Electromagnetic shielding structure and electronic equipment

Abstract

The invention discloses an electromagnetic shielding structure and electronic equipment, relates to the field of electromagnetic interference, and is used for reducing the electromagnetic coupling degree between modules in the electromagnetic shielding structure. The electromagnetic shielding structure comprises a shielding frame, a shielding cover and a tuning network, the shielding cover and the shielding frame are buckled, the shielding frame comprises a first cavity and a second cavity, the first cavity and the second cavity are spaced through a reinforcing rib, the first cavity is used for containing a first module, and the second cavity is used for containing a second module; the reinforcing ribs are grounded through the tuning network.

Description

Technical Field

[0001] The present application relates to the field of electromagnetic interference, and in particular to an electromagnetic shielding structure and electronic equipment. Background Art

[0002] In electronic devices, electromagnetic shielding structures are used to shield modules that generate or are susceptible to electromagnetic interference (such as direct current-direct current (DC-DC) power modules, memory, etc.) to prevent electromagnetic interference signals generated by these modules from affecting the normal operation of other devices, or to prevent electromagnetic interference signals generated by other devices from affecting the normal operation of these modules. However, if multiple modules are shielded in the same space, the electromagnetic coupling between the modules will increase, resulting in new electromagnetic interference problems. Summary of the invention

[0003] The embodiments of the present application provide an electromagnetic shielding structure and an electronic device, which are used to reduce the electromagnetic coupling between modules in the electromagnetic shielding structure.

[0004] To achieve the above objectives, the embodiments of the present application adopt the following technical solutions: In a first aspect, an electromagnetic shielding structure is provided, comprising: a shielding frame, a shielding cover and at least one tuning network, the shielding cover being buckled with the shielding frame, the shielding frame comprising a first cavity and a second cavity, the first cavity and the second cavity being separated by reinforcing ribs, the first cavity being used to accommodate a first module, and the second cavity being used to accommodate a second module; the reinforcing ribs being grounded through the tuning network.

[0005] The electromagnetic shielding structure provided in the embodiment of the present application connects a tuning network between the reinforcing ribs of the electromagnetic shielding structure and the ground, thereby changing the resonant state of the electromagnetic shielding structure (the resonant frequency remains unchanged, and the S parameter of the resonant frequency becomes smaller), suppressing the electromagnetic coupling between the first module and the second module and the reinforcing ribs, thereby suppressing the electromagnetic coupling between the first module and the second module, and reducing the electromagnetic coupling degree between the modules in the electromagnetic shielding structure.

[0006] In a possible implementation, the position on the reinforcing rib where the electric field is strongest in electromagnetic simulation is grounded through a tuning network, so as to balance the cost and the effect of suppressing electromagnetic coupling.

[0007] In a possible implementation, positions on the reinforcing ribs that are at least a predetermined distance apart are grounded through a tuning network, which can enhance the effect of suppressing electromagnetic coupling.

[0008] In a possible implementation, the tuning network includes at least one of the following: a capacitor, an inductor, a capacitor and an inductor connected in parallel, and a capacitor and an inductor connected in series. This implementation provides several possible structures of the tuning network.

[0009] In a possible implementation, when the tuning network includes a capacitor, or a capacitor and an inductor connected in parallel, the tuning network is used to suppress electromagnetic coupling greater than 1 GHz between the first module and the second module. The corresponding resonant network can be selected according to the frequency band of the electromagnetic coupling to be suppressed.

[0010] In a possible implementation, when the tuning network includes an inductor, or a capacitor and an inductor connected in series, the tuning network is used to suppress electromagnetic coupling between the first module and the second module at a frequency less than 1 GHz. The corresponding resonant network can be selected according to the frequency band of the electromagnetic coupling to be suppressed.

[0011] In one possible implementation, the capacitance is greater than or equal to 2pF. In this case, the tuning network can suppress the electromagnetic coupling between the first module and the second module greater than 1GHz. The tuning network will significantly change the S parameters between the first module and the reinforcement ribs, and in a specific frequency band, it will even be close to the S parameters when there is no electromagnetic shielding structure, thereby significantly reducing the electromagnetic coupling between the first module and the second module, and the inhibitory effect on the electromagnetic coupling between the modules inside the electromagnetic shielding structure is more obvious.

[0012] In a possible implementation, the inductance is greater than or equal to 8.2nH. At this time, the tuning network can suppress the electromagnetic coupling between the first module and the second module that is less than 1GHz. The tuning network will significantly change the S parameters between the first module and the reinforcement ribs. In a specific frequency band, it is even close to the S parameters when there is no electromagnetic shielding structure, thereby significantly reducing the electromagnetic coupling between the first module and the second module, and the inhibitory effect on the electromagnetic coupling between the modules inside the electromagnetic shielding structure is more obvious.

[0013] In a second aspect, an electronic device is provided, comprising a first module, a second module and the electromagnetic shielding structure described in the first aspect and any embodiment thereof, wherein the first cavity of the electromagnetic shielding structure is used to accommodate the first module, and the second cavity of the electromagnetic shielding structure is used to accommodate the second module.

[0014] The technical effects of the second aspect refer to the technical effects of the first aspect and any of its embodiments, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application; Figure 2 A schematic diagram of the structure of an electromagnetic shielding structure provided in an embodiment of the present application; Figure 3 A schematic diagram of S parameters of a shielding frame and a shielding cover before and after being fastened together provided in an embodiment of the present application; Figure 4 A schematic diagram of S parameters between an electromagnetic interference source and a disturbed object at different positions provided in an embodiment of the present application; Figure 5 A schematic diagram of S parameters between another electromagnetic interference source and a disturbed object at different positions provided in an embodiment of the present application; Figure 6 A schematic diagram of S parameters between another electromagnetic interference source and a disturbed object at different positions provided in an embodiment of the present application; Figure 7 A schematic diagram of S parameters between another electromagnetic interference source and disturbed objects at different positions provided in an embodiment of the present application; Figure 8 A schematic diagram of a simulation model and S parameters provided in an embodiment of the present application; Fig. 9 A schematic diagram of the electric field distribution of a simulation model and a physical model provided in an embodiment of the present application; Fig.10 A schematic diagram of magnetic field distribution of a simulation model and a physical model provided in an embodiment of the present application; Fig.11 A schematic diagram of S parameters of a reinforcing rib grounded through a shielding cover at different positions provided in an embodiment of the present application; Fig.12 A schematic diagram of S parameters of another reinforcing rib grounded through a shielding cover at different positions provided in an embodiment of the present application; Fig.13 A schematic diagram of electric field distribution and magnetic field distribution of a first module when there is no shielding frame provided in an embodiment of the present application; Fig.14 A schematic diagram of electric field distribution and magnetic field distribution of a first module when a shielding frame is provided in an embodiment of the present application; Fig.15 A schematic diagram of S parameters when a reinforcing rib and a shielding cover are short-circuited and insulated provided in an embodiment of the present application; Fig.16 A schematic diagram of S parameters of a capacitor connected between a reinforcing rib and a ground provided in an embodiment of the present application; Fig.17 A schematic diagram of S parameters of an inductor connected between a reinforcing rib and a ground provided in an embodiment of the present application; Fig.18 A schematic diagram of S parameters of a capacitor and an inductor connected in series between a reinforcing rib and a ground provided in an embodiment of the present application; Fig.19A schematic diagram of S parameters of a capacitor and an inductor connected in parallel between a reinforcing rib and a ground provided in an embodiment of the present application; Fig. 20 A schematic diagram of another electromagnetic shielding structure provided in an embodiment of the present application; Fig.21 A schematic diagram of electric field distribution and magnetic field distribution when different positions of a reinforcing rib are grounded through a resonant network provided in an embodiment of the present application; Fig. 22 A schematic diagram of S parameters between the first module and different positions of the reinforcement rib after the reinforcement rib is grounded through a resonant network provided in an embodiment of the present application; Fig.23 A schematic diagram of an S parameter between a first module and a position g on a reinforcing rib provided in an embodiment of the present application; Fig.24 A schematic diagram of an S parameter between a first module and a position h on a reinforcing rib provided in an embodiment of the present application; Fig.25 A schematic diagram of a shielding cover provided in an embodiment of the present application that is made of a flexible conductive material; Fig.26 A schematic diagram of an S parameter between a first module and a position g on a reinforcing rib when a flexible conductive material is insulated from a reinforcing rib provided in an embodiment of the present application; Fig. 27 A schematic diagram of an S parameter between a first module and a position g on a reinforcing rib when a flexible conductive material is short-circuited with a reinforcing rib provided in an embodiment of the present application; Fig.28 A schematic diagram of an S parameter between a first module and a position g on a reinforcing rib when the flexible conductive material is insulated from a vertical portion of the reinforcing rib and short-circuited with other portions of the reinforcing rib, provided in an embodiment of the present application; Fig.29 A schematic diagram of the S parameters between the first module and the position g on the reinforcing rib when the flexible conductive material is insulated from the horizontal portion of the reinforcing rib and short-circuited with other portions of the reinforcing rib is provided in an embodiment of the present application. DETAILED DESCRIPTION

[0016] First, some concepts involved in this application are described.

[0017] The terms "first", "second", etc. involved in the embodiments of the present application are only used to distinguish features of the same type and cannot be understood as indicating relative importance, quantity, order, etc.

[0018] The terms "exemplary" or "for example" and the like in the embodiments of the present application are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of the terms "exemplary" or "for example" is intended to present the related concepts in a specific way.

[0019] The terms "coupling" and "connection" involved in the embodiments of the present application should be understood in a broad sense. For example, they may refer to a direct physical connection, or an indirect connection achieved through electronic devices, such as a connection achieved through resistors, inductors, capacitors or other electronic devices.

[0020] Electromagnetic interference (EMI): EMI refers to any electromagnetic signal that interferes with the normal operation of electronic equipment, systems or circuits. This interference may come from natural sources (such as lightning) or man-made sources (such as electronic equipment, radio transmitters, etc.).

[0021] Electromagnetic shielding: Electromagnetic shielding refers to the use of electromagnetic shielding structures or shielding materials to wrap the module to block or weaken the propagation of electromagnetic fields, thereby preventing electromagnetic interference.

[0022] Scattering parameters (S parameters for short): S parameters S(b,a) represent the signal at position b (complex vector ) and the signal at position a (complex vector ) , a and b can be the same or different. When a and b are the same, the S parameter S(b,a) represents the reflection coefficient, that is, how much energy is reflected back to position a. When a and b are different, the S parameter S(b,a) represents the coupling coefficient, that is, how much energy is coupled from position a to position b. The larger the value, the more signal is coupled to position b. For example, assuming that position 1 is the input end of the signal, and positions 2 and 3 are the coupling ends of the signal, then S(1,1) (can be abbreviated as S11) represents the reflection coefficient, S(2,1) (can be abbreviated as S21) and S(3,1) (can be abbreviated as S31) represent the coupling coefficient.

[0023] The embodiment of the present application provides an electronic device, which can be mobile or fixed. The electronic device can be deployed on land (for example, indoors or outdoors, handheld or vehicle-mounted, etc.), on the water (for example, ships, etc.), or in the air (for example, airplanes, balloons, etc.). The electronic device can be called user equipment (UE), access terminal, terminal unit, subscriber unit, terminal station, mobile station (MS), mobile station, terminal agent or terminal device, etc. For example, the electronic device can be a mobile phone, tablet computer, laptop computer, smart bracelet, smart screen, smart watch, headset, smart speaker, terminal in industrial control, terminal in self driving, terminal in remote medical, terminal in smart grid, terminal in transportation safety, terminal in smart city, terminal in smart home, etc. The embodiment of the present application does not limit the specific type and structure of the electronic device. A possible structure of the electronic device is described below.

[0024] Figure 1 The electronic device 100 includes a first module 21 , a second module 22 , an electromagnetic shielding structure 23 , a printed circuit board (PCB) 24 , and optionally a battery 25 .

[0025] The electromagnetic shielding structure 23, the first module 21, and the second module 22 are arranged on the PCB 24. The first module 21 and the second module 22 are modules that generate electromagnetic interference or are susceptible to electromagnetic interference, such as direct current-direct current (DC-DC) power supply modules, memory, etc. The battery 25 is used to power the first module 21 and the second module 22.

[0026] The electromagnetic shielding structure 23 is made of conductive material and is used to shield the first module 21 and the second module 22 that generate electromagnetic interference or are susceptible to electromagnetic interference, to prevent the electromagnetic interference signals generated by these modules from affecting the normal operation of other devices, or to prevent the electromagnetic interference signals generated by other devices from affecting the normal operation of these modules.

[0027] Figure 2A schematic diagram of an electromagnetic shielding structure provided in an embodiment of the present application. The electromagnetic shielding structure 23 includes a shielding frame 231 and a shielding cover 232. The shielding frame 231 is made of rigid metal, and the shielding cover 232 can be made of rigid metal, or made of flexible conductive materials such as copper foil and conductive cloth.

[0028] The shielding frame 231 includes a first cavity 2311, a second cavity 2312 and a reinforcing rib 2313. The reinforcing rib 2313 may also be called a supporting rib, and is used to improve the structural strength of the shielding frame 231. The first cavity 2311 and the second cavity 2312 are the hole-digging areas on the shielding frame 231. The first cavity 2311 and the second cavity 2312 are separated by the reinforcing rib 2313, and the first cavity 2311 is used to accommodate the first module 21, and the second cavity 2312 is used to accommodate the second module 22.

[0029] It should be noted that Figure 2 A in the middle is a top view of the shielding frame 231, the shielding cover 232, the first cavity 2311, the second cavity 2312, the reinforcing rib 2313, the first module 21 and the second module 22; Figure 2 B is a top view of the electromagnetic shielding structure 23; Figure 2 Center C is a side view of the shielding frame 231 , the shielding cover 232 , the first cavity 2311 , the second cavity 2312 , the reinforcing rib 2313 , the first module 21 , and the second module 22 .

[0030] When the shielding frame 231 and the shielding cover 232 are buckled together, the first module 21 and the second module 22 are shielded in the electromagnetic shielding structure 23. Since the first module 21 generates electromagnetic resonance with the second module 22 through the electromagnetic shielding structure 23, the electromagnetic coupling degree between the first module 21 and the second module 22 increases, resulting in new electromagnetic interference problems.

[0031] For example, Figure 3 A schematic diagram of the S parameters of a shielding frame and a shielding cover before and after they are fastened together provided in an embodiment of the present application. Figure 3 A is the S parameter when the shielding frame 231 and the shielding cover 232 are not fastened together. Figure 3 B is the S parameter when the shielding frame 231 and the shielding cover 232 are buckled. Among them, S11 refers to the reflection coefficient of the first module 21 itself, and S22 refers to the reflection coefficient of the second module 22 itself. S21 refers to the S parameter (i.e., coupling coefficient) between the first module 21 and the second module 22 (the signal is from the first module 21 to the second module 22), and S12 refers to the S parameter (i.e., coupling coefficient) between the second module 22 and the first module 21 (the signal is from the second module 22 to the first module 21).

[0032] It can be seen that, compared with the case where the shielding frame 231 and the shielding cover 232 are not fastened together, after the shielding frame 231 and the shielding cover 232 are fastened together, S21 and S12 increase by about 20dB in the medium and high frequency (for example, greater than 1GHz) region, that is, the electromagnetic coupling between the first module 21 and the second module 22 increases by about 20dB. This indicates that the electromagnetic shielding structure does increase the electromagnetic coupling between the internal modules and reduce the isolation between the modules.

[0033] Since the first module 21 generates electromagnetic resonance with the second module 22 through the electromagnetic shielding structure 23, the electromagnetic coupling between the first module 21 and the second module 22 increases. To this end, the embodiment of the present application provides an electromagnetic shielding structure and an electronic device, by connecting a tuning network, such as a capacitor, an inductor, a series capacitor and an inductor, a parallel capacitor and an inductor, etc., between the reinforcing rib 2313 of the electromagnetic shielding structure 23 and the ground, thereby changing the resonance state of the electromagnetic shielding structure 23 (the resonance frequency remains unchanged, and the S parameter of the resonance frequency becomes smaller), suppressing the electromagnetic coupling between the first module 21 and the second module 22 and the reinforcing rib 2313, thereby suppressing the electromagnetic coupling between the first module 21 and the second module 22, and reducing the electromagnetic coupling between the modules in the electromagnetic shielding structure 23.

[0034] The electromagnetic coupling problem inside the electromagnetic shielding structure 23 is analyzed below. Figure 4 Middle A, Figure 5 Middle A, Figure 6 Middle A, Figure 7 The simulation model shown in A.

[0035] Figure 4 A schematic diagram of S parameters between an electromagnetic interference source and a disturbed object at different positions provided in an embodiment of the present application. Figure 4 As shown in Figure A, it is assumed that a microstrip line is constructed at the location of the second module 22, one end of the microstrip line is connected to a 50 ohm load, and the other end of the microstrip line is excited. This structure can be equivalent to a current loop, which is used to simulate the electromagnetic interference source. Several positions (positions 2 to 6) are selected around the second module 22 in the shielding frame 231, and a metal line is constructed respectively to simulate the affected body affected by electromagnetic interference. The S parameters of these positions are as follows Figure 4 As shown in B, S11 represents the S parameter (i.e., reflection coefficient) of the second module 22, S21 represents the S parameter (i.e., coupling coefficient) between the second module 22 and position 2, S31 represents the S parameter (i.e., coupling coefficient) between the second module 22 and position 3, S41 represents the S parameter (i.e., coupling coefficient) between the second module 22 and position 4, S51 represents the S parameter (i.e., coupling coefficient) between the second module 22 and position 5, and S61 represents the S parameter (i.e., coupling coefficient) between the second module 22 and position 6.

[0036] Figure 5 A schematic diagram of S parameters between another electromagnetic interference source and a disturbed object at different positions provided in an embodiment of the present application. Figure 5 As shown in A, assuming that Figure 4 On the basis of A in FIG. 1 , the shielding cover 232 is buckled on the second module 22 and the position 2 to the position 6 to form an electromagnetic shielding structure. The second module 22 and the position 2 to the position 6 are included in the electromagnetic shielding structure. Then, the S parameters of these positions are as follows: Figure 5 As shown in B.

[0037] By comparison Figure 4 and Figure 5 It can be seen that when the shielding frame 231 and the shielding cover 232 are buckled together, the second module 22 and position 2-position 6 are included in the electromagnetic shielding structure, and the S parameter (i.e., coupling coefficient) between the second module 22 and position 2-position 6 increases by about 20 dB. This shows that the electromagnetic shielding structure does increase the electromagnetic coupling between the internal modules and reduce the isolation between the internal modules.

[0038] Figure 6 A schematic diagram of S parameters between another electromagnetic interference source and a disturbed object at different positions provided in an embodiment of the present application. Figure 6 As shown in A, it is assumed that a microstrip line is constructed at the location of the first module 21, one end of the microstrip line is connected to a 50 ohm load, and an excitation is applied to the other end of the microstrip line. This structure can be equivalent to a current loop for simulating an electromagnetic interference source. Figure 4 At the same positions (position 2 to position 6) in A, a metal wire is constructed to simulate the affected body by electromagnetic interference. The S parameters at these positions are as follows Figure 6 As shown in B, S11 represents the S parameter (i.e., reflection coefficient) of the first module 21, S21 represents the S parameter (i.e., coupling coefficient) between the first module 21 and position 2, S31 represents the S parameter (i.e., coupling coefficient) between the first module 21 and position 3, S41 represents the S parameter (i.e., coupling coefficient) between the first module 21 and position 4, S51 represents the S parameter (i.e., coupling coefficient) between the first module 21 and position 5, and S61 represents the S parameter (i.e., coupling coefficient) between the first module 21 and position 6.

[0039] Figure 7 A schematic diagram of S parameters between another electromagnetic interference source and a disturbed object at different positions provided in an embodiment of the present application. Figure 7 As shown in A, assuming that Figure 6 On the basis of A in FIG. 1 , the shielding cover 232 is buckled on the positions 2 to 6 to form an electromagnetic shielding structure, and the positions 2 to 6 are included in the electromagnetic shielding structure. Then, the S parameters of these positions are as follows: Figure 7 As shown in B.

[0040] By comparison Figure 6 and Figure 7 It can be seen that when the shielding frame 231 and the shielding cover 232 are buckled together, positions 2 to 6 are included in the electromagnetic shielding structure, and the S parameter (i.e., coupling coefficient) between the first module 21 and positions 2 to 6 is basically unchanged. This indicates that the electromagnetic shielding structure does not increase the electromagnetic coupling between the external module and the internal modules, and does not change the isolation between the internal modules.

[0041] In order to further analyze the electromagnetic coupling problem inside the electromagnetic shielding structure, Figure 2 The physical model shown in A in the figure is scanned on the surface of the physical model using a near-field probe to test the electromagnetic field distribution of the near field and obtain the S parameter (ie, coupling coefficient) between the first module 21 and the second module 22 .

[0042] Figure 8 A schematic diagram of a simulation model and S parameters provided in an embodiment of the present application. Figure 8 The simulation model shown in A is used to simulate Figure 2 The structure shown in A. For example, Figure 8 The first module 21 in A is used as an electromagnetic interference source to simulate Figure 2 The first module 21 in. Figure 8 The second module 22 in A is used as a disturbed body to simulate Figure 2 The second module 22 in. Figure 8 The shielding frame 231 in A is used to simulate Figure 2 The shielding frame 231 in the Figure 8 The reinforcement rib 2313 in A is used to simulate Figure 2 Reinforcement rib 2313.

[0043] Figure 8 As shown in B, by continuously adjusting the parameters of the simulation model, the S parameter between the first module 21 and the second module 22 in the simulation model is made the same as the S parameter between the first module 21 and the second module 22 in the physical model, thereby achieving consistency and accuracy between the simulation model and the physical model, and facilitating simulation and analysis of the electromagnetic coupling of the physical model through the simulation model.

[0044] Among them, the measured S11 refers to the reflection coefficient of the first module 21 itself in the physical model, and the measured S22 refers to the reflection coefficient of the second module 22 itself in the physical model. The simulated S11 refers to the reflection coefficient of the first module 21 itself in the simulation model, and the simulated S22 refers to the reflection coefficient of the second module 22 itself in the simulation model. The measured S21 refers to the coupling coefficient between the first module 21 and the second module 22 in the physical model, and the measured S12 refers to the coupling coefficient between the second module 22 and the first module 21 in the physical model. The simulated S21 refers to the coupling coefficient between the first module 21 and the second module 22 in the simulation model, and the simulated S12 refers to the coupling coefficient between the second module 22 and the first module 21 in the simulation model.

[0045] Fig. 9 A schematic diagram of the electric field distribution of a simulation model and a physical model provided in an embodiment of the present application. Fig.10 A schematic diagram of the magnetic field distribution of a simulation model and a physical model provided in an embodiment of the present application. In order to verify the consistency and accuracy between the simulation model and the physical model, Figure 2 The physical model shown in A in the figure uses a near-field probe to scan the surface of the physical model and test the electromagnetic field distribution in the near field. Fig. 9 The X-axis electromagnetic field distribution shown in B, and Fig.10 The Y-axis electromagnetic field distribution is shown in B. Figure 8 The simulation model shown in A is scanned in the near field and the Fig. 9 The X-axis electromagnetic field distribution shown in A, and Fig.10 The Y-axis electromagnetic field distribution is shown in A. By comparison Fig. 9 A and B, and, contrast Fig.10 In A and B, it can be seen that the X-axis electromagnetic field distribution of the simulation model is consistent with that of the physical model, and the X-axis electromagnetic field distribution of the simulation model is consistent with that of the physical model, both of which are similar to the electromagnetic field generated by the magnetic dipole.

[0046] In addition, during the testing of the physical model, it was found that changing the shape of the reinforcing rib 2313 of the shielding frame 231 would affect the electromagnetic coupling between the modules inside the electromagnetic shielding structure. When the shielding frame 231 and the shielding cover 232 are buckled, if the reinforcing rib 2313 is insulated from the shielding cover 232, the electromagnetic coupling between the first module 21 and the second module 22 will also change by pressing the shielding cover 232. If the reinforcing rib 2313 is grounded through the shielding cover 232, the electromagnetic coupling between the first module 21 and the second module 22 will remain basically unchanged by pressing the shielding cover 232, indicating that the gap between the reinforcing rib 2313 and the shielding cover 232 will affect the electromagnetic coupling between the first module 21 and the second module 22.

[0047] The influence of the grounding of the reinforcing rib 2313 on the electromagnetic coupling between the first module 21 and the second module 22 is analyzed by simulation.

[0048] Fig.11 A schematic diagram of S parameters of a reinforcing rib grounded through a shielding cover at different positions provided in an embodiment of the present application. Fig.11 As shown in Figure A, by changing the grounding position of the reinforcing rib 2313 (position a-position d), the shielding cover is pressed to simulate deformation, so that the reinforcing rib 2313 is grounded through the shielding cover at different positions. Fig.11 As shown in B, when the reinforcing rib 2313 is grounded at position a-position d, compared with the reinforcing rib 2313 not being grounded, although the S parameter S21 (i.e., the coupling coefficient) between the first module 21 and the second module 22 changes, the impact is smaller because the electromagnetic coupling between the first module 21 and the second module 22 is not performed through the reinforcing rib 2313 at these positions.

[0049] Fig.12 A schematic diagram of S parameters of another reinforcing rib provided in an embodiment of the present application when it is grounded through a shielding cover at different positions. Fig.12 As shown in A, the position of the second module 22 is changed so that the second module 22 is located below the reinforcing rib 2313. By changing the grounding position (position a-position d) of the reinforcing rib 2313, the deformation caused by pressing the shielding cover is simulated, so that the reinforcing rib 2313 is grounded through the shielding cover at different positions. Fig.12 As shown in B, when the reinforcing ribs 2313 are grounded at positions a to d, compared with when the reinforcing ribs 2313 are not grounded, the S parameter S21 (i.e., the coupling coefficient) between the first module 21 and the second module 22 changes significantly. The reason is that electromagnetic coupling is performed between the first module 21 and the second module 22 through the reinforcing ribs 2313 at these positions.

[0050] Fig.13 A schematic diagram of electric field distribution and magnetic field distribution of a first module when there is no shielding frame is provided in an embodiment of the present application. Fig.14 A schematic diagram of electric field distribution and magnetic field distribution of a first module when a shielding frame is provided in an embodiment of the present application. Fig.13 A is a schematic diagram of the electric field distribution of the first module 21 when there is no shielding frame. Fig.13 B is a schematic diagram of the magnetic field distribution of the first module 21 when there is no shielding frame. Fig.14 A is a schematic diagram of the electric field distribution of the first module 21 when there is a shielding frame 231. Fig.14Figure B is a schematic diagram of the magnetic field distribution of the first module 21 when there is a shielding frame 231. The darker the color, the stronger the electric field strength or magnetic field strength. It can be seen that after adding the shielding frame, the electromagnetic energy in the area where the reinforcing rib 2313 is located is significantly enhanced. That is, the electromagnetic energy of the first module 21 will be coupled to the second port through the reinforcing rib 2313, resulting in a deterioration in the isolation between the first module 21 and the second port.

[0051] Fig.15 A schematic diagram of S parameters when the reinforcing rib and the shielding cover are short-circuited and insulated provided in an embodiment of the present application. In order to analyze the electromagnetic coupling between the first module 21 and the reinforcing rib 2313, the reinforcing rib 2313 is buckled with the shielding cover. The S parameters between the first module 21 and the reinforcing rib 2313 when the reinforcing rib 2313 and the shielding cover are short-circuited and insulated are compared, where S31 represents Fig. 22 The S parameter between the first module 21 and the reinforcing rib 2313 at position g, S41 represents Fig. 22 The S parameter between the first module 21 and the reinforcing rib 2313 at position h. It can be seen that when the reinforcing rib 2313 is insulated from the shielding cover, the S parameter (coupling coefficient) will be different in some frequency bands compared to when the reinforcing rib 2313 and the shielding cover are short-circuited, but the overall trend difference is not large. Therefore, the short-circuiting of the reinforcing rib 2313 and the shielding cover will not significantly change the electromagnetic coupling between the first module 21 and the reinforcing rib 2313, nor will it significantly change the isolation between the first module 21 and the second module 22.

[0052] like Figure 16-Figure 19 As shown, the following analyzes whether the isolation between the first module 21 and the second module 22 can be reduced by connecting different tuning networks between the reinforcing rib 2313 and the ground (that is, connecting the reinforcing rib 2313 to the ground through different tuning networks) for tuning. The tuning network may include at least one of the following: a capacitor, an inductor, a capacitor and an inductor in series, and a capacitor and an inductor in parallel. S31 indicates Fig. 22 The S parameter between the first module 21 and the reinforcing rib 2313 at position g.

[0053] Fig.16A schematic diagram of the S parameters of a capacitor connected between a reinforcing rib and the ground provided in an embodiment of the present application. When there is an electromagnetic shielding structure, the reinforcing rib 2313 is directly grounded or not grounded, and the change trend of the S parameter S31 remains the same, but compared with the case without an electromagnetic shielding structure, the S parameter S31 increases by about 20-30dB as a whole, that is, the electromagnetic coupling between the first module 21 and the reinforcing rib 2313 is obvious, which will cause the electromagnetic coupling between the first module 21 and the second module 22 to increase significantly. When the reinforcing rib 2313 is grounded through a 0.1pF capacitor, due to the small capacitance, the S parameter S31 is consistent with the change trend of the reinforcing rib 2313 being directly grounded or not grounded, and the inhibitory effect on the electromagnetic coupling between the modules inside the electromagnetic shielding structure is not obvious. When the capacitance is greater than or equal to 2pF, for example, 2pF, 5pF or 18pF, the S parameter between the first module 21 and the reinforcement rib 2313 will be significantly changed. In a specific frequency band, it is even close to the S parameter when there is no electromagnetic shielding structure, thereby significantly reducing the electromagnetic coupling between the first module 21 and the second module 22, and the inhibitory effect on the electromagnetic coupling between the modules inside the electromagnetic shielding structure is more obvious.

[0054] It should be noted that different capacitors may suppress electromagnetic coupling in different frequency bands. In engineering practice, it is necessary to simulate the frequency bands of electromagnetic coupling suppressed by various capacitors, and determine which capacitor to use in combination with the frequency band of the power consumption coupling that needs to be suppressed. For example, if you want to suppress electromagnetic coupling at 5.2 GHz, you can use a 2pF capacitor or an 18pF capacitor. If you want to suppress electromagnetic coupling at 2.8 GHz, you can use a 5pF capacitor. If you want to suppress electromagnetic coupling at 1.5 GHz, you can use an 18pF capacitor. If you want to suppress electromagnetic coupling in multiple frequency bands, you can connect multiple capacitors in parallel, and each capacitor suppresses the electromagnetic coupling in the corresponding frequency band. In the embodiment of the present application, the capacitance is greater than or equal to 2pF. According to Fig.16 It can be seen that the reinforcing rib 2313 is grounded through a capacitor, which can suppress the electromagnetic coupling between the first module 21 and the second module 22 greater than 1 GHz.

[0055] Fig.17A schematic diagram of the S parameters of an inductor connected between a reinforcing rib and the ground provided in an embodiment of the present application. When the reinforcing rib 2313 is grounded through a 0.1nH inductor or a 1nH inductor, due to the small inductance, the S parameter S31 is consistent with the trend of the reinforcing rib 2313 not being grounded, and the inhibitory effect on the electromagnetic coupling between the modules inside the electromagnetic shielding structure is not obvious. When the inductance is greater than or equal to 8.2nH, for example, 8.2nH, 18nH, 33nH, 68nH or 100nH, the S parameters between the first module 21 and the reinforcing rib 2313 will be significantly changed, and in a specific frequency band, it is even close to the S parameters when there is no electromagnetic shielding structure, thereby significantly reducing the electromagnetic coupling between the first module 21 and the second module 22, and the inhibitory effect on the electromagnetic coupling between the modules inside the electromagnetic shielding structure is more obvious.

[0056] It should be noted that different inductors may have different frequency bands for suppressing electromagnetic coupling. In engineering practice, it is necessary to simulate the frequency bands of electromagnetic coupling suppressed by various inductors, and determine which inductor to use in combination with the frequency band of the power consumption coupling that needs to be suppressed. For example, if you want to suppress electromagnetic coupling at 0.6GHz, you can use an 8.2nH inductor, 18nH inductor, 33nH inductor, 68nH inductor or 100nH inductor. In the embodiment of the present application, the inductor is greater than or equal to 8.2nH. According to Fig.17 It can be seen that the reinforcing rib 2313 can suppress the electromagnetic coupling less than 1 GHz between the first module 21 and the second module 22 through inductive grounding.

[0057] Fig.18 A schematic diagram of S parameters of a capacitor and an inductor connected in series between a reinforcing rib and ground provided in an embodiment of the present application. If a capacitor and an inductor are connected in series between the reinforcing rib 2313 and the ground for tuning, that is, the reinforcing rib 2313 is grounded through a capacitor and an inductor connected in series, it is similar to connecting an inductor between the reinforcing rib 2313 and the ground for tuning. For details, refer to Fig.17 Related description. For example, when the inductance is 0.1nH or 1nH, the S parameter S31 is consistent with the trend of the ungrounded reinforcement rib 2313, and the inhibitory effect on the electromagnetic coupling between the modules inside the electromagnetic shielding structure is not obvious. When the inductance is greater than or equal to 8.2nH, such as 8.2nH, 18nH, 33nH, 68nH or 100nH, the S parameters between the first module 21 and the reinforcement rib 2313 will be significantly changed. In a specific frequency band, it is even close to the S parameters when there is no electromagnetic shielding structure, thereby significantly reducing the electromagnetic coupling between the first module 21 and the second module 22, and the inhibitory effect on the electromagnetic coupling between the modules inside the electromagnetic shielding structure is more obvious. In the embodiment of the present application, the inductance is greater than or equal to 8.2pF. According to Fig.18It can be seen that the reinforcing rib 2313 is grounded through the capacitor and inductor connected in series, so that the electromagnetic coupling between the first module 21 and the second module 22 at a frequency less than 1 GHz can be suppressed.

[0058] It should be noted that in Fig.18 In the figure, the serial numbers in brackets are as shown in Table 1, indicating that the capacitor and inductor use the corresponding values. For example, S31(1) indicates that the capacitor and inductor use the values ​​corresponding to serial number 1 in Table 1.

[0059] Table 1

[0060] Fig.19 A schematic diagram of S parameters of a capacitor and an inductor connected in parallel between a reinforcing rib and ground provided in an embodiment of the present application. If a capacitor and an inductor are connected in parallel between the reinforcing rib 2313 and the ground for tuning, that is, the reinforcing rib 2313 is grounded through a capacitor and an inductor connected in parallel, it is similar to connecting a capacitor between the reinforcing rib 2313 and the ground for tuning. For details, refer to Fig.16 Related description. When the capacitance is 0.1pF, due to the small capacitance, the S parameter S31 is consistent with the trend of the change when the reinforcing rib 2313 is directly grounded and not grounded, and the inhibitory effect on the electromagnetic coupling between the modules inside the electromagnetic shielding structure is not obvious. When the capacitance is greater than or equal to 2pF, for example, 2pF, 5pF or 18pF, the S parameters between the first module 21 and the reinforcing rib 2313 will be significantly changed. In a specific frequency band, it is even close to the S parameters when there is no electromagnetic shielding structure, thereby significantly reducing the electromagnetic coupling between the first module 21 and the second module 22, and the inhibitory effect on the electromagnetic coupling between the modules inside the electromagnetic shielding structure is more obvious.

[0061] It should be noted that in Fig.19 In the figure, the serial numbers in brackets are as shown in Table 1, indicating that the capacitor and inductor use the corresponding values. For example, S31(1) indicates that the capacitor and inductor use the values ​​corresponding to serial number 1 in Table 1.

[0062] In addition, by comparing Figure 16-Figure 19It can be seen that by connecting a capacitor between the reinforcing rib 2313 and the ground for tuning, or by connecting a capacitor and an inductor in parallel between the reinforcing rib 2313 and the ground for tuning, in the high frequency band (for example, greater than 1 GHz), the electromagnetic coupling between the first module 21 and the second module 22 is more significantly reduced, that is, the electromagnetic coupling is more significantly suppressed. By connecting an inductor between the reinforcing rib 2313 and the ground for tuning, or by connecting a capacitor and an inductor in series between the reinforcing rib 2313 and the ground for tuning, in the low frequency band (for example, less than 1 GHz), the electromagnetic coupling between the first module 21 and the second module 22 is more significantly reduced, that is, the electromagnetic coupling is more significantly suppressed. Therefore, the corresponding resonant network can be selected according to the frequency band where the electromagnetic coupling to be suppressed is located.

[0063] In summary, Fig. 20 A schematic diagram of another electromagnetic shielding structure provided in an embodiment of the present application. Figure 2 On the basis of the electromagnetic shielding structure 23, the electromagnetic shielding structure 23 also includes at least one tuning network 26, and the reinforcing rib 2313 is grounded through the tuning network 26. For a more complex electromagnetic shielding structure 23, such as including more cavities to accommodate more modules, more tuning networks 26 can be included, and multiple positions of the shielding frame can be grounded through multiple tuning networks 26 to enhance the effect of suppressing the electromagnetic coupling between the first module 21 and the second module 22.

[0064] The tuning network 26 may include capacitors, inductors, capacitors and inductors connected in series, capacitors and inductors connected in parallel, etc. For how to select the form of the tuning network 26, please refer to Figure 16-Figure 19 The descriptions of different forms of the tuning network 26 are omitted here.

[0065] Any position of the reinforcing rib 2313 can be grounded through the tuning network 26. For example, when there are multiple tuning networks 26, positions spaced at least a predetermined distance apart on the reinforcing rib 2313 can be grounded through a tuning network 26 to enhance the effect of suppressing the electromagnetic coupling between the first module 21 and the second module 22. The positions on the reinforcing rib 2313 connected to the tuning network 26 can be equally spaced or unequally spaced.

[0066] For another example, the position of the strongest electric field in the electromagnetic simulation on the reinforcing rib 2313 can be grounded through the tuning network 26 to reduce the cost of the tuning network 26, and the cost and the effect of suppressing electromagnetic coupling can be balanced. There can be more than one position of the strongest electric field in the electromagnetic simulation on the reinforcing rib 2313, for example, N positions (i.e., TOP N positions) with the strongest electric field in the electromagnetic simulation on the reinforcing rib 2313. In the prior art, electromagnetic isolation is performed in all directions between the electromagnetic interference source and the disturbed body, which requires a large space cost and material cost. Tuning the position of the strongest electric field in the electromagnetic simulation on the reinforcing rib 2313 (i.e., the electromagnetic sensitive position) and ignoring other electromagnetic insensitive positions can reduce space cost and material cost.

[0067] For example, Fig.21 A schematic diagram of the electric field distribution and magnetic field distribution when different positions of a reinforcement rib are grounded through a resonant network provided in an embodiment of the present application. The darker the color, the stronger the electric field strength or magnetic field strength. The reinforcement rib is equivalent to a magnetic dipole along the x-axis direction, so the coupling degree with the magnetic field in the x-axis direction is the largest. After electromagnetic simulation, the electric field at position 1 of the reinforcement rib is the strongest. When the reinforcement rib is grounded through a tuning network at position 1, the electromagnetic coupling suppression is most obvious. Finally, it can be chosen to ground the reinforcement rib through a tuning network at position 1.

[0068] Fig. 22 A schematic diagram of S parameters between the first module and different positions of the reinforcing rib after the reinforcing rib is grounded through a resonant network provided in an embodiment of the present application. After the reinforcing rib 2313 is grounded through the tuning network 26, the S parameter (S31) between the first module 21 and the position g on the reinforcing rib 2313 and the S parameter (S41) between the first module 21 and the position h on the reinforcing rib 2313 are measured. Fig.23 The first module provided in the embodiment of the present application is connected to the reinforcing rib at position g (see Fig. 22 ) is a schematic diagram of the S parameters between Fig.24 The embodiment of the present application provides a first module and a position h on the reinforcing rib (see Fig. 22 ) between the S parameters. Fig.23 and Fig.24 It can be seen that compared with the tuning network 26 being a 0.1pF capacitor, a 2pF capacitor, or the reinforcing rib 2313 being grounded, or having no shielding frame, when the tuning network 26 is a 18pF capacitor, at a frequency of about 1.5GHz, the first module 21 and the position g on the reinforcing rib 2313 (see Fig. 22 ) between the S parameter S31, and the position h between the first module 21 and the reinforcing rib 2313 (see Fig. 22) are all at extremely low points, and the electromagnetic coupling between the first module 21 and the reinforcing rib 2313 is significantly reduced, thereby significantly suppressing the electromagnetic coupling between the first module 21 and the second module 22 through the reinforcing rib 2313, thereby improving the isolation between the first module 21 and the second module 22.

[0069] Fig.25 A schematic diagram of a shielding cover made of a flexible conductive material provided in an embodiment of the present application. If the shielding cover 232 is made of a flexible conductive material such as copper foil, conductive cloth, etc., the above-mentioned tuning network can also be used to suppress the electromagnetic coupling between the first module 21 and the second module 22 inside the electromagnetic shielding structure 23. Since the flexible conductive material is relatively soft, the differences from rigid metals mainly include: First, the flexible conductive material can be bonded to the reinforcing ribs through conductive glue or non-conductive glue to achieve local insulation. Experiments show that the insulation state between the flexible conductive material and the reinforcing ribs has a relatively small effect on the electromagnetic coupling between the first module and the second module, but it will significantly suppress the electromagnetic coupling between the first module 21 and the second module 22 in a specific frequency band. Second, the flexible conductive material will be deformed due to the influence of temperature and internal filling materials (such as thermal conductive gel, etc.), which will affect the suppression effect to a certain extent.

[0070] Fig.26 The embodiment of the present application provides a method in which when the flexible conductive material is insulated from the reinforcing rib, the first module is insulated from the reinforcing rib at position g (see Fig. 22 ) is a schematic diagram of the S parameters between . Fig. 27 The embodiment of the present application provides a method in which when the flexible conductive material is short-circuited with the reinforcing rib, the first module is connected to the position g on the reinforcing rib (see Fig. 22 ) is a schematic diagram of the S parameters between . Fig.28 The embodiment of the present application provides a method in which when the flexible conductive material is insulated from the vertical part of the reinforcing rib and short-circuited with other parts of the reinforcing rib, the first module is connected to the position g on the reinforcing rib (see Fig. 22 ) is a schematic diagram of the S parameters between . Fig.29 The embodiment of the present application provides a method in which when the flexible conductive material is insulated from the horizontal part of the reinforcing rib and short-circuited with other parts of the reinforcing rib, the first module is connected to the position g on the reinforcing rib (see Fig. 22 ) is a schematic diagram of the S parameters between .

[0071] By comparison Fig.26 and Fig. 27 It can be seen that for the connection modes of the reinforcing ribs being connected to ground through 0.1pF capacitors, 2pF capacitors, 5pF capacitors, 18pF capacitors, 33pF capacitors, or no capacitors, the first module 21 and the position g (see Fig. 22) keep the same trend of the S parameter S31 between them. Whether the reinforcing rib is insulated from the copper foil has little effect on the isolation between the first module 21 and the second module 22. Fig.28 and Fig.29 It can be seen that for the connection modes of the reinforcing ribs through 0.1pF capacitors, 2pF capacitors, 5pF capacitors, 18pF capacitors, 33pF capacitors and other grounding modes, the first module 21 and the position g (see Fig. 22 ) keep the same trend of the S parameter S31 between them, the flexible conductive material is insulated from different positions of the reinforcing ribs, and has little effect on the isolation between the first module 21 and the second module 22.

[0072] The electromagnetic shielding structure and electronic device provided in the embodiments of the present application connect a tuning network between the reinforcing ribs of the electromagnetic shielding structure and the ground, thereby changing the resonant state of the electromagnetic shielding structure (the resonant frequency remains unchanged, and the S parameter of the resonant frequency becomes smaller), suppressing the electromagnetic coupling between the first module and the second module and the reinforcing ribs, thereby suppressing the electromagnetic coupling between the first module and the second module, and reducing the electromagnetic coupling between the modules in the electromagnetic shielding structure.

[0073] In addition, in the prior art, board-level anti-interference protection can be achieved by using discrete shielding, electrical connection auxiliary materials (conductive foam, absorbing materials, copper foil), etc., and even requires structural adjustments (such as increasing shielding, increasing grounding points, etc.), which have a great impact on the structure, space and cost. The electromagnetic shielding structure and electronic equipment provided in the embodiments of the present application can achieve low-cost board-level anti-interference protection in a limited space, which can avoid the above problems.

[0074] The modules described as separate components may or may not be physically separated, and the components shown as modules may or may not be physical modules, that is, they may be located in one device or distributed on multiple devices. Some or all of the modules may be selected according to actual needs to achieve the purpose of the present embodiment.

[0075] In addition, each functional module in each embodiment of the present application may be integrated into one device, or each module may exist physically separately, or two or more modules may be integrated into one device.

[0076] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. An electromagnetic shielding structure, characterized in that: include: A shielding frame, a shielding cover and at least one tuning network, wherein the shielding cover is buckled with the shielding frame, the shielding frame comprises a first cavity and a second cavity, the first cavity and the second cavity are separated by reinforcing ribs, the first cavity is used to accommodate a first module, and the second cavity is used to accommodate a second module; The reinforcing rib is grounded through the tuning network.

2. The electromagnetic shielding structure according to claim 1, characterized in that: The position on the reinforcing rib where the electric field is strongest in electromagnetic simulation is grounded through the tuning network.

3. The electromagnetic shielding structure according to claim 1, characterized in that: Positions on the reinforcing ribs that are spaced at least a predetermined distance apart are grounded through the tuning network.

4. The electromagnetic shielding structure according to any one of claims 1 to 3, characterized in that: The tuning network includes at least one of the following: a capacitor, an inductor, a capacitor and an inductor connected in parallel, and a capacitor and an inductor connected in series.

5. The electromagnetic shielding structure according to claim 4, characterized in that: When the tuning network includes a capacitor, or a capacitor and an inductor connected in parallel, the tuning network is used to suppress electromagnetic coupling greater than 1 GHz between the first module and the second module.

6. The electromagnetic shielding structure according to claim 4, characterized in that: When the tuning network includes an inductor, or a capacitor and an inductor connected in series, the tuning network is used to suppress electromagnetic coupling between the first module and the second module at a frequency less than 1 GHz.

7. The electromagnetic shielding structure according to claim 4, characterized in that: The capacitance is greater than or equal to 2 pF.

8. The electromagnetic shielding structure according to claim 4, characterized in that: The inductance is greater than or equal to 8.2 nH.

9. An electronic device, characterized in that: It comprises a first module, a second module and the electromagnetic shielding structure according to any one of claims 1 to 8, wherein the first cavity of the electromagnetic shielding structure is used to accommodate the first module, and the second cavity of the electromagnetic shielding structure is used to accommodate the second module.

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