CN115684780A

CN115684780A - Electromagnetic signal measuring method, device, computer equipment and storage medium

Info

Publication number: CN115684780A
Application number: CN202211311468.3A
Authority: CN
Inventors: 邵伟恒; 薛姗
Original assignee: China Electronic Product Reliability and Environmental Testing Research Institute
Current assignee: China Electronic Product Reliability and Environmental Testing Research Institute
Priority date: 2022-10-25
Filing date: 2022-10-25
Publication date: 2023-02-03

Abstract

The application relates to an electromagnetic signal measuring method, an electromagnetic signal measuring device, computer equipment and a storage medium. The method comprises the following steps: firstly, acquiring a near-field probe calibration matrix of an electromagnetic near-field probe calibration system, wherein the near-field probe calibration matrix is generated based on the characteristics of transmission signals of the electromagnetic near-field probe calibration system in closed loops of different loads; then, correcting the initial electromagnetic signal of the electronic equipment to be tested according to the near-field probe calibration matrix to obtain a standard electromagnetic signal of the electronic equipment to be tested; and finally, determining an electromagnetic interference result of the tested electronic equipment according to the standard electromagnetic signal. The initial electromagnetic signal is obtained by measuring the electronic equipment to be tested through an electromagnetic field probe connected with the electromagnetic near-field probe calibration system. By adopting the method, the electromagnetic interference condition of the electronic equipment can be accurately analyzed.

Description

Electromagnetic signal measuring method, device, computer equipment and storage medium

Technical Field

The present application relates to the field of signal processing, and in particular, to an electromagnetic signal measurement method, apparatus, computer device, and storage medium.

Background

With the trend of miniaturization and high frequency of electronic devices, electromagnetic Interference (EMI) is becoming a technical bottleneck for improving the performance of electronic devices. Based on this, the electromagnetic interference problem of the electronic device can be diagnosed and analyzed by measuring the electromagnetic signal on the electronic device.

In the related art, a near field probe is usually connected with a network analyzer to form an electromagnetic near field probe calibration system, an electromagnetic signal of an electronic device is measured by the near field probe, and then the network analyzer analyzes the electromagnetic interference condition of the electronic device according to the electromagnetic signal measured by the near field probe.

However, the related art cannot accurately analyze the electromagnetic interference condition of the electronic device.

Disclosure of Invention

In view of the above, it is necessary to provide an electromagnetic signal measuring method, an apparatus, a computer device and a storage medium capable of accurately analyzing the electromagnetic interference condition of an electronic device.

In a first aspect, the present application provides an electromagnetic signal measurement method, applied to an electromagnetic near-field probe calibration system, including:

acquiring a near-field probe calibration matrix of the electromagnetic near-field probe calibration system; the near-field probe calibration matrix is generated based on the characteristics of transmission signals of the electromagnetic near-field probe calibration system in closed loops of different loads;

correcting the initial electromagnetic signal of the electronic equipment to be tested according to the near-field probe calibration matrix to obtain a standard electromagnetic signal of the electronic equipment to be tested; the initial electromagnetic signal is obtained by measuring the electronic equipment to be tested through an electromagnetic field probe connected with the electromagnetic near-field probe calibration system;

and determining the electromagnetic interference result of the tested electronic equipment according to the standard electromagnetic signal.

In one embodiment, a near field probe calibration matrix for an electromagnetic near field probe calibration system is obtained, comprising:

acquiring scattering coefficient transmission parameters of a plurality of calibration pieces through the plurality of calibration pieces connected with the electromagnetic near-field probe calibration system; each calibration piece is used as a standard piece error generation source of the electromagnetic near-field probe calibration system, and each calibration piece is connected with the electromagnetic near-field probe calibration system to form a closed loop with different loads;

and generating a near-field probe calibration matrix according to the scattering coefficient transmission parameters of the plurality of calibration pieces.

In one embodiment, acquiring scattering coefficient transmission parameters of a calibration piece through a plurality of calibration pieces connected with an electromagnetic near-field probe calibration system comprises:

acquiring a closed loop corresponding to each calibration piece and the electromagnetic near-field probe calibration system through a plurality of calibration pieces connected with the electromagnetic near-field probe calibration system;

acquiring a plurality of transmission parameters of the electromagnetic near-field probe calibration system in each closed loop according to the transmission characteristics of each closed loop;

and acquiring scattering coefficient transmission parameters of the electromagnetic near-field probe calibration system in each calibration piece according to a plurality of transmission parameters of the electromagnetic near-field probe calibration system in each closed loop.

In one embodiment, if the calibration member is a straight-through calibration member, the closed loop is a first straight-through loop;

if the calibration piece is a transmission line calibration piece, the closed loop is a second through loop.

In one embodiment, the scattering coefficient transmission parameters of the plurality of calibration pieces generate a near field probe calibration matrix, comprising:

acquiring a standard impedance parameter matrix between ports of an electromagnetic near-field probe calibration system;

acquiring a test port parameter matrix between ports of the electromagnetic near-field probe calibration system according to the scattering coefficient transmission parameters of the plurality of calibration pieces;

and generating a near-field probe calibration matrix according to the standard impedance parameter matrix and the test port parameter matrix.

In one embodiment, acquiring a test port parameter matrix between ports of an electromagnetic near-field probe calibration system according to scattering coefficient transmission parameters of a plurality of calibration pieces includes:

calculating an error parameter matrix according to the scattering coefficient transmission parameters;

and acquiring a test port parameter matrix between the ports of the electromagnetic near-field probe calibration system according to the error parameter matrix.

In one embodiment, generating a near field probe calibration matrix from the standard impedance parameter matrix and the test port parameter matrix comprises:

fusing the test port parameter matrix into a standard impedance parameter matrix to obtain a fused port parameter matrix;

and performing digital domain conversion processing on the fusion port parameter matrix to obtain a near-field probe calibration matrix.

In a second aspect, the application further provides an electromagnetic signal measuring device applied to the electromagnetic near-field probe calibration system. The device includes:

the matrix acquisition module is used for acquiring a near-field probe calibration matrix of the electromagnetic near-field probe calibration system; the near-field probe calibration matrix is generated based on the characteristics of transmission signals of the electromagnetic near-field probe calibration system in closed loops of different loads;

the signal acquisition module is used for correcting the initial electromagnetic signal of the electronic equipment to be tested according to the near-field probe calibration matrix to obtain a standard electromagnetic signal of the electronic equipment to be tested; the initial electromagnetic signal is obtained by measuring the electronic equipment to be tested through an electromagnetic field probe connected with the electromagnetic near-field probe calibration system;

and the result determining module is used for determining the electromagnetic interference result of the tested electronic equipment according to the standard electromagnetic signal.

In a third aspect, the present application also provides a computer device. The computer device comprises a memory storing a computer program and a processor implementing the steps of the method in any of the embodiments of the first aspect described above when the processor executes the computer program.

In a fourth aspect, the present application further provides a computer-readable storage medium. The computer-readable storage medium having stored thereon a computer program which, when executed by a processor, performs the steps of the method in any of the embodiments of the first aspect described above.

In a fifth aspect, the present application further provides a computer program product. The computer program product comprising a computer program that, when executed by a processor, performs the steps of the method in any of the embodiments of the first aspect described above.

According to the electromagnetic signal measuring method, the electromagnetic signal measuring device, the computer equipment and the storage medium, firstly, a near field probe calibration matrix of an electromagnetic near field probe calibration system is obtained, and the near field probe calibration matrix is generated based on the characteristics of transmission signals of the electromagnetic near field probe calibration system in closed loops of different loads; then, correcting the initial electromagnetic signal of the electronic equipment to be tested according to the near-field probe calibration matrix to obtain a standard electromagnetic signal of the electronic equipment to be tested; and finally, determining an electromagnetic interference result of the tested electronic equipment according to the standard electromagnetic signal. The initial electromagnetic signal is obtained by measuring the electronic equipment to be tested through an electromagnetic field probe connected with the electromagnetic near-field probe calibration system. The method is characterized in that on the basis of an initial electromagnetic signal, the obtained standard electromagnetic signal is obtained by combining a near-field probe calibration matrix generated by an electromagnetic near-field probe calibration system in closed loops of different loads. In the process of measuring the electromagnetic signal of the electronic device to be measured, the influence of the measuring part except the near-field probe in the electromagnetic near-field probe calibration system on the measuring result is considered, and the influencing factor is quantized into a near-field probe calibration matrix, so that the obtained measuring result of the electromagnetic signal of the electronic device to be measured is more accurate.

Drawings

FIG. 1 is a diagram of an exemplary embodiment of an electromagnetic signal measurement method;

FIG. 2 is a schematic flow chart of an electromagnetic signal measurement method in one embodiment;

FIG. 3 is a schematic flow chart illustrating a method for acquiring a calibration matrix of a near field probe according to an embodiment;

FIG. 4 is a schematic flow chart illustrating a method for obtaining scattering coefficient transmission parameters according to an embodiment;

FIG. 5 is a schematic diagram of a through alignment member according to one embodiment;

FIG. 6 is a schematic diagram of a transfer calibration piece in one embodiment;

FIG. 7 is a schematic flow chart illustrating a method for acquiring a calibration matrix of a near field probe according to another embodiment;

FIG. 8 is a schematic diagram of a probe measurement calibration model according to an embodiment;

FIG. 9 is a flowchart illustrating a method for obtaining a test port parameter matrix according to an embodiment;

FIG. 10 is a schematic flowchart of a method for acquiring a calibration matrix of a near field probe according to another embodiment;

FIG. 11 is a block diagram showing the structure of an electromagnetic signal measuring apparatus according to an embodiment;

FIG. 12 is a diagram illustrating an internal structure of a computer device according to an embodiment.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

The electromagnetic signal measuring method provided by the embodiment of the application can be applied to the application environment shown in fig. 1. The electromagnetic near-field probe calibration system 102 comprises a network analyzer 1021 and a near-field probe 1022, the near-field probe 1022 is provided with a probe, and when the probe moves on the surface of the electronic device 104 to be tested, the network analyzer 1021 acquires an electromagnetic signal of the electronic device 104 to be tested.

Generally, an electromagnetic field signal generated on the surface of an electronic device is measured by using a near field probe, and a microstrip line or a grounded coplanar waveguide (GCPW) is a very practical ultra wide band near field probe calibration method as a standard magnetic field source. The design, characterization and application of near field probes has been extensively studied in recent years as a practical tool for diagnostic analysis of electromagnetic interference. The main applications of the near field probe include conductive emission measurement, radiative emission measurement, electromagnetic interference source location, signal and noise measurement, insulated Gate Bipolar Transistor (IGBT) fault location, and the like. These applications are related to the characteristics of the probe, such as Frequency Response (FR), calibration Factor (CF), and Common Mode Rejection Ratio (CMRR).

It is considered that in most near field probe calibration methods, the frequency of the electromagnetic field limits the range of calibration. The related art proposes a calibration method using a standard electromagnetic field established in a Transverse Electric and Magnetic (TEM) chamber that can generate the standard electromagnetic field. Since the size of the probe is much smaller than the lateral electromagnetic field, the probe has little effect on the electromagnetic field, and is therefore a relatively accurate method of probe calibration. However, the frequency of the magnetic field established by this method is still limited by the frequency of the electromagnetic field, the frequency range up to 20GHz cannot be calibrated, and the measurement setup is very complicated. On the basis, the related art proposes a Gigahertz Transverse Electromagnetic (GTEM) unit method, a parallel plate method for calculating a probe of 9kHz to 100MHz, and a tapered transmission line method for calculating a probe of 9kHz to 20GHz, so as to generate an electromagnetic field with a wider frequency range, which facilitates the near-field probe to detect electromagnetic signals of electronic equipment.

While the above approach addresses the ultra-wideband frequency limitation, there are still some calibration issues that need to be addressed. One of the problems is that the calibration curve of the ultra-wideband near-field probe calibration method will be affected by embedded parts that ideally are not necessary but must be embedded to make measurements.

The related art proposes a calibration method based on an air or dielectric transmission line (e.g., a microstrip structure or a grounded coplanar waveguide structure) as a common method of a magnetic field probe. However, this approach may introduce other problems such as ripple of the CF, attenuation of the calibrator, and phase delay. These problems do not come from the probe itself, but from the embedded part of the calibrator. Based on the above, the embodiment of the present application provides a new electromagnetic signal measurement method based on a symmetric de-embedding technique of a GCPW calibrator, in which the influence of an embedded portion of the calibrator on a measurement result is quantized into a calibration matrix, and an initial measurement result is calculated according to the calibration matrix, so as to effectively reduce the influence of the embedded portion on a calibration curve, including reducing ripples, compensating for frequency response, and attenuating and phase delay of calibration factors.

In order to accurately analyze the electromagnetic interference condition of the electronic device, the present application provides an electromagnetic signal measuring method, which is described by taking the electromagnetic near-field probe calibration system 102 in fig. 1 as an example in the present embodiment, and as shown in fig. 2, the measuring method includes the following steps:

s220, acquiring a near-field probe calibration matrix of the electromagnetic near-field probe calibration system; the near field probe calibration matrix is generated based on characteristics of transmission signals of the electromagnetic near field probe calibration system in closed loops of different loads.

The electromagnetic near-field probe calibration system is a device for measuring electromagnetic signals of equipment, and specifically comprises a network analyzer and a near-field probe. The network analyzer is a new type of instrument for measuring network parameters, and can directly measure complex scattering parameters of active or passive, reversible or irreversible double-port and single-port networks, and give out amplitude and phase frequency characteristics of each scattering parameter in a frequency scanning mode. In the embodiment of the application, the network analyzer can be a vector network analyzer of electromagnetic wave energy, and can measure various parameter amplitudes and phases of a single-port network or a two-port network.

The near-field probe calibration matrix represents the difference between the measurement data of the tested electronic equipment and the actual data of the tested electronic equipment obtained by the network analyzer. When the network analyzer measures the electronic device to be tested, some embedded devices, such as a calibrator and a test cable, are usually included, and the embedded devices affect the accuracy of the measured data of the electronic device to be tested, thereby causing measurement errors. At the moment, the measurement result is corrected according to the near-field probe calibration matrix, so that the measurement error of the embedded equipment on the test data can be eliminated.

It should be noted that the embedded device is fixed during each measurement, and the measurement error generated by the embedded device during each measurement is also fixed. And correcting the measurement result according to the near-field probe calibration matrix generated by the embedded equipment during each measurement so as to eliminate the measurement error generated by the embedded equipment. That is, for the same measurement device, since the embedded device is the same, the near field probe calibration matrix is also the same, i.e., the near field probe calibration matrix has repeatability.

Specifically, the network analyzer is connected with different calibration pieces, electromagnetic near-field probe calibration systems corresponding to the different calibration pieces are constructed, then errors contained when the electromagnetic near-field probe calibration systems are connected with the near-field probe are obtained according to measurement parameters of the different electromagnetic near-field probe calibration systems, and the errors are used as a near-field probe calibration matrix to correct electromagnetic signals of the electronic device to be tested.

S240, correcting the initial electromagnetic signal of the electronic equipment to be tested according to the near-field probe calibration matrix to obtain a standard electromagnetic signal of the electronic equipment to be tested; the initial electromagnetic signal is obtained by measuring the electronic equipment to be tested through an electromagnetic field probe connected with the electromagnetic near-field probe calibration system.

The near-field probe is a device used for matching with a spectrum analyzer to search for an interference source. The near field probe may be classified into an electric field probe and a magnetic field probe according to the type of an electromagnetic field. If the voltage is high and the current is weak, the electric field plays a greater role, and an electric field probe is selected; if the voltage is low, the current is strong, the magnetic field plays a greater role, and the magnetic field probe is selected. It should be noted that, when the probe is gradually far away from the electronic device to be tested during near field measurement, the aging rate of the magnetic field is faster than that of the electric field, so the magnetic field probe is mostly used as the near field probe.

Specifically, the initial electromagnetic signal is obtained by moving the near-field probe on the surface of the electronic device to be tested, the near-field probe receives the electromagnetic signal of the electronic device to be tested, and then the near-field probe is connected with a port of the network analyzer and transmits the received electromagnetic signal to the network analyzer, and the network analyzer takes the electromagnetic signal of the electronic device to be tested, which is received by the near-field probe, as the initial electromagnetic signal.

Furthermore, the standard electromagnetic signal is obtained by obtaining an initial electromagnetic signal and a near-field probe calibration matrix of the electronic device to be tested, and then calculating according to the initial electromagnetic signal and the near-field probe calibration matrix, and outputting the standard electromagnetic signal of the electronic device to be tested.

Optionally, the near field probe calibration matrix may be embedded into a network analyzer, and the network analyzer outputs a standard electromagnetic signal of the electronic device to be tested according to the initial electromagnetic signal of the electronic device to be tested and the near field probe calibration matrix.

Optionally, the initial electromagnetic signal and the near-field probe calibration matrix may be input to the computer device, and the initial electromagnetic signal and the near-field probe calibration matrix are processed according to an algorithm preset by the computer device to obtain a standard electromagnetic signal of the electronic device to be tested.

And S260, determining an electromagnetic interference result of the tested electronic equipment according to the standard electromagnetic signal.

It should be noted that, when the near-field probe is continuously moving on the surface of the electronic device to be tested, the standard electromagnetic signal of the electronic device to be tested is continuous, and the electromagnetic interference condition of the electronic device to be tested is determined according to the continuous standard electromagnetic signal. Specifically, if the standard electromagnetic signal of the tested electronic equipment fluctuates within a preset range, the development and the use of the tested electronic equipment are represented to be normal; if the electromagnetic signal of the tested electronic equipment fluctuates greatly, the position of the tested electronic equipment corresponding to the near-field probe at the moment can be preliminarily judged as a fault point of the tested electronic equipment, and the position with the maximum fluctuation amplitude of the standard electromagnetic signal is the position with the most serious electromagnetic signal leakage of the tested electronic equipment, namely the interference source of the tested electronic equipment.

The electromagnetic signal measuring method provided by the embodiment of the application comprises the steps of firstly, acquiring a near-field probe calibration matrix of an electromagnetic near-field probe calibration system, wherein the near-field probe calibration matrix is generated based on the characteristics of transmission signals of the electromagnetic near-field probe calibration system in closed loops of different loads; then, correcting the initial electromagnetic signal of the electronic equipment to be tested according to the near-field probe calibration matrix to obtain a standard electromagnetic signal of the electronic equipment to be tested; and finally, determining an electromagnetic interference result of the tested electronic equipment according to the standard electromagnetic signal. The initial electromagnetic signal is obtained by measuring the electronic equipment to be tested through an electromagnetic field probe connected with the electromagnetic near-field probe calibration system. The method is characterized in that on the basis of an initial electromagnetic signal, the obtained standard electromagnetic signal is obtained by combining a near-field probe calibration matrix generated by an electromagnetic near-field probe calibration system in closed loops of different loads. In the process of measuring the electromagnetic signal of the electronic device to be measured, the influence of the measuring part except the near-field probe in the electromagnetic near-field probe calibration system on the measuring result is considered, and the influencing factor is quantized into a near-field probe calibration matrix, so that the obtained measuring result of the electromagnetic signal of the electronic device to be measured is more accurate.

When acquiring the electromagnetic signal of the electronic device to be tested, the near-field probe calibration matrix and the measured electromagnetic signal are generally combined to perform calculation so as to acquire an accurate standard electromagnetic signal. Based on this, a specific acquisition manner of the near field probe calibration matrix is described below by an embodiment.

In one embodiment, as shown in FIG. 3, the process of acquiring a near-field probe calibration matrix of an electromagnetic near-field probe calibration system comprises the steps of:

s320, acquiring scattering coefficient transmission parameters of a plurality of calibration pieces through the plurality of calibration pieces connected with the electromagnetic near-field probe calibration system; and each calibration piece is used as a standard piece error generation source of the electromagnetic near-field probe calibration system, and forms a closed loop with different loads after being connected with the electromagnetic near-field probe calibration system.

Wherein the scattering coefficient transmission parameters include return loss, back transmission coefficient, insertion loss, and reflection coefficient. Specifically, return loss and insertion loss transmission parameters are obtained according to the transmission loss characteristic of the closed loop, and a reverse transmission coefficient and a reflection coefficient are obtained according to the forward and reverse transmission characteristic of the closed loop.

When the electromagnetic near-field probe calibration system is connected with the near-field probe, the electromagnetic near-field probe calibration system can also be connected with embedded equipment related to the near-field probe, and errors generated by the embedded equipment can influence the final measurement result. In order to accurately quantify the influence of the embedded equipment on the measurement result, different calibration pieces are used as error generation sources of the electromagnetic near-field probe calibration system, and the scattering coefficient transmission parameters of the different calibration pieces are obtained by connecting a network analyzer with the different calibration pieces to form a closed loop. The calibration piece and the network analyzer can be directly connected to form an electromagnetic near-field probe calibration system, and can also be connected with other embedded equipment to form the electromagnetic near-field probe calibration system.

And S340, generating a near field probe calibration matrix according to the scattering coefficient transmission parameters of the plurality of calibration pieces.

The port of the network analyzer connected with the calibration piece is used as an actual port, the port of the network analyzer connected with the calibration piece after the error caused by the embedded equipment is removed is used as a virtual port, and the near field probe calibration matrix represents the error conversion relation between the actual port and the virtual port.

After acquiring multiple sets of scattering coefficient transmission parameters, a near field probe calibration matrix needs to be calculated. Specifically, firstly, conversion parameters of each group of actual ports and virtual ports are respectively obtained according to calculation of a plurality of groups of scattering coefficient transmission parameters, and then a matrix expression of each group of actual ports and virtual ports is obtained by combining matrix forms of each group of actual ports and virtual ports; then, substituting the matrix expression of each group of actual ports and virtual ports into the expression of the actual ports to obtain the matrix expression of the actual ports and the virtual ports; and taking the matrix expression of the actual ports and the virtual ports as a near field probe calibration matrix.

In the embodiment of the application, the scattering coefficient transmission parameters acquired by the plurality of calibration pieces are used for calculating the near field probe calibration matrix, the errors of the electromagnetic near field probe calibration system are acquired in a plurality of dimensionality representations, and the effectiveness of the near field probe calibration matrix is improved.

When the scattering coefficient transmission parameter is obtained, a closed loop is generally constructed according to a plurality of different loads, so as to improve the reliability of the scattering coefficient transmission parameter. Based on this, a specific manner of acquiring the scattering coefficient transmission parameter of the network analyzer is described below by an embodiment.

In one embodiment, as shown in fig. 4, the process of obtaining the scattering coefficient transmission parameter of the network analyzer through a plurality of calibration pieces connected to the network analyzer comprises the following steps:

and S420, acquiring a closed loop corresponding to each calibration piece and the electromagnetic near-field probe calibration system through the plurality of calibration pieces connected with the electromagnetic near-field probe calibration system.

Two ports of the network analyzer are connected with two ends of a calibration piece, and the ports of the network analyzer are connected with input voltage and input current, so that a closed loop comprising a standard piece and the network analyzer is obtained. When the network analyzer is connected with different calibration pieces, different closed loops are formed correspondingly.

Wherein, the calibration piece comprises a through calibration piece and a transmission line calibration piece. The selection of the standard is described with reference to fig. 5 to 6, fig. 5 is a schematic structural diagram of the through calibration piece, fig. 6 is a schematic structural diagram of the transmission calibration piece, and in fig. 5 to 6, a ₃ And b ₃ The port represents a port of the calibration piece, a ₄ And b ₄ The port represents the other port of the calibration piece, and the two ports of the calibration piece are simultaneously connected with the two ports of the network analyzer to form a closed loop. In the calculation process of the near field probe calibration matrix, the requirement of selecting the calibration piece is that the transmission line is longer than the through line.

Based on this, the selection criteria of the direct calibration element and the transmission line calibration element are explained as follows:

(1) Straight-through calibration piece

When the electrical length of the straight-through standard component is 0, the straight-through standard component has no loss and no reflection, and the transmission coefficient is 1; when the electrical length is not 0, the characteristic impedance of the through standard must be the same as that of the delay line standard without knowing the loss, and if used as a reference measurement plane, the specific value of the electrical length of the through standard must be known, and at the same time, if the group delay is set to 0, the reference measurement plane is located in the middle of the through standard.

(2) Transmission line/matched load calibration piece

The characteristic impedance of the transmission line is used as a reference impedance at the time of measurement, and the system impedance is defined to be in agreement with the characteristic impedance of the delay line. The insertion phase difference between the transmission line and the through line of the through calibration member must be between 20 degrees and 160 degrees (or-20 degrees to-160 degrees), and if the phase difference is close to 0 or 180 degrees, phase ambiguity is easily caused due to the characteristics of the tangent function. In addition, the optimum phase difference value is generally 1/4 wavelength or 90 degrees.

The transmission line calibration element is implemented by 2 100 Ω surface mounted impedances, and it is generally much easier to design a load at a low frequency than at a high frequency, which is one of the reasons for using multiple delay line standards when designing the calibration element at a high frequency.

The phase of the transmission line is related to the phase velocity, corresponding to the frequency, and the effective dielectric constant of the signal as it propagates. The microstrip line does not have a fixed dielectric constant, so the effective dielectric constant must be used to consider the influence of the mixed air and PCB board. The frequency ranges of the plurality of transmission lines preferably overlap during design, thereby ensuring that the plurality of transmission lines cover the desired frequency range.

When the operating frequency range is greater than 8:1, i.e., the ratio of the frequency span to the starting frequency is greater than 8, more than 1 transmission line must be used in order to cover the entire frequency range. When the operating frequency is too high, the physical size of the transmission line with 1/4 wavelength is short and is not good to make, at this time, a straight line with length different from 0 is generally selected, and the difference between the two is used to increase the physical size of the delay line.

The matched impedance also establishes the reference impedance at the time of measurement, while the reflection coefficient of the matched load must be the same at each test port.

And S440, acquiring a plurality of transmission parameters of the electromagnetic near-field probe calibration system in each closed loop according to the transmission characteristics of each closed loop.

The transmission characteristics include loss, dispersion, attenuation, polarization, nonlinear effect, and the like, and the corresponding transmission parameters include impedance loss, frequency attenuation, and the like. In the embodiment of the application, in a closed loop, according to the transmission loss characteristic, four transmission parameters of return loss, insertion loss, reverse transmission coefficient and reflection coefficient of a port of a network analyzer are obtained.

And S460, acquiring scattering coefficient transmission parameters of the electromagnetic near-field probe calibration system in each calibration piece according to a plurality of transmission parameters of the electromagnetic near-field probe calibration system in each closed loop.

A closed loop corresponds to a calibration piece and a group of transmission parameters, wherein the group of transmission parameters comprises four transmission parameters of return loss, reverse transmission coefficient, insertion loss and reflection coefficient. Then, for a plurality of closed loops, a plurality of sets of scattering coefficient transmission parameters are acquired. For example, if the network analyzer and two standards form a closed loop 1 and a closed loop 2, respectively, four transmission parameters of return loss, reverse transmission coefficient, insertion loss and reflection coefficient are generated in each closed loop, and the four transmission parameters form a group of scattering coefficient transmission parameters; because the two closed loops are adopted, 8 transmission parameters and two groups of scattering coefficient transmission parameters are generated in total.

In the embodiment of the application, the manufacturing cost of the calibration piece is low, a loop is formed by the calibration pieces and the network analyzer, the scattering coefficient transmission parameters are obtained, and the accuracy of the scattering coefficient transmission parameters can be ensured while the measurement cost is controlled.

The method comprises the steps that a through calibration piece is connected with a network analyzer to obtain a first through loop corresponding to the through calibration piece; and then obtaining the return loss, the reverse transmission coefficient, the insertion loss and the reflection coefficient of the first straight-through calibration piece according to the transmission characteristic of the first straight-through loop.

The transmission line calibration piece is connected with the network analyzer to obtain a second straight-through loop corresponding to the transmission line calibration piece; and then according to the transmission characteristics of the first transmission line loop, obtaining the return loss, the reverse transmission coefficient, the insertion loss and the reflection coefficient of the first transmission line calibration piece.

When acquiring electromagnetic signals of the electronic equipment to be tested, calculation is generally performed by calibration error data of a network analyzer to acquire more accurate system error data. Based on this, a specific acquisition manner of the near field probe calibration matrix is described below by an embodiment.

In one embodiment, as shown in fig. 7, the process of generating a near field probe calibration matrix based on the scattering coefficient transmission parameters of the plurality of calibration pieces comprises the steps of:

s720, acquiring a standard impedance parameter matrix between the ports of the electromagnetic near-field probe calibration system.

The standard impedance parameter matrix refers to known impedance between ports of the network analyzer. If the network analyzer has three actual ports in the measurement process, the three actual ports are respectively the port 2, the port 3 and the port 4. Then, the standard impedance parameter matrix is represented as:

u in equation 1 _i Represents the input voltage of port I, I _i Representing the input current, Z, of port i _ij Representing the impedance of port i to port j.

And S740, acquiring a test port parameter matrix among the ports of the electromagnetic near-field probe calibration system according to the scattering coefficient transmission parameters of the plurality of calibration pieces.

And taking a port of the network analyzer connected with the calibration piece as an actual port, taking the port of the network analyzer connected with the calibration piece after the error of the near-field probe is removed as a virtual port, and representing the error conversion relation between the actual port and the virtual port by using the near-field probe calibration matrix.

And (4) representing the connection mode of the standard component and the network analyzer in the form of an error box. The structure of the probe measurement calibration model is shown in fig. 8, where port 2, port 3 and port 4 are actual ports, port 2 is connected to the near-field probe, port 3 and port 4 are connected to two ports of one calibration piece, and port 5 and port 6 are virtual ports. And acquiring a test port parameter matrix of the actual port 3 and the virtual port 5 and a test port parameter matrix of the actual port 3 and the virtual port 5 according to the scattering coefficient transmission matrix of the actual port. The test port parameter matrix is expressed in the form of scattering coefficient transmission parameters.

And S760, generating a near-field probe calibration matrix according to the standard impedance parameter matrix and the test port parameter matrix.

Specifically, an initial near-field probe calibration matrix characterized in the form of scattering coefficient transmission parameters is obtained by calculating a test port parameter matrix and a standard impedance parameter matrix, and then different forms of conversion are performed on the initial near-field probe calibration matrix according to actual measurement requirements of the electronic device to be tested to generate the near-field probe calibration matrix.

According to the embodiment of the application, the error box is constructed according to the scattering coefficient transmission parameters, the near field probe calibration matrix is calculated by combining the standard impedance parameter matrix of each port of the network analyzer, the operation is simple, the logic is strong, and the calculation efficiency of the near field probe calibration matrix can be improved.

When the near field probe calibration matrix is obtained, calculation can be carried out through the scattering coefficient transmission parameters of the network analyzer. Based on this, a specific obtaining manner of the test port parameter matrix between the ports of the network analyzer is described below by an embodiment.

In one embodiment, as shown in fig. 9, the process of obtaining a test port parameter matrix between ports of the electromagnetic near-field probe calibration system according to the scattering coefficient transmission parameters of the plurality of calibration pieces includes the following steps:

and S920, calculating an error parameter matrix according to the scattering coefficient transmission parameters.

The scattering coefficient transmission parameters correspond to actual ports of the network analyzer, and the error parameter matrix corresponds to virtual ports of the network analyzer after system errors are removed.

For example, if in the probe measurement calibration model, in a through closed loop in which a through calibration piece is connected to a network analyzer, a scattering coefficient transmission parameter corresponding to an actual port of the network analyzer is T = [ T11T 12; T21T 22]; in a transmission line loop in which the transmission line calibration piece is connected with a network analyzer, a scattering coefficient transmission parameter corresponding to an actual port of the network analyzer is L = [ L11L 12; L21L 22]. Then the relevant parameters of the error box are calculated:

E ₁₁ ＝T ₁₁ -E ₂₂ T ₁₂ equation 3

E ₁₂ ＝E ₂₁ Equation 5

E in equation 2 ^-γl Represents the propagation factor, expressed as:

calculating an error parameter matrix according to the related parameters of the error box

Wherein Z is ₀ Is an impedance parameter inside the network analyzer.

And S940, acquiring a test port parameter matrix between the ports of the electromagnetic near-field probe calibration system according to the error parameter matrix.

After the error parameter matrix is obtained, the test port parameter matrix between the ports of the network analyzer can be obtained according to the connection mode of the error box.

Illustratively, in the probe measurement calibration model shown in fig. 8, the test port parameter matrices of the real port 3 and the virtual port 5, and the test port parameter matrices of the real port 4 and the virtual port 6 are calculated:

in the embodiment of the application, the transmission parameters of each port of the network analyzer are represented according to the error parameter matrix, the principle is simple, the logic is clear, and the test port parameters of each port of the network analyzer can be rapidly obtained.

When the near field probe calibration matrix is obtained, the effective standard electromagnetic signal can be calculated by correcting the initial electromagnetic signal of the tested electronic equipment. Based on this, a specific acquisition manner of the near field probe calibration matrix is described below by an embodiment.

In one embodiment, as shown in fig. 10, the process of generating the near field probe calibration matrix from the standard impedance parameter matrix and the test port parameter matrix comprises the following steps:

and S1020, fusing the test port parameter matrix into the standard impedance parameter matrix to obtain a fused port parameter matrix.

Specifically, the test port parameter matrix is substituted into the standard impedance parameter matrix to obtain a fusion port parameter matrix. It should be noted that, in this case, the fusion port parameter matrix is expressed in the form of impedance.

Illustratively, if in the probe measurement calibration model shown in fig. 8, the relationship matrix of the probe port 2, the virtual port 5 and the virtual port 6 is represented as:

the fusion port parameter matrix is:

and S1040, performing number domain conversion processing on the fusion port parameter matrix to obtain a near field probe calibration matrix.

After the fusion port parameter matrix is obtained, since the electromagnetic signal of the electronic device to be tested is characterized in a frequency form, such as a common mode rejection ratio, a calibration factor, and the like, it is necessary to convert the impedance expression form of the fusion port parameter matrix into a scattering parameter expression form for use in the calculation of the electromagnetic signal of the electronic device to be tested. At this time, the expression of the near field probe calibration matrix is:

the relationship of probe port 2, virtual port 5 and virtual port 6 is updated as:

optionally, if the magnetic field has both a common-mode response and a differential-mode response, then obtaining the common-mode rejection ratio of the tested electronic device:

FR in equation 17 _d For differential mode frequency response:

FR in formula 17 _c For common mode frequency response:

in the embodiment of the application, because the fusion port parameter matrix is characterized in the form of impedance parameters, the calculation is facilitated, and meanwhile, the conversion flexibility of the parameter form is high, so that the standard electromagnetic signals of the tested electronic equipment can be conveniently obtained.

In one embodiment, there is provided an electromagnetic signal measurement method, the embodiment including:

(1) And acquiring the transmission parameters of the plurality of calibration pieces through the plurality of calibration pieces connected with the electromagnetic near-field probe calibration system.

(2) And the scattering coefficient transmission parameter of the first straight-through loop is obtained by connecting the network analyzer with the reflection calibration piece.

(3) And the scattering coefficient transmission parameter of the second direct loop is obtained by connecting the network analyzer with the transmission line calibration piece.

(4) And calculating an error parameter matrix according to the scattering coefficient transmission parameters of the closed loops.

(5) And acquiring a test port parameter matrix among the ports of the network analyzer according to the error parameter matrix.

(6) And acquiring a standard impedance parameter matrix between the ports of the network analyzer.

(7) And fusing the test port parameter matrix into the standard impedance parameter matrix to obtain a fused port parameter matrix.

(8) And performing digital domain conversion processing on the fusion port parameter matrix to obtain a near field probe calibration matrix.

(9) And calibrating the initial electromagnetic signal of the electronic equipment to be tested according to the near-field probe calibration matrix to obtain the standard electromagnetic signal of the electronic equipment to be tested.

(10) And determining the electromagnetic interference result of the tested electronic equipment according to the standard electromagnetic signal.

In the embodiment of the application, a near-field probe calibration matrix of an electromagnetic near-field probe calibration system is obtained, wherein the near-field probe calibration matrix is generated based on the characteristics of transmission signals of the electromagnetic near-field probe calibration system in closed loops of different loads; then, correcting the initial electromagnetic signal of the electronic equipment to be tested according to the near-field probe calibration matrix to obtain a standard electromagnetic signal of the electronic equipment to be tested; and finally, determining an electromagnetic interference result of the tested electronic equipment according to the standard electromagnetic signal. The initial electromagnetic signal is obtained by measuring the electronic equipment to be tested through an electromagnetic field probe connected with the electromagnetic near-field probe calibration system. The method is characterized in that on the basis of an initial electromagnetic signal, the obtained standard electromagnetic signal is obtained by combining a near-field probe calibration matrix generated by an electromagnetic near-field probe calibration system in closed loops of different loads. In the process of measuring the electromagnetic signal of the electronic device to be measured, the influence of the measuring part except the near-field probe in the electromagnetic near-field probe calibration system on the measuring result is considered, and the influencing factor is quantized into a near-field probe calibration matrix, so that the obtained measuring result of the electromagnetic signal of the electronic device to be measured is more accurate.

It should be understood that, although the steps in the flowcharts related to the embodiments are shown in sequence as indicated by the arrows, the steps are not necessarily executed in sequence as indicated by the arrows. The steps are not performed in the exact order shown and described, and may be performed in other orders, unless explicitly stated otherwise. Moreover, at least a part of the steps in the flowcharts related to the above embodiments may include multiple steps or multiple stages, which are not necessarily performed at the same time, but may be performed at different times, and the order of performing the steps or stages is not necessarily sequential, but may be performed alternately or alternately with other steps or at least a part of the steps or stages in other steps.

Based on the same inventive concept, the embodiment of the present application further provides an electromagnetic signal measurement apparatus for implementing the above-mentioned electromagnetic signal measurement method. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the method, so specific limitations in one or more embodiments of the electromagnetic signal measurement device provided below can be referred to the limitations of the electromagnetic signal measurement method in the foregoing, and details are not described herein again.

In one embodiment, as shown in fig. 11, there is provided an electromagnetic signal measurement apparatus 110 for use in a network analyzer, comprising a matrix acquisition module 1120, a signal acquisition module 1140, and a result determination module 1160, wherein:

a matrix obtaining module 1120, configured to obtain a near-field probe calibration matrix of the electromagnetic near-field probe calibration system; the near field probe calibration matrix is generated based on characteristics of transmission signals of the electromagnetic near field probe calibration system in closed loops of different loads.

The signal acquisition module 1140 is used for correcting the initial electromagnetic signal of the electronic device to be tested according to the near-field probe calibration matrix to obtain a standard electromagnetic signal of the electronic device to be tested; the initial electromagnetic signal is obtained by measuring the electronic equipment to be tested through an electromagnetic field probe connected with the electromagnetic near-field probe calibration system.

And a result determining module 1160, configured to determine an electromagnetic interference result of the electronic device under test according to the standard electromagnetic signal.

In one embodiment, the matrix acquisition module 1120 includes:

the first acquisition unit is used for acquiring scattering coefficient transmission parameters of a plurality of calibration pieces through the plurality of calibration pieces connected with the electromagnetic near-field probe calibration system; each calibration piece is used as a standard piece error generation source of the electromagnetic near-field probe calibration system, and each calibration piece is connected with the electromagnetic near-field probe calibration system to form a closed loop with different loads;

and the second acquisition unit is used for generating a near-field probe calibration matrix according to the scattering coefficient transmission parameters of the plurality of calibration pieces.

In one embodiment, the first obtaining unit includes:

the first acquisition subunit is used for acquiring a closed loop corresponding to each calibration piece and the electromagnetic near-field probe calibration system through a plurality of calibration pieces connected with the electromagnetic near-field probe calibration system;

the second acquisition subunit is used for acquiring a plurality of transmission parameters of the electromagnetic near-field probe calibration system in each closed loop according to the transmission characteristics of each closed loop;

and the third acquisition subunit is used for acquiring scattering coefficient transmission parameters of the electromagnetic near-field probe calibration system in each calibration piece according to a plurality of transmission parameters of the electromagnetic near-field probe calibration system in each closed loop.

In one embodiment, the second obtaining unit includes:

the fourth acquisition subunit is used for acquiring a standard impedance parameter matrix between ports of the electromagnetic near-field probe calibration system;

the fifth acquiring subunit is used for acquiring a test port parameter matrix between the ports of the electromagnetic near-field probe calibration system according to the scattering coefficient transmission parameters of the plurality of calibration pieces;

and the sixth acquisition subunit is used for generating a near field probe calibration matrix according to the standard impedance parameter matrix and the test port parameter matrix.

In one embodiment, the fifth obtaining subunit is further configured to calculate an error parameter matrix according to the scattering coefficient transmission parameter; and acquiring a test port parameter matrix among the ports of the electromagnetic near-field probe calibration system according to the error parameter matrix.

In an embodiment, the sixth obtaining subunit is further configured to fuse the test port parameter matrix into the standard impedance parameter matrix to obtain a fused port parameter matrix; and performing digital domain conversion processing on the fusion port parameter matrix to obtain a near-field probe calibration matrix.

The modules in the electromagnetic signal measuring device can be wholly or partially realized by software, hardware and a combination thereof. The modules can be embedded in a hardware form or independent from a processor in the computer device, and can also be stored in a memory in the computer device in a software form, so that the processor can call and execute operations corresponding to the modules.

In one embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be as shown in fig. 12. The computer apparatus includes a processor, a memory, an input/output interface, a communication interface, a display unit, and an input device. The processor, the memory and the input/output interface are connected by a system bus, and the communication interface, the display unit and the input device are connected by the input/output interface to the system bus. Wherein the processor of the computer device is configured to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of an operating system and computer programs in the non-volatile storage medium. The input/output interface of the computer device is used for exchanging information between the processor and an external device. The communication interface of the computer device is used for carrying out wired or wireless communication with an external terminal, and the wireless communication can be realized through WIFI, a mobile cellular network, NFC (near field communication) or other technologies. The computer program is executed by a processor to implement an electromagnetic signal measurement method. The display unit of the computer device is used for forming a visual picture and can be a display screen, a projection device or a virtual reality imaging device. The display screen can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer equipment can be a touch layer covered on the display screen, a key, a track ball or a touch pad arranged on the shell of the computer equipment, an external keyboard, a touch pad or a mouse and the like.

Those skilled in the art will appreciate that the architecture shown in fig. 12 is merely a block diagram of some of the structures associated with the disclosed aspects and is not intended to limit the computing devices to which the disclosed aspects apply, as particular computing devices may include more or less components than those shown, or may combine certain components, or have a different arrangement of components.

In one embodiment, a computer device is provided, comprising a memory and a processor, the memory having a computer program stored therein, the processor implementing the following steps when executing the computer program:

In one embodiment, the processor when executing the computer program further performs the steps of:

In one embodiment, the processor, when executing the computer program, further performs the steps of:

In one embodiment, a computer-readable storage medium is provided, having stored thereon a computer program which, when executed by a processor, performs the steps of:

acquiring scattering coefficient transmission parameters of a plurality of calibration pieces through the plurality of calibration pieces connected with the electromagnetic near-field probe calibration system; each calibration piece is used as a standard piece error generation source of the electromagnetic near-field probe calibration system, and forms a closed loop with different loads after being connected with the electromagnetic near-field probe calibration system;

and generating a near field probe calibration matrix according to the standard impedance parameter matrix and the test port parameter matrix.

In one embodiment, a computer program product is provided, comprising a computer program which, when executed by a processor, performs the steps of:

It will be understood by those skilled in the art that all or part of the processes of the methods of the embodiments described above can be implemented by hardware related to instructions of a computer program, which can be stored in a non-volatile computer-readable storage medium, and when executed, the computer program can include the processes of the embodiments of the methods described above. Any reference to memory, database, or other medium used in the embodiments provided herein may include at least one of non-volatile and volatile memory. The nonvolatile Memory may include Read-Only Memory (ROM), magnetic tape, floppy disk, flash Memory, optical Memory, high-density embedded nonvolatile Memory, resistive Random Access Memory (ReRAM), magnetic Random Access Memory (MRAM), ferroelectric Random Access Memory (FRAM), phase Change Memory (PCM), graphene Memory, and the like. Volatile Memory can include Random Access Memory (RAM), external cache Memory, and the like. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM), for example. The databases referred to in various embodiments provided herein may include at least one of relational and non-relational databases. The non-relational database may include, but is not limited to, a block chain based distributed database, and the like. The processors referred to in the embodiments provided herein may be general purpose processors, central processing units, graphics processors, digital signal processors, programmable logic devices, quantum computing based data processing logic devices, etc., without limitation.

The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above examples only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present application. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present application shall be subject to the appended claims.

Claims

1. An electromagnetic signal measurement method is applied to an electromagnetic near-field probe calibration system, and comprises the following steps:

and determining an electromagnetic interference result of the tested electronic equipment according to the standard electromagnetic signal.

2. The method of claim 1, wherein said obtaining a near field probe calibration matrix of said electromagnetic near field probe calibration system comprises:

acquiring scattering coefficient transmission parameters of a plurality of calibration pieces through the plurality of calibration pieces connected with the electromagnetic near-field probe calibration system; each calibration piece is used as a standard piece error generation source of the electromagnetic near-field probe calibration system, and each calibration piece is connected with the electromagnetic near-field probe calibration system to form a closed loop of different loads;

and generating the near field probe calibration matrix according to the scattering coefficient transmission parameters of the plurality of calibration pieces.

3. The method of claim 2, wherein the obtaining scattering coefficient transmission parameters of the calibration piece via a plurality of calibration pieces connected to the electromagnetic near-field probe calibration system comprises:

4. The method of claim 3, wherein if the calibration piece is a pass-through calibration piece, the closed loop is a first pass-through loop;

if the calibration piece is a transmission line calibration piece, the closed loop is a second straight-through loop.

5. The method of any of claims 2-4, wherein generating the near field probe calibration matrix from the scattering coefficient transmission parameters of the plurality of calibration pieces comprises:

acquiring a standard impedance parameter matrix between ports of the electromagnetic near-field probe calibration system;

and generating the near field probe calibration matrix according to the standard impedance parameter matrix and the test port parameter matrix.

6. The method of claim 5, wherein obtaining a matrix of test port parameters between ports of the electromagnetic near-field probe calibration system based on scattering coefficient transmission parameters of the plurality of calibration pieces comprises:

7. The method of claim 5, wherein the generating the near field probe calibration matrix from the standard impedance parameter matrix and the test port parameter matrix comprises:

fusing the test port parameter matrix into the standard impedance parameter matrix to obtain a fused port parameter matrix;

and performing digital domain conversion processing on the fusion port parameter matrix to obtain the near-field probe calibration matrix.

8. An electromagnetic signal measuring apparatus, for use in an electromagnetic near field probe calibration system, the apparatus comprising:

the signal acquisition module is used for correcting the initial electromagnetic signal of the tested electronic equipment according to the near-field probe calibration matrix to obtain a standard electromagnetic signal of the tested electronic equipment; the initial electromagnetic signal is obtained by measuring the electronic equipment to be tested through an electromagnetic field probe connected with the electromagnetic near-field probe calibration system;

9. A computer device comprising a memory and a processor, the memory storing a computer program, characterized in that the processor, when executing the computer program, implements the steps of the method of any of claims 1 to 7.

10. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the steps of the method of any one of claims 1 to 7.