Electromagnetic field probe
By designing a stacked electromagnetic field probe, the electric and magnetic field signals are induced by the first and second electromagnetic field coils, increasing the signal amplitude. This solves the problem that traditional probes have difficulty capturing weak signals, and achieves high-sensitivity and high-precision electromagnetic field measurement.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA ELECTRONICS RELIABILITY AND ENVIRONMENTAL TESTING INSTITUTE ((THE FIFTH INSTITUTE OF ELECTRONICS MINISTRY OF INDUSTRY AND INFORMATION TECHNOLOGY) (CHINA SAIBAO LABORATORY)
- Filing Date
- 2022-04-12
- Publication Date
- 2026-07-14
AI Technical Summary
In existing technologies, traditional probes are unable to capture weak electromagnetic signals, thus failing to meet the requirements for electromagnetic reliability analysis of chips.
An electromagnetic field probe is designed that uses a stacked first ground layer, a first signal layer, and a second signal layer, combined with first and second electromagnetic field coils, to induce electric and magnetic field signals. By connecting the coils through a through-hole, the signal amplitude is increased, differential signal filtering is achieved to eliminate interference, and detection accuracy is enhanced.
It improves the detection sensitivity and accuracy of electromagnetic signals, enabling the detection of weaker electromagnetic field signals, achieving simultaneous measurement of electric and magnetic fields, and increasing the signal amplitude.
Smart Images
Figure CN114966230B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of electromagnetic detection technology, and in particular to an electromagnetic field probe. Background Technology
[0002] With the advancement of technology, chip integration is becoming increasingly sophisticated. As integration increases, the power consumption, size, and voltage of individual components within the chip are decreasing. This results in increasingly weak electromagnetic signals radiated by the chip. Therefore, to assess the electromagnetic reliability of a chip, it is necessary to capture the radiated electric and magnetic field signals for reliability analysis. Consequently, how to detect the radiated electric and magnetic field signals of a chip is a problem that needs to be solved.
[0003] In traditional techniques, electric and magnetic fields are detected using composite probes.
[0004] However, as the electromagnetic signals emitted by the chip become weaker and weaker, the amplitude of the electric and magnetic field signals captured by probes using traditional technology is too small to meet the needs of reliability analysis. Summary of the Invention
[0005] Therefore, it is necessary to provide an electromagnetic field probe that can increase the amplitude of measured electric and magnetic field signals by providing high gain, thereby enabling the measurement of weaker electric and magnetic fields, in order to address the aforementioned technical problems.
[0006] An electromagnetic field probe comprises a first ground layer, a first signal layer, a second signal layer, and a second ground layer stacked sequentially. The probe includes: a first electromagnetic field detection unit, comprising a first electromagnetic field coil wired on the first signal layer, for sensing a first electrical signal generated by the combined external magnetic and electric fields; a second electromagnetic field detection unit, comprising a second electromagnetic field coil wired on the second signal layer, for sensing a second electrical signal generated by the combined external magnetic and electric fields, wherein the orthographic projection of the first electromagnetic field coil onto the plane containing the second electromagnetic field coil is within the range of the second electromagnetic field coil, and the orthographic projections of both the first and second electromagnetic field coils onto the plane containing the first ground layer are both outside the range of the first ground layer; and a connecting via penetrating the first and second signal layers, connecting to the first and second electromagnetic field coils respectively, for connecting the first and second electromagnetic field coils.
[0007] In one embodiment, the probe further includes: a first signal transmission unit, comprising a first stripline, a first conversion via, and a first coplanar waveguide wire routed on a corresponding wiring layer, wherein a first end of the first stripline is connected to the first electromagnetic field coil, and a second end of the first stripline is connected to the first end of the first coplanar waveguide wire via the first conversion via; and a second signal transmission unit, comprising a second stripline, a second conversion via, and a second coplanar waveguide wire routed on a corresponding wiring layer, wherein a first end of the second stripline is connected to the second electromagnetic field coil, and a second end of the second stripline is connected to the first end of the second coplanar waveguide wire via the second conversion via.
[0008] In one embodiment, the probe further includes a measuring device connected to the second end of the first coplanar waveguide and the second coplanar waveguide, respectively, for determining the strength of the external magnetic field and the strength of the external electric field based on the first electrical signal and the second electrical signal.
[0009] In one embodiment, the measuring device is used to determine the strength of the external electric field based on the sum of the first electrical signal and the second electrical signal; and to determine the strength of the external magnetic field based on the difference between the first electrical signal and the second electrical signal.
[0010] In one embodiment, the first conversion via includes a first signal via and a plurality of first surrounding ground vias surrounding the first signal via at a preset distance; the second end of the first stripline is connected to the first end of the first coplanar waveguide through the conductive wall of the first signal via; the second conversion via includes a second signal via and a plurality of second surrounding ground vias surrounding the second signal via at the preset distance; the second end of the second stripline is connected to the first end of the second coplanar waveguide through the conductive wall of the second signal via.
[0011] In one embodiment, the transmission characteristic impedance of the first signal transmission unit is 50 ohms; the transmission characteristic impedance of the second signal transmission unit is 50 ohms.
[0012] In one embodiment, the first stripline includes: a first conductor strip, wired on the first signal layer; a first ground strip, wired on the first ground layer; and a second ground strip, wired on the second ground layer; the second stripline includes: a second conductor strip, wired on the second signal layer; a third ground strip, wired on the first ground layer; and a fourth ground strip, wired on the second ground layer.
[0013] In one embodiment, the first coplanar waveguide includes: a first center conductor strip wired on the first ground layer; a first ground conductor strip wired on the first ground layer; and a first metallic ground layer wired on the first signal layer; the second coplanar waveguide includes: a second center conductor strip wired on the first ground layer; a second ground conductor strip wired on the first ground layer; and a second metallic ground layer wired on the second signal layer.
[0014] In one embodiment, the measuring device is a spectrum analyzer or a network analyzer.
[0015] In one embodiment, the region enclosed by the first electromagnetic field coil and the region enclosed by the second electromagnetic field coil have the same shape and their central axes are collinear.
[0016] The aforementioned electromagnetic field probe comprises a first ground layer, a first signal layer, a second signal layer, and a second ground layer stacked sequentially. The first electromagnetic field detection unit senses a first electrical signal generated by the combined external electric and magnetic fields on a first electromagnetic field coil. The second electromagnetic field detection unit senses a second electrical signal generated by the combined external electric and magnetic fields on a second electromagnetic field coil. Thus, the first and second electrical signals together form a differential signal, which can filter out and suppress interference signals generated during the detection process, improving detection accuracy. Furthermore, the superposition of the first and second magnetic field coils increases the magnetic field detection area, resulting in a larger amplitude of the electrical signal converted from the external magnetic field, providing greater gain for the electrical signal generated by the external magnetic field, and enabling the detection of even weaker magnetic field signals. Moreover, both the first and second magnetic field coils are located outside the ground layer, not covered by it, thus enabling the sensing of electric field signals perpendicular to the coil direction. The structure of the two magnetic field coils achieves simultaneous measurement of electric and magnetic fields and increases the amplitude of the converted electrical signals. This allows for the simultaneous detection of lower frequency electric and magnetic field signals. Attached Figure Description
[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0018] Figure 1 This is a schematic diagram of the electromagnetic field probe in one embodiment;
[0019] Figure 2 This is a partial structural schematic diagram of an electromagnetic field probe in one embodiment;
[0020] Figure 3 This is a schematic diagram of the structure of the first signal layer of an electromagnetic field probe in one embodiment;
[0021] Figure 4 This is a schematic diagram of the structure of the second signal layer of the electromagnetic field probe in one embodiment;
[0022] Figure 5 This is a schematic diagram of the structure of an example magnetic field coil in one embodiment;
[0023] Figure 6 This is a schematic diagram of the signal transmission unit in one embodiment;
[0024] Figure 7 This is a schematic diagram of the conversion through hole in one embodiment;
[0025] Figure 8 This is a schematic diagram of the stripline structure in one embodiment;
[0026] Figure 9 This is a schematic diagram of the structure of a coplanar waveguide in one embodiment;
[0027] Figure 10 This is a schematic diagram of the electromagnetic field probe in another embodiment;
[0028] Figure 11 This is a schematic diagram of the complete structure of an electromagnetic field probe in one embodiment.
[0029] Explanation of reference numerals in the attached drawings: 10-First electromagnetic field coil, 20-Second electromagnetic field coil, 30-Connecting through hole, 40-First stripline, 50-Second stripline, 60-First conversion through hole, 70-Second conversion through hole, 80-First coplanar waveguide, 90-Second coplanar waveguide, 100-Measuring equipment. Detailed Implementation
[0030] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.
[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.
[0032] It is understood that the terms “first,” “second,” etc., used in this application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another.
[0033] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, the element or feature described as “below,” “under,” or “below” will be oriented “above” the other element or feature. Therefore, the exemplary terms “below” and “under” can include both above and below orientations. Furthermore, the device may also include other orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptive terms used herein will be interpreted accordingly.
[0034] It should be noted that when one element is considered to be "connected" to another element, it can be directly connected to the other element or connected to the other element through an intermediary element. Furthermore, in the following embodiments, "connection" should be understood as "electrical connection," "communication connection," etc., if there is transmission of electrical signals or data between the connected objects.
[0035] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising,” “including,” or “having,” etc., specify the presence of the stated feature, whole, step, operation, component, part, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof.
[0036] As described in the background section, existing probes have the problem of failing to detect relatively weak electromagnetic signals. The inventors have discovered that this problem arises because existing probes have low gain for electromagnetic field signals, resulting in an excessively small amplitude of the converted electrical signal.
[0037] For the reasons mentioned above, this invention provides an electromagnetic field probe that can increase the amplitude of measured electric and magnetic field signals by high gain, thereby enabling the measurement of weaker electric and magnetic fields.
[0038] In one embodiment, such as Figure 1As shown, an electromagnetic field probe is provided. The probe consists of a first ground layer, a first signal layer, a second signal layer, and a second ground layer stacked sequentially. The probe includes: a first electromagnetic field detection unit, a second electromagnetic field detection unit, and a connecting through-hole, wherein:
[0039] The first electromagnetic field detection unit includes a first electromagnetic field coil 10 wired on the first signal layer, used to sense a first electrical signal generated by the external magnetic field and electric field.
[0040] Specifically, the electrical signal generated by the external magnetic field is determined using the following formula:
[0041]
[0042] Wherein, I1 is the electrical signal generated by the external magnetic field on the first electromagnetic field coil, B1 is the strength of the external magnetic field, S1 is the area of the first electromagnetic field coil, and R1 is the resistance value of the first electromagnetic field coil.
[0043] The electrical signal generated by the external electric field can be determined using the following formula:
[0044]
[0045] Where I2 is the electrical signal generated by the external electric field on the first electromagnetic field coil, E1 is the intensity of the external electric field, d1 is the length of the portion of the first electromagnetic field coil perpendicular to the direction of the external electric field intensity, and R1 is the resistance value of the first electromagnetic field coil.
[0046] The first electrical signal can be obtained by adding the electrical signals generated by the external electric field and the external magnetic field on the first electromagnetic field coil.
[0047] The second electromagnetic field detection unit includes a second electromagnetic field coil 20 wired on the second signal layer, used to sense a second electrical signal generated by the external magnetic field and electric field.
[0048] Specifically, the second electrical signal is also obtained in the same way described above.
[0049] Specifically, the orthographic projection of the first electromagnetic field coil onto the plane containing the second electromagnetic field coil falls within the area of the second electromagnetic field coil. Furthermore, the orthographic projections of both the first and second electromagnetic field coils onto the plane containing the first grounding layer are both outside the area of the first grounding layer. Since the orthographic projection of the first electromagnetic field coil onto the plane containing the second electromagnetic field coil falls within the area of the second electromagnetic field coil, the areas of the first and second electromagnetic field coils can be superimposed, resulting in superimposed magnetic field signals and increased amplitude. Because neither the first nor the second electromagnetic field coil is covered by the grounding layer, they are exposed to the electric field and can sense electric field signals.
[0050] For example, such as Figure 2 The image shows a three-dimensional view of an electromagnetic field probe. The first and second electromagnetic field coils are located outside the grounding layer, and the areas enclosed by the first and second electromagnetic field coils have the same shape and are collinear. Figure 3 The image shown is a top view of the first electromagnetic field coil. Figure 4 The image shown is a top view of the second electromagnetic field coil. It can be seen that both the first and second electromagnetic field coils are outside the grounding layer.
[0051] Specifically, the magnetic field sensing area is not shielded by the ground layer, allowing it to sense changes in magnetic flux through magnetic field lines. The magnetic field sensing lines are routed along the magnetic field sensing area, generating radio frequency signals based on changes in magnetic flux within the area. Furthermore, the openings are axially aligned, meaning there are openings connecting the magnetic field sensing area in a direction perpendicular to the circuit board surface, allowing electric field lines to pass through. The magnetic field sensing lines can generate mutually inductive electric field signals through the electric field lines passing through the openings, thereby suppressing signal interference, improving the electric field suppression ratio, and enhancing the accuracy of the probe's detection data.
[0052] For example, the larger the area of the magnetic field coil, the larger the amplitude of the measured magnetic field signal, such as... Figure 5 As shown, Figure 5 The circuit shown is a magnetic field coil, including an inductor, a resistor, and a power source generated in the coil by electromagnetic induction from an external magnetic field. The voltage across the resistor is determined by the following formula:
[0053]
[0054] Where V0 is the voltage across the resistor, j is the imaginary number, ω is the frequency, u0 is the coefficient, H is the magnetic field strength on the magnetic field coil, s is the area of the magnetic field coil, L is the inductance, and Z... L This represents the resistance value.
[0055] As can be seen from the above formula, when the magnetic field strength remains constant, the larger the area of the magnetic field coil, the greater the voltage across the resistor. Therefore, by superimposing the first and second electromagnetic field coils, the area of the magnetic field coils is increased, resulting in a larger amplitude of the electrical signal generated by the same magnetic field strength, making it easier to measure. This allows for the detection of electromagnetic interference signals generated by lower-frequency chips, such as low-frequency MCU (Microcontroller Unit) chips like the STM32.
[0056] For example, the area of the specific magnetic field coil that optimizes the detection effect can be determined by simulation using HFSS (High Frequency Structure Simulator) software.
[0057] The connecting through-hole 30 penetrates the first signal layer and the second signal layer, and is connected to the first electromagnetic field coil 10 and the second electromagnetic field coil 20 respectively, for connecting the first electromagnetic field coil and the second electromagnetic field coil.
[0058] For example, such as Figure 2 As shown, both the first electromagnetic field coil 10 and the second electromagnetic field coil 20 are wound around the connecting through hole 30, and electrical signals are transmitted through the connecting through hole 30.
[0059] Specifically, the first electromagnetic field coil and the second electromagnetic field coil are connected by a connecting through hole, so that the first electrical signal and the second electrical signal can be superimposed.
[0060] Specifically, the first grounding layer and the second grounding layer are shielding layers used to shield the effects of external interference signals on the first and second electrical signals during transmission, that is, to shield the effects of external interference signals on the signals on the transmission line.
[0061] Specifically, the through-hole mentioned in this application is a hole that passes through the entire printed circuit board and can be used to realize internal interconnection or as a mounting and positioning hole for components; a layer of metal can be plated on the cylindrical surface of its hole wall by chemical deposition to connect the copper foils of the intermediate layers that need to be connected, and can play the role of electrical connection, fixing or positioning of devices.
[0062] In this embodiment, a first electromagnetic field detection unit senses a first electrical signal generated by the combined external electric and magnetic fields on a first electromagnetic field coil, and a second electromagnetic field detection unit senses a second electrical signal generated by the combined external electric and magnetic fields on a second electromagnetic field coil. The first and second electrical signals together form a differential signal, which can filter out and suppress interference signals generated during the detection process, improving detection accuracy. Furthermore, the superposition of the first and second magnetic field coils increases the magnetic field detection area, resulting in a larger amplitude of the electrical signal converted from the external magnetic field, providing greater gain for the electrical signal generated by the external magnetic field, and enabling the detection of even weaker magnetic field signals. Moreover, both the first and second magnetic field coils are located outside the grounding layer and are not covered by it, thus enabling the sensing of electric field signals perpendicular to the coils. The structure of the two magnetic field coils achieves simultaneous measurement of electric and magnetic fields and increases the amplitude of the converted electrical signals. This allows for the simultaneous detection of lower frequency electric and magnetic field signals, increasing detection sensitivity.
[0063] In one embodiment, such as Figure 1 As shown, the probe also includes: a first signal transmission unit and a second signal transmission unit, wherein:
[0064] The first signal transmission unit includes a first stripline 40, a first conversion via 60, and a first coplanar waveguide 80, all wired on a corresponding wiring layer. The first end of the first stripline 40 is connected to the first electromagnetic field coil 10, and the second end of the first stripline 40 is connected to the first end of the first coplanar waveguide 80 through the first conversion via 60.
[0065] The second signal transmission unit includes a second stripline 50, a second conversion via 70, and a second coplanar waveguide 90, all wired on a corresponding wiring layer. The first end of the second stripline 50 is connected to the second electromagnetic field coil 20, and the second end of the second stripline 50 is connected to the first end of the second coplanar waveguide 90 through the second conversion via 70.
[0066] Specifically, conversion vias can be used to convert stripline transmission structures into CB-CPW (Conductor-backed coplanar waveguide) transmission line structures. The conductive via wall enables conduction between the conductor strip of the stripline and the center conductor strip of the CB-CPW transmission line, ensuring impedance matching of the transmission characteristics, suppressing signal attenuation, and reducing transmission resonance.
[0067] Specifically, such as Figure 6 The image shown is a partial enlarged view of the signal transmission section. Figure 6This is a top view of the first grounding layer or the second grounding layer, wherein the first stripline (not shown in the figure) connects the first conversion via and the first electromagnetic field coil, and the second stripline (not shown in the figure) connects the second conversion via and the second electromagnetic field coil.
[0068] Specifically, the first conversion via includes a first signal via and a plurality of first surrounding ground vias that surround the first signal via at a preset distance; the second end of the first stripline is connected to the first end of the first coplanar waveguide through the conductive wall of the first signal via.
[0069] The second conversion via includes a second signal via and a plurality of second surrounding ground vias that surround the second signal via at a preset distance; the second end of the second stripline is connected to the first end of the second coplanar waveguide through the conductive hole wall of the second signal via.
[0070] The number of surrounding grounding vias and the preset distance from the signal vias can be adjusted according to parameters such as the probe structure, the size of the transmission structure, and the thickness of the substrate dielectric substrate.
[0071] For example, such as Figure 7 As shown, six coaxial vias surround the grounding via. This array of six vias compensates for the impedance mismatch caused by the central signal via, ensuring a transmission characteristic impedance of 50 ohms and improving the probe's transmission efficiency. The spacing between layers, as well as the size and material of the conductors, determine the conductor impedance. This can be calculated using commercially available software to determine the required design for the layer spacing, conductor size, and materials under a preset impedance. Through proper design, the characteristic impedance of the signal transmission section is achieved to be 50 ohms. Since the characteristic impedance of peripheral analysis devices is typically 50 ohms, this embodiment selects a 50-ohm characteristic impedance design to facilitate impedance matching with peripheral analysis devices and ensure low signal loss and low signal reflection during transmission.
[0072] Specifically, the first stripline includes: a first conductor strip, routed on the first signal layer; a first ground strip, routed on the first ground layer; and a second ground strip, routed on the second ground layer. The second stripline includes: a second conductor strip, routed on the second signal layer; a third ground strip, routed on the first ground layer; and a fourth ground strip, routed on the second ground layer.
[0073] For example, Figure 8 The diagram below shows the structure of a stripline in one embodiment. The stripline can be composed of two grounded metal strips and a rectangular cross-section conductor strip with a width of ω and a thickness of t in the middle. Since there are grounded metal strips on both sides, its impedance is easy to control and the shielding is good. The magnetic field stripline and the electric field stripline can be located in different wiring layers and can shield interference through their respective grounded metal strips to ensure low loss and low reflection in their respective signal transmission.
[0074] Specifically, the first coplanar waveguide includes: a first center conductor strip, wired in the first ground layer; a first ground conductor strip, wired in the first ground layer; and a first metallic ground layer, wired in the first signal layer; the second coplanar waveguide includes: a second center conductor strip, wired in the first ground layer; a second ground conductor strip, wired in the first ground layer; and a second metallic ground layer, wired in the second signal layer.
[0075] For example, such as Figure 9 As shown, the CB-CPW transmission line consists of a dielectric substrate, three conductive strips on the upper surface of the dielectric substrate, and a metal grounding layer on the lower surface of the dielectric substrate. The middle strip is a thin central conductor, and the two parallel grounding strips on either side are very close to it. The small gap between the central conductor and the grounding strips achieves low impedance, and the transmission characteristic impedance of the CB-CPW can be changed by adjusting this gap. The metal surface of the grounding strip is semi-infinite, but its area is finite in actual manufacturing. The grounding strip on the upper surface of the dielectric substrate is connected to the metal grounding layer on the lower surface of the dielectric substrate through metal-filled vias to achieve consistent grounding performance. Due to the enhanced grounding structure, the impedance of the grounding plane can be reduced, which is beneficial for the impedance design of the CB-CPW and the transmission of radio frequency signals, allowing the radio frequency signal to be transmitted with a 50-ohm impedance.
[0076] In this embodiment, a signal transmission unit is provided to transmit the electrical signal captured by the electromagnetic field detection unit. During the transmission process, the electrical signal is kept as free from interference as possible, and the transmission quality is improved as much as possible.
[0077] In one embodiment, such as Figure 6 As shown, the probe also includes multiple mounting through holes, each penetrating through each layer of the probe, for fixing the probe or for fixing the probe to external measuring equipment.
[0078] Specifically, mounting vias are used to mount the transmission line to the interface of an external testing device, allowing for better contact between the transmission line and the interface, thus facilitating better transmission of electrical signals to the external testing device. In one example, two mounting vias are provided on each side of the coplanar waveguide, and the mounting vias on both sides are symmetrical.
[0079] Specifically, the probe also includes shielding through holes, which serve as shielding devices and enhance the shielding effect of the probe against the electric field. The number of shielding through holes can be determined according to the actual size of the probe, and the spacing between adjacent shielding through holes can be determined according to the actual shielding effect against the electric field.
[0080] In this embodiment, by providing mounting through holes, the structure between the layers of the probe can be fixed, the probe can be easily connected to external devices, and it can also serve as a shield, enhancing the shielding effect on the transmission unit.
[0081] In one embodiment, such as Figure 10 As shown, the probe also includes:
[0082] The measuring device 100 is connected to the second end of the first coplanar waveguide and the second coplanar waveguide, respectively, and is used to determine the strength of the external magnetic field and the strength of the external electric field based on the first electrical signal and the second electrical signal.
[0083] Specifically, the measuring device is used to determine the strength of the external electric field based on the sum of the first and second electrical signals, and then multiply it by the corresponding calibration factor; and to determine the strength of the external magnetic field based on the difference between the first and second electrical signals, and then multiply it by the corresponding calibration factor.
[0084] For example, the measuring device is a spectrum analyzer or a network analyzer. The signal transmission section may be soldered with an SMA (Small AType, microwave high-frequency connector), one end of which is connected to the CB-CPW transmission line, and the other end is connected to the measuring device.
[0085] Specifically, a calibration system for an electromagnetic field probe can be built using a network analyzer and a microstrip line. The microstrip line used for calibration can be considered an external standard that can be used to emit a standard field. This microstrip line can generate a certain quasi-TEM (Transverse Electric and Magnetic Field) radio frequency electric field. By scanning this standard in the Y direction (perpendicular to the microstrip line's routing direction) using the electromagnetic field probe, the spatial resolution of the passive electromagnetic field probe can be obtained. The specific scanning method includes: probing at different locations with the probe, detecting the field strength, and using a network analyzer to plot the relationship between the field strength at different locations and the location, thereby deriving the spatial resolution. Furthermore, the probe's detection sensitivity can be calibrated by gradually decreasing the electromagnetic signal from the standard source. Using this calibration system and scanning method, the measurement results of the electromagnetic field probe can be calibrated.
[0086] In this embodiment, the strength of external electric and magnetic fields can be determined based on the first and second electrical signals using a measuring device.
[0087] For example, such as Figure 11 As shown, Figure 1 The electromagnetic field probe shown has four wiring layers stacked sequentially to obtain the following: Figure 11 The complete electromagnetic field probe shown.
[0088] In the description of this specification, references to terms such as "some embodiments," "other embodiments," and "ideal embodiments" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative descriptions of the above terms do not necessarily refer to the same embodiments or examples.
[0089] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0090] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.
Claims
1. An electromagnetic field probe, characterized in that, The probe comprises a first ground layer, a first signal layer, a second signal layer, and a second ground layer stacked sequentially. The probe includes: The first electromagnetic field detection unit includes a first electromagnetic field coil wired on the first signal layer, used to sense a first electrical signal generated by the external magnetic field and electric field. The second electromagnetic field detection unit includes a second electromagnetic field coil wired on the second signal layer, used to sense a second electrical signal generated by the combined external magnetic field and electric field. The orthographic projection of the first electromagnetic field coil onto the plane where the second electromagnetic field coil is located is within the range of the second electromagnetic field coil. The orthographic projections of both the first and second electromagnetic field coils onto the plane where the first ground layer is located are outside the range of the first ground layer. A connecting via penetrates the first signal layer and the second signal layer, and is connected to the first electromagnetic field coil and the second electromagnetic field coil respectively, for connecting the first electromagnetic field coil and the second electromagnetic field coil; The process by which the first electromagnetic field detection unit senses the first electrical signal generated by the combined external magnetic and electric fields includes: The first electromagnetic field detection unit senses the electrical signal generated by the external magnetic field, as shown in the following formula: in, The electrical signal generated on the first electromagnetic field coil by the external magnetic field. The strength of the external magnetic field. Let be the area of the first electromagnetic field coil. The resistance value of the first electromagnetic field coil; The first electromagnetic field detection unit senses the electrical signal generated by the external electric field, as shown in the following formula: in, The electrical signal generated by the external electric field on the first electromagnetic field coil. The strength of the external electric field. Let be the length of the portion of the first electromagnetic field coil perpendicular to the direction of the external electric field intensity. The resistance of the first electromagnetic field coil is given; the electrical signal generated by the external magnetic field and the electrical signal generated by the external electric field are added together to obtain the first electrical signal; the process by which the second electromagnetic field detection unit senses the second electrical signal generated by the external magnetic field and electric field is the same as the sensing process of the first electromagnetic field detection unit. The probe also includes: A first signal transmission unit includes a first stripline, a first conversion via, and a first coplanar waveguide wire routed on a corresponding wiring layer. A first end of the first stripline is connected to a first electromagnetic field coil, and a second end of the first stripline is connected to a first end of the first coplanar waveguide wire via the first conversion via. A second signal transmission unit includes a second stripline, a second conversion via, and a second coplanar waveguide wire routed on a corresponding wiring layer. A first end of the second stripline is connected to a second electromagnetic field coil, and a second end of the second stripline is connected to a first end of the second coplanar waveguide wire via the second conversion via. The first stripline includes: a first conductor strip, routed on the first signal layer; a first ground strip, routed on the first ground layer; and a second ground strip, routed on the second ground layer. The first coplanar waveguide includes: a first center conductor strip, wired on the first ground layer; a first ground conductor strip, wired on the first ground layer; and a first metallic ground layer, wired on the first signal layer. The second stripline includes: a second conductor strip, routed on the second signal layer; a third ground strip, routed on the first ground layer; and a fourth ground strip, routed on the second ground layer. The second coplanar waveguide includes: a second center conductor strip, wired on the first ground layer; a second ground conductor strip, wired on the first ground layer; and a second metallic ground layer, wired on the second signal layer.
2. The probe according to claim 1, characterized in that, The probe also includes: The measuring device is connected to the second end of the first coplanar waveguide and the second coplanar waveguide, respectively, and is used to determine the strength of the external magnetic field and the strength of the external electric field based on the first electrical signal and the second electrical signal.
3. The probe according to claim 2, characterized in that, The measuring device is used for, The strength of the external electric field is determined based on the sum of the first and second electrical signals. The strength of the external magnetic field is determined based on the difference between the first electrical signal and the second electrical signal.
4. The probe according to claim 1, characterized in that, The first conversion via includes a first signal via and a plurality of first surrounding ground vias that surround the first signal via at a preset distance; the second end of the first stripline is connected to the first end of the first coplanar waveguide through the conductive wall of the first signal via. The second conversion via includes a second signal via and a plurality of second surrounding ground vias that surround the second signal via at the preset distance; the second end of the second stripline is connected to the first end of the second coplanar waveguide through the conductive hole wall of the second signal via.
5. The probe according to claim 1, characterized in that, The characteristic impedance of the first signal transmission unit is 50 ohms; The characteristic impedance of the second signal transmission unit is 50 ohms.
6. The probe according to claim 2, characterized in that, The measuring device is a spectrum analyzer or a network analyzer.
7. The probe according to any one of claims 1-6, characterized in that, The region enclosed by the first electromagnetic field coil has the same shape as the region enclosed by the second electromagnetic field coil, and their central axes are collinear.