Printed circuit board, electromagnetic band gap structure and electromagnetic band gap structure design method

Abstract

The embodiment of the invention provides a printed circuit board, an electromagnetic band gap structure and an electromagnetic band gap structure design method, and the printed circuit board comprises a power supply layer plane; the electromagnetic band gap structure is distributed on the plane of the power supply layer, the shape of the electromagnetic band gap structure is a regular hexagon, a group of cross-shaped channels are embedded in the electromagnetic band gap structure, and the cross-shaped channels in the group of cross-shaped channels are hollowed slotted hole channels. And a capacitance effect is generated between adjacent cross-shaped channels in the group of cross-shaped channels. According to the invention, the problem of poor noise suppression effect of an EBG structure in the prior art is solved.

Description

Technical Field

[0001] The present application relates to the technical field of electronic equipment, and in particular to a printed circuit board, an electromagnetic bandgap structure, and an electromagnetic bandgap structure design method. Background Art

[0002] In high-speed digital circuit design, signal integrity is crucial, as it is related to the correct transmission of data and the stability of system performance. As signal transmission speed increases, signals may be affected by a variety of interference factors during transmission, such as signal ringing, reflection, crosstalk, switching noise, etc. These interferences may eventually cause signal distortion and affect the normal operation of the system. In order to maintain signal integrity, a series of measures need to be taken to reduce the impact of noise and interference.

[0003] In order to suppress the influence of noise signals, a linear channel EBG structure can be used in the related technology to construct a high impedance circuit to block the propagation of electromagnetic waves and thus suppress noise. However, the above-mentioned traditional linear channel EBG structure has limited effect in suppressing ground bounce noise in high-frequency digital circuits, especially its bandwidth and stop band depth are insufficient, and the noise still has a certain diffusion.

[0004] It can be seen that the EBG structure in the related art has the problem of poor noise suppression effect. Summary of the invention

[0005] The embodiments of the present application provide a printed circuit board, an electromagnetic bandgap structure and an electromagnetic bandgap structure design method, so as to at least solve the problem that the EBG structure in the related art has a poor noise suppression effect.

[0006] According to one aspect of an embodiment of the present application, a printed circuit board is provided, comprising: a power layer plane; and an electromagnetic band gap structure distributed on the power layer plane, wherein the electromagnetic band gap structure is in the shape of a regular hexagon, and a group of cross-shaped channels are embedded in the electromagnetic band gap structure, wherein the cross-shaped channels in the group of cross-shaped channels are hollowed-out slot channels, and a capacitance effect is generated between adjacent cross-shaped channels in the group of cross-shaped channels.

[0007] According to another aspect of an embodiment of the present application, an electromagnetic band gap structure is also provided, wherein the shape of the electromagnetic band gap structure is a regular hexagon; a group of cross-shaped channels are embedded in the electromagnetic band gap structure, wherein the cross-shaped channels in the group of cross-shaped channels are hollowed-out slot channels, and a capacitance effect is generated between adjacent cross-shaped channels in the group of cross-shaped channels.

[0008] According to another aspect of the embodiments of the present application, a method for designing an electromagnetic band gap structure is also provided, wherein a regular hexagonal electromagnetic band gap structure is formed on a power layer plane of a printed circuit board; a designated position of the electromagnetic band gap structure is hollowed out to form an embedded slot channel to obtain a group of cross-shaped channels, wherein a capacitive effect is generated between adjacent cross-shaped channels in the group of cross-shaped channels.

[0009] In an embodiment of the present application, a regular hexagonal EBG structure with a cross-shaped slot channel embedded in the power supply layer of the printed circuit board is designed, wherein a capacitance effect is generated between adjacent cross-shaped channels in the cross-shaped channel. Compared with a linear EBG structure, the capacitance effect can be enhanced, thereby increasing the bandwidth and improving the stop band depth, thereby achieving the technical effect of increasing the bandwidth of noise suppression and increasing the stop band depth, thereby solving the problem of poor noise suppression effect of the EBG structure in the related art. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a schematic structural diagram of an optional electromagnetic bandgap structure according to an embodiment of the present application;

[0011] Figure 2 is a schematic diagram of an optional equivalent circuit model according to an embodiment of the present application;

[0012] Figure 3 is a schematic structural diagram of an optional electromagnetic bandgap structure of a linear channel according to an embodiment of the present application;

[0013] Figure 4 is a schematic diagram of another optional equivalent circuit model according to an embodiment of the present application;

[0014] Figure 5 is a schematic structural diagram of an optional printed circuit board according to an embodiment of the present application;

[0015] Figure 6 is a schematic diagram of an optional cross-shaped channel according to an embodiment of the present application;

[0016] Figure 7 is a schematic diagram of another optional cross-shaped channel according to an embodiment of the present application;

[0017] Figure 8 is a schematic diagram of an optional hexagonal channel according to an embodiment of the present application;

[0018] Fig. 9 is a schematic diagram of an optional electromagnetic band gap structure according to an embodiment of the present application;

[0019] Fig.10 is a schematic structural diagram of another optional printed circuit board according to an embodiment of the present application;

[0020] Fig.11 is a schematic diagram of an optional simulation result according to an embodiment of the present application;

[0021] Fig.12 It is a flow chart of an optional electromagnetic bandgap structure design method according to an embodiment of the present application. DETAILED DESCRIPTION

[0022] The embodiments of the present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0023] It should be noted that the terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0024] According to one aspect of an embodiment of the present application, a printed circuit board is provided, on which an electromagnetic bandgap structure may be integrated, and the electromagnetic bandgap structure may be a metal sheet, which has the characteristic of effectively blocking surface currents, so that its electromagnetic waves are attenuated and not easy to propagate. In recent years, with the increase in the speed of high-frequency digital circuits, signals are more susceptible to interference during transmission. Therefore, it is crucial to ensure the integrity of the signal. When the signal is transmitted from the transmitting end to the receiving end, the waveform may be interfered and damaged, resulting in distortion of the received signal. Factors affecting signal integrity may include signal timing problems, signal ringing, signal reflection, near-end and far-end crosstalk, switch noise, ground bounce and power rebound, attenuation, capacitive load, electromagnetic radiation, battery interference, etc. It can be seen that reducing noise is an effective way to maintain signal integrity.

[0025] At present, smart products are gradually developing towards high speed, miniaturization and low voltage. Especially when the chip speed in high-performance servers is getting faster and faster, the impact of ground bounce noise (GBN) on the system is becoming more and more significant, and suppressing the GBN effect is becoming more and more important.

[0026] The electromagnetic bandgap structure was originally developed from the high impedance surface (HIS), and was initially used in antenna design. Later, its application range became wider and wider. The original structure of the electromagnetic bandgap structure was composed of a square metal patch and a via grounding. The geometric structure was arranged in a periodic manner, and the metal patch and the grounding layer were filled with dielectric material. Through the changes in this three-layer structure, this structure can produce an omnidirectional cutoff band in a specific frequency band to prevent the propagation of electromagnetic waves. Its overall structure is as follows: Figure 1 shown.

[0027] The lumped element circuit based on the electromagnetic bandgap structure (Lumped Element Circuit) shows how the electromagnetic bandgap structure blocks the propagation of electromagnetic waves. Figure 2 is the equivalent circuit model of the HIS structure. The circuit type formed is an LC parallel circuit, in which the capacitance value (C) is generated between the two metal patches (Patch), and the inductance value (L) is generated by the metal patch, the via and the ground layer respectively. The working principle of the above equivalent circuit is shown in formula (1):

[0028]

[0029] Among them, Zin refers to the impedance of the circuit; j refers to an imaginary unit, that is, ω refers to the angular frequency, the unit is radians per second; L refers to the inductance in the circuit; C refers to the capacitance in the circuit; a and t are auxiliary parameters introduced in the derivation process, which are used to represent a specific frequency in the circuit; the " / / " symbol represents parallel connection, that is, jωL in formula (1) calculates the impedance of the inductor, What is calculated is the impedance of the capacitor, and the entire formula calculates the total impedance of an inductor and a capacitor in parallel. After simplification and derivation, a resonant frequency can be obtained. Under the resonant frequency condition, the impedance of the inductor and the impedance of the capacitor in the circuit are equal and opposite, and the total impedance of the circuit reaches its maximum value, which theoretically tends to infinity.

[0030] From formula (1), we can see that when this equivalent circuit produces a resonance effect (Resonance), it is equivalent to a high-impedance propagation path, and the signal is not easy to propagate. Therefore, the electromagnetic bandgap structure will produce a cutoff frequency band for the frequency band of the electromagnetic wave, and the center frequency of the cutoff frequency band is also the resonant frequency fre of this equivalent circuit. s , its value can be obtained by formula (2):

[0031]

[0032] Through the above formula (2), we can understand how the HIS structure blocks the propagation of electromagnetic waves. The above structure was initially used only in antenna design, and its structural principle can be applied to PCB (Printed Circuit Board) to achieve the effect of suppressing noise. In order to increase the bandwidth of noise suppression and reduce the production cost, it is necessary to improve the design and construction of the above structure, so as to produce a variety of different types of electromagnetic bandgap structural forms.

[0033] According to the type of PCB application, the EBG structure can be divided into multiple types. In this embodiment, the design is based on the coplanar EBG structure, and its structure is to make regular shape cuts only on the power plane. The following first describes a basic structure, and then extends the design of a new structure for the coplanar channel structure to achieve better bandwidth and noise suppression effects.

[0034] Figure 3 is an example of a linear channel electromagnetic bandgap structure, and its noise suppression working principle can be explained by Figure 4 The equivalent circuit model shown is used to illustrate this. Figure 4 As shown in the figure, the equivalent circuit includes an inductor (L) and three capacitors (C1, C2 and C3), and the corresponding impedance is Z0. The parallel circuit formed by the inductor (L) and the capacitor (C1) of the above equivalent circuit will produce a resonance effect under a specific bandwidth, and its input impedance will approach infinity. For noise, this linear channel is equivalent to a high-impedance propagation path and is not easily transmitted.

[0035] Depend on Figure 3 As shown in the linear channel electromagnetic bandgap structure, the benchmarks for evaluating the quality of EBG design can include the following four characteristics: noise suppression bandwidth, center frequency, stop band depth, and signal integrity (SI). When designing a new EGB structure, it is necessary to consider at least some of these four characteristics, that is, to improve at least some of the characteristics. The linear channel electromagnetic bandgap structure in the related art has limited effect on suppressing noise in high-frequency digital circuits, especially its bandwidth and stop band depth are insufficient.

[0036] In order to at least partially solve the above technical problems, the EBG structure provided in this embodiment further optimizes the bandwidth by adding a cross-shaped channel in the EBG structure for structural adjustment. Figure 5 is a schematic diagram of the structure of an optional printed circuit board according to an embodiment of the present application, such as Figure 5 As shown, the printed circuit board includes:

[0037] A power plane 51, and

[0038] An electromagnetic bandgap structure 52 is distributed on the power layer plane 51 .

[0039] The power layer plane 51 is the main way to distribute power on the printed circuit board, and can provide the required power for each component on the printed circuit board. In addition, the power layer plane 51 can also reduce resistance, increase the electromagnetic compatibility of the circuit, and improve signal integrity. The electromagnetic bandgap structure 52 is distributed on the power layer plane 51, and the number can be one or more. Here, the original power layer of the printed circuit board is used to cut the EBG structure without adding a separate power layer. The EBG structure of the power plane is equivalent to a series LC parallel high-order band rejection filter, which can achieve the effect of suppressing ground bounce noise. In addition, Figure 5 The dotted box in the figure indicates the ground plane.

[0040] The electromagnetic bandgap structure 52 is in the shape of a regular hexagon, and a group of cross-shaped channels are embedded in the electromagnetic bandgap structure 52. The number of cross-shaped channels in a group of cross-shaped channels can be set as needed (for example, according to the required impedance, etc.). The cross-shaped channels in a group of cross-shaped channels are hollowed-out slot channels, and a capacitance effect is generated between adjacent cross-shaped channels in a group of cross-shaped channels. Combined with formula (2), it can be seen that the bandwidth of the equivalent circuit will be significantly increased, and the range of noise suppression will also be wider.

[0041] Through simulation, it can be known that, unlike other EGB structures that hollow out straight channels, the EBG structure with a cross-shaped channel embedded can improve the ground bounce effect noise. If this design is used on a high-speed signal printed circuit board, the power layer interference itself can be reduced. The principle is: due to the addition of the cross configuration, the capacitance value of the equivalent circuit is increased, so that its bandwidth can be increased and the cutoff depth and center frequency can also be moved to high frequency.

[0042] The printed circuit board provided by the present embodiment includes: a power layer plane; and an electromagnetic bandgap structure distributed on the power layer plane, wherein the electromagnetic bandgap structure is in the shape of a regular hexagon, and a group of cross-shaped channels are embedded in the electromagnetic bandgap structure, wherein the cross-shaped channels in the group of cross-shaped channels are hollowed-out slot channels, and a capacitance effect is generated between adjacent cross-shaped channels in the group of cross-shaped channels, which can solve the problem of poor noise suppression effect of the EBG structure in the related art, improve the bandwidth of noise suppression, and increase the stop band depth.

[0043] In one exemplary embodiment, a set of cross-shaped channels are symmetrically distributed along a designated symmetry axis of the EBG structure and produce a zigzag metal sheet arrangement.

[0044] In this embodiment, a group of cross-shaped channels can be symmetrically distributed along a specified symmetry axis of the electromagnetic bandgap structure. Here, the shape of the electromagnetic bandgap structure is a regular hexagon, which has multiple symmetry axes, for example, three symmetry axes formed by connecting the center points of two opposite sides, and for example, three symmetry axes formed by connecting the two opposite vertices. The specified symmetry axis can be a symmetry axis formed by connecting the center points of two opposite sides, and the specified symmetry axis can be selected based on the arrangement of components on the printed circuit board.

[0045] A group of cross-shaped channels are symmetrically distributed along the designated symmetry axis of the electromagnetic band gap structure, which can form a multi-row structure, for example, a two-row structure, a three-row structure, etc. The symmetry axis of each row of cross-shaped channels can be parallel to the designated stacking axis, and the cross-shaped channels of two connected rows are staggered to produce a zigzag metal sheet arrangement.

[0046] Through this embodiment, by setting the cross-shaped channels to be symmetrically distributed along the specified symmetry axis of the electromagnetic bandgap structure and generating a sawtooth metal sheet arrangement, the capacitance of the equivalent circuit can be easily adjusted, thereby improving the flexibility of circuit setting.

[0047] In an exemplary embodiment, Figure 6 As shown, a group of cross-shaped channels includes three rows of cross-shaped channels, wherein the number of cross-shaped channels included in the middle row is one more than the number of cross-shaped channels included in the two side rows, so as to form a zigzag metal sheet arrangement with the cross-shaped channels in the two side rows. The number of cross-shaped channels in the middle row can be four, and the number of cross-shaped channels in the two side rows can be three.

[0048] Among them, the symmetry axes of the cross-shaped channels in the four cross-shaped channels located in the middle are all designated symmetry axes, and the four cross-shaped channels are arranged side by side along the direction of the designated symmetry axes. Optionally, the adjacent cross-shaped channels in the four cross-shaped channels may be connected. The symmetry axes of the cross-shaped channels in the three cross-shaped channels are all parallel to the designated symmetry axes, and the three cross-shaped channels are arranged side by side along the direction of the designated symmetry axes, and the adjacent cross-shaped channels in the three cross-shaped channels are connected or disconnected. The three cross-shaped channels on both sides of the four cross-shaped channels are symmetrically distributed with the designated symmetry axes as the symmetry axes, and the four cross-shaped channels are arranged crosswise with the three cross-shaped channels.

[0049] The channel size of each cross-shaped channel in a group of cross-shaped channels may be the same or at least partially different. The channel size of each cross-shaped channel may be set according to the structural size of the EBG structure, and the structural size of the EBG structure may be set according to the size of the printed circuit board and the impedance of the corresponding equivalent circuit. Optionally, the structure of each cross-shaped channel may have at least one of the following characteristics: the channel size of each cross-shaped channel is 5mm×5mm; the thickness of each cross-shaped channel is 2mm; the intersection of each cross-shaped channel is located at the center of each cross-shaped channel.

[0050] For example, Figure 7 As shown, the channel dimensions of the ten cross-shaped channels are all 5 mm×5 mm; the thickness of each cross-shaped channel is 2 mm; and the intersection point of each cross-shaped channel is located at the center of each cross-shaped channel.

[0051] Through this embodiment, by symmetrically arranging the cross-shaped channels and setting the channel size and shape of the corresponding cross-shaped channels, a specific EBG structure can be adapted to improve the noise suppression effect in a specific scenario.

[0052] In one exemplary embodiment, the periphery of the EBG structure is hollowed out into hexagonal channels to form a protective wall to suppress noise sources.

[0053] In this embodiment, Figure 3 In addition to changing the square EBG structure shown in the figure to a hexagonal EBG structure, the outer linear channel is changed to a hexagonal channel hollowed out at the periphery. The hollowed-out hexagonal channel makes it a protective wall, which can suppress the noise source outside and avoid signal interference. An example of a hexagonal channel can be shown as follows Figure 8 shown.

[0054] According to this embodiment, the periphery of the hexagonal EBG structure is hollowed out to form a hexagonal channel, and the hollowed-out channel portion can isolate noise, prevent interference sources from spreading out, and improve the effect of noise suppression.

[0055] In one exemplary embodiment, the length of the outer side of the hexagonal channel is 20 mm, the length of the inner side of the hexagonal channel is 16 mm, and the channel width of the hexagonal channel is 2 mm.

[0056] In this embodiment, the channel size and channel width of the hexagonal channel correspond to the structural size of the EBG structure. In this embodiment, the length of the outer side of the hexagonal channel is 20 mm, and the length of the inner side of the hexagonal channel is 16 mm. In this case, the channel width of the hexagonal channel is also related to the channel thickness, and the channel width of the hexagonal channel in this embodiment is 2 mm.

[0057] For example, Fig. 9 As shown, the outer wall of the EBG structure (outer periphery, the outside of the hexagonal channel) is a 20mm hexagon, the hollowed-out channel is 2mm wide, and the inner wall EBG metal sheet (inner side of the hexagonal channel) is a 16mm hexagon. In addition, a cross-shaped slot channel (cross-shaped channel) is added to the hexagonal EBG structure to isolate the original noise source, thereby better suppressing noise interference. The cross-shaped channel size is 5mm in length and 5mm in width. Through several cross-shaped hollowed-out channels, a serrated metal EBG arrangement can be produced, and the serrated metal blocks and adjacent metal blocks can produce a capacitive effect.

[0058] Through this embodiment, by setting the channel size of the hexagonal channel, a specific EBG structure can be adapted to improve the noise suppression effect in a specific scenario.

[0059] In an exemplary embodiment, the number of electromagnetic bandgap structures is seven, and the seven electromagnetic bandgap structures are concentrated on the power layer plane. The seven electromagnetic bandgap structures are centered on a designated electromagnetic bandgap structure, and the remaining six electromagnetic bandgap structures are evenly arranged around the designated electromagnetic bandgap structure and have an adjacent edge with the designated electromagnetic bandgap structure.

[0060] In order to save the design space of the printed circuit board and reduce the cost, the electromagnetic bandgap structure can be directly designed on the printed circuit board. In this embodiment, by distributing multiple electromagnetic bandgap structures with embedded cross-shaped slot channels on the printed circuit board, the corresponding area on the printed circuit board can be covered to suppress the propagation of electromagnetic waves in the area. The multiple electromagnetic bandgap structures cut out on the printed circuit board can be independent or interconnected, and the layout of the electromagnetic bandgap structure unit can be adjusted as needed.

[0061] Optionally, seven electromagnetic band gap structures can be designed on the power layer plane on the printed circuit board, with a designated electromagnetic band gap structure as the center, and the remaining six electromagnetic band gap structures are evenly arranged around the executed electromagnetic band gap structure and have an adjacent edge with the designated electromagnetic band gap structure, thereby forming a uniform electromagnetic field distribution, improving the noise suppression effect, and avoiding the generation of gaps and local resonance points caused by uneven distribution, such as Fig.10 shown.

[0062] Optionally, with any one of the seven EBG structures as the center, EBG structures can be further designed outward, and the added EBG structures can still be evenly distributed around the newly designated EBG structure and have an adjacent edge, thereby increasing the number of EBG structures as needed.

[0063] For example, the hexagonal EBG structure can be concentrated on the power layer, and the original power layer plane can be used to cut the EBG structure without adding a separate power layer.

[0064] According to this embodiment, by distributing at least seven EBG structures on the power layer plane, the EBG structure can be cut conveniently, thereby improving the efficiency of cutting the EBG structure.

[0065] In this embodiment, a simulation analysis is performed on the loss difference between the EBG structure with a cross-shaped channel and the EBG structure with a straight channel. The simulation results are shown in FIG. Fig.11 As shown by Fig.11 From the simulation results, it can be seen that the embedded cross-shaped channel has a longer channel length than the straight channel. Therefore, the capacitance generated through the adjacent serrated metal sheets will be better. According to formula (2), if the capacitance increases, the bandwidth generated will also increase, and the cutoff depth of noise suppression will also deepen.

[0066] Depend on Fig.11 The simulation results show that the bandwidth range of the EBG structure with an embedded cross-shaped channel has increased significantly, from about 1GHz to 10GHz, the bandwidth has increased by about 9GHz, and the cutoff depth has also increased to about -90dB. In addition, due to the addition of an embedded cross-shaped channel in the middle of the EBG structure, its capacitance has also increased, which has a better effect of suppressing noise bandwidth.

[0067] Through the design of the EBG structure with a cross-shaped channel embedded in the power layer in this embodiment, the influence of the ground bounce effect in the power plane on the signal quality and electromagnetic radiation can be effectively suppressed. Compared with the EBG structure with a straight channel, the EBG structure with a cross-shaped channel embedded in the above structure can suppress the noise bandwidth and increase the stop band depth better, and also has a better effect on signal integrity, and can be used on a multi-layer printed circuit board; in addition, the above EBG structure can directly make channel cutting in the power layer to increase the number of cells without adding an additional power layer.

[0068] It should be noted that the description of the printed circuit board, EBG structure, etc. in this embodiment is described at the structural level. Some other structures or components required to form an equivalent circuit, such as winding, are not specifically shown in this embodiment. However, it cannot be considered that the possibility that the printed circuit board, EBG structure, etc. contain other structures or components is excluded in this embodiment.

[0069] According to another aspect of the embodiments of the present application, an electromagnetic bandgap structure is provided. The electromagnetic bandgap structure is the electromagnetic bandgap structure in the printed circuit board in the aforementioned embodiment. The electromagnetic bandgap structure has been described above and will not be described again here.

[0070] In this embodiment, the shape of the electromagnetic band gap structure is a regular hexagon; a group of cross-shaped channels are embedded in the electromagnetic band gap structure, wherein the cross-shaped channels in the group of cross-shaped channels are hollowed-out slot channels, and a capacitance effect is generated between adjacent cross-shaped channels in the group of cross-shaped channels.

[0071] The arrangement and size of the cross-shaped channel are similar to those in the above-mentioned embodiment and will not be described in detail. Optionally, the electromagnetic bandgap structure can be formed on the power layer plane of the printed circuit board or on a separate power layer plane, which is not limited in this embodiment.

[0072] Through the magnetic band gap structure provided by this embodiment, the shape of the electromagnetic band gap structure is a regular hexagon; a group of cross-shaped channels are embedded in the electromagnetic band gap structure, wherein the cross-shaped channels in a group of cross-shaped channels are hollowed-out slot channels, and a capacitance effect is generated between adjacent cross-shaped channels in a group of cross-shaped channels, which can solve the problem of poor noise suppression effect of the EBG structure in the related art, improve the bandwidth of noise suppression, and increase the stop band depth.

[0073] In one exemplary embodiment, the periphery of the EBG structure is hollowed out into hexagonal channels to form a protective wall to suppress noise sources.

[0074] In this embodiment, the periphery of the electromagnetic band gap structure is hollowed out into a hexagonal channel, which can form a protective wall to suppress noise sources. The channel size of the hexagonal channel can be similar to that in the aforementioned embodiment, which is not described in detail here.

[0075] According to this embodiment, the periphery of the hexagonal EBG structure is hollowed out to form a hexagonal channel, and the hollowed-out channel portion can isolate noise, prevent interference sources from spreading out, and improve the effect of noise suppression.

[0076] According to another aspect of the embodiments of the present application, a design method of an electromagnetic bandgap structure is provided. The design method of the electromagnetic bandgap structure can be applied to implement the printed circuit board or the electromagnetic bandgap structure in the aforementioned embodiments. The description of the printed circuit board or the electromagnetic bandgap structure has been explained and will not be repeated here.

[0077] Fig.12 is a flow chart of an optional electromagnetic bandgap structure design method according to an embodiment of the present application, such as Fig.12 As shown, the method comprises the following steps:

[0078] Step S1202, forming a regular hexagonal electromagnetic band gap structure on the power layer plane of the printed circuit board;

[0079] Step S1204 , hollowing out the designated position of the electromagnetic bandgap structure to form an embedded slot channel, thereby obtaining a group of cross-shaped channels, wherein a capacitance effect is generated between adjacent cross-shaped channels in the group of cross-shaped channels.

[0080] The design method of the electromagnetic bandgap structure in this embodiment can be to form the aforementioned electromagnetic bandgap structure on the power layer plane of an existing printed circuit board, or it can be applied to the preparation process of the printed circuit board, that is, as a part of the preparation process of the printed circuit board. When forming a regular hexagonal electromagnetic bandgap structure, the power layer plane can be cut to obtain the desired electromagnetic bandgap structure. At this time, the cross-shaped channel inside the electromagnetic bandgap structure has not yet been formed. Here, the thickness of the power layer plane can be adjusted as needed to adapt to the needs of cutting the electromagnetic bandgap structure.

[0081] The formed regular hexagonal electromagnetic band gap structure can be hollowed out at a designated position of the electromagnetic band gap structure to form an embedded slot channel to obtain a group of cross-shaped channels. The channel size of the cross-shaped channels can be pre-configured as needed, and a capacitance effect will be generated between adjacent cross-shaped channels in the formed group of cross-shaped channels.

[0082] Through the above steps, a regular hexagonal electromagnetic bandgap structure is formed on the power layer plane of the printed circuit board; the electromagnetic bandgap structure is hollowed out at a designated position to form an embedded slot channel, thereby obtaining a group of cross-shaped channels, wherein a capacitance effect is generated between adjacent cross-shaped channels in a group of cross-shaped channels, thereby solving the problem of poor noise suppression effect of the EBG structure in the related art, improving the bandwidth of noise suppression, and increasing the stop band depth.

[0083] In an exemplary embodiment, after forming a regular hexagonal EBG structure on the power layer plane of the printed circuit board, the method further includes: hollowing out the periphery of the EBG structure into a hexagonal channel according to a specified size to form a protective wall for suppressing noise sources.

[0084] In this embodiment, the periphery of the electromagnetic band gap structure is hollowed out into a hexagonal channel, and the hexagonal channel can form a protective wall to suppress the noise source, and the channel size of the hexagonal channel can be similar to that in the aforementioned embodiment, which is not described in detail here. Correspondingly, when preparing the electromagnetic band gap structure, the periphery of the electromagnetic band gap structure can be hollowed out into a hexagonal channel according to a specified size (here, it can be the channel size of the hexagonal channel) to form a protective wall to suppress the noise source. The timing of hollowing out the periphery of the electromagnetic band gap structure can be after the electromagnetic band gap structure is formed, or after a group of cross-shaped channels are formed, which is not limited in this embodiment.

[0085] According to this embodiment, the periphery of the hexagonal EBG structure is hollowed out to form a hexagonal channel, and the hollowed-out channel portion can isolate noise, prevent interference sources from spreading out, and improve the effect of noise suppression.

[0086] The above are only preferred embodiments of the present application and are not intended to limit the embodiments of the present application. For those skilled in the art, the embodiments of the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the principles of the embodiments of the present application shall be included in the protection scope of the embodiments of the present application.

Claims

1. A printed circuit board, It is characterized in that include: Power planes; and, An electromagnetic bandgap structure distributed on the plane of the power layer, wherein the shape of the electromagnetic bandgap structure is a regular hexagon, a group of cross-shaped channels are embedded in the electromagnetic bandgap structure, the cross-shaped channels in the group of cross-shaped channels are hollowed-out slot channels, and a capacitance effect is generated between adjacent cross-shaped channels in the group of cross-shaped channels.

2. The printed circuit board according to claim 1, It is characterized in that The set of cross-shaped channels are symmetrically distributed along a designated symmetry axis of the electromagnetic bandgap structure and produce a zigzag metal sheet arrangement.

3. The printed circuit board according to claim 2, It is characterized in that The group of cross-shaped channels includes four cross-shaped channels located in the middle and three cross-shaped channels located on both sides of the four cross-shaped channels, wherein: The symmetry axes of the cross-shaped channels in the four cross-shaped channels are all the designated symmetry axes, the four cross-shaped channels are arranged side by side along the direction of the designated symmetry axes, and the adjacent cross-shaped channels in the four cross-shaped channels are connected; The symmetry axes of the cross-shaped channels in the three cross-shaped channels are all parallel to the designated symmetry axis, the three cross-shaped channels are arranged side by side along the direction of the designated symmetry axis, and the adjacent cross-shaped channels in the three cross-shaped channels are connected or disconnected; The three cross-shaped channels on both sides of the four cross-shaped channels are symmetrically distributed with the designated symmetry axis as the symmetry axis, and the four cross-shaped channels are arranged crosswise with the three cross-shaped channels; Wherein, the structure of each cross-shaped channel in the group of cross-shaped channels has at least one of the following features: The size of each cross-shaped channel is 5mm×5mm; The thickness of each cross-shaped channel is 2 mm; The intersection point of each cross-shaped channel is located at the center position of each cross-shaped channel.

4. The printed circuit board according to claim 1, It is characterized in that The periphery of the electromagnetic bandgap structure is hollowed out into a hexagonal channel to form a protective wall to suppress noise sources.

5. The printed circuit board according to claim 4, It is characterized in that The length of the outer side of the hexagonal channel is 20 mm, the length of the inner side of the hexagonal channel is 16 mm, and the channel width of the hexagonal channel is 2 mm.

6. The printed circuit board according to any one of claims 1 to 5, It is characterized in that The number of the electromagnetic band gap structures is seven, and the seven electromagnetic band gap structures are concentrated on the power layer plane. The seven electromagnetic band gap structures are centered on a designated electromagnetic band gap structure, and the remaining six electromagnetic band gap structures are evenly arranged around the designated electromagnetic band gap structure and have an adjacent edge with the designated electromagnetic band gap structure.

7. An electromagnetic bandgap structure, It is characterized in that The shape of the electromagnetic band gap structure is a regular hexagon; A group of cross-shaped channels are embedded in the electromagnetic bandgap structure, wherein the cross-shaped channels in the group of cross-shaped channels are hollowed-out slot channels, and a capacitance effect is generated between adjacent cross-shaped channels in the group of cross-shaped channels.

8. The electromagnetic bandgap structure according to claim 7, It is characterized in that The periphery of the electromagnetic bandgap structure is hollowed out into a hexagonal channel to form a protective wall to suppress noise sources.

9. A design method for an electromagnetic bandgap structure, It is characterized in that A regular hexagonal electromagnetic band gap structure is formed on a power layer plane of a printed circuit board; A designated position of the electromagnetic band gap structure is hollowed out to form an embedded slot channel, thereby obtaining a group of cross-shaped channels, wherein a capacitance effect is generated between adjacent cross-shaped channels in the group of cross-shaped channels.

10. The method according to claim 9, It is characterized in that After forming a regular hexagonal electromagnetic bandgap structure on the power layer plane of the printed circuit board, the method further comprises: The periphery of the electromagnetic band gap structure is hollowed out into a hexagonal channel according to a specified size to form a protective wall for suppressing noise sources.

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