CN116436546A - Electromagnetic coupling time domain analysis method and system for PCB electromagnetic leakage acting transmission line - Google Patents
Electromagnetic coupling time domain analysis method and system for PCB electromagnetic leakage acting transmission line Download PDFInfo
- Publication number
- CN116436546A CN116436546A CN202310443266.2A CN202310443266A CN116436546A CN 116436546 A CN116436546 A CN 116436546A CN 202310443266 A CN202310443266 A CN 202310443266A CN 116436546 A CN116436546 A CN 116436546A
- Authority
- CN
- China
- Prior art keywords
- transmission line
- field
- pcb
- electromagnetic
- dipole array
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 230000005540 biological transmission Effects 0.000 title claims abstract description 130
- 238000010168 coupling process Methods 0.000 title claims abstract description 60
- 230000008878 coupling Effects 0.000 title claims abstract description 59
- 238000005859 coupling reaction Methods 0.000 title claims abstract description 59
- 238000004458 analytical method Methods 0.000 title claims abstract description 32
- 230000005855 radiation Effects 0.000 claims abstract description 69
- 238000000034 method Methods 0.000 claims abstract description 66
- 230000004044 response Effects 0.000 claims abstract description 33
- 238000013507 mapping Methods 0.000 claims abstract description 30
- 238000004364 calculation method Methods 0.000 claims abstract description 27
- 230000001052 transient effect Effects 0.000 claims abstract description 27
- 230000005670 electromagnetic radiation Effects 0.000 claims abstract description 19
- 230000009471 action Effects 0.000 claims abstract description 14
- 239000011159 matrix material Substances 0.000 claims description 11
- 238000005516 engineering process Methods 0.000 claims description 9
- 239000006185 dispersion Substances 0.000 claims description 5
- 238000010276 construction Methods 0.000 claims description 3
- 230000005672 electromagnetic field Effects 0.000 abstract description 11
- 238000004422 calculation algorithm Methods 0.000 description 19
- 238000010586 diagram Methods 0.000 description 13
- 238000004088 simulation Methods 0.000 description 8
- 239000000758 substrate Substances 0.000 description 5
- 230000005284 excitation Effects 0.000 description 4
- 150000003071 polychlorinated biphenyls Chemical class 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- 235000013599 spices Nutrition 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 238000013459 approach Methods 0.000 description 2
- 239000004020 conductor Substances 0.000 description 2
- 238000009795 derivation Methods 0.000 description 2
- 230000005684 electric field Effects 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 230000005669 field effect Effects 0.000 description 2
- 230000014509 gene expression Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000004806 packaging method and process Methods 0.000 description 2
- 238000012795 verification Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000000191 radiation effect Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000008054 signal transmission Effects 0.000 description 1
- 238000004613 tight binding model Methods 0.000 description 1
- 239000013598 vector Substances 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B17/00—Monitoring; Testing
- H04B17/30—Monitoring; Testing of propagation channels
- H04B17/309—Measuring or estimating channel quality parameters
- H04B17/345—Interference values
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L41/00—Arrangements for maintenance, administration or management of data switching networks, e.g. of packet switching networks
- H04L41/14—Network analysis or design
- H04L41/142—Network analysis or design using statistical or mathematical methods
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L41/00—Arrangements for maintenance, administration or management of data switching networks, e.g. of packet switching networks
- H04L41/14—Network analysis or design
- H04L41/145—Network analysis or design involving simulating, designing, planning or modelling of a network
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Physics & Mathematics (AREA)
- Algebra (AREA)
- Electromagnetism (AREA)
- Quality & Reliability (AREA)
- General Physics & Mathematics (AREA)
- Mathematical Analysis (AREA)
- Mathematical Optimization (AREA)
- Mathematical Physics (AREA)
- Probability & Statistics with Applications (AREA)
- Pure & Applied Mathematics (AREA)
- Management, Administration, Business Operations System, And Electronic Commerce (AREA)
Abstract
The invention discloses an electromagnetic coupling time domain analysis method and system of a transmission line with a PCB electromagnetic leakage function, which relate to the field of electromagnetic interference analysis and have the technical scheme that: constructing a mapping relation between the dipole array and the PCB electromagnetic leakage field, and solving the mapping relation inversely to obtain an equivalent dipole array model of the PCB electromagnetic leakage field; simulating electromagnetic radiation of the equivalent dipole array model by using an FDTD method to obtain space radiation field distribution of an equivalent dipole array, and constructing a transmission line equation of a PCB electromagnetic leakage action transmission line according to the space radiation field distribution; and performing differential discretization on the transmission line equation by using a central differential format of the FDTD method, and performing iterative solution to obtain the transient response of voltage and current generated by coupling of the PCB leakage field on the transmission line. The invention realizes the cooperative calculation of the space electromagnetic field and the transient response of the transmission line, and greatly improves the electromagnetic coupling efficiency of the transmission line for analyzing the action of the leakage field.
Description
Technical Field
The invention relates to the field of electromagnetic interference analysis of PCB acting transmission lines, in particular to an electromagnetic coupling time domain analysis method and an electromagnetic coupling time domain analysis system of a PCB electromagnetic leakage acting transmission line.
Background
With the rapid development of wireless communication technology, the operating frequency of printed circuit boards (Printed Circuit Board, PCBs) is increasing, causing some components on the PCB circuitry to radiate electromagnetic energy. The electromagnetic leakage of the PCB acts on the transmission line of the equipment through a radiation field formed in the space to generate interference signals through coupling and flow into a termination circuit, so that the normal operation of the equipment is affected. Therefore, in order to improve the electromagnetic safety of the equipment, the simulation analysis of the electromagnetic coupling of the PCB leakage field acting transmission line has very important research significance. Because the PCB contains abundant components and a large number of microstrip lines, the structure is fine and complex, the cable structure for electric power and signal transmission in the equipment is very fine, and the electromagnetic coupling process of the transmission line for the PCB leakage field effect uses a full-wave algorithm to carry out numerical simulation, so that the amount of the split grids is large and the calculation efficiency is low. At present, the equivalent radiation source modeling algorithm mainly comprises an equivalent electro/magneto-rheological source method and an equivalent dipole method. The equivalent electric/magnetic current source method is based on an electric field integral equation, a matrix relation between near-field data and an equivalent electric/magnetic current source is constructed by using a moment method, and an equivalent electric/magnetic current source of a radiation field is obtained by solving. But this method is not effective in analyzing near field interference of the radiation field of the interference source to the surrounding circuit structure. Compared with an equivalent electric/magnetic current source method, the method has the core idea that an equivalent source model of the integrated circuit leakage field is constructed according to a mapping matrix between the array unit and all observation point positions of a scanning plane above the integrated circuit.
Aiming at the electromagnetic coupling problem of the transmission line acted by the space electromagnetic field, the electromagnetic coupling calculation can be realized by BLT equation, FDTD-SPICE method, FDTD-TL and other methods. The traditional BLT equation is based on electromagnetic topology theory, a transmission line and a reflection matrix are constructed, and rapid calculation of terminal load response is realized, but the algorithm can reduce calculation efficiency when the coupling problem of broadband signals of an interference source is processed. The FDTD-SPICE method is based on a transmission line equation, a SPICE equivalent circuit model of the transmission line is constructed, an excitation field of the transmission line is obtained by combining FDTD, and then the transient response of the termination load is obtained by utilizing SPICE software simulation. However, this approach requires a large amount of formula derivation in the solution process and does not enable collaborative calculation of the spatial electromagnetic field radiation and the terminal load transient response. In addition, the existing field line coupling algorithm cannot be directly applied to electromagnetic coupling calculation of the transmission line with electromagnetic leakage effect of the integrated circuit of the device, because the fine structure of the integrated circuit of the device must be directly modeled when the full-wave algorithm is used for calculating the excitation field of the transmission line, which results in low calculation efficiency.
Disclosure of Invention
In order to solve the defects of the prior art, the invention provides an electromagnetic coupling time domain analysis method and system for a transmission line with the electromagnetic leakage function of a PCB.
The technical aim of the invention is realized by the following technical scheme:
in a first aspect of the present application, there is provided a method for electromagnetic coupling time domain analysis of a PCB electromagnetic leakage acting transmission line, the method comprising:
constructing a mapping relation between the dipole array and the PCB electromagnetic leakage field, and solving the mapping relation inversely to obtain an equivalent dipole array model of the PCB electromagnetic leakage field;
simulating electromagnetic radiation of the equivalent dipole array model by using an FDTD method to obtain space radiation field distribution of an equivalent dipole array, and constructing a transmission line equation of a PCB electromagnetic leakage action transmission line according to the space radiation field distribution;
and performing differential discretization on the transmission line equation by using a central differential format of the FDTD method, and performing iterative solution to obtain the transient response of voltage and current generated by coupling of the PCB leakage field on the transmission line.
In one implementation, constructing a mapping relationship between a dipole array and a PCB electromagnetic leakage field includes:
acquiring near field information of PCB electromagnetic leakage, wherein a near field scanning technology is adopted to measure near field scanning points of the PCB electromagnetic leakage so as to obtain the near field information;
the radiation source of the PCB electromagnetic leakage is equivalent through a dipole array, and the radiation field of the dipole array replaces near field information generated by the PCB electromagnetic leakage;
and taking a relation matrix of a radiation field of the dipole array at any point in space and polar moment and magnetic moment of the array element as a mapping relation between the dipole array and the PCB electromagnetic leakage field, wherein the radiation field of the dipole array at any point in space is generated by co-radiation of the dipole array and a mirror image source thereof.
In one implementation scheme, the number of array elements of the dipole array is N, each array element is composed of two magnetic dipoles in the horizontal direction and one electric dipole in the vertical direction, wherein N is a positive integer, the two horizontal directions of the magnetic dipoles are the x direction and the y direction respectively, and the vertical direction of the electric dipoles is the z direction.
In one implementation, the number N of array elements of the dipole array is less than or equal to the number M of near field scanning points of the near field scanning technology.
In one implementation, simulating electromagnetic radiation of the equivalent dipole array model using an FDTD method to obtain a spatial radiation field distribution of the equivalent dipole array comprises:
determining magnetic field components generated by the magnetic dipole moment in the x direction and the y direction according to the amplitude and phase information of the magnetic dipole moment;
dispersing magnetic field components generated by magnetic dipole moment in the x direction and the y direction by utilizing a differential format of an FDTD method to respectively obtain radiation field distribution of magnetic dipoles of near-field scanning points in the x direction and the y direction;
describing electromagnetic radiation generated by a magnetic dipole by using Maxwell's equations according to the relation between magnetic current and magnetic moment;
converting Maxwell's equation into a scalar equation to obtain electromagnetic radiation generated by an electric dipole;
determining a magnetic field component generated by the electric dipole moment in the z direction according to the amplitude and phase information of the electric dipole moment;
dispersing magnetic field components generated by the electric dipole moment in the z direction by utilizing a differential format of an FDTD method to obtain the radiation field distribution of the electric dipoles of the near-field scanning points in the z direction;
the radiation field distribution of the magnetic dipoles of the near field scanning point in the x direction and the y direction and the radiation field distribution of the electric dipoles of the near field scanning point in the z direction are combined to obtain the space radiation field distribution of the equivalent dipole array in the x, y and z directions.
In one implementation, the differential discrete is performed on the transmission line equation using a central differential format of the FDTD method, and the transient response of the voltage and the current generated by coupling the PCB leakage field on the transmission line is obtained by iterative solution, including:
performing differential dispersion on the transmission line equation by using a central differential format of the FDTD method to obtain an iterative formula of voltage and current on the transmission line;
and carrying out iterative solution by using an iterative formula of forward differential and backward differential pair voltage and current to obtain the transient response of the voltage and current generated by coupling the PCB leakage field on the transmission line.
In one implementation, the transmission line equations include a distributed voltage source equation and a distributed current source equation.
In a second aspect of the present application, there is provided an electromagnetic coupling time domain analysis system for a PCB electromagnetic leakage acting transmission line, the system comprising:
the first module is used for constructing a mapping relation between the dipole array and the PCB electromagnetic leakage field, and solving the mapping relation in an inverse way to obtain an equivalent dipole array model of the PCB electromagnetic leakage field;
the second module is used for simulating electromagnetic radiation of the equivalent dipole array model by utilizing an FDTD method so as to obtain space radiation field distribution of the equivalent dipole array, and constructing a transmission line equation of a PCB electromagnetic leakage action transmission line according to the space radiation field distribution;
and the analysis module is used for carrying out differential discretization on the transmission line equation by utilizing a central differential format of the FDTD method, and carrying out iterative solution to obtain the transient response of the voltage and the current generated by coupling of the PCB leakage field on the transmission line.
In one implementation, a first module includes:
the information acquisition module is used for acquiring near field information of the PCB electromagnetic leakage, wherein a near field scanning technology is adopted to measure near field scanning points of the PCB electromagnetic leakage so as to acquire the near field information;
the equivalent module is used for carrying out equivalent on the near field of the PCB electromagnetic leakage through the dipole array, and the radiation field of the dipole array replaces near field information generated by the PCB electromagnetic leakage;
the mapping relation construction module is used for taking a relation matrix of a radiation field of the dipole array at any point in space and polar moment and magnetic moment of the array element as a mapping relation between the dipole array and the PCB electromagnetic leakage field, wherein the radiation field of the dipole array at any point in space is generated by the common radiation of the dipole array and a mirror image source thereof.
In one implementation, an analysis module includes:
the differential discrete module is used for carrying out differential discrete on the transmission line equation by utilizing a central differential format of the FDTD method to obtain an iterative formula of voltage and current on the transmission line;
and the transient response calculation module is used for carrying out iterative solution by utilizing an iterative formula of forward differential and backward differential pair voltage and current to obtain the transient response of the voltage and current generated by coupling the PCB leakage field on the transmission line.
Compared with the prior art, the invention has the following beneficial effects:
the invention combines the equivalent dipole method and the FDTD algorithm to form a high-efficiency time domain hybrid algorithm, realizes the electromagnetic coupling rapid simulation of the transmission line with the action of the PCB leakage field, avoids the direct modeling of the fine structure of the PCB and the transmission line, realizes the cooperative calculation of the space electromagnetic field and the transient response of the transmission line, and greatly improves the electromagnetic coupling efficiency of the transmission line with the action of the analysis leakage field, thereby providing technical support for the electromagnetic safety evaluation of electronic equipment.
Drawings
The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiments of the invention. In the drawings:
fig. 1 is a flow chart of an electromagnetic coupling time domain analysis method of a PCB electromagnetic leakage transmission line according to an embodiment of the present disclosure;
fig. 2 is a schematic diagram of a field line coupling model of a PCB leakage field effect transmission line provided in an embodiment of the present application;
FIG. 3 is a schematic diagram of equivalent source modeling of a PCB leakage field provided by an embodiment of the present application;
fig. 4 is a schematic diagram of a packaged PCB circuit model according to an embodiment of the present disclosure;
fig. 5 (a) is a magnetic field distribution diagram of a PCB circuit provided in an embodiment of the present application at z=25 mm;
fig. 5 (b) is a magnetic field distribution diagram of an equivalent dipole array model provided in the embodiments of the present application at z=25 mm;
FIG. 6 is a schematic diagram of a field line coupling model of an integrated circuit radiating a single transmission line with an externally-shielded cavity according to an embodiment of the present application;
fig. 7 is a schematic diagram of a voltage response on a load R2 according to an embodiment of the present disclosure;
fig. 8 is a structural block diagram of an electromagnetic coupling time domain analysis system of a PCB electromagnetic leakage acting transmission line according to an embodiment of the present application.
Detailed Description
For the purpose of making apparent the objects, technical solutions and advantages of the present invention, the present invention will be further described in detail with reference to the following examples and the accompanying drawings, wherein the exemplary embodiments of the present invention and the descriptions thereof are for illustrating the present invention only and are not to be construed as limiting the present invention.
As described in the background, the conventional BLT equation constructs a transmission line and a reflection matrix based on electromagnetic topology theory, so as to implement rapid calculation of a terminal load response, but the algorithm reduces calculation efficiency when processing a coupling problem that an interference source is a broadband signal. The FDTD-SPICE method is based on a transmission line equation, a SPICE equivalent circuit model of the transmission line is constructed, an excitation field of the transmission line is obtained by combining FDTD, and then the transient response of the termination load is obtained by utilizing SPICE software simulation. However, this approach requires a large amount of formula derivation in the solution process and does not enable collaborative calculation of the spatial electromagnetic field radiation and the terminal load transient response. In addition, the existing field line coupling algorithm cannot be directly applied to electromagnetic coupling calculation of the transmission line with electromagnetic leakage effect of the integrated circuit of the device, because the fine structure of the integrated circuit of the device must be directly modeled when the full-wave algorithm is used for calculating the excitation field of the transmission line, which results in low calculation efficiency. Therefore, the embodiment provides an electromagnetic coupling time domain analysis method and an electromagnetic coupling time domain analysis system for a transmission line with a PCB electromagnetic leakage function, which combine an equivalent dipole method and an FDTD algorithm to form an efficient time domain mixing algorithm, realize the electromagnetic coupling rapid simulation of the transmission line with the PCB leakage field function, avoid the direct modeling of a fine structure of the PCB and the transmission line, realize the cooperative calculation of a space electromagnetic field and a transient response of the transmission line, and greatly improve the electromagnetic coupling efficiency of the transmission line with the analysis leakage field function, thereby providing technical support for the electromagnetic safety evaluation of electronic equipment.
Referring to fig. 1, fig. 1 is a schematic flow chart of an electromagnetic coupling time domain analysis method of a PCB electromagnetic leakage acting transmission line according to an embodiment of the present application, as shown in fig. 1, the method includes the following steps:
s110, constructing a mapping relation between the dipole array and the PCB electromagnetic leakage field, and solving the mapping relation in an inverse mode to obtain an equivalent dipole array model of the PCB electromagnetic leakage field.
As shown in fig. 2, fig. 2 is a schematic diagram of an electromagnetic coupling model of a typical transmission line for a leakage field of a printed circuit board, and the physical process includes: the PCB generates electromagnetic leakage and radiates in space to form electromagnetic field distribution; the spatial electromagnetic field acts on the transmission line coupling to generate a current signal that flows into the termination load causing interference. Therefore, in this embodiment, the mapping relationship between the dipole array and the PCB electromagnetic leakage field is constructed according to the mirroring principle and the green function, and the nature of the mapping relationship is a linear equation, so further, the mapping relationship is solved inversely, to obtain the equivalent dipole array model of the PCB electromagnetic leakage field.
As shown in fig. 3, the PCB is formed of a section of U-shaped microstrip line, with the start end excited with a lumped voltage source and the end loaded. It should be noted that, the present embodiment is directed to a PCB with a known design structure, and uses commercial electromagnetic simulation software to extract near-field magnetic field information of the PCB adjacent to the observation plane, so as to meet the verification requirement of the confidence level of the time-domain hybrid algorithm.
S120, simulating electromagnetic radiation of the equivalent dipole array model by using an FDTD method to obtain space radiation field distribution of the equivalent dipole array, and constructing a transmission line equation of a PCB electromagnetic leakage action transmission line according to the space radiation field distribution.
S130, performing differential dispersion on the transmission line equation by using a central differential format of the FDTD method, and performing iterative solution to obtain the transient response of voltage and current generated by coupling of the PCB leakage field on the transmission line.
In this embodiment, the distributed source term of the transmission line equation is irrelevant to the scattering field of the transmission line, so that direct modeling of the transmission line structure can be avoided, and a space step required by FDTD calculation is not required to be determined according to the fine size of the transmission line, so that the situation that the grid quantity is large and the calculation efficiency is low is avoided.
In one embodiment, constructing a mapping relationship between a dipole array and a PCB electromagnetic leakage field includes: acquiring near field information of PCB electromagnetic leakage, wherein a near field scanning technology is adopted to measure near field scanning points of the PCB electromagnetic leakage so as to obtain the near field information; the radiation source of the PCB electromagnetic leakage is equivalent through a dipole array, and the radiation field of the dipole array replaces near field information generated by the PCB electromagnetic leakage; and taking a relation matrix of a radiation field of the dipole array at any point in space and polar moment and magnetic moment of the array element as a mapping relation between the dipole array and the PCB electromagnetic leakage field, wherein the radiation field of the dipole array at any point in space is generated by co-radiation of the dipole array and a mirror image source thereof.
In this embodiment, an equivalent source of PCB electromagnetic leakage is extracted, primarily to obtain near field information of PCB leakage, typically measured using near field scanning techniques. Limited by experimental conditions, the verification requirement of the confidence level of the time domain mixing algorithm is met by designing a PCB with a known structure and extracting a near-field magnetic field of the PCB adjacent to the observation plane by using commercial electromagnetic simulation software. As shown in fig. 3, the PCB is formed of a section of U-shaped microstrip line, with the start end excited with a lumped voltage source and the end loaded.
Furthermore, according to the antenna radiation theory, the microstrip line structure generating electromagnetic leakage on the PCB is equivalent through the dipole array, and then the radiation field of the dipole array replaces the leakage field generated by the actual PCB. As a preferred embodiment, the number of the array elements of the dipole array is N, each array element is composed of two magnetic dipoles in a horizontal direction and one electric dipole in a vertical direction, where N is a positive integer, the two horizontal directions of the magnetic dipoles are x and y directions respectively, and the vertical direction of the electric dipoles is a z direction. Specifically, the number of array elements of the dipole array is N, each array element consists of 2 magnetic dipoles (M x And M is as follows y ) And 1 electric dipole (P) z ) Composition is prepared. Since the PCB substrate is an ideal conductor ground plane, in order to reduce diffraction effects of the dipole array at the edge of the substrate, the height of the dipole array is h and is distributed in a region 6h to 10h smaller than the substrate, where h represents the height of the dipole array from the substrate. According to the mirror image principle, the radiation field of the dipole array at any point in space is generated by the joint radiation of the dipole array and a mirror image source thereof, and the relation matrix of the near-field magnetic field radiated by the dipole array and the polar moment of the array element is expressed as follows:
In one embodiment, simulating electromagnetic radiation of the equivalent dipole array model using an FDTD method to obtain a spatial radiation field distribution of the equivalent dipole array comprises: determining magnetic field components generated by the magnetic dipole moment in the x direction and the y direction according to the amplitude and phase information of the magnetic dipole moment; dispersing magnetic field components generated by magnetic dipole moment in the x direction and the y direction by utilizing a differential format of an FDTD method to respectively obtain radiation field distribution of magnetic dipoles of near-field scanning points in the x direction and the y direction; describing electromagnetic radiation generated by a magnetic dipole by using Maxwell's equations according to the relation between magnetic current and magnetic moment;
converting Maxwell's equation into a scalar equation to obtain electromagnetic radiation generated by an electric dipole; determining a magnetic field component generated by the electric dipole moment in the z direction according to the amplitude and phase information of the electric dipole moment; dispersing magnetic field components generated by the electric dipole moment in the z direction by utilizing a differential format of an FDTD method to obtain the radiation field distribution of the electric dipoles of the near-field scanning points in the z direction;
the radiation field distribution of the magnetic dipoles of the near field scanning point in the x direction and the y direction and the radiation field distribution of the electric dipoles of the near field scanning point in the z direction are combined to obtain the space radiation field distribution of the equivalent dipole array in the x, y and z directions.
In this embodiment, for implementation of electromagnetic coupling time domain analysis of a transmission line, it is critical how to accurately obtain the spatial electromagnetic field distribution around the transmission line. Electromagnetic field distribution formed by PCB electromagnetic leakage in space can be obtained by simulating electromagnetic radiation of the equivalent dipole array through an FDTD method. The specific process is as follows:
according to magnetic current J m The relation with the magnetic moment M, the electromagnetic radiation generated by a magnetic dipole can be described by Maxwell's equationsThe method comprises the following steps:
Here, a magnetic moment M of one dipole x For example, the FDTD calculation formula for the dipole array electromagnetic radiation is derived. In this case, equation (2) is converted into a scalar equation and written as
At time t=nΔt and H x The nodes are
Equation (4) is discretized by using the differential format of FDTD to obtain H x At M x The FDTD iterative formula for the location is expressed as:
and the radiation field expressions of the y-direction magnetic dipole and the z-direction electric dipole in the FDTD calculation region are obtained by analogy, wherein the expressions are respectively:
In one embodiment, the differential discrete is performed on the transmission line equation by using a central differential format of the FDTD method, and the transient response of the voltage and the current generated by coupling the PCB leakage field on the transmission line is obtained by iterative solution, including: performing differential dispersion on the transmission line equation by using a central differential format of the FDTD method to obtain an iterative formula of voltage and current on the transmission line; and carrying out iterative solution by using an iterative formula of forward differential and backward differential pair voltage and current to obtain the transient response of the voltage and current generated by coupling the PCB leakage field on the transmission line.
In this embodiment, the transmission line in the electronic device is at a height from the conductive plate that is less than the minimum wavelength of the PCB leakage field, at which time the radiation effect of the transmission line is negligible. The electromagnetic coupling of a PCB leakage field acting multi-conductor transmission line is expressed using the transmission line equation:
wherein V (y, t) and I (y, t) are voltage and current vectors of the multi-wire, respectively. R, L, C, G are matrices of capacitive and inductive parameters, respectively, per unit length. V (V) F (y, t) and I F (y, t) represent the distributed voltage and current source terms, respectively.
The distributed source term of the transmission line equation is independent of the scattering field of the transmission line, and thus direct modeling of the transmission line structure can be avoided. In order to obtain the voltage response of the terminating load of the transmission line, the central differential format of FDTD is utilized to carry out differential dispersion on the formulas (8) and (9) to obtain an iterative formula of voltage and current on the transmission line, and then the forward differential and the backward differential are combined to calculate the voltage current response on the load of the transmission line.
Further, the transmission line equation includes a distributed voltage source equation and a distributed current source equation.
The embodiment also provides two specific calculation modes, as follows:
calculation example 1: and carrying out equivalent modeling on the packaged PCB structure, and verifying the correctness of the method by comparing the radiation magnetic field diagram of the original model and the equivalent model. The encapsulated PCB model is shown in FIG. 4, the dimensions of the PCB are 100mm by 1mm, and the dielectric substrate material is set to FR4. The U-shaped microstrip line is used as a main carrier of the PCB circuit, a 1V sinusoidal voltage signal is fed in from the left port of the microstrip line, and electromagnetic energy is conducted and radiated outwards along the microstrip line. And packaging a shielding cavity with the size of 120mm multiplied by 5mm around the PCB structure, wherein the upper surface of the shielding cavity is provided with a hole seam with the size of 20mm multiplied by 20mm, so as to simulate the leakage of the PCB, and the working frequency of the PCB for generating electromagnetic leakage is set to be 1GHz.
The defined equivalent source is composed of equivalent electromagnetic hybrid dipoles, the number of which is 11×11=121 according to the size of the packaged PCB structure, the plane size is 50mm×50mm, the plane height is 1mm, and the interval between the dipoles is 5mm. The magnetic field information at the heights of z=15 mm and z=25 mm is obtained through simulation by using electromagnetic simulation software, the plane size is selected to be 150mm multiplied by 150mm, and the interval between the field points in the x and y directions is 5mm.
Fig. 5 (a) and fig. 5 (b) show the magnetic field distribution contrast diagrams of the original packaging model and the equivalent dipole array model in the x and y directions on the plane with the dimensions of 150mm×150mm at the z=25mm, respectively, so that the reconstructed magnetic field distribution diagram can be well matched with the simulation result of the MOM method.
Calculation example 2: the single transmission line was irradiated using the equivalent dipole array of example 1 as a radiation source, as shown in fig. 6. Placing a package structure with a size L at the bottom 3 ×W 3 ×H 3 PEC plate of 200mm x 5mm, with one dimension L placed on the right side 4 ×W 3 ×H 4 Ideal conductive plate =5 mm×200mm, its material is PEC. The transmission line is placed along the Y-axis direction, and the length, the height and the radius of the transmission line are respectively as follows: 100mm, 15mm, 1mm. The load across the transmission line was 50 and 100 ohms, respectively.
Fig. 7 shows a voltage response graph obtained by simulation of the time domain mixing algorithm and the MOM method. It can be seen that when the time domain mixing algorithm is used for solving the field line coupling problem of the leakage field acting transmission line, the same calculation precision as that of MOM simulation can be maintained, and the correctness of the mixing algorithm is verified.
Based on the same inventive concept, corresponding to the electromagnetic coupling time domain analysis method of the PCB electromagnetic leakage acting transmission line described in the above embodiment, the present embodiment further provides an electromagnetic coupling time domain analysis system of the PCB electromagnetic leakage acting transmission line, please refer to fig. 8, fig. 8 is a block diagram of an electromagnetic coupling time domain analysis system of the PCB electromagnetic leakage acting transmission line provided in the present application, as shown in fig. 8, the system includes:
a first module 810, configured to construct a mapping relationship between the dipole array and the PCB electromagnetic leakage field, and solve the mapping relationship inversely to obtain an equivalent dipole array model of the PCB electromagnetic leakage field;
a second module 820, configured to simulate electromagnetic radiation of the equivalent dipole array model by using an FDTD method, so as to obtain a spatial radiation field distribution of the equivalent dipole array, and construct a transmission line equation of a PCB electromagnetic leakage acting transmission line according to the spatial radiation field distribution;
and the analysis module 830 is configured to perform differential discretization on the transmission line equation by using a central differential format of the FDTD method, and obtain a transient response of voltage and current generated by coupling the PCB leakage field on the transmission line by performing iterative solution.
According to the electromagnetic coupling time domain analysis system for the PCB electromagnetic leakage action transmission line, the equivalent dipole method and the FDTD algorithm are combined to form an efficient time domain mixing algorithm, so that the electromagnetic coupling of the PCB leakage field action transmission line is simulated rapidly, direct modeling of a fine structure of the PCB and the transmission line is avoided, cooperative calculation of a space electromagnetic field and transient response of the transmission line is realized, the electromagnetic coupling efficiency of the analysis leakage field action transmission line is improved greatly, and technical support is provided for electromagnetic safety assessment of electronic equipment.
In one embodiment, a first module comprises: the information acquisition module is used for acquiring near field information of the PCB electromagnetic leakage, wherein a near field scanning technology is adopted to measure near field scanning points of the PCB electromagnetic leakage so as to acquire the near field information; the equivalent module is used for carrying out equivalent on a transmission line structure corresponding to the near field information of the PCB electromagnetic leakage through the dipole array, and the radiation field of the dipole array replaces the near field information generated by the PCB electromagnetic leakage; the mapping relation construction module is used for taking a relation matrix of a radiation field of the dipole array at any point in space and polar moment and magnetic moment of the array element as a mapping relation between the dipole array and the PCB electromagnetic leakage field, wherein the radiation field of the dipole array at any point in space is generated by the common radiation of the dipole array and a mirror image source thereof.
In one embodiment, an analysis module includes: the differential discrete module is used for carrying out differential discrete on the transmission line equation by utilizing a central differential format of the FDTD method to obtain an iterative formula of voltage and current on the transmission line; and the transient response calculation module is used for carrying out iterative solution by utilizing an iterative formula of forward differential and backward differential pair voltage and current to obtain the transient response of the voltage and current generated by coupling the PCB leakage field on the transmission line.
The foregoing description of the embodiments has been provided for the purpose of illustrating the general principles of the invention, and is not meant to limit the scope of the invention, but to limit the invention to the particular embodiments, and any modifications, equivalents, improvements, etc. that fall within the spirit and principles of the invention are intended to be included within the scope of the invention.
Claims (10)
1. An electromagnetic coupling time domain analysis method of a transmission line for PCB electromagnetic leakage action is characterized by comprising the following steps:
constructing a mapping relation between the dipole array and the PCB electromagnetic leakage field, and solving the mapping relation inversely to obtain an equivalent dipole array model of the PCB electromagnetic leakage field;
simulating electromagnetic radiation of the equivalent dipole array model by using an FDTD method to obtain space radiation field distribution of an equivalent dipole array, and constructing a transmission line equation of a PCB electromagnetic leakage action transmission line according to the space radiation field distribution;
and performing differential discretization on the transmission line equation by using a central differential format of the FDTD method, and performing iterative solution to obtain the transient response of voltage and current generated by coupling of the PCB leakage field on the transmission line.
2. The method of claim 1, wherein constructing a mapping relationship between the dipole array and the leakage field of the PCB electromagnetic leakage action transmission line comprises:
acquiring near field information of PCB electromagnetic leakage, wherein a near field scanning technology is adopted to measure near field scanning points of the PCB electromagnetic leakage so as to obtain the near field information;
the radiation source of the PCB electromagnetic leakage is equivalent through a dipole array, and the radiation field of the dipole array replaces near field information generated by the PCB electromagnetic leakage;
and taking a relation matrix of a radiation field of the dipole array at any point in space and polar moment and magnetic moment of the array element as a mapping relation between the dipole array and the PCB electromagnetic leakage field, wherein the radiation field of the dipole array at any point in space is generated by co-radiation of the dipole array and a mirror image source thereof.
3. The method of claim 2, wherein the number of elements of the dipole array is N, each element is composed of two magnetic dipoles in a horizontal direction and one electric dipole in a vertical direction, wherein N is a positive integer, the two horizontal directions of the magnetic dipoles are x and y directions, respectively, and the vertical direction of the electric dipoles is z direction.
4. A method according to claim 3, wherein the number N of array elements of the dipole array is less than or equal to the number M of near field scanning points of the near field scanning technique.
5. A method according to claim 3, wherein simulating electromagnetic radiation of the equivalent dipole array model using the FDTD method to obtain a spatial radiation field distribution of the equivalent dipole array comprises:
determining magnetic field components generated by the magnetic dipole moment in the x direction and the y direction according to the amplitude and phase information of the magnetic dipole moment;
dispersing magnetic field components generated by magnetic dipole moment in the x direction and the y direction by utilizing a differential format of an FDTD method to respectively obtain radiation field distribution of magnetic dipoles of near-field scanning points in the x direction and the y direction;
describing electromagnetic radiation generated by a magnetic dipole by using Maxwell's equations according to the relation between magnetic current and magnetic moment;
converting Maxwell's equation into a scalar equation to obtain electromagnetic radiation generated by an electric dipole;
determining a magnetic field component generated by the electric dipole moment in the z direction according to the amplitude and phase information of the electric dipole moment;
dispersing magnetic field components generated by the electric dipole moment in the z direction by utilizing a differential format of an FDTD method to obtain the radiation field distribution of the electric dipoles of the near-field scanning points in the z direction;
the radiation field distribution of the magnetic dipoles of the near field scanning point in the x direction and the y direction and the radiation field distribution of the electric dipoles of the near field scanning point in the z direction are combined to obtain the space radiation field distribution of the equivalent dipole array in the x, y and z directions.
6. The method of claim 1, wherein performing differential discretization on the transmission line equation using a central differential format of the FDTD method, and iteratively solving for a transient response of voltage and current generated by coupling the PCB leakage field on the transmission line, comprises:
performing differential dispersion on the transmission line equation by using a central differential format of the FDTD method to obtain an iterative formula of voltage and current on the transmission line;
and carrying out iterative solution by using an iterative formula of forward differential and backward differential pair voltage and current to obtain the transient response of the voltage and current generated by coupling the PCB leakage field on the transmission line.
7. The method of claim 6, wherein the transmission line equation comprises a distributed voltage source equation and a distributed current source equation.
8. An electromagnetic coupling time domain analysis system for a PCB electromagnetic leakage acting transmission line, the system comprising:
the first module is used for constructing a mapping relation between the dipole array and the PCB electromagnetic leakage field, and solving the mapping relation in an inverse way to obtain an equivalent dipole array model of the PCB electromagnetic leakage field;
the second module is used for simulating electromagnetic radiation of the equivalent dipole array model by utilizing an FDTD method so as to obtain space radiation field distribution of the equivalent dipole array, and constructing a transmission line equation of a PCB electromagnetic leakage action transmission line according to the space radiation field distribution;
and the analysis module is used for carrying out differential discretization on the transmission line equation by utilizing a central differential format of the FDTD method, and carrying out iterative solution to obtain the transient response of the voltage and the current generated by coupling of the PCB leakage field on the transmission line.
9. The system of claim 8, wherein the first module comprises:
the information acquisition module is used for acquiring near field information of the PCB electromagnetic leakage, wherein a near field scanning technology is adopted to measure near field scanning points of the PCB electromagnetic leakage so as to acquire the near field information;
the equivalent module is used for carrying out equivalent on the near field of the PCB electromagnetic leakage through the dipole array, and the radiation field of the dipole array replaces near field information generated by the PCB electromagnetic leakage;
the mapping relation construction module is used for taking a relation matrix of a radiation field of the dipole array at any point in space and polar moment and magnetic moment of the array element as a mapping relation between the dipole array and the PCB electromagnetic leakage field, wherein the radiation field of the dipole array at any point in space is generated by the common radiation of the dipole array and a mirror image source thereof.
10. The system of claim 8, wherein the analysis module comprises:
the differential discrete module is used for carrying out differential discrete on the transmission line equation by utilizing a central differential format of the FDTD method to obtain an iterative formula of voltage and current on the transmission line;
and the transient response calculation module is used for carrying out iterative solution by utilizing an iterative formula of forward differential and backward differential pair voltage and current to obtain the transient response of the voltage and current generated by coupling the PCB leakage field on the transmission line.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310443266.2A CN116436546A (en) | 2023-04-21 | 2023-04-21 | Electromagnetic coupling time domain analysis method and system for PCB electromagnetic leakage acting transmission line |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310443266.2A CN116436546A (en) | 2023-04-21 | 2023-04-21 | Electromagnetic coupling time domain analysis method and system for PCB electromagnetic leakage acting transmission line |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116436546A true CN116436546A (en) | 2023-07-14 |
Family
ID=87081358
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310443266.2A Pending CN116436546A (en) | 2023-04-21 | 2023-04-21 | Electromagnetic coupling time domain analysis method and system for PCB electromagnetic leakage acting transmission line |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116436546A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117634187A (en) * | 2023-11-28 | 2024-03-01 | 北京航空航天大学 | Safety threshold evaluation method for harm of electromagnetic field coupling discharge to fuel oil |
-
2023
- 2023-04-21 CN CN202310443266.2A patent/CN116436546A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117634187A (en) * | 2023-11-28 | 2024-03-01 | 北京航空航天大学 | Safety threshold evaluation method for harm of electromagnetic field coupling discharge to fuel oil |
| CN117634187B (en) * | 2023-11-28 | 2024-06-07 | 北京航空航天大学 | Safety threshold evaluation method for harm of electromagnetic field coupling discharge to fuel oil |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Zhang et al. | Source reconstruction for IC radiated emissions based on magnitude-only near-field scanning | |
| Huang et al. | Physics-based dipole moment source reconstruction for RFI on a practical cellphone | |
| Pan et al. | Radio-frequency interference estimation using equivalent dipole-moment models and decomposition method based on reciprocity | |
| Tong et al. | Modeling electromagnetic emissions from printed circuit boards in closed environments using equivalent dipoles | |
| CN101625388B (en) | Method for detecting coupling response of cable under excitation of electromagnetic wave | |
| CN101697177B (en) | Method for modeling field-path cooperative model for predicting field line coupled system response | |
| Radchenko et al. | Transfer function method for predicting the emissions in a CISPR-25 test-setup | |
| Wang et al. | Reconstruction of equivalent emission sources for PCBs from near-field scanning using a differential evolution algorithm | |
| Hwang et al. | IC placement optimization for RF interference based on dipole moment sources and reciprocity | |
| Archambeault et al. | Electromagnetic radiation resulting from PCB/high-density connector interfaces | |
| CN116436546A (en) | Electromagnetic coupling time domain analysis method and system for PCB electromagnetic leakage acting transmission line | |
| Huang et al. | MoM-based ground current reconstruction in RFI application | |
| Yu et al. | Heat-sink modeling and design with dipole moments representing IC excitation | |
| Wang et al. | A hybrid CN-FDTD-SPICE solver for field-circuit analyses in low-frequency wideband problems | |
| Li et al. | Radio-frequency interference estimation by reciprocity theorem with noise source characterized by Huygens's equivalent model | |
| Ding et al. | Near-field scanning based shielding effectiveness analysis of system in package | |
| Li et al. | An efficient approach for analyzing shielding effectiveness of enclosure with connected accessory based on equivalent dipole modeling | |
| Leone et al. | On the electromagnetic radiation of printed-circuit-board interconnections | |
| Dahl et al. | Efficient simulation of substrate-integrated waveguide antennas using a hybrid boundary element method | |
| Hsieh et al. | A new approach for fast analysis of spurious emissions from RF/microwave circuits | |
| Volski et al. | Auxiliary dipoles to compensate for the finite size of the planar scanning area in near-to-far-field transformations | |
| CN111079357A (en) | Electromagnetic interference time domain analysis method of microstrip line on PCB under action of electromagnetic wave | |
| Raad et al. | Inverse MoM approach to near-field prediction and RFI estimation in electronic devices with multiple radiating elements | |
| Ke et al. | Modeling radiated emissions due to power bus noise from circuit boards with attached cables | |
| Wu et al. | An Improved dipole extraction method from magnitude-only electromagnetic-field data |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |