Circuit board and shielding test system

Abstract

The application provides a circuit board and a shielding test system, relates to the technical field of signal shielding detection, and can effectively detect the shielding effect of the shielding scheme of an electronic device, and the accuracy of the detection result is high. The circuit board comprises a multilayer stacking structure and an electrical connecting piece. The electrical connecting piece extends along the stacking direction of the multilayer stacking structure. The multilayer stacking structure comprises at least one conductive layer and at least one insulating layer. The at least one insulating layer and the at least one conductive layer are alternately stacked. The electrical connecting piece forms a dipole, or at least part of the at least one conductive layer and the electrical connecting piece form a dipole. The circuit board is used for detecting the shielding effect of a shielding cover.

Description

Technical Field

[0001] This application relates to the field of signal shielding detection technology, and in particular to a circuit board and shielding testing system. Background Technology

[0002] Electronic products (such as mobile phones, tablets, and computers) generally contain multiple electronic components. Some of these components generate electric or magnetic fields during operation, which can create noise sources and cause electromagnetic interference to other electronic components (such as antennas). Therefore, electronic products typically include shielding covers around these noise-generating components to protect them from noise and prevent it from affecting other electronic devices.

[0003] The shielding effectiveness of a shield is a key factor determining noise interference. Therefore, testing the shielding effectiveness of a shield is a crucial step. However, existing testing methods for shields cannot provide accurate results for the aforementioned electronic equipment scenarios, resulting in low accuracy of the test results. Summary of the Invention

[0004] This application provides a circuit board and a shielding testing system, which can effectively test the shielding effect of shielding schemes for electronic devices, and the test results are highly accurate.

[0005] To achieve the above objectives, this application adopts the following technical solution:

[0006] In a first aspect, this application provides a circuit board including a multilayer stacked structure and an electrical connector. The electrical connector extends along the stacking direction of the multilayer stacked structure. The multilayer stacked structure includes at least one conductive layer and at least one insulating layer. The at least one insulating layer and the at least one conductive layer are alternately stacked. The electrical connector forms a dipole, or at least a portion of the at least one conductive layer and the electrical connector form a dipole.

[0007] The circuit board provided in this application allows electrical connectors to form dipoles, or at least a portion of at least one conductive layer and electrical connectors to form dipoles. Dipoles can simulate noise-generating electronic devices in electronic equipment. The shielding test system provided in this application, by detecting the shielding effect of the shielding cover under test on the field distribution generated by the dipole, can be equivalent to detecting the shielding effect of the shielding cover under test on the noise-generating electronic devices in electronic equipment. It can accurately measure the shielding effect of the shielding cover under test on the electronic devices in electronic equipment, resulting in good test performance and accurate results.

[0008] In one possible implementation of the first aspect, the dipole includes a magnetic dipole. The magnetic dipole extends in a ring shape, and its axis is perpendicular to or intersects the stacking direction of the multilayer stacked structure. Under excitation, the magnetic dipole can generate a magnetic field, thereby simulating a noise source that generates magnetic field noise in electronic devices. Since the plane in which the magnetic dipole extends is parallel to the stacking direction of the multilayer stacked structure, the magnetic field direction of the magnetic dipole is consistent with the magnetic field direction of the noisy electronic device, enabling better detection of the shielding effect of the shielding cover under test.

[0009] In one possible implementation of the first aspect, the dipole includes an electric dipole. At least a portion of the electric dipole extends in a direction parallel to or intersecting the stacking direction of the multilayer stacked structure. Thus, the electric dipole can simulate a noise source capable of generating electric field noise in an electronic device, thereby enabling the detection of the shielding effect of the shield under test against electric field noise. Since the extension direction of the electric dipole can be parallel to the stacking direction of the multilayer stacked structure, the electric field direction of the electric dipole is consistent with the electric field direction of the noisy electronic device in the electronic device, allowing for better detection of the shielding effect of the shield under test.

[0010] In one possible implementation of the first aspect, there are multiple conductive layers and multiple electrical connectors. The multiple conductive layers include a first conductive layer, a second conductive layer, and a third conductive layer. The first conductive layer includes a first conductive portion. The second conductive layer is located on one side of the first conductive layer and includes two spaced-apart second conductive portions. The third conductive layer is located on the side of the second conductive layer away from the first conductive layer. The multiple electrical connectors include two first electrical connectors and two second electrical connectors. The two first electrical connectors are located between the first and second conductive layers and extend along the stacking direction of the multilayer stacked structure. One end of one first electrical connector is connected to one end of a first conductive portion, and the other end is connected to one end of a second conductive portion. One end of the other first electrical connector is connected to the other end of a first conductive portion, and the other end is connected to one end of another second conductive portion. The two second electrical connectors are located between the second and third conductive layers and extend along the stacking direction of the multilayer stacked structure. One end of one second electrical connector is connected to the other end of a second conductive portion, and the other end is connected to the third conductive layer. One end of the other second electrical connector is connected to the other end of another second conductive portion. One end of each of the two second electrical connectors is located between the other ends of the two first electrical connectors. The two first electrical connectors, the two second electrical connectors, the first conductive portion, and the two second conductive portions form a magnetic dipole. In this way, the distance between the two second electrical connectors is smaller than the distance between the two first electrical connectors, resulting in a smaller distance between the two ends of the current loop of the formed magnetic dipole. This provides some shielding against the electric field, making the magnetic field formed by the magnetic dipole purer and less susceptible to the influence of the electric field.

[0011] In one possible implementation of the first aspect, there are multiple conductive layers and multiple electrical connectors. The multiple conductive layers include a first conductive layer and a third conductive layer. The first conductive layer includes a first conductive portion, and the third conductive layer is located on one side of the first conductive layer. The multiple electrical connectors include two first electrical connectors. The two first electrical connectors are located between the first conductive layer and the third conductive layer, extending along the stacking direction of the multilayer stacked structure. One end of one first electrical connector is connected to one end of the first conductive portion, and the other end is connected to the third conductive layer. One end of the other first electrical connector is connected to the other end of the first conductive portion. The two first electrical connectors and the first conductive portion form a magnetic dipole. In this case, the shape of the magnetic dipole is relatively simple, and it is also more convenient and simpler to manufacture.

[0012] In one possible implementation of the first aspect, the plurality of conductive layers further includes a fourth conductive layer. The fourth conductive layer is located on the side of the first conductive layer away from the third conductive layer and includes two spaced-apart third conductive portions, with a portion of each third conductive portion opposite to the first conductive portion. The plurality of electrical connectors also includes two third electrical connectors. The two third electrical connectors are located between the third and fourth conductive layers and extend along the stacking direction of the multilayer stacked structure. One end of one third electrical connector is connected to one end of a third conductive portion, and the other end is connected to the third conductive layer. One end of the other third electrical connector is connected to one end of another third conductive portion, and the other end is connected to the third conductive layer. The other ends of the two third conductive portions are located between the ends of the two third conductive portions. By providing two third conductive portions and two third electrical connectors, a circuit breaker structure can be provided around the magnetic dipole, which can cancel the electric field generated by the magnetic dipole, thereby allowing the magnetic dipole to form a purer magnetic field and avoiding electric field interference affecting the test results.

[0013] In one possible implementation of the first aspect, the magnetic dipole has an axisymmetric structure along the central axis of the first conductive portion. When the magnetic dipole has a symmetrical structure, the electromagnetic field distribution of the magnetic dipole is relatively simpler, thus facilitating subsequent analysis and testing.

[0014] In one possible implementation of the first aspect, the two third electrical connectors are symmetrical about each other along the central axis of the first conductive portion. The two third conductive portions are also symmetrical about each other. Based on this scheme, the two third electrical connectors and the two third conductive portions can better cancel out the electric field, thereby enabling the magnetic dipole to form a relatively pure magnetic field.

[0015] In one possible implementation of the first aspect, the electrical connector includes a fourth electrical connector. The fourth electrical connector extends along the stacking direction of the multilayer stacked structure. The fourth electrical connector forms an electric dipole. Thus, an electric dipole can be easily and conveniently formed using the fourth electrical connector.

[0016] In one possible implementation of the first aspect, there are multiple conductive layers, with one end of the fourth electrical connector flush with one side of the multiple conductive layers and the other end of the fourth electrical connector flush with the other side of the multiple conductive layers. Therefore, the fourth electrical connector is relatively long, resulting in a stronger electric field distribution and thus facilitating detection.

[0017] In one possible implementation of the first aspect, the length of the dipole is less than or equal to one-tenth of a preset wavelength. The preset wavelength range is 500 MHz to 6 GHz. When the length of the dipole is within the above range, the preset wavelength of the testable frequency band is also 500 MHz to 6 GHz, which provides a wide range of testable frequencies and can cover the frequency band of noise generated by electronic devices in electronic equipment.

[0018] In one possible implementation of the first aspect, the length of the dipole is greater than or equal to one-twentieth of a preset wavelength. When the length of the dipole is within the aforementioned range, the length of the dipole is relatively moderate, which can better form a magnetic or electric field, so as to better perform detection and testing.

[0019] Secondly, this application provides a shielding detection system, including a shielding cover to be tested, a signal transceiver, a testing device, and a circuit board as described in any one of the first aspects. The shielding cover to be tested is disposed on the circuit board and covers a dipole. The signal transceiver is electrically connected to the dipole. The testing device is electrically connected to the signal transceiver and is located on the side of the shielding cover to be tested away from the dipole.

[0020] In one possible implementation of the second aspect, the testing apparatus includes a transverse electromagnetic wave chamber.

[0021] In one possible implementation of the second aspect, the testing apparatus includes a near-field scanner.

[0022] In one possible implementation of the second aspect, the signal transceiver includes a vector network analyzer.

[0023] In one possible implementation of the second aspect, the signal transceiver includes a spectrum analyzer and a signal source.

[0024] The technical effects of the second aspect can be found in the technical effects of different design methods in the first aspect, and will not be repeated here. Attached Figure Description

[0025] Figure 1 A schematic diagram of a structure used for shielding effectiveness testing in related technologies;

[0026] Figure 2 This is a schematic diagram of the structure of a shielding test system provided in an embodiment of this application;

[0027] Figure 3 A schematic diagram of a circuit board structure provided in an embodiment of this application;

[0028] Figure 4 This is a schematic diagram of another circuit board structure provided in an embodiment of this application;

[0029] Figure 5 This is a schematic diagram of another circuit board structure provided in an embodiment of this application;

[0030] Figure 6 This is a schematic diagram of another circuit board structure provided in an embodiment of this application;

[0031] Figure 7 This is a schematic diagram of another circuit board structure provided in an embodiment of this application;

[0032] Figure 8 This is a three-dimensional structural diagram of a portion of a circuit board provided in an embodiment of this application;

[0033] Figure 9 This is a schematic diagram of another circuit board structure provided in an embodiment of this application;

[0034] Figure 10 This is a three-dimensional structural diagram of a portion of a circuit board provided in an embodiment of this application;

[0035] Figure 11 A schematic flowchart illustrating a testing method for a shielding testing system provided in an embodiment of this application;

[0036] Figure 12 A schematic diagram showing the shielding effect of different schemes;

[0037] Figure 13 This is a schematic diagram of another circuit board structure provided in an embodiment of this application;

[0038] Figure 14 This is a schematic diagram of another circuit board structure provided in an embodiment of this application;

[0039] Figure 15 This is a schematic diagram of a circuit board during installation, provided as an embodiment of this application.

[0040] Explanation of reference numerals in the attached figures:

[0041] 010-Antenna shield; 011-Shield body; 012-Cover; 013-Adhesive; 014-Receiving antenna; 015-Radiation source;

[0042] 100-Shielding test system; 10-Signal transceiver; 20-Test device; 30-Shielding cover to be tested; 40-Circuit board; 41-Stacked structure; 42-Electrical connector; 421-First electrical connector; 422-Second electrical connector; 423-Third electrical connector; 424-Fourth electrical connector; 43-Conductive layer; 431-First conductive layer; 4311-First conductive part; 432-Second conductive layer; 4321-Second conductive part; 433-Third conductive layer; 434-Fourth conductive layer; 4341-Third conductive part; 44-Insulating layer; 45-Dipole; 50-Mounting box. Detailed Implementation

[0043] In the embodiments of this application, the terms "exemplarily" or "for example" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplarily" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplarily" or "for example" is intended to present the relevant concepts in a specific manner.

[0044] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the terms "installation", "connection" and "linking" should be interpreted broadly. For example, "linking" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium.

[0045] In the description of embodiments of this application, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0046] As used herein, “parallel,” “perpendicular,” and “equal” include the described situation and situations that are similar to the described situation, within an acceptable deviation range, which is determined by those skilled in the art taking into account the measurement under discussion and the error associated with the measurement of a particular quantity (i.e., the limitations of the measurement system). For example, “parallel” includes absolute parallelism and approximate parallelism, where the acceptable deviation range for approximate parallelism can be, for example, within ±10°; “perpendicular” includes absolute perpendicularity and approximate perpendicularity, where the acceptable deviation range for approximate perpendicularity can also be, for example, within ±10°. “equal” includes absolute equality and approximate equality, where the acceptable deviation range for approximate equality can be, for example, a difference between the two equals being less than or equal to 5% of either one.

[0047] Mobile phones, tablets, and computers are among the most frequently used electronic devices in daily life. These devices typically contain numerous electronic components, some of which generate electric or magnetic fields and thus noise during normal operation. For example, integrated circuit (IC) chips, power inductors, and double-data-rate SDRAM (DDR) all contribute to noise. These noise-generating electronic components can cause electromagnetic interference to other components within the electronic device (such as antennas), affecting their normal operation.

[0048] Therefore, in order to ensure the normal and stable operation of electronic devices, electronic devices are also equipped with shielding covers. The shielding covers can be placed around the aforementioned electronic devices that generate noise to shield the noise they generate, thereby preventing the noise from affecting the normal operation of other electronic devices.

[0049] The shielding effect of a shielding cover can be affected by various factors. For example, the material, size, shape, and location of the noise source inside the shielding cover will all have different effects on the shielding effect, resulting in different shielding performance and varying degrees of noise leakage.

[0050] For example, electronic devices include radio frequency (RF) devices, such as power amplifiers (PAs), which are sources of high-intensity harmonics. Therefore, the RF devices are enclosed in an RF shield. For ease of routing, routing openings can be provided on the sidewalls of the shield. However, if the size of these routing openings is too large, harmonics generated by the RF devices may leak into the far field through these openings, causing excessive radiated spurious emissions (RES).

[0051] For example, the electronic device may also include a system-on-a-chip (SOC) and a DDR chip. The components can be shielded using a two-piece interlocking shield (i.e., two shielding parts interlocking), or a copper foil shield can be used to cover and adhere to the outside. However, if the two-piece shield fails to interlock properly, or if the copper foil shield fails to adhere properly, noise leakage will occur. This leaked noise will couple to the antenna of the electronic device, interfering with the antenna and reducing its receiving sensitivity.

[0052] Therefore, to ensure shielding effectiveness, testing and evaluating the shielding effect of shielding covers is particularly important to ensure that they provide good shielding when used in electronic devices. For example, the national standard GB / T 30142-2013 provides a scheme for testing shielding effectiveness, which mainly tests the far-field distribution of a plane wave after it passes through a planar material, thereby determining the shielding performance of the planar material.

[0053] For example, such as Figure 1 As shown, Figure 1 This is a schematic diagram of a structure used for shielding effectiveness testing in related technologies. A receiving antenna 014 is housed within an antenna shield 010. The antenna shield 010 may include a housing 011 and a cover 012. The cover 012 is connected to the housing 011 via adhesive 013. A radiation source 015 is positioned above the cover 012. This shielding performance measurement scheme detects shielding performance by measuring the far-field distribution, and is only applicable to... Figure 1 The shielding effect of electromagnetic waves through the leakage path X can be detected, but the shielding effect of electromagnetic waves through the leakage path Y cannot be detected.

[0054] Furthermore, the shielding performance measurement scheme of related technologies measures the shielding effect by testing the far-field distribution of the noise source after passing through the shield. However, the distance between the noise-generating electronic components and other easily affected electronic components in electronic devices is small, and this method of measuring the far-field distribution does not match the characteristics of near-field coupling in electronic devices. At the same time, the radiation source selected (usually emitting TEM waves) is different from the type of noise source in the electronic device, and cannot simulate the noise-generating electronic components in the electronic device.

[0055] Therefore, a shielding cover that demonstrates good shielding performance using the above-mentioned method may not necessarily have good shielding effectiveness when applied to electronic devices. The aforementioned shielding cover testing method cannot accurately test the shielding effectiveness of shielding covers used in electronic devices, and the test results cannot accurately measure the shielding effectiveness and noise leakage of the cover.

[0056] Based on this, embodiments of this application provide a shielding testing system, such as... Figure 2 As shown, Figure 2 This is a schematic diagram of a shielding testing system 100 provided in an embodiment of this application. The shielding testing system 100 may include a signal transceiver 10, a testing device 20, a shielding cover 30 to be tested, and a circuit board 40. The shielding cover 30 to be tested is the component whose shielding effect needs to be tested.

[0057] The signal transceiver 10 can be used to transmit or receive signals. The signal transceiver 10 can test the shielding effect of the shielding cover 30 to be tested by the difference between the transmitted signal and the received signal.

[0058] The testing device 20 can be electrically connected to the signal transceiver 10. The testing device 20 can detect the magnetic or electric field distribution after being shielded by the shielding cover 30, and the detection results can be transmitted to the signal transceiver 10. The signal transceiver 10 can then obtain the magnetic or electric field distribution after being shielded by the shielding cover 30, and thus analyze its shielding effect.

[0059] To ensure more accurate testing results for the shielding cover 30 under test, and to guarantee its effective shielding when used in shielding electronic devices, such as... Figure 3 As shown, Figure 3 This is a schematic diagram of the structure of a circuit board 40 provided in an embodiment of this application. The circuit board 40 may include a multi-layer stacked structure 41 and an electrical connector 42.

[0060] The multilayer stacked structure 41 may include at least one conductive layer 43 and at least one insulating layer 44. The at least one insulating layer 44 and the at least one conductive layer 43 are alternately stacked. Different circuit routing can be achieved by designing the conductive layer 43.

[0061] The electrical connector 42 extends along the stacking direction of the multilayer stacked structure 41. When there are multiple conductive layers 43, the electrical connector 42 can connect with conductors within different conductive layers 43, achieving circuit connectivity between the different conductive layers 43. For example, vias may be formed in the multilayer stacked structure 41, and the electrical connector 42 can be disposed within these vias. The electrical connector 42 can be made of a material with conductive properties. For example, the electrical connector 42 can be made of copper.

[0062] The electrical connector 42 may form a dipole 45, or at least a portion of at least one conductive layer 43 and the electrical connector 42 may form a dipole 45.

[0063] In the shielding test system 100 provided in this application embodiment, the shielding cover 30 to be tested can be disposed on the circuit board 40 and cover the dipole 45. The signal transceiver 10 can be electrically connected to the dipole 45. The test device 20 can be located on the side of the shielding cover 30 to be tested away from the dipole 45. Since the signal transceiver 10 is electrically connected to the dipole 45, the signal transceiver 10 can excite the dipole 45 to generate a field distribution. At the same time, the test device 20 can detect the field distribution of the dipole 45 after passing through the shielding cover 30 to be tested and transmit the result to the signal transceiver 10. The signal transceiver 10 can then obtain the shielding effect of the shielding cover 30 to the field distribution generated by the dipole 45 by comparing the transmitted and received field distributions.

[0064] It is known that the radiator can be approximated as a combination of dipoles 45. Therefore, the dipoles 45 can simulate the noise-generating electronic devices in an electronic device. Thus, the shielding test system 100 provided in this application, by detecting the shielding effect of the shielding cover 30 on the field distribution generated by the dipoles 45, can be equivalent to detecting the shielding effect of the shielding cover 30 on the noise-generating electronic devices in the electronic device. This allows for a relatively accurate measurement of the shielding effect of the shielding cover 30 on the electronic devices in the electronic device, resulting in better test performance and more accurate results.

[0065] To test the shielding effect of the shielding cover 30 on the dipole 45, in some embodiments, the testing device 20 may include a transverse electromagnetic wave chamber. Using a transverse electromagnetic wave chamber allows for a relatively accurate assessment of the shielding effect of the shielding cover 30, and is simple, convenient, and cost-effective. For example, when using a transverse electromagnetic wave chamber to test the shielding cover 30, the two oppositely positioned ports of the chamber are electrically connected to the signal transceiver 10, and the circuit board 40 is disposed inside the chamber, between the two ports. In this case, the shielding effect of the shielding cover can be determined by testing the changes in the electromagnetic field at the two ports.

[0066] Of course, in other embodiments, the testing device 20 may include a near-field scanner. When using a near-field scanner to test the shielding effect of the shielding cover 30, the testing accuracy is high, and the shielding effect can be precisely determined. For example, when using a near-field scanner to test the shielding cover 30, the near-field scanner can be located on the side of the shielding cover 30 away from the dipole 45, scanning the near-field distribution of the dipole 45 after passing through the shielding cover 30 to obtain the final shielding effect.

[0067] In some embodiments, the signal transceiver 10 may include a vector network analyzer. The vector network analyzer can provide a stable, tunable radio frequency signal as an excitation source to excite the dipole 45. Simultaneously, the vector network analyzer can receive signals from the test device 20 and process the data to obtain the final measurement result. Furthermore, the above-described detection method requires only one instrument, resulting in a relatively simple setup.

[0068] Of course, in other embodiments, the signal transceiver 10 may include a spectrum analyzer and a signal source. The spectrum analyzer may be electrically connected to the detection device, and can receive and analyze the data measured by the detection device. The signal source may be electrically connected to the dipole 45, and can be used to excite the dipole 45 to generate a field distribution for subsequent testing of the shielding effect of the shielding cover 30 under test. Simultaneously, the signal source may be electrically connected to the spectrum analyzer. In this way, the spectrum analyzer can acquire data from the signal source, and thus easily compare it with the data measured by the detection device to obtain the final shielding effect of the shielding cover 30 under test. Furthermore, the measurement using the above-described equipment allows for a relatively large measurable frequency band range.

[0069] It is understood that the specific type and material composition of the shielding cover 30 to be tested in this application embodiment are not specifically limited, and the shielding effect can be tested for different types of shielding covers 30 to be tested. For example, the shielding cover 30 to be tested can be made of conventional materials such as conductive copper foil or conductive cloth. Alternatively, the shielding cover 30 to be tested can also be made of novel materials such as carbon fiber or wave-absorbing materials.

[0070] For example, the shielding cover 30 to be tested can be a shielding frame, which is connected to the circuit board 40 by welding or bonding, covering the dipole 45. Alternatively, the shielding cover 30 to be tested can also be a thin film structure, which is directly coated on the circuit board 40 and covers the dipole 45. The specific type of shielding cover 30 to be tested can be selected according to the actual situation. This is only an example for illustration.

[0071] The dipole 45 in the circuit board 40 provided in the embodiments of this application will be further illustrated below.

[0072] In some embodiments, the number of dipoles 45 formed in the circuit board 40 can be multiple. As mentioned above, the radiator can be approximated as a combination of dipoles 45. Thus, when designing the dipoles 45 in the circuit board 40, the dipoles 45 can be designed according to the electronic devices that generate noise in the electronic device, so that the dipoles 45 in the circuit board 40 can correspond to the corresponding electronic devices, and the shielding result is consistent with the effect of the shielding cover 30 under test when it is actually applied to shield the corresponding electronic devices.

[0073] For example, when manufacturing the circuit board 40, a detection device can be used to obtain the field distribution formed by the electronic devices in the electronic device, and then the number and shape of the corresponding dipoles 45 can be obtained based on the field distribution. Then, the number and shape of the dipoles 45 can be manufactured when manufacturing the circuit board 40 to obtain a combination of dipoles 45 with a field distribution equivalent to that of the electronic devices in the electronic device.

[0074] Of course, in some embodiments, the number of dipoles 45 formed in the circuit board 40 can also be a single one. In this case, the number of dipoles 45 on the circuit board 40 is smaller, and the structure is simpler. Generally, electronic devices that generate noise in electronic devices can be essentially equivalent to the field distribution generated by a single dipole 45. Thus, by testing the shielding effect of the shielding cover 30 under test on a single dipole 45, the actual effect of the shielding cover 30 under test on shielding the corresponding electronic device can be tested.

[0075] Of course, when the number of dipoles 45 formed in the circuit board 40 is a single one, if the electronic device that generates noise in the electronic device is equivalent to multiple dipoles 45, then by detecting the shielding effect of the shielding cover 30 under test against a single dipole 45, software simulation can be performed based on the test results to simulate the shielding effect of the shielding cover 30 under test against the radiators equivalent to multiple dipoles 45, and a more accurate shielding test result can be obtained.

[0076] In some embodiments, dipole 45 may include a magnetic dipole. It is understood that a magnetic dipole can be viewed as a model capable of generating a magnetic field by forming a current loop. Thus, the magnetic dipole can generate a magnetic field under excitation, thereby simulating a noise source that generates magnetic field noise in electronic devices. Therefore, by detecting the magnetic field distribution of the magnetic dipole before and after shielding, the noise effect of the shield 30 on magnetic field noise can be detected.

[0077] The magnetic dipole extends along a ring, and the axis of the magnetic dipole is perpendicular to or intersects the stacking direction of the multilayer stacked structure 41, that is, the magnetic field direction of the magnetic dipole is perpendicular to or intersects the stacking direction of the multilayer stacked structure 41.

[0078] In practical applications, noisy electronic components in electronic devices are generally also mounted on circuit board 40. In three-dimensional space, the magnetic field directions generated by these noise-generating components can be defined as Mx, My, and Mz. Mx and My are two magnetic field directions parallel to and perpendicular to the plane of circuit board 40, respectively, while Mz is perpendicular to both the planes containing Mx and My. Since circuit board 40 has a mirror effect, the magnetic field in the Mz direction is canceled out and does not generate noise. Therefore, we only need to test the shielding effect of the magnetic fields in the Mx and My directions.

[0079] Therefore, since the axis of the magnetic dipole is perpendicular to or intersects the stacking direction of the multilayer stacked structure 41, the magnetic field direction of the magnetic dipole is consistent with the magnetic field direction of the electronic device that generates noise in the electronic device, which can better detect the shielding effect of the shielding cover 30 under test.

[0080] It is understandable that the relationship between the axis of the magnetic dipole and the stacking direction of the multilayer stacked structure 41 can be designed according to the actual situation. For example, the axis of the magnetic dipole can be perpendicular to the stacking direction of the multilayer stacked structure 41. Of course, the axis of the magnetic dipole can also intersect the stacking direction of the multilayer stacked structure 41, that is, the angle between the axis of the magnetic dipole and the stacking direction of the multilayer stacked structure 41 is greater than 0° and less than 90°.

[0081] As mentioned above, the magnetic field generated by the noisy electronic devices includes directions Mx and My. Therefore, when designing the circuit board 40, different circuit boards 40 with the aforementioned magnetic dipoles can be designed separately for Mx and My, and the shielding effect of the shielding cover 30 under test for magnetic field directions Mx and My can be tested respectively.

[0082] Of course, in actual testing, a circuit board 40 can also be used. After testing the shielding effect in a certain magnetic field direction, the circuit board 40 can be rotated 90 degrees to rotate the magnetic field direction of the magnetic dipole by 90 degrees. Then the shielding effect for another magnetic field direction can be measured.

[0083] In some embodiments, dipole 45 may include an electric dipole. In this way, the electric dipole can simulate a noise source in an electronic device that can generate electric field noise, thereby enabling the detection of the shielding effect of the shield 30 under test on electric field noise.

[0084] The electric dipole can extend in a direction that is parallel to or intersects the stacking direction of the multilayer stacked structure 41, i.e., the electric field direction is parallel to the stacking direction of the multilayer stacked structure 41.

[0085] As mentioned above, in practical applications, the electronic devices that generate noise in electronic devices are generally also located on the circuit board 40. In three-dimensional space, the magnetic field directions generated by the electronic devices that produce electric field noise can be defined as Px, Py, and Pz. Px and Py are two electric field directions that are parallel to and perpendicular to the plane containing the circuit board 40, respectively, while Pz is perpendicular to the plane containing Mx and My. Since the circuit board 40 has a mirror effect, the electric fields in the Px and Py directions are canceled out, and no noise is generated. Therefore, we only need to test the shielding effect of the electric field in the Pz direction.

[0086] Therefore, since at least a portion of the extension direction of the electric dipole can be parallel to or intersect with the stacking direction of the multilayer stacked structure 41, the electric field direction generated by the portion of the electric dipole whose extension direction is parallel to or intersects with the stacking direction of the multilayer stacked structure 41 is consistent with the electric field direction of the electronic device that generates noise in the electronic device, thus enabling better detection of the shielding effect of the shielding cover 30 under test.

[0087] Understandably, the relationship between the extension direction of the electric dipole and the stacking direction of the multilayer stacked structure can be designed according to the actual situation. For example, at least a portion of the extension direction of the electric dipole can be parallel to the stacking direction of the multilayer stacked structure 41. Alternatively, at least a portion of the extension direction of the electric dipole can intersect with the stacking direction of the multilayer stacked structure 41 (i.e., the included angle is greater than 0° and less than 90°). Of course, the entire extension direction of the electric dipole can also intersect with the stacking direction of the multilayer stacked structure 41, or the entire extension direction of the electric dipole can be parallel to the stacking direction of the multilayer stacked structure 41.

[0088] In order for the circuit board 40 to form a magnetic dipole, such as Figure 3 As shown, in some embodiments, the multiple conductive layers 43 may include a first conductive layer 431, a second conductive layer 432, and a third conductive layer 433. Different conductive structures can be designed using multiple conductive layers 43. Furthermore, when there are multiple conductive layers 43, there are also multiple insulating layers 44, with the multiple insulating layers 44 and the multiple conductive layers 43 being stacked alternately.

[0089] like Figure 3 As shown, the first conductive layer 431 may include a first conductive portion 4311. For example, the first conductive portion 4311 of the first conductive layer 431 may be made of a conductive material, which can be formed by depositing a conductive material on an insulating layer 44.

[0090] The second conductive layer 432 is located on one side of the first conductive layer 431 and includes two second conductive portions 4321 spaced apart. Similarly, the second conductive portions 4321 of the second conductive layer 432 can also be made of conductive material, which can be achieved by applying conductive material to an insulating layer 44.

[0091] The third conductive layer 433 is located on the side of the second conductive layer 432 away from the first conductive layer 431.

[0092] For example, based on Figure 3 In the illustrated scheme, on the circuit board 40, a third conductive layer 433 can be fabricated first. Next, an insulating material is deposited on the third conductive layer 433 to form an insulating layer 44. Then, a second conductive layer 432 is formed on the insulating layer 44, and two spaced-apart second conductive portions 4321 are formed using conductive material. Then, an insulating layer 44 and a first conductive layer 431 are fabricated sequentially, and a first conductive portion 4311 is formed using conductive material.

[0093] Continue to refer to Figure 3The plurality of electrical connectors 42 may include two first electrical connectors 421 and two second electrical connectors 422. The two first electrical connectors 421 are located between the first conductive layer 431 and the second conductive layer 432 and extend along the stacking direction of the multilayer stacked structure 41.

[0094] One end of a first electrical connector 421 is connected to one end of a first conductive portion 4311, and the other end is connected to one end of a second conductive portion 4321. One end of another first electrical connector 421 is connected to the other end of the first conductive portion 4311, and the other end is connected to one end of another second conductive portion 4321.

[0095] For example, during the fabrication of the circuit board 40, after the first conductive layer 431 and the second conductive layer 432 are formed, vias can be made in the first conductive layer 431, the second conductive layer 432 and the insulating layer 44 between them, and conductive material can be placed in the vias to form the aforementioned first electrical connector 421.

[0096] Two second electrical connectors 422 are located between the second conductive layer 432 and the third conductive layer 433, extending along the stacking direction of the multilayer stacked structure 41. One end of one second electrical connector 422 is connected to the other end of a second conductive portion 4321, and the other end is connected to the third conductive layer 433. One end of the other second electrical connector 422 is connected to the other end of another second conductive portion 4321.

[0097] For example, during the fabrication of the circuit board 40, after the third conductive layer 433 and the second conductive layer 432 are formed, vias can be made in the third conductive layer 433, the second conductive layer 432 and the insulating layer 44 between them, and conductive material can be placed in the vias to form the aforementioned second electrical connector 422.

[0098] Two first electrical connectors 421, two second electrical connectors 422, a first conductive portion 4311, and two second conductive portions 4321 form a magnetic dipole. Thus, a circuit loop can be formed to create a magnetic dipole through the aforementioned two first electrical connectors 421, two second electrical connectors 422, a first conductive portion 4311, and two second conductive portions 4321.

[0099] like Figure 3 As shown, one end of each of the two second electrical connectors 422 is located between the other ends of the two first electrical connectors 421. Thus, the distance between the two second electrical connectors 422 is smaller than the distance between the two first electrical connectors 421. The smaller distance between the two ends of the current loop of the formed magnetic dipole provides some shielding against the electric field, making the magnetic field formed by the magnetic dipole purer and less susceptible to the influence of the electric field.

[0100] In order for the magnetic dipoles to form a circuit, the other end of the second electrical connector 422 can be electrically connected to the signal transceiver 10. For example... Figure 3 As shown, in order to facilitate the electrical connection of the other end of the second electrical connector 422 to the signal transceiver 10, the other end of the second electrical connector 422 can pass through the third conductive layer 433.

[0101] In other embodiments, such as Figure 4 As shown, Figure 4 This is a schematic diagram of another circuit board 40 provided in an embodiment of this application. The other ends of the two first electrical connectors 421 can also be located between one end of the two second electrical connectors 422. In this way, the two first electrical connectors 421, the two second electrical connectors 422, the first conductive portion 4311, and the two second conductive portions 4321 can also form a magnetic dipole.

[0102] In other embodiments, such as Figure 5 As shown, Figure 5 This is a schematic diagram of another circuit board 40 provided in an embodiment of this application. The number of conductive layers 43 and electrical connectors 42 are also multiple. The multiple conductive layers 43 may include a first conductive layer 431 and a third conductive layer 433. The first conductive layer 431 also includes a first conductive portion 4311. The third conductive layer 433 is located on one side of the first conductive layer 431.

[0103] The plurality of electrical connectors 42 includes two first electrical connectors 421. The two first electrical connectors 421 are located between a first conductive layer 431 and a third conductive layer 433, extending along the stacking direction of the multilayer stacked structure 41. One end of one first electrical connector 421 is connected to one end of a first conductive portion 4311, and the other end is connected to the third conductive layer 433. One end of the other first electrical connector 421 is connected to the other end of the first conductive portion 4311. The two first electrical connectors 421 and the first conductive portion 4311 form a magnetic dipole.

[0104] At this point, the magnetic dipole has a relatively simple shape, making it easier and simpler to manufacture. For example, based on... Figure 5 In the illustrated scheme, during the fabrication of circuit board 40, a third conductive layer 433, an insulating layer 44, and a second conductive layer 432 can be fabricated sequentially. When fabricating the second conductive layer 432, the aforementioned first conductive portion 4311 is formed using a conductive material. Next, vias can be formed in the first conductive layer 431, the third conductive layer 433, and the insulating layer 44 between them, and conductive material can be placed within the vias to form the aforementioned first electrical connector 421.

[0105] Furthermore, based on Figure 5 According to the scheme shown, the circuit board 40 only needs two conductive layers 43 and one insulating layer 44 to form a magnetic dipole, and the overall stacking structure 41 of the circuit board 40 can also be designed to be relatively simple.

[0106] Of course, when the magnetic dipole consists of two first electrical connectors 421 and a first conductive portion 4311, the circuit board 40 can also have other forms. In other embodiments, such as Figure 6 As shown, Figure 6 This is a schematic diagram of another circuit board 40 provided in an embodiment of this application. The plurality of conductive layers 43 may also include a second conductive layer 432. The second conductive layer 432 is located between the first conductive layer 431 and the third conductive layer 433.

[0107] In some embodiments, such as Figure 3 As shown, the magnetic dipole can be a symmetrical structure along the central axis of the first conductive portion 4311. When the magnetic dipole has a symmetrical structure, the electromagnetic field distribution of the magnetic dipole is relatively simpler, thus making subsequent analysis and testing easier. Of course, in some other embodiments, the magnetic dipole can also be an asymmetrical structure along the central axis of the first conductive portion 4311.

[0108] It is understandable that the shape of the magnetic dipole formed by the circuit board 40 can be set according to the actual situation. As long as it can form a loop to generate a magnetic field, it can be used as dipole 45. The different shapes of the magnetic dipoles mentioned above are only used as examples for illustration.

[0109] Of course, in other embodiments, the magnetic dipole may not be a symmetrical structure.

[0110] In some embodiments, such as Figure 7 As shown, Figure 7 This is a schematic diagram of another circuit board 40 provided in an embodiment of this application. The plurality of conductive layers 43 may further include a fourth conductive layer 434. The fourth conductive layer 434 is located on the side of the first conductive layer 431 away from the third conductive layer 433, and includes two spaced third conductive portions 4341, and a portion of the third conductive portions 4341 is disposed opposite to the first conductive portions 4311.

[0111] The plurality of electrical connectors 42 also includes two third electrical connectors 423. The two third electrical connectors 423 are located between the third conductive layer 433 and the fourth conductive layer 434, extending along the stacking direction of the multilayer stacked structure 41. One end of one third electrical connector 423 is connected to one end of a third conductive portion 4341, and the other end is connected to the third conductive layer 433. One end of the other third electrical connector 423 is connected to one end of another third conductive portion 4341, and the other end is connected to the third conductive layer 433.

[0112] The other end of the two third conductive portions 4341 is located between one end of the two third conductive portions 4341.

[0113] For example, the third conductive portion 4341 can be made of a conductive material during the fabrication of the fourth conductive layer 434. Then, after the fourth conductive layer 434 is fabricated, a via can be formed between the fourth conductive layer 434 and the third conductive layer 433 and between the two, and then conductive material is disposed in the via to form the aforementioned third electrical connector 423.

[0114] like Figure 7 As shown, by setting two third conductive parts 4341 and two third electrical connectors 423, a circuit-breaking structure can be set around the magnetic dipole, which can cancel the electric field generated by the magnetic dipole, thereby allowing the magnetic dipole to form a purer magnetic field and avoiding electric field interference affecting the test results. Of course, in some other embodiments, the third conductive parts 4341 and third electrical connectors 423 may not be set around the magnetic dipole. It is understood that when the electric field generated by the magnetic dipole will not have a significant impact on the test results, it is also possible to choose not to set a circuit-breaking structure around the magnetic dipole to cancel the electric field generated by the magnetic dipole. The specific design can be made according to the actual situation.

[0115] In some embodiments, such as Figure 7 As shown, along the central axis of the first conductive portion 4311, the two third electrical connectors 423 and the two third conductive portions 4341 can be symmetrical to each other. Based on this design, the two third electrical connectors 423 and the two third conductive portions 4341 can better cancel out the electric field, thereby enabling the magnetic dipole to form a relatively pure magnetic field. Of course, in other embodiments, along the central axis of the first conductive portion 4311, the two third electrical connectors 423 and the two third conductive portions 4341 can also be asymmetrical.

[0116] The specific form of circuit board 40 can be designed according to the actual situation. For example, such as Figure 8 As shown, Figure 8 This is a three-dimensional structural diagram of a portion of a circuit board 40 provided in an embodiment of this application. The first electrical connector 421 and the third electrical connector 423 can be square columnar structures, and the first conductive portion 4311 and the third conductive portion 4341 can be elongated sheet-like structures.

[0117] In some embodiments, such as Figure 9 As shown, Figure 9This is a schematic diagram of another circuit board 40 provided in an embodiment of this application. The electrical connector 42 may include a fourth electrical connector 424. The fourth electrical connector 424 extends along the stacking direction of the multilayer stacked structure 41. The fourth electrical connector 424 forms an electric dipole. For example, as shown... Figure 10 As shown, Figure 10 This is a three-dimensional structural diagram of a portion of a circuit board 40 provided in an embodiment of this application. The fourth electrical connector 424 can be a square columnar structure.

[0118] Therefore, an electric dipole can be easily and conveniently formed using the fourth electrical connector 424. For example, after fabricating the multilayer stacked structure 41 of the circuit board 40, conductive vias are formed in the direction of the multilayer stacked structure 41 of the circuit board 40, and then conductive material is added into the conductive vias to form the aforementioned fourth electrical connector 424.

[0119] In some embodiments, there are multiple conductive layers 43. One end of the fourth electrical connector 424 is flush with one side of the multiple conductive layers 43, and the other end of the fourth electrical connector 424 is flush with the other side of the multiple conductive layers 43. As a result, the fourth electrical connector 424 is relatively long, and the electric field distribution formed by the longer fourth electrical connector 424 is stronger, which makes detection more convenient.

[0120] For example, such as Figure 9 As shown, the plurality of conductive layers 43 include a fourth conductive layer 434, a first conductive layer 431, a second conductive layer 432, and a third conductive layer 433 arranged sequentially. One end of the fourth electrical connector 424 is flush with the side of the fourth conductive layer 434 away from the first conductive layer 431, and the other end is flush with the side of the third conductive layer 433 away from the second conductive layer 432.

[0121] Of course, in other embodiments, the two ends of the fourth electrical connector 424 may not be flush with the sides of the plurality of conductive layers 43. In this case, the fourth electrical connector 424 is shorter in length, making it easier to manufacture, and can also form an electric field to simulate the electronic devices that generate noise in electronic devices.

[0122] In some embodiments, the length of the dipole 45 may be less than or equal to one-tenth of a preset wavelength. The preset wavelength range may be 500 MHz to 6 GHz. When the length of the dipole 45 is within this range, the preset wavelength of the testable frequency band is also 500 MHz to 6 GHz, providing a wide range of testable frequencies that can cover the frequency bands of noise generated by electronic devices in electronic equipment.

[0123] In some embodiments, the length of the dipole 45 may be greater than or equal to one-twentieth of the preset wavelength. When the length of the dipole 45 is within the above range, the length of the dipole 45 is relatively moderate, which can better form a magnetic field or electric field, so as to better perform detection and testing. When the length of the dipole 45 is too small, the formed electric field or magnetic field is weak, which is inconvenient for subsequent testing and analysis.

[0124] Based on the shielding test system provided in the embodiments of this application, the test method of the shielding test system will be described by way of example. For example, taking a circuit board including a magnetic dipole and a test device including a transverse electromagnetic wave chamber as an example, such as... Figure 11 As shown, Figure 11 This is a flowchart illustrating a testing method for a shielding testing system provided in an embodiment of this application. The method may include steps S100-S500.

[0125] S100: Place the shielding cover to be tested onto the circuit board. It is understood that, as mentioned above, the specific type of shielding cover to be tested can be set according to the actual situation. For example, the shielding cover to be tested can be a thin film type, directly coated onto the circuit board.

[0126] S200: Place the circuit board with the shield to be tested on the transverse electromagnetic wave chamber.

[0127] S300: Parameter Sx is detected and recorded using a transverse electromagnetic wave chamber and signal transceiver.

[0128] S400: After rotating the circuit board 90 degrees, the parameter Sy is detected and recorded again using the transverse electromagnetic wave chamber and signal transceiver.

[0129] S500: Magnetic field leakage data are obtained by analyzing and calculating parameters Sx and Sy.

[0130] Therefore, by following the above steps, the shielding effect of the shielding cover to be tested on the magnetic dipole in different magnetic field directions can be measured using a single circuit board.

[0131] It is understandable that when the dipole on the circuit board is an electric dipole, the shielding effect of the shielding cover on the electric dipole can be detected by following similar steps. The specific steps will not be explained further, but can be operated by referring to the above steps.

[0132] Based on the shielding testing system provided in the embodiments of this application, such as Figure 12 As shown, Figure 12 The diagram shows the shielding effect curves of different schemes. The shielding test system provided in this application can accurately test the shielding performance of the shielding cover under test.

[0133] In other embodiments, such as Figure 13 As shown, Figure 13 This is a schematic diagram of another circuit board 40 provided in an embodiment of this application. A portion of the dipole 45 extends out from one side of the multilayer stacked structure 41. In this case, the dipole 45 can form a probe structure, which is used to test the shielding effect.

[0134] For example, such as Figure 13 As shown, Figure 13 The dipole 45 formed by the circuit board 40 is an electric dipole, capable of generating an electric field distribution, which can be used to test the shielding effect of the shielding cover under test on electric field noise. Of course, as... Figure 14 As shown, Figure 14 This is a schematic diagram of another circuit board 40 provided in an embodiment of this application. The dipole 45 formed by the circuit board 40 can also be a magnetic dipole, which can form a magnetic field distribution and can be used to detect the shielding effect of the shielding cover to be tested on magnetic field noise.

[0135] based on Figure 14 The structure shown is used Figure 14 The circuit board shown is an example, such as... Figure 15 As shown, Figure 15 This is a schematic diagram of a circuit board installation according to an embodiment of the present application. The circuit board can be placed inside the mounting box 50. The mounting box 50 has an opening, through which the dipole 45 can extend out of the mounting box. The mounting box 50 can be used to fix the circuit board in place.

[0136] In the description of this specification, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0137] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A circuit board, characterized in that, It includes a multi-layer stacked structure and electrical connectors; the electrical connectors extend along the stacking direction of the multi-layer stacked structure. The multi-layer stacked structure includes: At least one conductive layer; and, At least one insulating layer is alternately stacked with the at least one conductive layer; Wherein, at least a portion of the at least one conductive layer and the electrical connector form a dipole; The dipole includes a magnetic dipole; the magnetic dipole extends in a ring shape; the axial direction of the magnetic dipole is perpendicular to or intersects the stacking direction of the multilayer stacked structure; The number of the conductive layer and the electrical connector are both multiple; the multiple conductive layers include: The first conductive layer includes a first conductive portion; A second conductive layer, located on one side of the first conductive layer, includes two spaced-apart second conductive portions; and... The third conductive layer is located on the side of the second conductive layer that is away from the first conductive layer; The plurality of electrical connections include: Two first electrical connectors are located between the first conductive layer and the second conductive layer; one end of one first electrical connector is connected to one end of the first conductive portion, and the other end is connected to one end of a second conductive portion; one end of the other first electrical connector is connected to the other end of the first conductive portion, and the other end is connected to one end of another second conductive portion; and... Two second electrical connectors are located between the second conductive layer and the third conductive layer, extending along the stacking direction of the multilayer stacked structure; one end of one second electrical connector is connected to the other end of one second conductive portion, and the other end is connected to the third conductive layer; one end of the other second electrical connector is connected to the other end of the other second conductive portion; the one end of the two second electrical connectors is located between the other ends of the two first electrical connectors. The magnetic dipole is formed by two first electrical connectors, two second electrical connectors, the first conductive portion, and the two second conductive portions.

2. The circuit board according to claim 1, characterized in that, The plurality of conductive layers further include: The fourth conductive layer is located on the side of the first conductive layer away from the third conductive layer, and includes two spaced third conductive portions, with a portion of the third conductive portion being disposed opposite to the first conductive portion; The plurality of electrical connections also include: Two third electrical connectors are located between the third conductive layer and the fourth conductive layer, extending along the stacking direction of the multilayer stacked structure; one end of one third electrical connector is connected to one end of one third conductive portion, and the other end is connected to the third conductive layer; one end of the other third electrical connector is connected to one end of the other third conductive portion, and the other end is connected to the third conductive layer. The other end of each of the two third conductive portions is located between the two ends of the third conductive portions.

3. The circuit board according to claim 2, characterized in that, The magnetic dipole has a symmetrical structure along the central axis of the first conductive portion.

4. The circuit board according to claim 3, characterized in that, Along the central axis of the first conductive portion, the two third electrical connectors are symmetrical to each other, and the two third conductive portions are symmetrical to each other.

5. A circuit board, characterized in that, It includes a multi-layer stacked structure and electrical connectors; the electrical connectors extend along the stacking direction of the multi-layer stacked structure. The multi-layer stacked structure includes: At least one conductive layer; and, At least one insulating layer is alternately stacked with the at least one conductive layer; Wherein, at least a portion of the at least one conductive layer and the electrical connector form a dipole; The dipole includes a magnetic dipole; the magnetic dipole extends in a ring shape; the axial direction of the magnetic dipole is perpendicular to or intersects the stacking direction of the multilayer stacked structure; The number of the conductive layer and the electrical connector are both multiple; the multiple conductive layers include: A first conductive layer, including a first conductive portion; and... The third conductive layer is located on one side of the first conductive layer; The plurality of electrical connections include: Two first electrical connectors are located between the first conductive layer and the third conductive layer, extending along the stacking direction of the multilayer stacked structure; one end of one first electrical connector is connected to one end of the first conductive portion, and the other end is connected to the third conductive layer; one end of the other first electrical connector is connected to the other end of the first conductive portion. The two first electrical connectors and the first conductive portion form the magnetic dipole.

6. The circuit board according to any one of claims 1-5, characterized in that, The length of the dipole is less than or equal to one-tenth of a preset wavelength; the preset wavelength ranges from 500 MHz to 6 GHz.

7. The circuit board according to claim 6, characterized in that, The length of the dipole is greater than or equal to one-twentieth of the preset wavelength.

8. A shielding testing system, characterized in that, include: The circuit board according to any one of claims 1-7; A shielding cover to be tested is disposed on the circuit board and covers the dipole; A signal transceiver is electrically connected to the dipole. as well as, The testing device, electrically connected to the signal transceiver, is located on the side of the shield to be tested away from the dipole.

9. The shielding test system according to claim 8, characterized in that, The testing device includes a transverse electromagnetic wave chamber.

10. The shielding test system according to claim 8, characterized in that, The testing apparatus includes a near-field scanner.

11. The shielding test system according to any one of claims 8-10, characterized in that, The signal transceiver device includes a vector network analyzer.

12. The shielding test system according to any one of claims 8-10, characterized in that, The signal transceiver includes a spectrum analyzer and a signal source.

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