 2; This represents the z-direction component of the magnetic field in a piezoelectric material with spatial dimension index i and time dimension index n+1 / 2. This represents the velocity vector in the piezoelectric layer material with spatial dimension index i+1 / 2 and time dimension index n; This represents the stress vector in a piezoelectric material with spatial dimension index i and time dimension index n+1 / 2. This represents the stress vector in a material with spatial dimension index i and time dimension index n+1 / 2. This represents the stress vector in a material with spatial dimension index i-1 and time dimension index n-1 / 2.

[0096] It should be noted that equation (15) is applicable to both piezoelectric layer materials and magnetostrictive layer materials, therefore, in magnetostrictive layer materials... It can be replaced by T i n+1 / 2 Replace with The same applies to piezoelectric layer materials.

[0097] In step S200, a geometric model of the receiving antenna is established, and the model parameters required for simulation are set in the geometric model. The model parameters include at least the geometric parameters, material parameters, mesh parameters, and excitation frequency of the magnetic induction excitation source of the receiving antenna. The mesh parameters are related to the internal bulk acoustic waves of the material used in the receiving antenna.

[0098] The antenna geometry model established in this embodiment may include: a piezoelectric layer and a magnetostrictive layer disposed above and / or below the piezoelectric layer; wherein, a positive electrode is disposed at the upper end of the piezoelectric layer and a negative electrode is disposed at the lower end of the piezoelectric layer, and both the positive electrode and the negative electrode are connected to an oscilloscope (or other load) through wires to realize voltage measurement or output to the radio frequency front end.

[0099] Please see Figure 2 ,like Figure 2 Taking the symmetrical stacked structure shown as an example, from top to bottom, the layers are: a first magnetostrictive layer, a piezoelectric layer, and a second magnetostrictive layer. In this embodiment, the geometric parameters of the receiving antenna and the spatial nodes for simulation calculation can be set in the geometric structure model. For convenience, the thickness of each material layer can be set to h, so the total thickness of the antenna is 3h. The positive and negative electrodes are distributed at the upper and lower ends of the piezoelectric layer, respectively. The effective length of the receiving antenna can be set to L, and the width can be set to W.

[0100] It should be noted that for simulations of novel high-frequency antennas, the aspect ratio needs to be set to 50 or higher, while for simulations of novel low-frequency antennas, the aspect ratio needs to be set to 10 or higher. To fully investigate the magnetoelectric coupling effect, the electrodes in this embodiment can be idealized, i.e., the electrode thickness can be ignored.

[0101] In this embodiment, the spatial step size for the simulation calculation in the z-direction can be set to Δ. z Then the total number of simulation space nodes n z For: n z =3h / Δ z 3h is the total thickness of the antenna. The spatial nodes of the first magnetostrictive layer, the piezoelectric layer, and the second magnetostrictive layer are allocated as follows: (1, n z / 3), (n z / 3+1,2n z / 3), (2n z / 3+1,n z ).

[0102] It should be noted that a magnetostrictive layer can also be placed only above or below the piezoelectric layer. In this case, the receiving antenna has only two layers, with a thickness of 2h. During simulation calculations, the parameters related to the number of spatial nodes in the two-layer antenna structure are different from those in the three-layer structure. For example, the number of spatial nodes for variables H, T, and V is different, while other settings remain the same.

[0103] In this embodiment, the iterative calculation and solution of the equation system based on the model parameters until the preset simulation duration also includes: initializing the field quantities by initializing the magnetic field of the magnetostrictive layer, the electric field of the piezoelectric layer, the overall stress field, and the overall velocity field vector to zero; and setting the boundary conditions to zero. Since the acoustic impedance in air is much smaller than that of the electrode material, the zero nodes in the z-direction of the geometric mesh at the boundary between the magnetostrictive layer and air can be set to n. z The field quantity of each node is always 0, where the component of node 0 in the Z direction is 0, and n z The component of the node in the Z direction is the total thickness of the antenna. That is, setting the stress field T to 0 at z = 0 and z = 3h can be expressed as: T M | z＝0 =T M | z＝3h =0.

[0104] In one embodiment of the present invention, the process of iteratively calculating and solving the system of equations based on model parameters until the preset simulation duration further includes: setting electromagnetic constant parameters, setting material parameters of the piezoelectric layer material, and setting material parameters of the magnetostrictive layer material.

[0105] Specifically, basic electromagnetic constants can be set, and the value of the free magnetic permeability can be set to μ0 = 4π × 10⁻⁶. -7H / m, set the value of the vacuum dielectric constant to ε0 = 8.854187817 × 10 -12 F / m, the speed of light is 299,792,458 m / s, and the wave impedance is Z0 = 377 Ω.

[0106] Select the piezoelectric material and the magnetostrictive layer material, and set the following parameters: strain permeability, Young's modulus, and stress constant and mechanical stiffness constant measured under constant magnetic flux conditions of the magnetostrictive layer; strain dielectric constant, conductivity, Young's modulus, and stress constant and mechanical stiffness constant measured under constant electric flux conditions of the piezoelectric layer.

[0107] In one embodiment of the present invention, before iteratively calculating the solution system of equations according to the model parameters until a preset simulation duration is reached, the method further includes: setting the excitation source and activation function of the magnetic induction intensity field.

[0108] To study the resonant characteristics of the antenna, the magnetic induction excitation source is set as a Gaussian pulse sine wave, the expression of which is shown in equation (16):

[0109]

[0110] Where B(t) is the magnetic induction excitation source, B m The amplitude of the magnetic induction excitation source is t0, and the time delay is t_0. u The parameter reflecting the width of the Gaussian pulse is equal to the time difference between the peak of the Gaussian pulse waveform and the point where the pulse drops to 0.3679 times its peak value; f is the frequency of the excitation signal, i.e., the excitation frequency, which should usually be the same as the resonant frequency of the antenna.

[0111] To study the antenna receiving performance, the magnetic induction excitation source is set as a sine wave, and its expression is shown in equation (17):

[0112]

[0113] in, This is the initial phase of the excitation signal.

[0114] Given the power P of the received signal sig That is, P sig =SA, where A is the effective receiving area of ​​the receiving antenna, S is the Poynting vector, and S = Z0(B m / μ0) 2 Therefore, B can be calculated using the Poynting vector. m .

[0115] The cycloidal motion switching function is set as shown in equation (18):

[0116]

[0117] Among them, t s Let t be the time when the excitation source is turned on. Therefore, the waveform of the excitation source gradually turning on is B(t)×ws(t).

[0118] The iterative calculation and solution of the equation system based on the model parameters until the preset simulation duration also includes: setting the spatial nodes for the simulation calculation, and setting the spatial step size and time step size of the simulation based on the preset stability conditions and material parameters; wherein, the preset stability conditions are related to the internal bulk acoustic waves of the material used in the receiving antenna at the simulation resonant frequency.

[0119] Specifically, the spatial step size in the Z direction during simulation calculation can be set as shown in equation (19):

[0120]

[0121] Where Δz is the spatial step size in the Z direction, and λ ac,min This represents the minimum wavelength of the bulk acoustic wave in the material at the simulated resonant frequency. It can be understood that λ... ac,min To simulate the resonant frequency, the minimum value is selected from the bulk acoustic wavelengths of the piezoelectric layer material and the magnetostrictive layer material.

[0122] Specifically, the time step can be set as shown in equation (20):

[0123]

[0124] Where Δt is the time step, v ac,max This is to simulate the maximum sound velocity of a bulk acoustic wave in a material at the resonant frequency. It can be understood that v... ac,max The maximum value of the bulk acoustic wave velocity is taken from the piezoelectric layer material and the magnetostrictive layer material at the simulated resonant frequency. The formula for calculating the bulk acoustic wave velocity is shown in equation (21):

[0125]

[0126] Where E is Young's modulus.

[0127] It should be noted that the preset stability conditions in this embodiment include equations (20) and (21).

[0128] The receiving antenna simulated in this embodiment is an acoustically excited antenna, whose resonant frequency is related to the speed of sound waves (several thousand to tens of thousands of m / s), rather than the speed of electromagnetic waves (the speed of light, 3 × 10⁻⁶ m / s). 8 The resonant frequency of a traditional receiving antenna is related to the speed of light (m / s). According to the half-wave resonance theory, the relationship between the size of the receiving antenna and its resonant frequency is: f r = v / 2d; where d is the dimension of the receiving antenna resonant direction, f rLet be the resonant frequency of the receiving antenna, and v be the speed of sound or the speed of light. For receiving antennas with the same resonant frequency, based on the ratio of the speed of sound to the speed of light, it can be known that the size of an acoustically excited antenna can be reduced by 3-5 orders of magnitude compared to the size of a traditional antenna.

[0129] In step S300, the system of equations is iteratively calculated and solved according to the model parameters until the preset simulation time is reached, so as to obtain the simulation results of the receiving antenna based on acoustic excitation.

[0130] This part mainly utilizes the main loop program for iterative calculations, which may include: first updating the magnetic induction intensity excitation source, and then updating the magnetostrictive layer. and Next, update the piezoelectric layer. Finally, update the magnetostrictive layer and the piezoelectric layer separately. When the number of iterations reaches the predetermined value T t The loop ends at a certain point, and the output voltage field quantity can be used for further post-processing to study antenna performance. Storing the field quantity at all times in an array in time-dimension order allows for further analysis of the time-domain characteristics of the field quantity.

[0131] The total simulation time is the preset simulation time t. total It should be greater than 10 times the period of the electromagnetic wave corresponding to the resonant frequency. Note that the field quantities T and H... x E z Both are sampled at integer multiples of the time step, i.e., t = nΔt, n = 1, 2, 3, ...; v is sampled at an integer plus 1 / 2 times the time step, i.e., t = (n + 1 / 2)Δt. The sampling rules are the same in the spatial dimension, and the field quantities T and H are sampled at the same time step. x E z All samples are taken at integer multiples of the time step, i.e., i = nΔz, n = 1, 2, 3, ..., n z v is sampled at an integer time step plus 1 / 2, i.e., z = (n + 1 / 2)Δz, n = 1, 2, 3, ..., n t n t =t total / Δt; However, it should be noted that in actual programming, the field quantity update calculation is performed by adding 1 times the number of nodes instead of adding 1 / 2 times the number of nodes.

[0132] In step S400, the simulated resonant frequency of the receiving antenna is calculated based on the simulation results. The geometric parameters and material parameters in the geometric structure model are adjusted so that the simulated resonant frequency is equal to the excitation frequency. The geometric parameters are taken as the optimal geometric parameters and the material parameters as the optimal material parameters.

[0133] In one embodiment of the present invention, the resonance characteristics are analyzed using a stress field, the output voltage field is calculated using the electric field quantity at both ends of the piezoelectric layer, and the receiving performance of the novel antenna, such as the receiving efficiency of the antenna, is calculated and analyzed based on the obtained electric field quantity.

[0134] Specifically, the frequency domain results of the stress field and piezoelectric layer electric field, as well as the power spectral density plot, can be obtained using the Fast Fourier Transform method. This allows for analysis of the antenna's simulated resonance characteristics and determination of its simulated resonant frequency. It is then determined whether the power spectral density of the stress field and piezoelectric layer electric field reaches its maximum value at the frequency of the excitation source. If so, the simulated resonant frequency of the receiving antenna is the frequency of the excitation source (excitation frequency); otherwise, the simulated resonant frequency of the receiving antenna is not the frequency of the excitation source.

[0135] Furthermore, the time-domain waveform of the stress field at the center of the antenna in the z-direction can be used to help determine whether the frequency of the excitation source is the simulated resonant frequency of the receiving antenna. By adjusting the geometric parameters (sizes) and material parameters of each layer in the receiving antenna, the simulated resonant frequency of the receiving antenna can reach the frequency of the excitation source (ideal value), thereby optimizing the geometric and material parameters. The resulting geometric parameters are the optimal geometric parameters, and the resulting material parameters are the optimal material parameters.

[0136] The potential between piezoelectric layers is calculated as: U Z =E Z H, H∈[0,h], where H is the distance set for calculating the potential between piezoelectric layers. The receiving efficiency η of the receiving antenna is calculated as shown in equation (22):

[0137]

[0138] Among them, P rec P represents the signal power received by the receiving antenna, i.e., the power output to the load or RF front end. in U is the signal power of the input antenna, h is the thickness of the piezoelectric layer and the magnetostrictive layer, and U is the signal power of the input antenna. z,m The voltage when H = h, i.e., U z,m The voltage is set at a distance h for calculating the potential between piezoelectric layers. The gain of the receiving antenna is G = 10log(η).

[0139] The method provided in this embodiment can be used to construct a simulation of the receiving signal function of a novel antenna. In addition, the chip-type receiving antenna simulation method and device provided by this invention also have functions such as simulation of different material parameters, simulation of geometric parameters, and antenna performance research.

[0140] This embodiment provides a simulation method for chip-type receiving antennas based on the finite-difference time-domain (FDTD) method. It establishes a set of multi-physics coupled differential equations based on the electromagnetic, stress, and acoustic fields of the receiving antenna, enabling coupled simulation of magneto-elastic-electric multi-physics fields and solving the multi-physics problem of the receiving antenna. The differential equations are then transformed into a set of solution equations based on the FDTD method. Solving these equations using the model parameters allows for rapid acquisition of simulation results for the receiving antenna. Compared to traditional finite element simulation methods, the FDTD method is more efficient and requires less storage resources. Based on the magneto-electric coupling effect and acoustic excitation, the size of the receiving antenna can reach the micrometer or even nanometer scale. Compared to traditional antennas, the size of the chip-type receiving antenna can be reduced by 3-5 orders of magnitude. The simulation results can be used to further analyze the receiving performance of the novel chip-type receiving antenna, providing technical support for its application.

[0141] Please see Figure 3 The present invention also provides another embodiment of a chip-type receiving antenna simulation method based on the finite-difference time-domain method, including:

[0142] (1) Establish a set of differential equations for magneto-elastic-electric coupling, replace the differential equations with the central second-order difference form, and establish a set of recursive solution equations based on the FDTD algorithm.

[0143] (2) Establish the antenna geometric structure model and set the geometric parameters and calculation nodes;

[0144] (3) Initialize the field quantities and set the boundary conditions;

[0145] (4) Set the material parameters and electromagnetic constants according to different solution domains;

[0146] (5) Set the magnetic field excitation source and the activation function;

[0147] (6) Set the time and space grid size according to stability conditions and material parameters;

[0148] (7) Finally, perform iterative calculations based on the FDTD equations obtained in step (1) until the preset simulation duration ends.

[0149] (8) Calculate and analyze the receiving performance of the new receiving antenna, including: analyze the resonance characteristics of the antenna based on the stress field obtained by calculation, calculate the output voltage field using the electric field quantity at both ends of the piezoelectric layer, and calculate the receiving efficiency of the antenna based on the obtained electric field quantity, etc.

[0150] The novel antenna described in this embodiment is based on the magneto-electric coupling effect and is excited by acoustic waves, thus its size can reach the micrometer or even nanometer scale. This type of novel antenna has become a research hotspot in the field of antenna miniaturization technology in recent years. Because it does not rely on current resonance but on the acoustic wave resonance of the bulk acoustic waves inside the elastic material, the size of the novel antenna can be reduced by 3-5 orders of magnitude compared to traditional antennas.

[0151] Please see Figure 4 The present invention also provides an embodiment of a chip-type receiving antenna simulation device based on the finite-difference time-domain method, including:

[0152] The equation system construction module 11 is used to establish a set of differential equations with multi-physics coupling based on the electromagnetic field, stress field and sound field of the receiving antenna, and to transform the set of differential equations into a set of solution equations based on the finite difference method in the time domain.

[0153] The model parameter setting module 22 is used to establish the geometric structure model of the receiving antenna and set the model parameters required for simulation in the geometric structure model. The model parameters include at least the geometric parameters, material parameters, mesh parameters and excitation frequency of the magnetic induction excitation source of the receiving antenna. The mesh parameters are related to the internal bulk acoustic waves of the material used in the receiving antenna.

[0154] The simulation result acquisition module 33 is used to iteratively calculate the solution system of equations according to the model parameters until the preset simulation time, so as to obtain the simulation results of the receiving antenna based on acoustic excitation.

[0155] The optimal parameter determination module 44 is used to calculate the simulated resonant frequency of the receiving antenna based on the simulation results, adjust the geometric parameters and the material parameters in the geometric structure model so that the simulated resonant frequency is equal to the excitation frequency, and use the geometric parameters as the optimal geometric parameters and the material parameters as the optimal material parameters.

[0156] The chip-type receiving antenna simulation device based on the finite-difference time-domain (FDTD) method provided in this embodiment establishes a set of multi-physics coupled differential equations based on the electromagnetic field, stress field, and acoustic field of the receiving antenna. This enables coupled simulation of magneto-elastic-electric multi-physics fields, solving the multi-physics problem of the receiving antenna. The differential equations are then transformed into a set of solution equations based on the FDTD method. Solving the equations based on the model parameters allows for rapid acquisition of the simulation results of the receiving antenna. Compared with traditional finite element simulation methods, the FDTD method is more efficient and requires less storage resources. Based on the magneto-electric coupling effect and acoustic excitation, the size of the receiving antenna can reach the micrometer or even nanometer scale. Compared with traditional antennas, the size of the chip-type receiving antenna can be reduced by 3-5 orders of magnitude. The simulation results can be used to further analyze the receiving performance of the novel chip-type receiving antenna, providing technical support for its application.

[0157] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0158] In the embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection between devices or units through some interfaces, and may be electrical, mechanical, or other forms.

[0159] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0160] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0161] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0162] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A simulation method for chip-type receiving antennas based on the finite-difference time-domain method, characterized in that, include: A set of multi-physics coupled differential equations is established based on the electromagnetic field, stress field, and acoustic field of the receiving antenna, and the set of differential equations is transformed into a set of solution equations based on the finite difference method in the time domain. Establish a geometric structure model of the receiving antenna, and set the model parameters required for simulation in the geometric structure model. The model parameters include at least the geometric parameters, material parameters, mesh parameters and excitation frequency of the magnetic induction excitation source of the receiving antenna. The mesh parameters are related to the internal bulk acoustic waves of the material used in the receiving antenna. The system of equations is iteratively calculated based on the model parameters until the preset simulation duration, thereby obtaining the simulation results of the receiving antenna based on acoustic excitation. The simulated resonant frequency of the receiving antenna is calculated based on the simulation results. The geometric parameters and material parameters are adjusted in the geometric structure model so that the simulated resonant frequency is equal to the excitation frequency. The geometric parameters are taken as the optimal geometric parameters and the material parameters are taken as the optimal material parameters.

2. The simulation method for a chip-type receiving antenna based on the finite-difference time-domain method according to claim 1, characterized in that, The geometric structure model includes: A piezoelectric layer and a magnetostrictive layer disposed above and / or below the piezoelectric layer; A positive electrode is provided at the upper end of the piezoelectric layer, and a negative electrode is provided at the lower end of the piezoelectric layer. Both the positive electrode and the negative electrode are connected to an oscilloscope to achieve voltage measurement.

3. The simulation method for a chip-type receiving antenna based on the finite-difference time-domain method according to claim 2, characterized in that, The system of differential equations is as follows: Where E is the electric field vector, H is the magnetic field vector, D is the electric flux density vector, B is the magnetic flux density vector, r is the stress, P represents the piezoelectric layer material, M represents the magnetostrictive layer material, and T... M For the stress of the magnetostrictive layer material, e D e is the stress constant of the piezoelectric layer B c is the stress constant of the magnetostrictive layer. D c is the mechanical stiffness constant of the piezoelectric layer. B ε is the mechanical stiffness constant of the magnetostrictive layer. S μ is the strain-free dielectric constant of the piezoelectric layer. S σ is the strain-free permeability of the magnetostrictive layer, σ is the conductivity of the piezoelectric layer material, and v is the velocity vector. P Let v be the velocity vector in the piezoelectric layer material. M Let E be the velocity vector in the magnetostrictive layer material, z represent the z-direction in the Cartesian coordinate system, and E Z H represents the z-direction component of the electric field in the piezoelectric layer material. X denoted as the x-direction component of the magnetic field in the magnetostrictive layer material. This represents the derivative of a partial differential, where t is time.

4. The simulation method for a chip-type receiving antenna based on the finite-difference time-domain method according to claim 3, characterized in that, The solution set of equations based on the finite-difference time-domain method is as follows: Where Δt is the time step and Δz is the spatial step; n and i are the indices of the field quantity in the time and spatial dimensions, respectively; This represents the x-direction component of the magnetic field in a magnetostrictive layer material with spatial dimension index i and time dimension index n+1 / 2; B represents the velocity vector in the magnetostrictive layer material with spatial dimension index i+1 / 2 and time dimension index n; n +1 / 2 This represents the magnetic flux density vector with spatial dimension index n+1 / 2; This represents the stress vector in the magnetostrictive layer material with spatial dimension index i and time dimension index n+1 / 2; This represents the z-direction component of the magnetic field in a piezoelectric material with spatial dimension index i and time dimension index n+1 / 2. This represents the velocity vector in the piezoelectric layer material with spatial dimension index i+1 / 2 and time dimension index n; This represents the stress vector in a piezoelectric material with spatial dimension index i and time dimension index n+1 / 2. This represents the stress vector in a material with spatial dimension index i and time dimension index n+1 / 2. This represents the stress vector in a material with spatial dimension index i-1 and time dimension index n-1 / 2.

5. The simulation method for a chip-type receiving antenna based on the finite-difference time-domain method according to claim 2 or 4, characterized in that, Also includes: The receiving efficiency of the receiving antenna is calculated based on the simulation results, and the receiving efficiency is: Among them, P rec P represents the signal power received by the receiving antenna, i.e., the power output to the load or RF front end. in Z0 is the signal power of the input antenna, Z0 is the wave impedance, μ0 is the free permeability, and B is the signal power of the input antenna. m U is the amplitude of the magnetic induction excitation source, σ is the conductivity of the piezoelectric layer material, h is the thickness of the piezoelectric layer or magnetostrictive layer, and U is the magnetic induction excitation source. z,m The voltage is set at a distance h for calculating the potential between piezoelectric layers.

6. The simulation method for a chip-type receiving antenna based on the finite-difference time-domain method according to claim 2, characterized in that, The process of iteratively calculating the system of equations based on the model parameters until the preset simulation duration also includes: Initialize the field quantities by setting the magnetic field of the magnetostrictive layer, the electric field of the piezoelectric layer, the overall stress field, and the overall velocity field vector to zero vectors. Set boundary conditions to set the stress field of the first boundary node and the second boundary node in the Z direction of the geometric mesh of the magnetostrictive layer and the air boundary to zero. The component of the first boundary node in the Z direction is 0, and the component of the second boundary node in the Z direction is the total thickness of the antenna.

7. The simulation method for a chip-type receiving antenna based on the finite-difference time-domain method according to claim 1, characterized in that, The process of iteratively calculating the system of equations based on the model parameters until the preset simulation duration also includes: Set the spatial nodes for simulation calculations, and set the spatial step size and time step size for simulation based on preset stability conditions and the material parameters; The preset stability condition is related to the internal bulk acoustic wave of the material used in the receiving antenna at the simulated resonant frequency.

8. The simulation method for a chip-type receiving antenna based on the finite-difference time-domain method according to claim 7, characterized in that, The spatial step size is: Where Δz is the spatial step size in the Z direction, and λ ac,min This is the minimum wavelength of the bulk acoustic wave in the material at the simulated resonant frequency.

9. The simulation method for a chip-type receiving antenna based on the finite-difference time-domain method according to claim 7, characterized in that, The time step is: Where Δt is the time step, v ac,max To simulate the maximum sound velocity of bulk sound waves in a material at the resonant frequency.

10. A chip-type receiving antenna simulation device based on the finite-difference time-domain method, characterized in that, include: The equation system construction module is used to establish a set of differential equations coupled with multiple physics fields based on the electromagnetic field, stress field and acoustic field of the receiving antenna, and to transform the set of differential equations into a set of solution equations based on the finite difference method in the time domain. The model parameter setting module is used to establish the geometric structure model of the receiving antenna, and to set the model parameters required for simulation in the geometric structure model. The model parameters include at least the geometric parameters, material parameters, mesh parameters and excitation frequency of the magnetic induction excitation source of the receiving antenna. The mesh parameters are related to the internal bulk acoustic waves of the material used in the receiving antenna. The simulation result acquisition module is used to iteratively calculate the solution system of equations based on the model parameters until the preset simulation time, so as to obtain the simulation results of the receiving antenna based on acoustic excitation. The optimal parameter determination module is used to calculate the simulated resonant frequency of the receiving antenna based on the simulation results, adjust the geometric parameters and material parameters in the geometric structure model so that the simulated resonant frequency is equal to the excitation frequency, and use the geometric parameters as the optimal geometric parameters and the material parameters as the optimal material parameters.

Images