A local signal enhanced magnetic field probe and a time-domain current reconstruction method and system thereof

Abstract

The application discloses a local signal enhanced magnetic field probe and a time domain current reconstruction method and system thereof. The magnetic field probe comprises a first shielding ground layer, a second magnetic field signal layer, a third magnetic field signal layer and a fourth shielding ground layer which are arranged in a stack. The second magnetic field signal layer and the third magnetic field signal layer are respectively provided with corresponding magnetic field induction and signal transmission structures, and the two layers of magnetic field induction and signal transmission structures are symmetrically arranged to form a differential detection channel, and a strip transmission line is arranged in the magnetic field induction and signal transmission structure. One end of the strip transmission line of each magnetic field signal layer is provided with an SMA interface, and the other end of the strip transmission line is provided with an L-shaped bypass grounding shielding structure in the adjacent area, and the short shaft end of the L-shaped bypass grounding shielding structure is connected with the first shielding ground layer and the fourth shielding ground layer through a grounding via hole. The application can improve the detection capability of weak magnetic field signals.

Description

Technical Field

[0001] This invention relates to the field of near-field electromagnetic compatibility testing and electromagnetic interference source localization technology, and particularly to a magnetic field probe for local signal enhancement and its time-domain current reconstruction method and system. Background Technology

[0002] In near-field electromagnetic compatibility testing and electromagnetic interference source localization of high-speed integrated circuits and printed circuit boards, near-field magnetic field probes are important measurement tools for obtaining local magnetic field information.

[0003] As chip integration density and operating frequency continue to increase, the electromagnetic environment surrounding the object under test becomes increasingly complex. Parasitic coupling of the electric field can interfere with the measurement results of magnetic field probes, reducing the measurement signal-to-noise ratio. Simultaneously, traditional passive magnetic field probes have limited response capabilities to weak magnetic field signals in certain frequency bands, affecting the effective detection of weak magnetic field signals. Near-field magnetic field probes can also achieve non-contact reconstruction of the current waveform of the measured conductor by combining time-domain signal processing; however, the probe's own frequency response characteristics and electric field coupling interference can further affect the time-domain current reconstruction results.

[0004] Therefore, it is necessary to further improve the electric field suppression capability and target frequency band magnetic field response of the near-field magnetic field probe, so as to provide more reliable measurement signals for weak magnetic field measurement and subsequent time-domain current reconstruction. Summary of the Invention

[0005] The purpose of this invention is to provide a magnetic field probe with local signal enhancement and its time-domain current reconstruction method and system, aiming to solve the technical problems in existing near-field magnetic field measurements, such as electric field coupling interference, insufficient detection capability of weak magnetic fields in the target frequency band, and the influence of frequency response characteristics on the accuracy of time-domain current reconstruction. The various technical effects of the preferred technical solutions provided by this invention are detailed below.

[0006] To achieve the above objectives, the present invention provides the following technical solution: The present invention provides a magnetic field probe with local signal enhancement, comprising a first shielding ground layer, a second magnetic field signal layer, a third magnetic field signal layer, and a fourth shielding ground layer stacked together; The second magnetic field signal layer and the third magnetic field signal layer are respectively provided with corresponding magnetic field induction and signal transmission structures. The two magnetic field induction and signal transmission structures are symmetrically arranged to form a differential detection channel. A strip transmission line is arranged inside the magnetic field induction and signal transmission structure. Each magnetic field signal layer has an SMA interface at one end of its strip transmission line, and an L-shaped bypass grounding shield structure is set in the adjacent area at the other end. The short axis end of the L-shaped bypass grounding shield structure is connected to the first shielding ground layer and the fourth shielding ground layer through a grounding via.

[0007] In some embodiments, the L-shaped bypass grounding shield structure is spaced apart from the magnetic field induction and signal transmission structure.

[0008] In some embodiments, a continuously arranged array of grounding vias is provided on both sides of the strip transmission line of each magnetic field signal layer for shielding the transmission path.

[0009] In some embodiments, at the transition position between the strip transmission line of each magnetic field signal layer and the SMA interface, a coaxial through-hole transition structure consisting of a central signal through-hole and six surrounding grounding through-holes is provided for the interface layer transition.

[0010] In some embodiments, a central signal via is provided at the transition position between the strip transmission line of each magnetic field signal layer and the SMA interface. The induced magnetic field signal is transmitted along the internal strip transmission line and transitions to the grounded coplanar waveguide through the central signal via, and is finally output to the external measurement equipment through the SMA interface.

[0011] According to another aspect of the present invention, a time-domain current reconstruction system is also provided, comprising a frequency-domain near-field measurement system and a time-domain near-field measurement system. The frequency-domain near-field measurement system includes a local signal enhancement magnetic field probe, a vector network analyzer, a grounded coplanar waveguide, and a load, as described above. The vector network analyzer is connected to the SMA interface of both the grounded coplanar waveguide and the magnetic field probe. The grounded coplanar waveguide is connected to the load. The magnetic field probe acquires and detects a reference magnetic field signal generated above a standard transmission line corresponding to the conductor under test. The time-domain near-field measurement system includes a local signal enhancement magnetic field probe, an oscilloscope, a grounded coplanar waveguide, and a signal source, as described above. The oscilloscope is connected to the SMA interface of the grounded coplanar waveguide and the magnetic field probe. The grounded coplanar waveguide is connected to the signal source. The magnetic field probe acquires the time-domain magnetic field response above the conductor under test.

[0012] According to another aspect of the present invention, a time-domain current reconstruction method is also provided, used to perform frequency domain processing and current inversion on a time-domain signal acquired by a time-domain current reconstruction system described above, so as to reconstruct the time-domain current waveform, the method comprising: Calculate the system frequency response of the frequency domain near-field measurement system based on the frequency domain voltage at the input terminal of the grounded coplanar waveguide and the frequency domain voltage output by the magnetic field probe. By mirroring the time-domain voltage output by the magnetic field probe of the time-domain near-field measurement system with the sign reversed, an odd harmonic signal is obtained. The constructed odd harmonic signal is subjected to a fast Fourier transform to obtain the corresponding frequency domain signal; Based on the characteristic impedance of the grounded coplanar waveguide, the system frequency response, and the frequency domain signal, the frequency domain current of the conductor under test is retrieved. The time-domain current waveform of the conductor under test is obtained by performing an inverse fast Fourier transform on the frequency domain current.

[0013] In some embodiments, the system frequency response The calculation formula is: ; in, The frequency domain voltage at the input terminal of the grounded coplanar waveguide. This is the frequency domain voltage output by the magnetic field probe. ω is the angular frequency.

[0014] In some embodiments, the time-domain voltage output by the magnetic field probe of the time-domain near-field measurement system is constructed by mirroring it with the opposite sign according to the following formula: ; in, for The odd harmonic signal obtained by constructing time intervals, for The original time-domain output voltage signal acquired by the magnetic field probe. The sampling termination time of the original time-domain output voltage signal is given.

[0015] In some embodiments, the frequency domain current of the conductor under test is inverted. The formula is: ; in, The characteristic impedance of a grounded coplanar waveguide. To The frequency domain signal obtained by performing a fast Fourier transform.

[0016] Implementing one of the above-described technical solutions of the present invention has the following advantages or beneficial effects: This invention employs a differential magnetic field detection structure (two-layer magnetic field induction and signal transmission structure) to acquire the near-field magnetic field signal generated by the object under test. A symmetrical detection channel reduces the influence of electric field coupling on magnetic field measurement. An L-shaped bypass grounding shield structure is set in the magnetic field detection area to further suppress electric field coupling. By changing the distributed parameters and electromagnetic coupling state near the detection area, the probe forms a local enhanced response in the target frequency band, improving the detection capability of weak magnetic field signals. Attached Figure Description

[0017] The accompanying drawings used are briefly described below. It is obvious that the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort. In the drawings: Figure 1 This is a front view of a magnetic field probe for local signal enhancement according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the first layer of a magnetic field probe for local signal enhancement according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the second layer of a magnetic field probe for local signal enhancement according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the third layer of a magnetic field probe for local signal enhancement according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the fourth layer of a magnetic field probe for local signal enhancement according to an embodiment of the present invention; Figure 6 This is a schematic diagram of an L-shaped bypass grounding shield structure for a magnetic field probe with local signal enhancement according to an embodiment of the present invention; wherein, (a) is a stacked structure (hiding the first layer); (b) is a second layer structure; and (c) is a third layer structure. Figure 7 This is a schematic diagram of the frequency domain near-field measurement system structure of a time-domain current reconstruction system according to an embodiment of the present invention; Figure 8 This is a schematic diagram of the time-domain near-field measurement system structure of a time-domain current reconstruction system according to an embodiment of the present invention; Figure 9 This is a flowchart of a time-domain current reconstruction method according to an embodiment of the present invention.

[0018] In the picture: 10. SMA interface; 11. Strip transmission line; 12. L-shaped bypass grounding shield structure; 13. Grounding through-hole array; 14. Center signal through-hole; 15. Mounting hole; 16. SMA mounting hole. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the present invention clearer, various exemplary embodiments described below will be referenced to the accompanying drawings, which form part of the exemplary embodiments, illustrating various exemplary embodiments that may be used to implement the present invention. Unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. It should be understood that they are merely examples of processes, methods, and apparatuses consistent with some aspects of the present invention disclosed as detailed in the appended claims, and other embodiments may be used, or structural and functional modifications may be made to the embodiments listed herein without departing from the scope and spirit of the present invention.

[0020] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," etc., indicate the orientation or positional relationship based on the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the referred element must have a specific orientation, or be constructed and operated in a specific orientation. The terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. The term "multiple" means two or more. The terms "connected" and "linked" should be interpreted broadly, for example, they can be fixed connections, detachable connections, integral connections, mechanical connections, electrical connections, communication connections, direct connections, indirect connections through an intermediate medium, and can be the internal connection of two elements or the interaction relationship between two elements. The term "and / or" includes any and all combinations of one or more of the related listed items. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0021] To illustrate the technical solution described in this invention, specific embodiments are described below, showing only the parts related to the embodiments of this invention.

[0022] Example 1: like Figures 1-6 As shown, this invention provides a magnetic field probe with local signal enhancement, comprising a first shielding ground layer, a second magnetic field signal layer, a third magnetic field signal layer, and a fourth shielding ground layer stacked together. The second and third magnetic field signal layers each have corresponding magnetic field sensing and signal transmission structures, symmetrically arranged to form a differential detection channel. A strip transmission line 11 is laid inside the magnetic field sensing and signal transmission structures. One end of the strip transmission line 11 in each magnetic field signal layer has an SMA interface 10, and the adjacent area at the other end has an L-shaped bypass grounding shielding structure 12. The short axis end of the L-shaped bypass grounding shielding structure 12 is connected to the first and fourth shielding ground layers through a grounding via.

[0023] In a specific embodiment, the magnetic field probe adopts a PCB stack-up structure, that is, a four-layer PCB structure. The substrate of the magnetic field probe is provided with mounting holes 15 for mounting and fixing the magnetic field probe to the near-field scanning platform; the SMA interface 10 is provided with corresponding SMA mounting holes 16 for mounting and fixing the SMA connector.

[0024] In some embodiments, the L-shaped bypass grounding shield structure 12 is spaced apart from the magnetic field induction and signal transmission structure. That is, there is no direct metal connection between the two, and its short axis end is connected to the shielding ground layer through a grounding via, which is used to suppress electric field coupling near the induction area and reduce its influence on the magnetic field measurement signal.

[0025] It should be noted that the introduction of the L-shaped bypass grounding shield structure alters the distributed parameters and electromagnetic coupling state near the magnetic field induction area, causing the probe to exhibit a localized enhanced response in a specific frequency band. In this embodiment, this localized enhanced response occurs in the frequency range of 2.5 GHz to 5 GHz, with a peak at 4.34 GHz, thereby improving the detection capability of weak magnetic field signals within this frequency band.

[0026] In some embodiments, a continuously arranged array of grounding vias 13 is provided on both sides of the strip transmission line 11 of each magnetic field signal layer for shielding the transmission path.

[0027] Furthermore, at the layer transition position between the strip transmission line 11 of each magnetic field signal layer and the SMA interface 10, a coaxial through-hole transition structure is provided, consisting of a central signal through-hole 14 and six grounding through-holes around it (the central signal through-hole is distributed in an arc shape on the upper and lower sides of the figure, with three on each side), for the interface layer transition.

[0028] The magnetic field signal obtained by induction is transmitted along the internal strip transmission line 11, and then transitions to the grounded coplanar waveguide through the central signal through-hole 14, and is finally output to the external measuring equipment through the SMA interface 10.

[0029] For ease of understanding, grounding via arrays 13 are provided on both sides of the strip transmission line 11 to enhance the grounding continuity and shielding effect of the transmission area. At the layer transition position between the strip transmission line 11 and the SMA interface 10, a coaxial via transition structure consisting of a central signal via 14 and six surrounding grounding vias is provided to realize the signal transition between the internal strip transmission line 11, the grounded coplanar waveguide, and the SMA interface 10. The L-shaped bypass grounding shield structure 12 is used to suppress electric field coupling near the sensing area and change the local electromagnetic coupling state; the signal sensed by the probe is transmitted along the strip transmission line 11, and the interlayer transition is achieved through the central signal via 14, and finally output through the SMA interface 10. Through the above design, electric field coupling suppression, local enhancement of the target frequency band, and stable output of the magnetic field signal are achieved.

[0030] In summary, this invention employs a differential magnetic field detection structure (two-layer magnetic field induction and signal transmission structure) to acquire the near-field magnetic field signal generated by the object under test. A symmetrical detection channel reduces the influence of electric field coupling on magnetic field measurement. An L-shaped bypass grounding shield structure is incorporated in the magnetic field detection area to further suppress electric field coupling. Furthermore, by altering the distributed parameters and electromagnetic coupling state near the detection area, the probe achieves a locally enhanced response in the target frequency band, thereby improving the detection capability of weak magnetic field signals.

[0031] Example 2: like Figures 7-8As shown, this embodiment provides a time-domain current reconstruction system, including a frequency-domain near-field measurement system and a time-domain near-field measurement system. The frequency-domain near-field measurement system includes a local signal enhancement magnetic field probe as described in Embodiment 1, a vector network analyzer, a grounded coplanar waveguide, and a load. The vector network analyzer is connected to the SMA interface of both the grounded coplanar waveguide and the magnetic field probe. The grounded coplanar waveguide is connected to the load. The magnetic field probe acquires and detects the reference magnetic field signal generated above the standard transmission line corresponding to the conductor under test. The time-domain near-field measurement system includes a local signal enhancement magnetic field probe, an oscilloscope, a grounded coplanar waveguide, and a signal source, as described in Example 1. The oscilloscope is connected to the SMA interface of the grounded coplanar waveguide and the magnetic field probe. The grounded coplanar waveguide is connected to the signal source. The magnetic field probe acquires the time-domain magnetic field response above the conductor under test.

[0032] To put it simply, the SMA output port of the magnetic field probe is connected to an external measurement device, such as a vector network analyzer or oscilloscope, and the near-field magnetic field signal generated by the object under test is acquired through the magnetic field sensing structure of the magnetic field probe. Based on the magnetic field response measured by the magnetic field probe, and in conjunction with the corresponding simulation or calibration relationships, the magnetic field information of the object under test can be obtained.

[0033] The vector network analyzer was connected to the grounded coplanar waveguide calibration device and the output port of the near-field probe, respectively. The reference magnetic field signal generated above the standard transmission line was acquired through the probe, and the system frequency response, including the characteristics of the probe and the transmission link, was measured. (See Example 3) as calibration parameters for subsequent time-domain current reconstruction.

[0034] By mounting this magnetic field probe on a near-field scanning platform, it can perform two-dimensional scanning and imaging of the magnetic field distribution on the surface of objects under test, such as PCBs and chips, for analyzing local magnetic field distribution and locating electromagnetic interference sources. After completing system frequency response calibration, this magnetic field probe can be used to acquire the time-domain magnetic field signal of the conductor under test, and combined with the time-domain current reconstruction method described later, the time-domain current waveform of the conductor under test can be obtained.

[0035] Example 3: like Figure 9 As shown, this embodiment provides a time-domain current reconstruction method for performing frequency domain processing and current inversion on the time-domain signal acquired by the time-domain current reconstruction system described in Embodiment 2, so as to reconstruct the time-domain current waveform. The method includes: S100. Calculate the system frequency response of the frequency domain near-field measurement system based on the frequency domain voltage at the input terminal of the grounded coplanar waveguide and the frequency domain voltage output by the magnetic field probe.

[0036] In this step, according to the frequency domain near-field measurement system in Example 2, the vector network analyzer is connected to the grounded coplanar waveguide calibration device and the output port of the near-field probe, respectively. By detecting the reference magnetic field signal generated above the standard transmission line through the probe, the system frequency response including the characteristics of the probe and the transmission link is measured. : ; in, The frequency domain voltage at the input of the calibration component for the grounded coplanar waveguide. This is the frequency domain voltage at the output of the magnetic field probe. This is the angular frequency. The obtained... It includes the amplitude and phase response of the measurement system and serves as calibration parameters for subsequent frequency domain current inversion.

[0037] S200. The time-domain voltage output by the magnetic field probe of the time-domain near-field measurement system is reversed and mirrored to obtain the odd harmonic signal.

[0038] In this step, according to the time-domain near-field measurement system in Example 2, the time-domain magnetic field response above the device under test (e.g., DUT) is acquired using a probe to obtain the time-domain voltage output by the magnetic field probe. By mirroring the measured time-domain signal with the opposite sign, the odd harmonic signal is obtained. : ; in, for The odd harmonic signal (odd symmetric extended time domain signal) is obtained by constructing the time-domain signal. for The original time-domain output voltage signal acquired by the magnetic field probe. This represents the sampling termination time of the original time-domain output voltage signal.

[0039] S300. Perform a fast Fourier transform on the constructed odd harmonic signal to obtain the corresponding frequency domain signal.

[0040] Perform a Fast Fourier Transform on the constructed odd harmonic signal: .

[0041] Based on the frequency range of interest in the actual measurement, from and system frequency response Data from the corresponding frequency band is extracted and used for subsequent frequency domain current inversion.

[0042] S400: Based on the characteristic impedance of the grounded coplanar waveguide, the system frequency response, and the frequency domain signal, the frequency domain current of the conductor under test is inverted to obtain the corresponding frequency domain current.

[0043] In some embodiments, the frequency domain current of the conductor under test is inverted. The formula is: ; in, The characteristic impedance of a grounded coplanar waveguide.

[0044] The characteristic impedance of the grounded coplanar waveguide calibration component used in this embodiment is 50Ω, therefore: .

[0045] Through the above frequency domain inversion, the actual amplitude and phase response of the probe and transmission link are incorporated into the current calculation process.

[0046] S500: Perform inverse fast Fourier transform on the frequency domain current to obtain the time domain current waveform of the conductor under test.

[0047] In this step, the inverse fast Fourier transform is performed on the frequency domain current obtained by the inversion to obtain the time domain current waveform of the conductor under test: .

[0048] Through the above process, while utilizing the local signal enhancement characteristics of the probe's target frequency band, the actual frequency response of the probe and transmission link is incorporated into the current inversion process, overcoming the shortcomings of time-domain current reconstruction that relies on ideal frequency response and is susceptible to electric field coupling interference, thus achieving high-precision current waveform restoration.

[0049] It should be noted that the probe of this invention reduces electric field coupling interference through a bypass grounding shielding structure and forms local signal enhancement in the target frequency band, thereby improving the detection capability of weak magnetic field signals. Because the local enhancement causes a significant change in the probe's frequency response in the corresponding frequency band, the actual frequency response of the probe and transmission link no longer meets the ideal flatness characteristic. If this amplitude and phase change is ignored during the time-domain current reconstruction process, the accuracy of the reconstruction results will be affected. Therefore, this invention combines system frequency response calibration parameters to perform frequency domain processing and current inversion on the time-domain signal acquired by the probe. While leveraging the advantages of local signal enhancement, it compensates for the frequency response of the actual measurement system, thereby achieving time-domain current waveform reconstruction.

[0050] The above description is merely a preferred embodiment of the present invention. Those skilled in the art will understand that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the present invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A magnetic field probe for local signal enhancement, characterized in that, It includes a first shielding ground layer, a second magnetic field signal layer, a third magnetic field signal layer, and a fourth shielding ground layer, which are stacked together. The second magnetic field signal layer and the third magnetic field signal layer are respectively provided with corresponding magnetic field induction and signal transmission structures. The two magnetic field induction and signal transmission structures are symmetrically arranged to form a differential detection channel. A strip transmission line is arranged inside the magnetic field induction and signal transmission structure. Each magnetic field signal layer has an SMA interface at one end of its strip transmission line, and an L-shaped bypass grounding shield structure is set in the adjacent area at the other end. The short axis end of the L-shaped bypass grounding shield structure is connected to the first shielding ground layer and the fourth shielding ground layer through a grounding via.

2. The magnetic field probe for local signal enhancement according to claim 1, characterized in that, The L-shaped bypass grounding shield structure is spaced apart from the magnetic field induction and signal transmission structure.

3. A magnetic field probe for local signal enhancement according to claim 1, characterized in that, Each magnetic field signal layer has a strip transmission line with a continuously arranged array of grounding vias on both sides for shielding the transmission path.

4. A magnetic field probe for local signal enhancement according to claim 1, characterized in that, At the layer transition position between the strip transmission line of each magnetic field signal layer and the SMA interface, a coaxial through-hole transition structure consisting of a central signal through-hole and six surrounding grounding through-holes is provided for the interface layer transition.

5. A magnetic field probe for local signal enhancement according to claim 1, characterized in that, A central signal via is provided at the transition position between the strip transmission line of each magnetic field signal layer and the SMA interface. The induced magnetic field signal is transmitted along the internal strip transmission line and transitions to the grounded coplanar waveguide through the central signal via, and is finally output to the external measurement equipment through the SMA interface.

6. A time-domain current reconstruction system, characterized in that, The system includes a frequency domain near-field measurement system and a time domain near-field measurement system. The frequency domain near-field measurement system includes a local signal enhancement magnetic field probe as described in any one of claims 1-5, a vector network analyzer, a grounded coplanar waveguide, and a load. The vector network analyzer is connected to the SMA interface of both the grounded coplanar waveguide and the magnetic field probe. The grounded coplanar waveguide is connected to the load. The magnetic field probe acquires and detects the reference magnetic field signal generated above the standard transmission line corresponding to the conductor under test. The time-domain near-field measurement system includes a local signal enhancement magnetic field probe, an oscilloscope, a grounded coplanar waveguide, and a signal source as described in any one of claims 1-5; the oscilloscope is connected to the SMA interface of the grounded coplanar waveguide and the magnetic field probe, the grounded coplanar waveguide is connected to the signal source, and the magnetic field probe acquires the time-domain magnetic field response above the conductor under test.

7. A time-domain current reconstruction method, used to perform frequency domain processing and current inversion on the time-domain signal acquired by the time-domain current reconstruction system of claim 6, so as to realize the reconstruction of the time-domain current waveform, characterized in that, The method includes: Calculate the system frequency response of the frequency domain near-field measurement system based on the frequency domain voltage at the input terminal of the grounded coplanar waveguide and the frequency domain voltage output by the magnetic field probe. By mirroring the time-domain voltage output by the magnetic field probe of the time-domain near-field measurement system with the sign reversed, an odd harmonic signal is obtained. The constructed odd harmonic signal is subjected to a fast Fourier transform to obtain the corresponding frequency domain signal; Based on the characteristic impedance of the grounded coplanar waveguide, the system frequency response, and the frequency domain signal, the frequency domain current of the conductor under test is retrieved. The time-domain current waveform of the conductor under test is obtained by performing an inverse fast Fourier transform on the frequency domain current.

8. The time-domain current reconstruction method according to claim 7, characterized in that, The system frequency response The calculation formula is: ； in, The frequency domain voltage at the input terminal of the grounded coplanar waveguide. This is the frequency domain voltage output by the magnetic field probe. ω is the angular frequency.

9. The time-domain current reconstruction method according to claim 8, characterized in that, The time-domain voltage output by the magnetic field probe of the time-domain near-field measurement system is constructed by reversing the sign and mirroring it according to the following formula: ； in, for The odd harmonic signal obtained by constructing time intervals, for The original time-domain output voltage signal acquired by the magnetic field probe. The sampling termination time of the original time-domain output voltage signal is given.

10. A time-domain current reconstruction method according to claim 9, characterized in that, Inverting the frequency domain current of the conductor under test The formula is: ； in, The characteristic impedance of a grounded coplanar waveguide. To The frequency domain signal obtained by performing a fast Fourier transform.

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