A method and system for realizing bus port excitation based on finite element

Abstract

The present invention discloses a method and system for realizing a bus port excitation source based on finite element, including: creating a configuration file of a model to be solved, calling a mesh generation tool to mesh the model to be solved; marking all boundary surfaces after mesh generation, and creating bus ports on the port surfaces; reading the mesh tag mark of the bus port to obtain the bus port mesh ID; calculating the electromagnetic field of the meshed area, establishing a finite element matrix equation satisfied by the model to be solved, and introducing lumped elements on the bus port; using the voltage-current relationship of the lumped element to replace the excitation source, merging the lumped element into the finite element matrix equation, and realizing bus port excitation. The present invention uses the voltage-current relationship of the lumped circuit element to introduce an external current source excitation to the simulation model, and the excitation implementation method is simple, and the physical meaning is clear, so as to analyze the network parameters of the circuit model faster and more accurately.

Description

Technical Field

[0001] The present invention relates to the field of electromagnetic simulation technology, in particular to the field of electronic design automation (EDA) software technology, and in particular to a method and system for realizing collective bus port excitation based on finite elements. Background Art

[0002] Various numerical analysis methods, as the development foundation of computational electromagnetics, have become indispensable numerical experimental tools in the field of engineering design through the combination with computer technology. Since the beginning of related research, excellent numerical calculation methods for different problems and fields have emerged in an endless stream. Among them, the most widely used in the fields of computational electromagnetics include finite difference method, finite volume method, moment method, finite element method, etc.

[0003] Among them, the finite element method uses an unstructured grid partitioning model, which can better fit models with complex and fine structures. In 1980, Nedelec proposed using the vector basis function based on edge elements as the interpolation basis function of the finite element method, which ensures that the electromagnetic field at the interface of different media only satisfies tangential continuity and is conducive to the imposition of boundary conditions.

[0004] Both wave ports and lumped ports are common ways to introduce external excitation in electromagnetic field problems. As an option for exciting circuit structures, lumped ports have several advantages over wave ports: First, it is much easier to add excitation vectors when constructing the finite element matrix, while wave ports require modal analysis on the port plane to extract propagation constants and analyze the modal fields of each mode to construct the port boundary condition matrix and excitation vector. However, lumped ports only need to add one or more non-zero values ​​directly to the excitation vector. In addition, the excitation field of the lumped port does not change complexly with frequency, and can be conveniently defined in the structure between two adjacent conductors as a gap source, while the wave port must be defined on the out-of-plane boundary of the computational domain.

[0005] However, some fundamental issues still limit the effectiveness of lumped ports. For example, at high frequencies, the electric potential on the conductor surface is not constant due to distributed effects, which can lead to inaccurate parameter extraction of lumped ports.

[0006] Although lumped ports are not accurate at high frequencies, they are still valuable, especially when wave ports cannot be defined. They also provide a convenient way to obtain the input impedance and S parameters of the network. Input impedance and S parameters are important parameters for analyzing the transmission characteristics of network ports and play a big role in actual circuit analysis. Therefore, lumped ports are widely used as external excitations added to simulation models of some circuits. Some mature finite element commercial software such as HFSS, when adding lumped port excitation, according to the manual description, calculates the eigenvalue equation of the lumped port surface the same as that of the wave port, and takes the main mode field of the port as the excitation source to add the lumped port.

[0007] However, the above lumped port implementation method brings many inconveniences to the calculation process, specifically:

[0008] It is necessary to solve the eigenvalue equation of the lumped port surface similar to that of the wave port surface, and to analyze the port mode, which is equivalent to taking the main mode of the port surface for excitation. This makes the solution process more complicated, increases the calculation time and memory consumption, and makes the simulation of complex models more prone to errors. It cannot meet our needs for fast and accurate analysis of network parameters (S parameters) containing transmission line circuit models. Summary of the invention

[0009] One of the purposes of the present invention is to provide a method and system for realizing a lumped bus port excitation source based on finite elements. In an embodiment of the present invention, the lumped bus port utilizes the voltage-current relationship of lumped circuit elements to introduce an external current source excitation to a simulation model. The excitation implementation method is simple and the physical meaning is clear. It is different from the method of performing characteristic analysis on the excitation port surface adopted by the currently mature finite element commercial software. It can analyze the network parameters (S parameters) of the circuit model more quickly and accurately.

[0010] In order to solve the above technical problems, in a first aspect, an embodiment of the present invention provides a method for realizing a bus port excitation source based on finite elements, the method comprising:

[0011] Create a configuration file for the model to be solved, and call the meshing tool to mesh the model to be solved;

[0012] Mark all boundary surfaces after meshing, create a bus port on the port surface, read the grid tag of the bus port, and obtain the grid ID of the bus port;

[0013] Calculate the electromagnetic field in the grid area of ​​the bus port, establish the finite element matrix equation satisfied by the model to be solved, and introduce lumped elements on the bus port;

[0014] The voltage-current relationship of lumped elements is used to replace the excitation source, and the lumped elements are incorporated into the finite element matrix equation to achieve lumped bus port excitation.

[0015] Furthermore, the method further comprises:

[0016] The finite element matrix equation is solved to obtain the bus port S parameters and the transmission characteristic parameters of the bus port of the model to be solved.

[0017] Preferably, the bus port is defined on a line segment, and the configuration file contains grid information of the bus port, and the grid information includes coordinate information and size and shape.

[0018] Preferably, the calculating of the electromagnetic field of the bus port grid area comprises: calculating the electromagnetic field of the bus port grid area by edge vector interpolation basis function, and the calculating of the electromagnetic field of the bus port grid area by edge vector interpolation basis function comprises:

[0019] The basis function formula is as follows:

[0020]

[0021]

[0022]

[0023]

[0024]

[0025]

[0026] In the above formula, L1, L2, L3, and L4 are the volume coordinates of a point inside the tetrahedron and the three vertices of the tetrahedron. i , i=1.2...6) is the length of each edge, is a differential operator, and the vector field in the tetrahedral element is expanded as follows:

[0027]

[0028] Among them, E i represents the tangential electric field coefficient along the i-th edge in each tetrahedron.

[0029] Preferably, the establishment of a finite element matrix equation satisfied by the model to be solved specifically includes:

[0030] The constitutive relation Substituting into Maxwell's equations:

[0031]

[0032]

[0033] eliminate The vector wave equation satisfied by the model to be solved is obtained:

[0034]

[0035] in, are the relative permittivity and relative magnetic permeability, is a free space beam, ω=2πf is the angular frequency, is the characteristic impedance of free space, ε0=8.854×10 -12 (F / m) and μ0=4π×10 -7 (H / m) are the permittivity and magnetic permeability of free space, respectively; It is an external excitation source, serving as the excitation source of the bus port;

[0036] Starting from Maxwell's equations, the vector wave equation is obtained through the constitutive relationship, and the vector wave equation is transformed into a functional:

[0037]

[0038] Solving the stationary points of the above functional, we obtain the finite element solution of the vector wave equation;

[0039] The introduction of lumped elements on the bus port specifically includes: the bus port is introduced by the third excitation term in the functional formula:

[0040]

[0041] Among them, the excitation J is defined by the user, and the voltage and impedance parameters of the bus port are obtained by solving the bus port current;

[0042] Create a finite element based matrix:

[0043] Ax=B

[0044] Among them, the B matrix corresponds to the excitation term J, which is the excitation term of the finite element matrix introduced by the bus port excitation.

[0045] Preferably, the excitation items of the matrix of the finite element introduced by the bus port excitation specifically include:

[0046] The bus port excitation distributes a constant current source along the edge of the element connecting two adjacent conductors, that is, distributes the local unit current density on the grid line corresponding to the bus segment port The lumped current source of

[0047] The current source in the finite element mesh is divided into multiple series-connected current sources, each of which is defined on the edge of the element and carries the same amount of current;

[0048] When the lumped current source is used as excitation, the excitation term in the finite element matrix becomes:

[0049]

[0050] in, is a free-space beam, is the free space characteristic impedance, represents the direction of the lumped current, k represents the number of edges of the lumped bus port, and the sum is performed on all edges of the lumped bus port;

[0051] The electric field is expanded using the edge vector basis function to determine the right-hand side excitation term in the finite element matrix:

[0052]

[0053] in, is an array of all vector basis functions defined on the bus port. k is the length of edge k, and the integral is obtained by the following definition of the edge vector basis function:

[0054]

[0055] Preferably, the use of the voltage-current relationship of the lumped element instead of the excitation source, incorporating the lumped element into the finite element matrix equation, and realizing the lumped bus port excitation specifically includes:

[0056] Incorporate lumped elements into the finite element model. First, provide a 1A current source excitation on the lumped bus port. Then, use the voltage-current relationship satisfied by the lumped elements to provide lumped excitation on the lumped bus port. Replace the current source excitation with the lumped excitation. Finally, merge the lumped elements into the finite element matrix. The voltage-current relationship is given by the following formula:

[0057]

[0058] Among them, V r is the port voltage, R is the port impedance, is a unit vector, and when the port resistance is distributed along the lumped element, the discretized subfunction is generated:

[0059]

[0060] in, is an array of all vector basis functions defined on the bus port. k is the length of edge k, x krepresents the electric field coefficient on the edge;

[0061] When the current source is replaced by a lumped element, the lumped element is connected in parallel with the original system, and its discretization model is as follows:

[0062] Y R =jk0Z0·R -1 I k 2

[0063] The discretized model is added to the finite element matrix A, and when the lumped element is assigned to multiple edge edges, the voltage across the lumped element is assigned as the sum of all voltage drops.

[0064] On the other hand, in order to solve the technical problem of the present invention, an embodiment of the present invention further provides a system for realizing a bus port excitation source based on finite elements, the system comprising:

[0065] The meshing module is used to create a configuration file for the model to be solved and call the meshing tool to mesh the model to be solved;

[0066] The bus port creation module is used to mark all boundary surfaces after meshing, create bus ports on the port surfaces, read the grid tag of the bus port, and obtain the grid ID of the bus port;

[0067] The first calculation module is used to calculate the electromagnetic field in the meshed area, establish the finite element matrix equation satisfied by the model to be solved, and introduce the lumped element on the bus port;

[0068] The excitation realization module is used to use the voltage-current relationship of the lumped elements to replace the excitation source, merge the lumped elements into the finite element matrix equation, and realize the lumped bus port excitation.

[0069] Furthermore, the system further comprises:

[0070] The second calculation module is used to solve the finite element matrix equation to obtain the bus port S parameters and the transmission characteristic parameters of the bus port of the model to be solved.

[0071] Preferably, the incentive implementation module specifically includes:

[0072] Replacement unit is used to incorporate lumped elements into the finite element model. First, a current source excitation of 1A is provided on the lumped bus port. Then, a lumped excitation is provided on the lumped bus port using the voltage-current relationship satisfied by the lumped element. The current source excitation is replaced by the lumped excitation. Finally, the lumped element is merged into the finite element matrix. The voltage-current relationship is given by the following formula:

[0073]

[0074] Among them, V r is the port voltage, R is the port impedance, is a unit vector;

[0075] Discrete cells are used to generate discretized subfunctions when the port resistance is distributed along lumped elements:

[0076]

[0077] in, is an array of all vector basis functions defined on the bus port. k is the length of edge k, x k represents the electric field coefficient on the edge;

[0078] When the current source is replaced by a lumped element, the lumped element is connected in parallel with the original system, and the discretized model is as follows:

[0079] Y R =jk0Z0·R -1 I k 2

[0080] The discretized model is added to the finite element matrix A, and when the lumped element is assigned to multiple edge edges, the voltage across the lumped element is assigned as the sum of all voltage drops.

[0081] Compared with the prior art, the finite element-based bus port excitation source implementation method and system provided in the embodiment of the present invention have at least the following beneficial effects:

[0082] The embodiment of the present invention provides an innovative implementation method of the lumped bus port, which utilizes the voltage-current relationship of the lumped circuit element to introduce the lumped element at the lumped port, connects the lumped element in parallel with the original system through the discretized grid lines at the lumped bus port, and derives the finite element matrix equation satisfied by the lumped bus port through the discretized model of the lumped port to realize the excitation of the lumped bus port. The embodiment of the present invention defines the lumped bus port between the signal line and the reference ground, simplifies the discretized grid of the lumped port, and makes the definition clear. It is also more convenient to use the meshing tool to mark the lumped bus port. The lumped bus port grid ID can be easily obtained by simply marking the lumped grid lines.

[0083] In addition, after solving the finite element matrix to obtain the voltage and current at the port, the embodiment of the present invention can obtain the network transmission characteristic parameters of the model network, which is convenient for the subsequent analysis of the transmission characteristics of the model network. The physical definition is clear, the implementation method is simple, the calculation amount of the discrete grid at the port is reduced, and the calculation accuracy is guaranteed to be small compared with mature commercial software. BRIEF DESCRIPTION OF THE DRAWINGS

[0084] The preferred implementation modes will be described below in a clear and understandable manner with reference to the accompanying drawings to further illustrate the above-mentioned characteristics, technical features, advantages and implementation methods of the present invention.

[0085] Figure 1 It is a flow chart of a method for realizing a bus port excitation source based on finite elements according to an embodiment of the present invention;

[0086] Figure 2 is a mesh division diagram of a model of another embodiment of the present invention;

[0087] Figure 3 is a schematic diagram of mesh generation of a microstrip transmission line model according to an embodiment of the present invention;

[0088] Figure 4 is a schematic diagram of bus port markings of a microstrip transmission line model set according to an embodiment of the present invention;

[0089] Figure 5 is a schematic diagram of an embodiment of the present invention using a voltage-current relationship of a lumped circuit element to replace a current source and incorporating it into a finite element mesh;

[0090] Figure 6 It is a comparison diagram of the S11 parameter calculated by the bus port in the embodiment of the present invention and the S11 parameter calculated by the lumped port excitation using the commercial software;

[0091] Figure 7 It is a comparison diagram of the S21 parameter calculated by the bus port in the embodiment of the present invention and the S21 parameter calculated by the lumped port excitation of the commercial software;

[0092] Figure 8 The invention is a block diagram of a finite element-based bus port excitation source implementation system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0093] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings and other implementation methods can be obtained based on these drawings without creative work.

[0094] In order to simplify the drawings, only the parts related to the invention are schematically shown in each figure, and they do not represent the actual structure of the product. In addition, in order to simplify the drawings and facilitate understanding, in some figures, only one of the parts with the same structure or function is schematically drawn or marked. In this article, "one" not only means "only one", but also means "more than one".

[0095] The following mainly takes some specific embodiments as examples to describe in detail the implementation of the technical solution of the present invention.

[0096] Therefore, the present invention adopts the finite element method to calculate the simulation model with lumped port excitation.

[0097] like Figure 1 As shown, a method for realizing a bus port excitation source based on finite elements in an embodiment of the present invention includes the following steps:

[0098] S1. Create a configuration file for the model to be solved, and call a meshing tool to mesh the model to be solved;

[0099] S2. Mark all boundary surfaces after meshing, create a bus port on the port surface, read the grid tag of the bus port, and obtain the grid ID of the bus port;

[0100] S3. Calculate the electromagnetic field in the meshed area, establish the finite element matrix equation satisfied by the model to be solved, and introduce lumped elements at the bus port;

[0101] S4. Use the voltage-current relationship of the lumped element to replace the excitation source, merge the lumped element into the finite element matrix equation, and realize the lumped bus port excitation.

[0102] In an embodiment of the present invention, first, a configuration file of the model to be solved needs to be defined. The configuration file of the model to be solved contains the coordinates, dimensions and material information of the model, including information of various boundary conditions contained in the model.

[0103] In one embodiment of the present invention, Figure 1 The simulation model shown is a microstrip transmission line model. The size of the signal line on it is 4mil×1mil×40mil, and the material property is COPPER. The size of the middle dielectric layer is 100mil×1mil×40mil, and the material property is FR4. The size of the bottom ground floor is 100mil×1mil×40mil, and the material property is COPPER.

[0104] As a boundary condition, the lumped excitation port is generally defined between the signal line signal and the reference ground ground in the prior art, and is defined on a rectangular plane in the commonly used mature commercial software HFSS; however, the lumped bus port in the embodiment of the present invention is defined on a line segment, so the configuration file contains the coordinate information of the lumped bus port.

[0105] like Figure 2As shown, the mesh division diagram of the model in the embodiment of the present invention. According to the working frequency, the minimum division wavelength required for the grid division is set, and the model is meshed by the mesh division tool. The mesh is a tetrahedral mesh, and the node and line numbers of the bus port are marked.

[0106] Then, the mesh data is exported from the mesh generation tool to obtain the mesh tag information; the mesh tag information is read to obtain the ID of the bus port;

[0107] like Figure 3 As shown, when the model meshing result is obtained, since the position coordinates and size shape of the bus port are set in the configuration file, the node coordinates and line ID of the bus port can be marked at the same time. Figure 3 In the figure, the bus port ID is 0, and the node numbers at both ends are 7 and 536, which are marked on the figure. Therefore, the grid information can be used for subsequent processing of the edge basis function.

[0108] Furthermore, the electromagnetic field of the region is calculated by introducing an edge vector interpolation basis function, including the following steps:

[0109] The present invention uses a zero-order edge vector basis function to expand the electric field in each tetrahedron, and the basis function formula is as follows:

[0110]

[0111]

[0112]

[0113]

[0114]

[0115]

[0116] In the above formula, (L1, L2, L3, L4) are the volume coordinates of a point inside the tetrahedron and the three vertices of the tetrahedron. i , i=1.2...6) is the length of each edge, As a differential operator, the vector field in the tetrahedral element can be expanded as:

[0117]

[0118] Here E i represents the tangential electric field coefficient along the i-th edge in each tetrahedron;

[0119] Next, we can establish the finite element matrix equations satisfied by the model to be solved and introduce lumped elements on the excitation port, including the following steps:

[0120] The constitutive relation Substituting into Maxwell's equations:

[0121]

[0122]

[0123] Eliminate from the above formula The vector wave equation satisfied by the model to be solved is obtained:

[0124]

[0125] In the formula, are the relative permittivity and relative magnetic permeability, is a free space beam, ω=2πf is the angular frequency, is the characteristic impedance of free space, ε0=8.854×10 -12 (F / m) and μ0=4π×10 -7 (H / m) are the dielectric constant and magnetic permeability of free space respectively.

[0126] It is an external excitation source, which is a bus port excitation source in the present invention.

[0127] The basic equations based on finite element solution are deduced below. First, starting from Maxwell's equations, the vector wave equation is obtained using the constitutive relationship. The above equation is transformed into a functional through the Ritz variation method:

[0128]

[0129] By solving the stationary points of the above functional, the finite element solution of the vector wave equation can be obtained.

[0130] The introduction of lumped elements on the bus port specifically includes: the bus port is introduced by the third excitation term in the functional formula:

[0131]

[0132] Among them, the excitation J is defined by the user, and the voltage and impedance parameters of the bus port are obtained by solving the bus port current;

[0133] Create a finite element based matrix:

[0134] Ax=B

[0135] Among them, the B matrix corresponds to the excitation term J, which is the excitation term of the finite element matrix introduced by the bus port excitation.

[0136] like Figure 5 As shown, the excitation term of the matrix introduced into the finite element by the bus port excitation includes the following steps:

[0137] The lumped excitation in the present invention distributes a constant current source along the edge of the element connecting two adjacent conductors, that is, distributes a local unit current density on the grid line corresponding to the lumped bus segment. The current source in the finite element mesh is actually divided into multiple series-connected current sources, each of which is defined on the edge of the element and carries the same amount of current.

[0138] When using this lumped current source as excitation, the excitation term in the finite element matrix becomes:

[0139]

[0140] In the formula is a free-space beam, is the free space characteristic impedance, Represents the direction of the lumped current, k represents the number of edges of the lumped bus port, and the sum of the above formula is performed on all edges of the lumped bus port.

[0141] The electric field is expanded using the above edge vector basis function to determine the right-hand side excitation term in the finite element matrix:

[0142]

[0143] In the formula is an array of all vector basis functions defined on the bus port. k is the length of edge k. The integral of the above equation is obtained from the following definition of edge vector basis function:

[0144]

[0145] Therefore, in the embodiment of the present invention, for a model with multiple lumped port excitations, the impedance parameter can be obtained by correlating the current and voltage at the lumped port, as shown in the following formula:

[0146] Where:

[0147] V i is the voltage at port i, I j is the current at port j, Z ij is the network impedance parameter of each lumped port.

[0148]

[0149] Since the current source at each port provides a fixed current of 1A, once the voltage at the port is obtained, the impedance parameters can be obtained.

[0150] like Figure 5 As shown in the figure, the voltage-current relationship of the lumped circuit element is used to replace the excitation source, and the lumped element is merged into the finite element matrix equation to realize the lumped bus port excitation, which specifically includes:

[0151] Next, we incorporate lumped circuit elements into the finite element model. First, we provide a 1A current source excitation on the lumped bus port. Then, we use the voltage-current relationship satisfied by the lumped element to provide a lumped excitation on the lumped bus port, replace the current source excitation with the lumped excitation, and finally merge the lumped element into the finite element matrix. The relationship is given by the following equation:

[0152]

[0153] V r is the port voltage, R is the port impedance, is a unit vector, and when the port resistance is distributed along the lumped element, its sub-function discretization produces:

[0154]

[0155] In the formula is an array of all vector basis functions defined on the bus port. k is the length of edge k, x k Represents the electric field coefficient on the edge.

[0156] Therefore, when the current source is replaced by a lumped element, the lumped element is actually connected in parallel with the original system, and its discretized model is as follows:

[0157] Y R =jk0Z0·R -1 I k 2

[0158] The above discretized model is added to the finite element matrix on the left. When the lumped element is assigned to multiple edge edges, the voltage across the lumped element is assigned as the sum of all voltage drops.

[0159] That is, in the technical solution of the embodiment of the present invention, the voltage-current relationship of the lumped element is used to replace the current source with the lumped element to introduce the lumped bus excitation. Therefore, the embodiment of the present invention can excite the model by introducing the lumped bus port excitation at any place in the transmission line model where the external excitation needs to be introduced, and obtain the information such as the S parameters and input impedance of the port.

[0160] The port S parameters of the two-port microstrip transmission line model shown in the present invention, such as S11 and S21, can be calculated by the above formula. Figure 6 and Figure 7 As shown, the results are in good agreement with mature commercial software based on finite element analysis, further demonstrating the correctness of the method of the embodiment of the present invention.

[0161] Through the above technical solutions, the embodiment of the present invention significantly improves the efficiency of electromagnetic simulation applicable to the lumped port model while maintaining the accuracy basically consistent with the commercial software simulation, and provides sufficient flexibility and adaptability, and can be used in any scenario where lumped ports are required. Different from the method used by existing commercial software, the present invention uses the voltage-current relationship of lumped circuit elements to replace lumped current source excitation with lumped elements, connects the lumped elements in parallel with the original system, and can realize the excitation of the bus port. It has clear physical meaning and simple implementation, which has brought substantial progress to the field of electronic design automation (EDA) technology.

[0162] On the other hand, in order to solve the technical problem of the present invention, an embodiment of the present invention further provides a system for realizing a bus port excitation source based on finite elements, the system comprising:

[0163] The meshing module is used to create a configuration file for the model to be solved and call the meshing tool to mesh the model to be solved;

[0164] The bus port creation module is used to mark all boundary surfaces after meshing, create bus ports on the port surfaces, read the grid tag of the bus port, and obtain the grid ID of the bus port;

[0165] The first calculation module is used to calculate the electromagnetic field in the meshed area, establish the finite element matrix equation satisfied by the model to be solved, and introduce the lumped element on the bus port;

[0166] The excitation realization module is used to use the voltage-current relationship of the lumped elements to replace the excitation source, merge the lumped elements into the finite element matrix equation, and realize the lumped bus port excitation.

[0167] Furthermore, the system further comprises:

[0168] The second calculation module is used to solve the finite element matrix equation to obtain the bus port S parameters and the transmission characteristic parameters of the bus port of the model to be solved.

[0169] Preferably, the incentive implementation module specifically includes:

[0170] Replacement unit is used to incorporate lumped elements into the finite element model. First, a current source excitation of 1A is provided on the lumped bus port. Then, a lumped excitation is provided on the lumped bus port using the voltage-current relationship satisfied by the lumped element. The current source excitation is replaced by the lumped excitation. Finally, the lumped element is merged into the finite element matrix. The voltage-current relationship is given by the following formula:

[0171]

[0172] Among them, V r is the port voltage, R is the port impedance, is a unit vector;

[0173] Discrete cells are used to generate discretized subfunctions when the port resistance is distributed along lumped elements:

[0174]

[0175] in, is an array of all vector basis functions defined on the bus port. k is the length of edge k, x k represents the electric field coefficient on the edge;

[0176] When the current source is replaced by a lumped element, the lumped element is connected in parallel with the original system, and the discretized model is as follows:

[0177] Y R =jk0Z0·R -1 I k 2

[0178] The discretized model is added to the finite element matrix A, and when the lumped element is assigned to multiple edge edges, the voltage across the lumped element is assigned as the sum of all voltage drops.

[0179] Here, a finite element-based bus port excitation source implementation system is used, and the implementation method of the system is consistent with the method implementation method, which will not be described in detail.

[0180] Compared with the prior art, the finite element-based bus port excitation source implementation method and system provided in the embodiment of the present invention have at least the following beneficial effects:

[0181] The embodiment of the present invention provides an innovative implementation method of the lumped bus port, which utilizes the voltage-current relationship of the lumped circuit element to introduce the lumped element at the lumped port, connects the lumped element in parallel with the original system through the discretized grid lines at the lumped bus port, and derives the finite element matrix equation satisfied by the lumped bus port through the discretized model of the lumped port to realize the excitation of the lumped bus port. The embodiment of the present invention defines the lumped bus port between the signal line and the reference ground, simplifies the discretized grid of the lumped port, and makes the definition clear. It is also more convenient to use the meshing tool to mark the lumped bus port. The lumped bus port grid ID can be easily obtained by simply marking the lumped grid lines.

[0182] In addition, after solving the finite element matrix to obtain the voltage and current at the port, the embodiment of the present invention can obtain the network transmission characteristic parameters of the model network, which is convenient for the subsequent analysis of the transmission characteristics of the model network. The physical definition is clear, the implementation method is simple, the calculation amount of the discrete grid at the port is reduced, and the calculation accuracy is guaranteed to be small compared with mature commercial software.

[0183] It should be noted that the above embodiments can be freely combined as needed. The above are only preferred embodiments of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A method for realizing a bus port excitation source based on finite element, characterized in that: The method comprises: Create a configuration file for the model to be solved, and call the meshing tool to mesh the model to be solved; Mark all boundary surfaces after meshing, create a bus port on the port surface, read the grid tag of the bus port, and obtain the grid ID of the bus port; Calculate the electromagnetic field in the grid area of ​​the bus port, establish a finite element matrix equation satisfied by the model to be solved, and introduce a lumped element on the bus port; wherein the establishment of the finite element matrix equation satisfied by the model to be solved specifically includes: converting the constitutive relation Substituting into Maxwell's equations: eliminate The vector wave equation satisfied by the model to be solved is obtained: in, are the relative permittivity and relative magnetic permeability, is a free space beam, ω=2πf is the angular frequency, is the characteristic impedance of free space, ε0=8.854×10 -12 (F / m) and μ0=4π×10 -7 (H / m) are the permittivity and magnetic permeability of free space, respectively; It is an external excitation source, serving as the excitation source of the bus port; Starting from Maxwell's equations, the vector wave equation is obtained through the constitutive relationship, and the vector wave equation is transformed into a functional: Solving the stationary points of the above functional, we obtain the finite element solution of the vector wave equation; The introduction of lumped elements on the bus port specifically includes: the bus port is introduced by the third excitation term in the functional formula: The excitation J is defined by the user, and the voltage and impedance parameters of the bus port are obtained by solving the bus port current. Create a finite element based matrix: Ax=B Among them, the B matrix corresponds to the excitation term J, which is the excitation term of the matrix of the finite element introduced by the bus port excitation; The voltage-current relationship of the lumped element is used instead of the excitation source, and the lumped element is incorporated into the finite element matrix equation to realize the lumped bus port excitation, including: Incorporate lumped elements into the finite element model. First, provide a 1A current source excitation on the lumped bus port. Then, use the voltage-current relationship satisfied by the lumped elements to provide lumped excitation on the lumped bus port. Replace the current source excitation with the lumped excitation. Finally, merge the lumped elements into the finite element matrix. The voltage-current relationship is given by the following formula: Among them, V r is the port voltage, R is the port impedance, is a unit vector, and when the port resistance is distributed along the lumped element, the discretized subfunction is generated: in, is an array of all vector basis functions defined on the bus port. k is the length of edge k, x k represents the electric field coefficient on the edge; When the current source is replaced by a lumped element, the lumped element is connected in parallel with the original system, and its discretization model is as follows: Y R =jk0Z0·R -1 I k 2 The discretized model is added to the finite element matrix A, and when the lumped element is assigned to multiple edge edges, the voltage across the lumped element is assigned as the sum of all voltage drops.

2. The method for realizing a bus port excitation source based on finite element as claimed in claim 1, characterized in that: The method further comprises: The finite element matrix equation is solved to obtain the bus port S parameters and the transmission characteristic parameters of the bus port of the model to be solved.

3. The method for realizing a bus port excitation source based on finite element as claimed in claim 1, characterized in that: The bus port is defined on a line segment, and the configuration file contains grid information of the bus port, wherein the grid information includes coordinate information and size and shape.

4. The method for realizing a bus port excitation source based on finite element as claimed in claim 1, characterized in that: The calculating of the electromagnetic field of the bus port grid area specifically includes: calculating the electromagnetic field of the bus port grid area by edge vector interpolation basis function, and the calculating of the electromagnetic field of the bus port grid area by edge vector interpolation basis function specifically includes: The basis function formula is as follows: In the above formula, L1, L2, L3, and L4 are the volume coordinates of a point inside the tetrahedron and the three vertices of the tetrahedron. i , i=1.2...6) is the length of each edge, is a differential operator, and the vector field in the tetrahedral element is expanded as follows: Among them, E i represents the tangential electric field coefficient along the i-th edge in each tetrahedron.

5. The method for realizing a bus port excitation source based on finite element as claimed in claim 1, characterized in that: The excitation items of the finite element matrix introduced by the bus port excitation include: The bus port excitation distributes a constant current source along the edge of the element connecting two adjacent conductors, that is, distributes the local unit current density on the grid line corresponding to the bus segment port The lumped current source of The current source in the finite element mesh is divided into multiple series-connected current sources, each of which is defined on the edge of the element and carries the same amount of current; When the lumped current source is used as excitation, the excitation term in the finite element matrix becomes: in, is a free-space beam, is the free space characteristic impedance, represents the direction of the lumped current, k represents the number of edges of the lumped bus port, and the sum is performed on all edges of the lumped bus port; The electric field is expanded using the edge vector basis function to determine the right-hand side excitation term in the finite element matrix: in, is an array of all vector basis functions defined on the bus port. k is the length of edge k, and the integral is obtained by the following definition of the edge vector basis function:

6. A finite element based bus port excitation source realization system, characterized in that: The system comprises: The meshing module is used to create a configuration file for the model to be solved and call the meshing tool to mesh the model to be solved; The bus port creation module is used to mark all boundary surfaces after meshing, create bus ports on the port surfaces, read the grid tag of the bus port, and obtain the grid ID of the bus port; The first calculation module is used to calculate the electromagnetic field of the meshed area, establish a finite element matrix equation satisfied by the model to be solved, and introduce a lumped element on the bus port. The establishment of the finite element matrix equation satisfied by the model to be solved specifically includes: converting the constitutive relation Substituting into Maxwell's equations: eliminate The vector wave equation satisfied by the model to be solved is obtained: in, are the relative permittivity and relative magnetic permeability, is a free space beam, ω=2πf is the angular frequency, is the characteristic impedance of free space, ε0=8.854×10 -12 (F / m) and μ0=4π×10 -7 (H / m) are the permittivity and magnetic permeability of free space, respectively; It is an external excitation source, serving as the excitation source of the bus port; Starting from Maxwell's equations, the vector wave equation is obtained through the constitutive relationship, and the vector wave equation is transformed into a functional: Solving the stationary points of the above functional, we obtain the finite element solution of the vector wave equation; The introduction of lumped elements on the bus port specifically includes: the bus port is introduced by the third excitation term in the functional formula: The excitation J is defined by the user, and the voltage and impedance parameters of the bus port are obtained by solving the bus port current. Create a finite element based matrix: Ax=B Among them, the B matrix corresponds to the excitation term J, which is the excitation term of the matrix of the finite element introduced by the bus port excitation; The excitation realization module is used to replace the excitation source with the voltage-current relationship of the lumped element, merge the lumped element into the finite element matrix equation, and realize the lumped bus port excitation. The excitation realization module specifically includes: Replacement unit is used to incorporate lumped elements into the finite element model. First, a current source excitation of 1A is provided on the lumped bus port. Then, a lumped excitation is provided on the lumped bus port using the voltage-current relationship satisfied by the lumped element. The current source excitation is replaced by the lumped excitation. Finally, the lumped element is merged into the finite element matrix. The voltage-current relationship is given by the following formula: Among them, V r is the port voltage, R is the port impedance, is a unit vector; Discrete cells are used to generate discretized subfunctions when the port resistance is distributed along lumped elements: in, is an array of all vector basis functions defined on the bus port. k is the length of edge k, x k represents the electric field coefficient on the edge; When the current source is replaced by a lumped element, the lumped element is connected in parallel with the original system, and its discretization model is as follows: Y R =jk0Z0·R -1 I k 2 The discretized model is added to the finite element matrix A, and when the lumped element is assigned to multiple edge edges, the voltage across the lumped element is assigned as the sum of all voltage drops.

7. The finite element based bus port excitation source realization system according to claim 6, characterized in that: The system further comprises: The second calculation module is used to solve the finite element matrix equation to obtain the bus port S parameters and the transmission characteristic parameters of the bus port of the model to be solved.

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