CN216491175U

CN216491175U - Circuit board structure

Info

Publication number: CN216491175U
Application number: CN202120877243.9U
Authority: CN
Inventors: 李劲松
Original assignee: SZ DJI Technology Co Ltd
Current assignee: SZ DJI Technology Co Ltd
Priority date: 2021-04-26
Filing date: 2021-04-26
Publication date: 2022-05-10
Anticipated expiration: 2031-04-26

Abstract

The application discloses a circuit board structure, which comprises a substrate, wherein the surface of the substrate comprises a film area covered with a shielding film, and the film area is provided with a connector enclosed in the shielding film; the substrate is internally provided with an electromagnetic band gap structure region, the electromagnetic band gap structure region is provided with an electromagnetic band gap structure, the electromagnetic band gap structure region and the film region are arranged in a vertically stacked mode, and the electromagnetic band gap structure is used for suppressing interference noise generated based on the connector. By the mode, the electromagnetic compatibility of the product can be improved under the condition that extra space is not added.

Description

Circuit board structure

Technical Field

The application relates to the technical field of transmission architecture, in particular to a circuit board structure.

Background

Due to the complex and compact structure of electronic products, high-speed digital signals often need to be transmitted across multiple circuit boards. The plurality of circuit boards are connected to each other by a small and ultra-thin Board-to-Board connector (BTB) or a connector such as a micro coaxial cable. These connectors tend not to have excellent shielding performance due to structural size limitations of the connectors.

SUMMERY OF THE UTILITY MODEL

Based on this, the application provides a circuit board structure, can promote the electromagnetic compatibility ability of product under the condition of not additionally increasing the space.

In a first aspect, the present application provides a circuit board structure comprising a substrate, a surface of the substrate comprising a film area covered with a shielding film, the film area being provided with a connector enclosed within the shielding film; the substrate comprises an electromagnetic band gap structure region, the electromagnetic band gap structure region is provided with an electromagnetic band gap structure, the electromagnetic band gap structure region and the film region are arranged in an up-down stacked mode, and the electromagnetic band gap structure is used for suppressing interference noise generated based on the connector.

In the circuit board structure of the present application, the electromagnetic band gap structure region includes a plurality of circuit units, and each circuit unit includes the conducting layer of the ground plane layer, the power plane layer and the dull and stereotyped conducting wire that is provided with the electromagnetic band gap structure that stack up the setting, the dull and stereotyped conducting wire of the electromagnetic band gap structure respectively with the power plane of power plane layer the connector electricity is connected.

In the circuit board structure of this application, the membrane region still is provided with and seals irregular microstrip flat conductor wire in the screened film, irregular microstrip flat conductor wire respectively with the earth mat that the horizon belongs to the power net electricity connection that the power plane belongs to.

In the circuit board structure of the present application, the irregular microstrip flat conductive line includes a first irregular microstrip flat conductive line electrically connected to the power grid and a second irregular microstrip flat conductive line electrically connected to the ground grid, the first irregular microstrip flat conductive line and the second irregular microstrip flat conductive line are respectively provided with a plurality of protrusions at intervals.

In the circuit board structure of the present application, the positions of the protrusions on the first irregular microstrip flat conductive line and the positions of the protrusions on the second irregular microstrip flat conductive line are staggered with each other.

In the circuit board structure of the application, on the first irregular microstrip flat conductive line and the second irregular microstrip flat conductive line, the spacing distance between two adjacent protrusions is greater than the width of the protrusions.

In the circuit board structure of the present application, two ends of the irregular microstrip flat conductive line are electrically connected to the connector and the electromagnetic band gap structure region, respectively.

In the circuit board structure of the present application, the film region is further provided with a passive device enclosed in the shielding film, the passive device is electrically connected with the electromagnetic band gap structure region.

In the circuit board structure of the present application, one end of the irregular microstrip flat conductive line is electrically connected to the electromagnetic bandgap structure region.

In the circuit board structure of the present application, the film region is further provided with a passive device enclosed in the shielding film, and the passive device is electrically connected to the other end of the irregular microstrip flat conductive wire;

or one end of the passive device is electrically connected with the electromagnetic band gap structure region, and the other end of the passive device is electrically connected with the other end of the irregular microstrip flat conductive wire;

or two ends of the passive device are respectively and electrically connected with the connector and the electromagnetic band gap structure region.

In the circuit board structure of the application, a first irregular microstrip flat conductive wire is electrically connected with a power pin of the connector, and a second irregular microstrip flat conductive wire is electrically connected with a ground pin of the connector.

In the circuit board structure of the present application, the film region is further provided with a spark gap enclosed in the shielding film, the spark gap includes a first electrode and a second electrode which are oppositely arranged, the first electrode is arranged at the tail end of the power pin of the connector, and the second electrode is arranged at the tail end of the ground pin of the connector.

In the circuit board structure of the present application, two opposite ends of the first electrode and the second electrode are respectively triangular, and vertexes of the two triangular ends are opposite.

In the circuit board structure of this application, the quantity of the dull and stereotyped conducting wire of electromagnetism band gap structure is four at least, the power plane with be provided with at least one power hole respectively in corresponding the position on the dull and stereotyped conducting wire of electromagnetism band gap structure, the dull and stereotyped conducting wire of four at least electromagnetism band gap structures passes through the power hole with the power plane electricity is connected, the horizon with be provided with two at least holes respectively in corresponding the position on the dull and stereotyped conducting wire of electromagnetism band gap structure.

In the circuit board structure of the present application, the flat conductive lines of at least two of the electromagnetic bandgap structures overlap the shadow of the ground via.

In the circuit board structure of the present application, the length of the flat conductive line of the electromagnetic bandgap structure is greater than or equal to a first length threshold, and is less than or equal to a second length threshold, where the first length threshold is a difference between a reference length and a length error, the second length threshold is a sum of the reference length and the length error, and the reference length is a quarter of a wavelength of a suppressed frequency band.

In the circuit board structure of this application, the quantity of the dull and stereotyped conducting wire of electromagnetic band gap structure is four, four dull and stereotyped conducting wire mutually perpendicular of electromagnetic band gap structure sets up and forms four ends, four dull and stereotyped conducting wire of electromagnetic band gap structure passes through four ends with the power supply hole with the power plane electricity is connected.

In the circuit board structure of the present application, the shielding film is obtained by plating, and the shielding film includes a material having a magnetic permeability greater than 1 and a metal material.

In the circuit board structure of the present application, the power plane layer is provided with a clearance area in an area overlapping with the power pins of the connector.

In the circuit board structure of the present application, the clearance area is provided with a bent strip-shaped conductive line crossing the flat conductive line of the electromagnetic bandgap structure; the length of the strip-shaped conductive line is greater than or equal to a first length threshold value and less than or equal to a second length threshold value, the first length threshold value is the difference between a reference length and a length error, the second length threshold value is the sum of the reference length and the length error, and the reference length is one quarter of the wavelength of the suppressed frequency band.

The embodiment of the application provides a circuit board structure, which comprises a substrate, wherein the surface of the substrate comprises a film area covered with a shielding film, and the film area is provided with a connector enclosed in the shielding film; the substrate comprises an electromagnetic band gap structure region, the electromagnetic band gap structure region is provided with an electromagnetic band gap structure, the electromagnetic band gap structure region and the film region are arranged in an up-down stacked mode, and the electromagnetic band gap structure is used for suppressing interference noise generated based on the connector. Because the connector arranged on the surface of the substrate is sealed in the shielding film, the electromagnetic radiation generated by the connector can be limited in the shielding film, so that the electromagnetic radiation is inhibited or attenuated; the substrate also comprises an electromagnetic band gap structure region provided with an electromagnetic band gap structure, and the electromagnetic band gap structure is used for inhibiting the interference noise generated by the connector, so that the inhibiting effect on the interference noise generated by the connector can be further increased; the shielding film of the closed connector does not occupy extra space, and the electromagnetic band gap structure region is arranged in the substrate and does not occupy extra space, so that the electromagnetic compatibility of the connector can be improved under the condition of not additionally increasing the space. In addition, the obtaining mode of the shielding film is not limited, and the electromagnetic compatibility of the connector is not only ensured by the shielding film, but also doubly ensured by the shielding film and the electromagnetic band gap structure, so that the shielding film can be generated by adopting a low-cost and easily-realized film coating mode under the condition of ensuring the electromagnetic compatibility of the connector, the film forming cost is reduced, and the mass production is improved.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts. Wherein:

FIG. 1 is a schematic structural diagram of an embodiment of a circuit board structure according to the present application;

FIG. 2 is a schematic top view of another embodiment of the circuit board structure of the present application;

FIG. 3 is a side schematic view of FIG. 2;

FIG. 4 is a schematic structural diagram of another embodiment of the circuit board structure of the present application;

FIG. 5 is a schematic structural diagram of another embodiment of the circuit board structure of the present application;

FIG. 6 is a schematic diagram of a shielding effect according to an embodiment of the present invention;

FIG. 7 is a schematic diagram of the electric field screen performance of the shielding film according to one embodiment of the present invention;

FIG. 8 is a diagram illustrating the magnetic field screen performance of the shielding film according to an embodiment of the present invention.

Description of the main elements and symbols:

100. a circuit board structure;

1. a substrate; 11. a substrate surface; 12. within the substrate; 2. a membrane region; 3. a connector; 31. a power supply pin; 32. a ground pin; 4. an electromagnetic bandgap structure region; 5. an electromagnetic bandgap structure; 51. a ground plane layer; 52. a power plane layer; 521. a headroom region; 522. a strip-shaped conductive wire; 53. a conductive layer; 531. a flat conductive line of an electromagnetic bandgap structure; 54. a power supply hole; 55. a ground hole; 6. an irregular microstrip flat conductive line; 61. a first irregular microstrip planar conductive line; 62. a second irregular microstrip planar conductive line; 7. a protrusion; 8. a passive device; 9. a spark gap; 91. a first electrode; 92. a second electrode.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It is also to be understood that the terminology used in the description of the present application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in the specification of the present application and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

It should be further understood that the term "and/or" as used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

High-speed digital signals often need to be transmitted across multiple circuit boards due to the complex and compact structure of electronic products. The plurality of circuit boards are connected to each other by using a connector such as a small and ultra-thin BTB or ultra-thin coaxial cable. These connectors often do not have excellent shielding performance due to structural size limitations of the connectors.

Referring to fig. 1, fig. 1 is a schematic structural diagram of an embodiment of a circuit board structure according to the present application.

The circuit board structure 100 comprises a substrate 1, the substrate surface 11 comprising a membrane area 2 covered with a shielding membrane, the membrane area 2 being provided with a connector 3 enclosed within the shielding membrane; the substrate 12 includes an electromagnetic bandgap structure region 4, the electromagnetic bandgap structure region 4 is provided with an electromagnetic bandgap structure 5, the electromagnetic bandgap structure region 4 and the film region 2 are stacked up and down, and the electromagnetic bandgap structure 5 is used for suppressing interference noise generated by the connector 3.

In this embodiment, the circuit board may be referred to as a printed wiring board or a printed circuit board. The Circuit Board is classified into a Flexible Printed Circuit Board (FPC), a rigid Printed Circuit Board (PCB), and a Flexible Printed Circuit Board (FPCB) according to characteristics. The circuit boards are divided into three categories, namely single-sided boards, double-sided boards and multilayer circuit boards according to the number of layers.

Electromagnetic shielding is one of the effective methods widely used in electromagnetic compatibility to suppress electromagnetic interference. Electromagnetic shielding is the attenuation of electromagnetic energy generated by an electromagnetic radiation field source by reflection (i.e., reflection losses at the incident surface), attenuation (i.e., absorption losses that are not reflected into the shield), etc. of the shield, without the flow entering the shielded area. The shielding film can be a thin film made of a material with conductive properties (e.g., Ag, ITO indium tin oxide, etc.), belongs to the shielding body, and does not occupy additional space, and is generated in many ways, for example: sputter gold, metal sputtering, electroplating, ion plating, and the like. The shielding film can be generally formed by a plating process (e.g., electroplating, electroless plating, etc.) that is low in plating cost and easy to mass-produce.

The connector 3 may be a circuit board connector, which is a kind of electronic connector, and is a connecting device specially used for connecting and fixing a printed circuit board or a printed circuit board.

The Electromagnetic Band Gap structure 5 (EBG) is essentially a Band-stop filter formed by periodically arranging units of different media, conductive metals or other mixtures, and has frequency Band Gap characteristics, slow wave characteristics, high-impedance surface characteristics and the like, so that Electromagnetic waves in certain frequency bands cannot pass through the Band-stop filter. The band-stop principle of the electromagnetic band gap structure 5 is to utilize the resonance characteristic of the structure, so that the electromagnetic wave forms resonance in the structure and cannot continuously propagate. In this embodiment, the electromagnetic bandgap structure region 4 is provided with the electromagnetic bandgap structure 5, the electromagnetic bandgap structure region 4 and the film region 2 are stacked up and down (in practical application, the overlapping portion of the electromagnetic bandgap structure region 4 and the film region 2 exceeds 50% of the electromagnetic bandgap structure region 4 or the film region 2, and it can be considered that the electromagnetic bandgap structure region 4 and the film region 2 are stacked up and down), and the electromagnetic bandgap structure 5 is used for suppressing the interference noise generated by the connector 3, so that the suppression effect on the interference noise generated by the connector 3 can be further increased, and the electromagnetic compatibility of the connector 3 is improved.

The shielding film is obtained by coating, and comprises a material with magnetic permeability greater than 1 and a metal material. The metal material may be plated on the outermost layer. The film area 2 of the substrate surface 11 can also be provided with more than 1 contact point for interconnection with a conductor on the substrate 1, which contact points are enclosed within said shielding film. In the application, a metal film is not plated on the side wall of the surface of the substrate by adopting a side wall metal plating process, wherein the metal plating on the side wall can be added with an alloy material to ensure that the magnetic permeability of the metal film is more than 1.

The circuit board structure 100 provided by the embodiment of the present application includes a substrate 1, where the substrate surface 11 includes a film region 2 covered with a shielding film, and the film region 2 is provided with a connector 3 enclosed in the shielding film; the substrate 12 includes an electromagnetic bandgap structure region 4, the electromagnetic bandgap structure region 4 is provided with an electromagnetic bandgap structure 5, the electromagnetic bandgap structure region 4 and the film region 2 are stacked up and down, and the electromagnetic bandgap structure 5 is used for suppressing interference noise generated by the connector 3. Since the connector 3 provided on the substrate surface 11 is enclosed in the shielding film, electromagnetic radiation generated by the connector 3 can be confined in the shielding film, so that the electromagnetic radiation is suppressed or attenuated; since the substrate 12 further includes the electromagnetic bandgap structure region 4 provided with the electromagnetic bandgap structure 5, the electromagnetic bandgap structure 5 is used for suppressing the interference noise generated by the connector 3, so that the suppression effect on the interference noise generated by the connector 3 can be further increased; the shielding film of the closed connector 3 does not occupy additional space, and the electromagnetic band gap structure region 4 is disposed in the substrate 12, and does not occupy additional space, so that the electromagnetic compatibility of the connector 3 can be improved without additionally increasing space. In addition, the obtaining mode of the shielding film is not limited, and the electromagnetic compatibility of the connector 3 is not only ensured by the shielding film, but is doubly ensured by the shielding film and the electromagnetic band gap structure 5, so that the shielding film can be generated by adopting a film coating mode which is low in cost and easy to realize under the condition of ensuring the electromagnetic compatibility of the connector 3, the film forming cost is reduced, and the mass production is improved.

The electromagnetic bandgap structure 5 can be classified into a large number of types according to its different characteristics and performance, and no matter what type of electromagnetic bandgap structure 5 is, the purpose of suppressing the interference noise generated by the connector 3 in the embodiment of the present application can be achieved.

Along with the increasingly powerful functions and data processing capabilities of electronic products, the structures of the electronic products are more compact, and the electronic products are more developed to be miniaturized and light and thin.

Referring to fig. 2 and 3 in combination, in an embodiment, in order to effectively suppress interference noise generated in a thin circuit board by the connector 3 and reduce the size of the EBG structure 5, the electromagnetic bandgap structure region 4 includes a plurality of circuit units, each of which includes a ground plane layer 51, a power plane layer 52, and a conductive layer 53 provided with a flat conductive line 531 of an electromagnetic bandgap structure, the flat conductive line 531 of the electromagnetic bandgap structure being electrically connected to the power plane of the power plane layer 52 and the connector 3, respectively.

The simplest transmission line consists of two basic elements: a signal path, a reference path (also referred to as a return path). Signals are transmitted on transmission lines in the form of electromagnetic waves, and two basic elements of the transmission lines constitute the physical environment for electromagnetic wave transmission. From the perspective of electromagnetic wave transmission, the signal path and the reference path together form a special physical structure in which the electromagnetic wave is transmitted. From a current loop perspective, the signal path carries a signal current and the reference path carries a return current, and thus the reference path is also referred to as a return path.

In this embodiment, the ground plane layer 51 may refer to a layer on which a ground plane or a ground plane is located, and the power plane layer 52 may refer to a layer on which a power plane is located. The ground plane is a simpler way for the circuit board to improve performance and prevent problems. The ground plane may generally be referred to as a return signal path or reference plane. The boards of circuit boards are now becoming more miniaturized and the devices are becoming smaller, the crowded boards do not allow for wider traces and provide a very ample space for placing the devices in an optimal position, in which case the "ground plane" can improve overall performance by providing very low impedance for the signal loops. The use of a ground plane reduces the loop impedance, reduces noise caused by variations in the return current, and also provides a more uniform ground voltage across the board (low impedance means lower voltage drop). The ground plane enables the PCB layout and wiring work to be simple and convenient, components can be more compact, and the size of the PCB can be reduced; the ground plane can be accessed locally anywhere a via can be made on the PCB, which is much simpler than routing to ground in various ways. The ground plane may improve the performance of the circuit: the single PCB wire is connected with the ground at a plurality of places, so that a loop can easily appear, and the conductive loop can easily receive magnetic interference; by directly connecting the "ground plane" with vias or through-holes, the impedance of the connection between the component and the "ground" at any point is very low. The ground plane prevents electromagnetic interference (radiation and reception), especially when there are components on both sides of the circuit board, which is more efficient with a conductive housing.

The power plane may refer to a supply Voltage (VCC) and a power voltage of the circuit, and may be a plane connected to a power supply, and the purpose of the power plane is to provide a stable voltage for the circuit board. Power planes are typically provided on circuit boards having four or more layers. The power plane can be equivalent to a network formed by a plurality of inductors and capacitors, and as with a common LC network, the power network formed by the capacitors and the inductors can generate a resonance phenomenon at a certain frequency, thereby affecting the impedance of the power plane layer. The power plane has many advantages over the traces: (1) improving the decoupling between the circuits: an inter-board capacitor is formed between the power plane and the adjacent ground plane, and a plurality of distributed power capacitors are added to the whole circuit board to play a certain decoupling role so as to prevent noise from being transmitted from one circuit to the other circuit through the power supply; (2) the return path is shorter: the convenience of powering the circuit from the signal layer down to the power plane along the vias, shorter return paths may lead to better Electromagnetic Compatibility (EMC); (3) greater current carrying capacity: the circuit board can handle current exceeding the wires or the wires, thereby reducing the operating temperature of the circuit board.

Each circuit unit comprises a ground plane layer 51, a power plane layer 52 and a conducting layer 53, wherein the conducting line in the conducting layer 53 is a flat conducting line in a flat plate structure, the ground plane layer 51, the power plane layer 52 and the conducting layer 53 are arranged in a laminated mode, the size of the EBG structure 5 can be effectively reduced, the flat conducting line 531 is electrically connected with the power plane of the power plane layer 52 and the connector 3 respectively, interference noise in signals input through the connector 3 can be suppressed through the EBG structure 5 in a one-step advancing mode, and therefore the interference noise generated based on the connector 3 can be effectively suppressed.

Among them, the plate conductive line 531 may be defined as a transmission line having a width not less than 2 times the dielectric thickness to the adjacent layer.

With reference to fig. 4 and 5, in an embodiment, in order to suppress the coupling at the far end, the near end is preferentially used as a return path, the film region 2 is further provided with an irregular microstrip flat conductive line 6 enclosed in the shielding film, and the irregular microstrip flat conductive line 6 is electrically connected to a ground grid where the ground plane is located and a power grid where the power plane is located, respectively. The irregular microstrip flat conductive line 6 may refer to a microstrip transmission line of an irregular shape, a flat plate structure. Microstrip may refer to a microwave integrated circuit transmission line formed by a metal conduction band on a dielectric substrate and a conductive ground plane on the bottom surface. The microstrip has the advantages of small volume, light weight, wide frequency band, high reliability, low cost and convenient integration. Microstrip generally has two roles: firstly, high-frequency signals can be effectively transmitted; and secondly, the signal output end and the load are well matched by forming a matching network with other solid devices such as an inductor, a capacitor and the like. The irregular microstrip flat conductive line 6 is arranged in the membrane region 2, is sealed in the shielding membrane and can shield radiation.

In an embodiment, the irregular microstrip flat conductive line 6 includes a first irregular microstrip flat conductive line 61 electrically connected to the power grid and a second irregular microstrip flat conductive line 62 electrically connected to the ground grid, and a plurality of protrusions 7 are respectively disposed on the first irregular microstrip flat conductive line 61 and the second irregular microstrip flat conductive line 62 at intervals. A plurality of projections 7 (metal material) are provided at intervals, and the effect of suppressing high-frequency noise can be improved by mutual capacitance and mutual inductance between the projections 7. In one application, the bumps 7 can be implemented with irregular traces.

In one embodiment, the position of the protrusion 7 on the first irregular microstrip flat conductive line 61 and the position of the protrusion 7 on the second irregular microstrip flat conductive line 62 are staggered. Therefore, mutual capacitance and mutual inductance can be generated between the protrusions 7 on the first irregular microstrip flat conductive line 61, mutual capacitance and mutual inductance can be generated between the protrusions 7 on the second irregular microstrip flat conductive line 62, mutual capacitance and mutual inductance can be generated between the protrusions 7 on the first irregular microstrip flat conductive line 61 and the protrusions 7 on the second irregular microstrip flat conductive line 62, and therefore the suppression effect of high-frequency noise can be better improved.

In one embodiment, the spacing distance between two adjacent protrusions 7 on the first irregular microstrip flat conductive line 61 and the second irregular microstrip flat conductive line 62 is greater than the width of the protrusions 7. This can improve the suppression effect of high-frequency noise.

The connection relationship of the irregular microstrip flat conductive line has various conditions, which are specifically described as follows:

in one case, both ends of the irregular microstrip flat conductive line 6 are electrically connected to the connector 3 and the electromagnetic bandgap structure region 4, respectively. Namely, the connector 3 is connected with the irregular microstrip flat conductive wire 6 and then connected with the electromagnetic band gap structure region 4.

In one embodiment, the first irregular microstrip flat conductive line 61 is electrically connected to the power pin of the connector 3, and the second irregular microstrip flat conductive line 62 is electrically connected to the ground pin of the connector 3.

With combined reference to fig. 4, in an embodiment, said membrane region 2 is further provided with a passive device 8 enclosed within said shielding membrane, said passive device 8 being electrically connected to said electromagnetic bandgap structure region 4. Namely, the connector 3 is connected with the irregular microstrip flat conductive wire 6, then is connected with the electromagnetic band gap structure region 4, and then is connected with the passive device 8.

The passive devices mainly comprise resistors, capacitors, inductors, converters, graduators, matching networks, resonators, filters, mixers, switches and the like; an electronic element capable of displaying its characteristics without an external power supply; the common characteristic of the two is that the circuit can work under the condition of a signal without adding a power supply.

Alternatively, one end of the irregular microstrip flat conductive line 6 is electrically connected to the electromagnetic bandgap structure region 4. One end of the irregular microstrip flat conductive wire 6 is connected with the electromagnetic band gap structure region 4.

The film region 2 is further provided with a passive device 8 enclosed in the shielding film, and the passive device 8 is electrically connected with the other end of the irregular microstrip flat conductive line 6. Namely, the other end of the irregular microstrip flat conductive wire 6 is connected with the passive device 8. The connection relationship together is: the connector 3 is connected with the electromagnetic band gap structure region 4, then connected with the irregular micro-strip flat conductive wire 6 and then connected with the passive device 8.

Or one end of the passive device 8 is electrically connected with the electromagnetic band gap structure region 4, and the other end of the passive device 8 is electrically connected with the other end of the irregular microstrip flat conductive line 6. Namely, two ends of the passive device 8 are respectively connected with the electromagnetic band gap structure region 4 and the irregular microstrip flat conductive line 6. The connection relationship together is: the connector 3 is connected with the electromagnetic band gap structure region 4, then connected with the passive device 8 and then connected with the irregular micro-strip flat conductive wire 6.

Alternatively, both ends of the passive device 8 are electrically connected to the connector 3 and the electromagnetic bandgap structure region 4, respectively. I.e. the two ends of the passive component 8 are connected to the connector 3 and the electromagnetic bandgap structure region 4, respectively. The connection relationship together is: the connector 3 is connected with a passive device 8, then is connected with the electromagnetic band gap structure region 4, and then is connected with the irregular micro-strip flat conductive wire 6.

Referring to fig. 4 and 5 in combination, in an embodiment, in order to improve the electrostatic influence and improve the transient surge voltage and surge current exceeding the stable value, a discharge structure circuit is arranged on the surface of the substrate: a Spark gap 9 (Spark-gap). I.e. the membrane region 2 is further provided with a spark gap 9 enclosed within the shielding membrane, said spark gap 9 comprising a first electrode 91 and a second electrode 92 arranged opposite each other, said first electrode 91 being arranged at the end of the power pin 31 of the connector 3 and said second electrode 92 being arranged at the end of the ground pin 32 of the connector 3.

In one embodiment, the opposite ends of the first electrode 91 and the second electrode 92 are triangular, and the vertexes of the two triangular ends are opposite.

Details of the electromagnetic bandgap structure region 4 are described in detail below.

Referring to fig. 2 and fig. 3 in combination, in an embodiment, the number of the flat conductive lines 531 of the electromagnetic bandgap structure is at least four, the power plane is electrically connected to the flat of the electromagnetic bandgap structure, at least one power hole 54 is respectively disposed at a corresponding position on the flat conductive lines 531 of the electromagnetic bandgap structure, the flat conductive lines 531 of the at least four electromagnetic bandgap structures are electrically connected to the power plane through the power holes 54, and the ground plane is respectively disposed at a corresponding position on the flat conductive lines 531 of the electromagnetic bandgap structure with at least two ground holes 55.

The number of the flat conductive wires 531 of the electromagnetic band gap structure is at least four, at least one power supply hole 54 is arranged, and the flat conductive wires 531 of the at least four electromagnetic band gap structures are electrically connected with the power supply plane through the power supply holes 54, so that on one hand, the impedance of the ground plane in the electromagnetic band gap structure area is minimum, the noise caused by the change of the return current on the return path can be reduced to the minimum, and the noise suppression effect is improved; on the other hand, at least four ports can be provided for the flat conductive lines 531 with at least four electromagnetic band gap structures, so that input and output can be flexibly changed; and the flat conductive lines 531 with at least four electromagnetic band gap structures are all on the same layer, so that the input and the output can be flexibly changed, and the additional space is not increased.

In an embodiment, the plate conductive lines 531 of at least two of the electromagnetic bandgap structures overlap with the shadow of the ground hole 55. In one application, the distance between the plate conductive line 531 of the electromagnetic bandgap structure and the ground hole 55 is not less than 75 nm.

In one embodiment, the length of the plate conductive line 531 of the electromagnetic bandgap structure is greater than or equal to a first length threshold, which is a difference between a reference length and a length error, and less than or equal to a second length threshold, which is a sum of the reference length and the length error, and the reference length is a quarter of a wavelength of the suppressed band. Therefore, the influence of a specific frequency band can be effectively inhibited, and the electromagnetic compatibility of the specific key frequency band in the connector is improved.

In one embodiment, the number of the flat conductive lines 531 of the electromagnetic bandgap structure is four, the flat conductive lines 531 of four electromagnetic bandgap structures are perpendicular to each other and form four ends, and the flat conductive lines 531 of four electromagnetic bandgap structures are electrically connected to the power plane through the four ends and the power hole 54. Thus, a bipolar winding cascade structure is formed, the suppression effect can be improved, and the input and the output can be flexibly changed without increasing extra space.

Referring to fig. 2 and 5 in combination, in one embodiment, the power plane layer 52 is provided with a clearance area 521 in the area overlapping the power pins 31 of the connector 3. The clearance area 521 may be an area without copper foil, and is used for electromagnetic isolation protection, mainly for electrostatic and surge protection in electromagnetic compatibility.

Referring to fig. 2 in combination, in an embodiment, the clearance area 521 is provided with a strip-shaped conductive line 522 bent to intersect with the flat conductive line of the electromagnetic bandgap structure; the length of the strip-shaped conductive line 522 is greater than or equal to a first length threshold value, which is a difference between a reference length and a length error, and less than or equal to a second length threshold value, which is a sum of the reference length and the length error, and the reference length is a quarter of a wavelength of a suppressed band. Therefore, the influence of a specific frequency band can be effectively inhibited, and the electromagnetic compatibility of the specific key frequency band in the connector is improved. In one application, a strip-shaped conductive line may be defined as: a transmission line having a width no greater than 1.5 times the thickness of the adjacent layer dielectric.

The suppression effect of the circuit board structure according to the embodiment of the present application will be described below by taking the circuit board structure according to the embodiment of the present application as an example for suppressing a specific frequency band. The specific frequency bands to be suppressed in this embodiment include: 900MHz-1GHz, 1.2GHz-1.7GHz, 2.3GHz-2.5GHz and 5.7GHz-5.8 GHz.

Referring to fig. 6 (small font beside the curve please ignore), the abscissa represents frequency, and the ordinate represents insertion loss (S21), i.e. insertion loss (insertion loss), expressed in dB (decibel), which may refer to the loss of load power due to the insertion of an element or device, and is expressed as the ratio (in dB) of the power received by the element or device on the load before insertion to the power received by the same load after insertion. The circuit board structure corresponding to the curve with light gray color (same size 30mmX30mm) does not have the shielding film and the conductive layer, and the circuit board structure corresponding to the curve with dark gray color (same size 30mmX30mm) is the circuit board structure of the embodiment of the present application. As can be seen from the figure, the circuit board structure of the embodiment of the application inhibits the specific frequency bands which need to be inhibited from 900MHz-1GHz, 1.2GHz-1.7GHz, 2.3GHz-2.5GHz and 5.7GHz-5.8GHz, and obtains a good inhibition effect.

Next, a comparison of Shielding Effectiveness (SE) corresponding to the material of the Shielding film is described.

Referring to fig. 7 (the small characters beside the curve are omitted), the abscissa in fig. 7 represents frequency, and the ordinate represents electric field shielding effectiveness, in dB, where the electric field shielding effectiveness can be the ratio of electric field strength or power of the shield (i.e., shielding film) after placement to electric field strength or power before placement, and then logarithmically (the larger the absolute value, the better the electric field shielding effect). Of the two curves in fig. 7, the upper curve represents the maximum barrier performance curve for conventional copper material at the same thickness (10 mmX10mm x 2mm barrier film size), and the lower curve represents the maximum barrier performance curve for nickel-plated copper material at the same thickness (10 mmX10mm x 2mm barrier film size). As can be seen from the figure, the shielding film of nickel-plated copper material has better electric field shielding effect under the same thickness.

Referring to fig. 8 (the small characters beside the curve are omitted), the abscissa in fig. 8 represents frequency, the ordinate represents magnetic shielding effectiveness, the unit is dB, the magnetic shielding effectiveness may refer to a ratio of magnetic field strength or power of the shielding body (i.e., shielding film) after and before being placed, and then the logarithm is taken (the larger the absolute value is, the better the electric field shielding effect is). Of the two curves in fig. 8, the top curve represents the maximum barrier performance curve for conventional copper material at the same thickness (barrier film size 10mmX10mm x 2mm), and the bottom curve represents the maximum barrier performance curve for nickel-plated copper material at the same thickness (barrier film size 10mmX10mm x 2 mm). As can be seen from the figure, the shielding film made of nickel-plated copper material has better magnetic field shielding effect under the same thickness.

It is to be understood that the terminology used in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

It should also be understood that the term "and/or" as used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

The above description is only for the specific embodiment of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive various equivalent modifications or substitutions within the technical scope of the present application, and these modifications or substitutions should be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A circuit board structure comprises a substrate and is characterized in that,

the substrate surface comprises a film region covered with a shielding film, and the film region is provided with a connector enclosed in the shielding film; the substrate comprises an electromagnetic band gap structure region, the electromagnetic band gap structure region is provided with an electromagnetic band gap structure, the electromagnetic band gap structure region and the film region are arranged in an up-down stacked mode, and the electromagnetic band gap structure is used for suppressing interference noise generated based on the connector.

2. The structure according to claim 1, wherein the electromagnetic bandgap structure region comprises a plurality of circuit units, each circuit unit comprises a ground plane layer, a power plane layer and a conductive layer provided with a flat conductive line of an electromagnetic bandgap structure, which are stacked, and the flat conductive line of the electromagnetic bandgap structure is electrically connected with the power plane of the power plane layer and the connector respectively;

the membrane area is also provided with an irregular microstrip flat conductor wire enclosed in the shielding membrane, and the irregular microstrip flat conductor wire is respectively and electrically connected with a ground grid where the ground plane is located and a power supply grid where the power supply plane is located.

3. The structure of claim 2, wherein the irregular microstrip flat conductive line comprises a first irregular microstrip flat conductive line electrically connected to the power grid and a second irregular microstrip flat conductive line electrically connected to the ground grid, and a plurality of protrusions are respectively disposed on the first irregular microstrip flat conductive line and the second irregular microstrip flat conductive line at intervals;

the positions of the bulges on the first irregular microstrip flat conductive wire and the positions of the bulges on the second irregular microstrip flat conductive wire are staggered;

and the spacing distance between two adjacent bulges on the first irregular microstrip flat conductive line and the second irregular microstrip flat conductive line is greater than the width of the bulges.

4. The structure of claim 2, wherein both ends of the irregular microstrip flat conductive line are electrically connected with the connector and the electromagnetic bandgap structure region, respectively;

the film region is also provided with a passive device enclosed in the shielding film, and the passive device is electrically connected with the electromagnetic band gap structure region;

the first irregular microstrip flat conductive wire is electrically connected with a power supply pin of the connector, and the second irregular microstrip flat conductive wire is electrically connected with a ground pin of the connector.

5. The structure of claim 2, wherein one end of the irregular microstrip plate conductive line is electrically connected to the electromagnetic bandgap structure region;

the film area is also provided with a passive device enclosed in the shielding film, and the passive device is electrically connected with the other end of the irregular micro-strip flat conductive wire;

6. The structure of claim 1, wherein the membrane region is further provided with a spark gap enclosed within the shielding membrane, the spark gap including oppositely disposed first and second electrodes, the first electrode being disposed at a distal end of a power pin of the connector and the second electrode being disposed at a distal end of a ground pin of the connector;

the two opposite tail ends of the first electrode and the second electrode are respectively triangular, and the vertexes of the two triangular tail ends are opposite.

7. The structure of claim 2, wherein the number of the plate conductive wires of the electromagnetic bandgap structure is at least four, the power plane and the plate conductive wires of the electromagnetic bandgap structure are respectively provided with at least one power hole at a corresponding position, the plate conductive wires of the at least four electromagnetic bandgap structures are electrically connected to the power plane through the power holes, and the ground plane and the plate conductive wires of the electromagnetic bandgap structure are respectively provided with at least two ground holes at corresponding positions.

8. The structure of claim 7, wherein the flat plate conductive lines of at least two of said electromagnetic bandgap structures overlap with the shadow of said ground via;

the length of the flat conductive line of the electromagnetic band gap structure is greater than or equal to a first length threshold value and less than or equal to a second length threshold value, the first length threshold value is the difference between a reference length and a length error, the second length threshold value is the sum of the reference length and the length error, and the reference length is one quarter of the wavelength of the suppressed frequency band;

the number of the flat conductive wires of the electromagnetic band gap structure is four, the flat conductive wires of the four electromagnetic band gap structures are perpendicular to each other and form four tail ends, and the flat conductive wires of the four electromagnetic band gap structures are electrically connected with the power plane through the four tail ends and the power hole.

9. The structure according to claim 1, characterized in that said shielding film is obtained by means of plating, said shielding film comprising a material having a permeability greater than 1 and a metallic material.

10. The structure of claim 2, wherein said power plane layer is provided with a clearance area in an area overlapping a power pin of said connector;

the clearance area is provided with a bent strip-shaped conductive wire which is crossed with the flat conductive wire of the electromagnetic band gap structure; the length of the strip-shaped conductive line is greater than or equal to a first length threshold value and less than or equal to a second length threshold value, the first length threshold value is the difference between a reference length and a length error, the second length threshold value is the sum of the reference length and the length error, and the reference length is one quarter of the wavelength of the suppressed frequency band.