Electromagnetic band gap structure and circuit board

Abstract

The invention discloses an electromagnetic band gap structure and a circuit board, and is applied to the field of high-frequency circuits. The signal connecting line is connected with the central part and extends along the direction far away from the central part; the metal wires are located on the periphery of the central part, the metal wires and the signal connecting wires are distributed at intervals, the two ends of each metal wire are connected with the central part, and a shielding groove is formed between each metal wire and the central part. According to the electromagnetic band gap structure provided by the invention, the cut-off frequency depth increase of noise is inhibited, the grounding bounce effect of the power supply layer can be effectively inhibited, and the effect of the grounding bounce effect on signal quality and electromagnetic radiation is further reduced; the shielding groove can prevent a signal interference source from diffusing, so that the integrity of signal transmission is ensured.

Description

Technical Field

[0001] The invention relates to the field of high-frequency circuits, and in particular to an electromagnetic bandgap structure and a circuit board. Background Art

[0002] In recent years, in high-frequency digital circuits, as the signal transmission speed is getting faster and faster, the signal will be interfered by many factors during the transmission process. At this time, the integrity of the signal is particularly important. When the signal is transmitted from the transmitter to the receiver, the waveform may be interfered and damaged, resulting in distortion of the received signal. The influencing factors 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., so reducing noise is the best way to maintain the signal.

[0003] In related technologies, EBG (Electromagnetic Band Gap) is generally used to control the propagation of electromagnetic waves. By adjusting the size, material and shape of the scattering medium, electromagnetic waves can be prevented from propagating in certain frequency bands. There are many types of electromagnetic band gap structures in related technologies, but the bandwidth for suppressing noise is often relatively small, which will affect the integrity of signal transmission.

[0004] Therefore, how to ensure the integrity of signal transmission in high-frequency circuits is a technical problem that those skilled in the art currently need to solve. Summary of the invention

[0005] The purpose of the present invention is to provide an electromagnetic bandgap structure and a circuit board, which can effectively suppress the ground bounce effect of the power layer and ensure the integrity of signal transmission in the high-frequency circuit.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] An electromagnetic bandgap structure, comprising:

[0008] Central part;

[0009] A signal connection line connected to the central portion and extending in a direction away from the central portion;

[0010] A metal wire is located at the periphery of the central part, the metal wire and the signal connection wire are spaced apart, both ends of the metal wire are connected to the central part, and a shielding groove is formed between the metal wire and the central part.

[0011] On the other hand, the central portion is square, and each of the four sides of the central portion is connected to at least one of the signal connection lines, and the signal connection lines extend in a straight line.

[0012] On the other hand, each of the four corners of the central portion is connected with a metal wire, and the metal wire extends from one side of the corner of the central portion to the other side of the corner.

[0013] On the other hand, the metal wire is in an arc shape, and two ends of the metal wire are respectively connected to two adjacent side edges of the central part.

[0014] On the other hand, the central part is rectangular, and the center positions of the two long sides and the two short sides of the central part are each connected with a signal connection line, and the distance between the signal connection line and the adjacent metal wire is the same;

[0015] The metal wires include a first connection wire, a second connection wire, a third connection wire and a fourth connection wire connected in sequence, the first connection wire and the fourth connection wire are both connected to the central portion, the first connection wire and the fourth connection wire are respectively perpendicular to the extension direction of the side connection wires of the central portion at corresponding positions, the second connection wire is perpendicular to the first connection wire, the third connection wire is perpendicular to the second connection wire, and the fourth connection wire is perpendicular to the third connection wire;

[0016] The second connection line has the same length as the third connection line, the first connection line has a shorter length than the signal connection line at an adjacent position, and the fourth connection line has a shorter length than the signal connection line at an adjacent position; and the first connection line is connected to the short side of the central portion, the second connection line is connected to the long side of the central portion, and the first connection line has a shorter length than the second connection line;

[0017] The shielding groove is L-shaped, the first side of the shielding groove is used to form the first connecting line and the second connecting line, and the second side of the shielding groove is used to form the third connecting line and the fourth connecting line; the first side width of the shielding groove is greater than the second side width of the shielding groove.

[0018] On the other hand, the electromagnetic band gap structure is a centrosymmetric structure.

[0019] On the other hand, the line width of the signal connection line is the same as the line width of the metal line.

[0020] On the other hand, there are multiple electromagnetic bandgap structures, which are arranged in sequence in the horizontal and vertical directions to form an electromagnetic bandgap structure array; the signal connection lines at corresponding positions on adjacent electromagnetic bandgap structures are connected and conductive.

[0021] On the other hand, the electromagnetic band gap structure array is an integrated structure.

[0022] The present invention also provides a circuit board, comprising any one of the electromagnetic bandgap structures described above.

[0023] The electromagnetic bandgap structure provided by the present invention includes: a central part; a signal connection line connected to the central part and extending in a direction away from the central part; a metal wire located at the periphery of the central part, the metal wire and the signal connection line are spaced apart, both ends of the metal wire are connected to the central part, and a shielding groove is formed between the metal wire and the central part.

[0024] The electromagnetic bandgap structure provided by the present invention has the beneficial effect that: by improving the linear electromagnetic bandgap structure in the related art into an electromagnetic bandgap structure having the central part, and arranging the electromagnetic bandgap structure in the form of a metal wire on the periphery of the central part, by connecting the two ends of the metal wire to the central part, the channel length of the electromagnetic bandgap structure is extended, and the capacitance generated by the adjacent electromagnetic bandgap structure will increase, that is, the capacitance value of the equivalent circuit formed between the power layer and the ground layer having the electromagnetic bandgap structure will increase, and when the capacitance increases, the bandwidth range generated will be increased accordingly, and then the cut-off frequency depth for suppressing noise will also be increased, so that the ground bounce effect of the power layer can be effectively suppressed, thereby reducing the impact of the ground bounce effect on signal quality and electromagnetic radiation. effect; the electromagnetic bandgap structure can directly make channel cutting on the existing power layer to increase the number of electromagnetic bandgap structural units without adding an additional power layer, so as to achieve the effect of increasing capacitance, easy operation and low production cost; and, since the shielding groove is formed between the metal wire and the central part, the shielding groove is a closed groove, and the formation of the shielding groove creates a certain interval between the metal wire and the central part, thereby increasing the length of the metal wire. Since the length of the metal wire is increased, the equivalent inductance can be increased. At the same time, the setting of the shielding groove makes it a protective wall, which can suppress the noise source in the shielding groove, and can avoid the diffusion of the signal interference source, thereby ensuring the integrity of the signal transmission, and can be used on a multi-layer PCB circuit printed board.

[0025] In one embodiment, after a plurality of the electromagnetic bandgap structures are arranged in sequence in the horizontal and vertical directions, an array structure having a plurality of rows and a plurality of columns is formed, namely, an electromagnetic bandgap structure array. The electromagnetic bandgap structure array can form an equivalent circuit with the ground layer. Since the structure of the metal wire and the shielding slot is added to the electromagnetic bandgap structure, the channel length of the electromagnetic bandgap structure is extended, and the capacitance generated by the adjacent electromagnetic bandgap structure is increased, so that the cutoff frequency depth of noise suppression is also increased. Therefore, the equivalent circuit formed between the electromagnetic bandgap structure array after the array arrangement and the ground layer can also increase the capacitance. The bandwidth range is thereby increased, and the cutoff frequency depth for suppressing noise is also increased, which can effectively suppress the ground bounce effect of the power layer, thereby reducing the effect of the ground bounce effect on the signal quality and electromagnetic radiation. At the same time, through the arrangement of the signal connection line in the electromagnetic bandgap structure, after a plurality of the electromagnetic bandgap structures are arranged to form the electromagnetic bandgap structure array, adjacent electromagnetic bandgap structures can be connected and conducted through the signal connection line, which is convenient for processing. At the same time, the electromagnetic bandgap structure array can be processed on the same metal plate, and adjacent electromagnetic bandgap structures can be integrated through the signal connection line, which is convenient for processing and has high strength.

[0026] The circuit board provided by the present invention is provided with the above-mentioned electromagnetic bandgap structure. Since the electromagnetic bandgap structure has the above-mentioned technical effects, the circuit board provided with the electromagnetic bandgap structure should also have corresponding technical effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the drawings required for use in the embodiments or related technical descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 It is a structural schematic diagram of an electromagnetic bandgap structure in the related art;

[0029] Figure 2 An equivalent circuit model of a high impedance surface structure in the related art;

[0030] Figure 3 A schematic diagram of a linear channel electromagnetic bandgap structure in the related art;

[0031] Figure 4 is an equivalent circuit model of a linear channel structure in the related art;

[0032] Figure 5A schematic structural diagram of a specific implementation mode of the electromagnetic bandgap structure provided by the present invention;

[0033] Figure 6 for Figure 5 A schematic diagram of the structure after the electromagnetic band gap structure is formed into an array;

[0034] Figure 7 A schematic structural diagram of another specific implementation mode of the electromagnetic bandgap structure provided by the present invention;

[0035] Figure 8 for Figure 7 A schematic diagram of the structure after the electromagnetic band gap structure is formed into an array;

[0036] Fig. 9 This is a schematic diagram of the position structure of the power layer and the ground layer in the circuit board provided by the present invention;

[0037] Fig.10 The figure is a comparison diagram of simulation results of the electromagnetic bandgap structure provided by the present invention and the electromagnetic bandgap structure in the related art.

[0038] Reference numerals:

[0039] Power layer 100 ; electromagnetic bandgap structure 110 ; central portion 111 ; signal connection line 112 ; metal line 113 ; first connection line 1131 ; second connection line 1132 ; third connection line 1133 ; fourth connection line 1134 ; shielding slot 114 ; connecting column 200 ; grounding layer 300 . DETAILED DESCRIPTION

[0040] The core of the present invention is to provide an electromagnetic bandgap structure 110 and a circuit board, which can effectively suppress the diffusion of noise sources, ensure the integrity of signal transmission, and significantly increase the cutoff frequency depth of noise suppression.

[0041] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] As technology products develop towards high speed, small size, low voltage, etc., especially when high-performance servers are getting faster and faster, the GBN (Ground Bounce Noise) effect has an increasingly significant impact on the system, and it is very important to suppress the GBN effect. The PBG (Photonic band-gap) structure is used to make the power plane 100 (Power Plane) and the complete ground plane (Ground Plane) form a parallel plate waveguide structure, referred to as EBG (Electromagnetic Band-Gap, electromagnetic band gap structure 110), EBG is a periodic structure that can control the propagation of electromagnetic waves. By adjusting the size, material and shape of the scattering medium, electromagnetic waves can be prevented from propagating in certain frequency bands; the EBG structure of the power layer 100 is equivalent to a series LC circuit, and a high-order band rejection filter is connected in parallel to achieve the effect of suppressing the ground bounce noise GBN effect; the series LC circuit, that is, the LC series resonant circuit, is a circuit composed of an inductor (L) and a capacitor (C) in series; the high-order band rejection filter, also known as a high-order band stop filter or a high-order notch filter, is a frequency selective circuit that can block or at least severely attenuate the frequency band within two cut-off frequency points; the following are some key characteristics and applications of the series LC circuit:

[0043] The name of the electromagnetic energy gap structure was originally developed from HIS (High Impedance surface), and was mostly used in antenna design at the time. The characteristic of this special structure is that it can effectively block surface currents so that its electromagnetic waves are attenuated and not easy to propagate. Its original structural form is composed of a square metal sheet (Patch) plus a connecting column 200 (Via) grounded. The geometric structure formed by the side-by-side combination is arranged in a periodic manner, and the metal sheet and the grounding layer 300 are filled with dielectric material; through the changes in the three-layer structure, this structure will 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.

[0044] The way in which this structure can block the propagation of electromagnetic waves can be seen through the use of lumped element circuits; Figure 2 As shown in the figure, it is the equivalent circuit model of HIS structure. The high impedance surface is as follows in the equivalent circuit: Figure 2As shown in the middle A area, 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 connecting column 200 and the grounding layer 300 respectively; when this equivalent circuit produces a resonance effect, it is equivalent to a high impedance propagation path, so it is not easy to propagate. Therefore, it can be found that it will produce a cutoff band for the frequency band of electromagnetic waves, and the center frequency on the cutoff band is the resonant frequency of this equivalent circuit. This structure is usually only used in antenna design at the beginning. Later, the principle of this structure can be used on PCB printed circuit boards to achieve noise suppression. It has been confirmed through research that it does have a good noise suppression effect. Its main purpose is to increase the bandwidth of noise suppression and reduce the production cost. Therefore, many different types of electromagnetic energy gap structure types have been produced so far.

[0045] According to the type of EBG structure applied on the PCB, it can be divided into many types. This article introduces the design of the linear channel electromagnetic energy gap (Coplanar EBG) structure. Its structure is to make regular shape cuts only on the power layer 100. Figure 3 As shown, Figure 3 is a schematic diagram of a linear channel electromagnetic bandgap structure 110, and its noise suppression working principle can be explained through its equivalent circuit model, such as Figure 4 As shown, Figure 4 The equivalent circuit model of the linear channel structure is mainly a parallel circuit formed by inductance (L) and capacitance (C1). Under a specific bandwidth, a resonance effect will occur, and its input impedance will approach infinity. Figure 4 The capacitance (C2) shown in the figure refers to the capacitance formed between the power layer 100 and the ground layer 300. The equivalent capacitance generated by stacking two layers of circuit boards can be imagined as the C2 capacitance generated by stacking two metal layers. Therefore, for noise, this linear channel is equivalent to a high-impedance propagation path, so noise is not easily transmitted.

[0046] Through the structural analysis of the previous linear channel, it can be found that the impact of EBG structure design focuses on: 1. Noise suppression bandwidth, 2. Center frequency, 3. Cutoff frequency depth, 4. Signal integrity (SI). These four characteristics are used as the basis for judgment. Therefore, these four characteristics must be considered when designing a new structure. However, the results of the previous linear channel coplanar structure showed that the first three characteristics have been greatly improved, and only the signal integrity is affected by the gap between the basic unit and the gap between the central body of the channel, which causes the incompleteness of the power plane. Therefore, it is considered to design and develop a new structure to increase the noise suppression bandwidth in exchange for signal integrity. In the past, the structure of the relevant technology was to hollow out the linear channel, but the simulation results showed that the signal integrity was affected to some extent, so different EBG structures were tried to improve the integrity of signal transmission.

[0047] In this embodiment, please refer to Figure 5 and Figure 6 , the electromagnetic bandgap structure 110 comprises:

[0048] Central part 111;

[0049] A signal connection line 112 connected to the central portion 111 and extending in a direction away from the central portion 111;

[0050] The metal wire 113 is located at the periphery of the central portion 111 . The metal wire 113 and the signal connection wire 112 are spaced apart. Both ends of the metal wire 113 are connected to the central portion 111 , and a shielding groove 114 is formed between the metal wire 113 and the central portion 111 .

[0051] Specifically, the central part 111, the signal connection line 112 and the metal wire 113 can be cut and processed by metal plate. The signal connection line 112 and the metal wire 113 should have a certain width. For example, the width of the signal connection line 112 and the metal wire 113 is 1.5-2.5mm, that is, the signal connection line 112 and the metal wire 113 should also be plate-shaped. The signal connection line 112 and the metal wire 113 and the central part 111 together constitute a metal sheet of the electromagnetic band gap structure 110.

[0052] The electromagnetic bandgap structure 110 is improved from the linear electromagnetic bandgap structure 110 in the related art to an electromagnetic bandgap structure 110 having a central portion 111, and a metal wire 113 is arranged on the periphery of the central portion 111. By connecting the two ends of the metal wire 113 to the central portion 111, the channel length of the electromagnetic bandgap structure 110 is extended, and the capacitance generated by the adjacent electromagnetic bandgap structures 110 is increased. In other words, the capacitance value of the equivalent circuit formed between the power layer 100 and the ground layer 300 having the electromagnetic bandgap structure 110 is increased. When the capacitance is increased, the bandwidth range generated is increased accordingly, and the cut-off frequency depth of noise suppression is also increased, so that the ground bounce effect of the power layer 100 can be effectively suppressed, thereby reducing the effect of the ground bounce effect on the signal quality and electromagnetic radiation; The electromagnetic bandgap structure 110 can directly make channel cutting on the existing power layer 100 to increase the number of electromagnetic bandgap structure 110 units without adding additional power layers 100, so as to achieve the effect of increasing capacitance, which is easy to operate and has low production cost. In addition, since a shielding groove 114 is formed between the metal wire 113 and the central part 111, the shielding groove 114 is a closed groove. The formation of the shielding groove 114 creates a certain interval between the metal wire 113 and the central part 111, thereby increasing the length of the metal wire 113. Since the length of the metal wire 113 is increased, the equivalent inductance can be increased. At the same time, the setting of the shielding groove 114 makes it a protective wall, which can suppress the noise source in the shielding groove 114, and can prevent the signal interference source from spreading, thereby ensuring the integrity of signal transmission, and can be used on a multi-layer PCB circuit printed board.

[0053] In some embodiments, the central portion 111 is square, for example, a rectangular structure, the length of the central portion 111 is 23-27 mm, and can be 25 mm, and the width can be set as needed. The four sides of the central portion 111 are each connected to at least one signal connection line 112, and the signal connection line 112 extends in a straight line. Specifically, the signal connection line 112 extends in a direction away from the side of the central portion 111. In order to facilitate the connection and conduction between adjacent central portions 111 and reduce the length of the signal connection line 112, the extension direction of the signal connection line 112 can be perpendicular to the central portion The side extension direction of the corresponding position on 111 is set in this way. After the two adjacent electromagnetic band gap structures 110 are turned on, the signal connection lines 112 on the two electromagnetic band gap structures 110 can be easily connected and turned on, and the processing is more convenient; of course, if conditions permit, the extension direction of the signal connection line 112 can also be set obliquely relative to the side extension direction of the corresponding position on the central part 111. It should be noted that the positions of the signal connection lines 112 on the two adjacent electromagnetic band gap structures 110 should correspond to each other to ensure that the two adjacent electromagnetic band gap structures 110 can be smoothly turned on and the reliability of signal transmission is ensured.

[0054] In some embodiments, each of the four corners of the central portion 111 is connected to a metal wire 113, and the metal wire 113 extends from one side of the corner of the central portion 111 to the other side of the corner. Specifically, Figure 5 As shown, by setting a metal wire 113 at each of the four corners of the central part 111, the channel length of the metal sheet formed by the central part 111 and the metal wires 113 at the four corners is longer than the distance of the straight channel, and the capacitance generated by the adjacent electromagnetic bandgap structure 110 metal sheet will be better. When the capacitance increases, the bandwidth generated will be longer, and the cutoff frequency depth (Cutoff Frequency) for suppressing noise will also be deeper.

[0055] In some embodiments, please refer to Figure 7 and Figure 8 , the metal wire 113 is in an arc shape, and the two ends of the metal wire 113 are respectively connected to the two adjacent sides of the central part 111; specifically, the metal wire 113 can extend in an arc shape, and a shielding groove 114 is formed between the arc-shaped metal wire 113 and the central part 111, which can also suppress the noise source and reduce the generation of signal interference sources; specifically, the metal wire 113 can be selected to be in an arc shape. The arc-shaped metal wire 113 is easy to process and is conducive to increasing the channel length, thereby increasing the capacitiveness of the equivalent circuit formed between the electromagnetic bandgap structure 110 and the ground layer 300.

[0056] In some embodiments, the central portion 111 is rectangular, and a signal connection line 112 is connected to the center positions of the two long sides and the two short sides of the central portion 111, that is, the signal connection line 112 is arranged in the middle position of the corresponding side of the central portion 111. Such an arrangement can ensure the stability of the electromagnetic band gap structure 110, facilitate processing, and the distance between the signal connection line 112 and its adjacent metal wires 113 is the same. Specifically, a metal wire 113 can be arranged on each side of the signal connection line 112, and the metal wires 113 on both sides of the signal connection line 112 are symmetrically arranged relative to the signal connection line 112, which is convenient for processing and has a uniform structure.

[0057] Further, the metal wire 113 includes a first connection wire 1131, a second connection wire 1132, a third connection wire 1133 and a fourth connection wire 1134 connected in sequence, the first connection wire 1131 and the fourth connection wire 1134 are both connected to the central portion 111, the second connection wire 1132 and the third connection wire 1133 are connected in sequence between the first connection wire 1131 and the fourth connection wire 1134, and the first connection wire 1131 and the fourth connection wire 1134 are respectively perpendicular to the extension direction of the side connection wires of the central portion 111 at the corresponding position. The second connection line 1132 is perpendicular to the first connection line 1131, the third connection line 1133 is perpendicular to the second connection line 1132, and the fourth connection line 1134 is perpendicular to the third connection line 1133; that is, the second connection line 1132 and the third connection line 1133 are connected to the first connection line 1131 and its extended portion, and the fourth connection line 1134 and its extended portion, and can jointly communicate a square structure, and the extended portion of the first connection line 1131 and the extended portion of the fourth connection line 1134 are both located on the central portion 111;

[0058] Further, the second connection line 1132 and the third connection line 1133 have the same length, that is, the second connection line 1132 and the third connection line 1133, connecting the first connection line 1131 and its extension, and the fourth connection line 1134 and its extension, can communicate a square structure together; specifically, the length of the first connection line 1131 is less than the length of the signal connection line 112 at the adjacent position, and the length of the fourth connection line 1134 is less than the length of the signal connection line 112 at the adjacent position. This arrangement is to prevent the metal wires 113 on adjacent electromagnetic band gap structures 110 from contacting each other after the plurality of electromagnetic band gap structures 110 are arranged to form an array structure, and the adjacent electromagnetic band gap structures 110 are connected and conducted only through the signal connection line 112; and the first connection line 1131 is connected to the central portion 11 1, the second connecting line 1132 is connected to the long side of the central part 111, the length of the first connecting line 1131 is less than the length of the second connecting line 1132, and since the structure of the central part 111 is a rectangle, the length of the first connecting line 1131 is set to be less than the length of the second connecting line 1132, so that the length of the second connecting line 1132 and the third connecting line 1133 can be the same; that is, the first connecting line 1131 starts from the edge of the solid area of ​​the middle part, extends in the direction away from the short side of the central part 111, and turns when it is a predetermined length away from the side of the central part 111 and extends in a direction parallel to the short side of the central part 111; after passing through the second connecting line 1132 and the third connecting line 1133 in sequence, it passes through the fourth connecting line 1134 and extends to the central part 111;

[0059] The shielding groove 114 is L-shaped, and the first side of the shielding groove 114 is used to form the first connecting line 1131 and the second connecting line 1132. Specifically, the first side of the shielding groove 114 is located between the first connecting line 1131, the second connecting line 1132 and the central part 111, and the second side of the shielding groove 114 is used to form the third connecting line 1133 and the fourth connecting line 1134. The second side of the shielding groove 114 is located between the third connecting line 1133, the fourth connecting line 1134 and the central part 111; the width of the first side of the shielding groove 114 is greater than the width of the second side of the shielding groove 114, also to meet the rectangular structure of the central part 111.

[0060] The above-mentioned setting changes the straight channel in the related art into a metal wire 113 with four connecting wires. The metal wire 113 is extended by bending, so that the channel length of the metal wire 113 is extended, thereby increasing its equivalent inductance. By increasing its equivalent inductance, the capacitance value of the equivalent circuit formed between the power layer 100 and the ground layer 300 having the electromagnetic bandgap structure 110 will increase. When the capacitance increases, the bandwidth range generated will be increased accordingly, and the cut-off frequency depth of noise suppression will also be increased, so that the ground bounce effect of the power layer 100 can be effectively suppressed, thereby reducing the effect of the ground bounce effect on the signal quality and electromagnetic radiation. In addition, by hollowing out the position between the metal wire 113 and the central part 111, a shielding groove 114 is formed. The shielding groove 114 will become a protective wall, which can suppress the noise source inside and avoid the generation of signal interference sources. In a specific embodiment, the outer wall structure of the electromagnetic band gap structure 110 can be a square with a side length of 30 mm, with a rectangle with a length of 25 mm and a width of 20 mm in the middle, and then metal wires 113 with a width of 2 mm need to be added to the four corners of the outer periphery of the rectangle, and the lengths of the second connecting wire 1132 and the third connecting wire 1133 are 8 mm. Figure 5 The structure of an EBG cell is shown, which is the basic unit that constitutes the electromagnetic bandgap structure 110; these cells can be periodic or non-periodic, and they are separated by a specific gap width; EBG cells are usually composed of metal patches printed on a substrate, and these patches are also called cells; these cells are connected to the surface of the ground layer 300 through conductive pins, wires or connecting columns 200.

[0061] In some embodiments, one end of the metal wire 113 starts from the edge of the central portion 111 and extends in a direction away from the central portion 111. The metal wire 113 extends in a serpentine reciprocating structure, or the metal wire 113 extends in a curve or fold line direction. A shielding groove 114 with a bent edge is formed between the metal wire 113 and the central portion 111, and the other end of the metal wire 113 extends to the central area. The above configuration can maximize the length of the metal wire 113 within a limited space by extending the metal wire 113 in a fold line or curve manner, thereby extending the channel length of the electromagnetic bandgap structure 110, increasing the capacitance generated through the adjacent electromagnetic bandgap structure 110, and increasing the generated bandwidth range accordingly, thereby increasing the cutoff frequency depth for suppressing noise, thereby achieving the purpose of suppressing the ground bounce effect of the power layer 100 and reducing the effect of the ground bounce effect on signal quality and electromagnetic radiation.

[0062] In some embodiments, the electromagnetic bandgap structure 110 is a centrally symmetrical structure, which is easy to process and has a uniform effect on increasing the equivalent inductance, thereby ensuring that it can stably suppress the ground bounce effect of the power layer 100; at the same time, Figure 5 and Figure 7 As shown, the electromagnetic bandgap structure 110 may also be a left-right symmetrical structure, or a top-bottom symmetrical structure, which is convenient for processing and array arrangement.

[0063] In some embodiments, the line width of the signal connection line 112 is the same as the line width of the metal line 113. By setting the line width of the signal connection line 112 to be the same as the line width of the metal line 113, processing is convenient and it is helpful to calculate the cutting position of the metal plate.

[0064] In some embodiments, Figure 6 and Figure 8 As shown, there are multiple electromagnetic bandgap structures 110, and each electromagnetic bandgap structure 110 is arranged in sequence in the horizontal and vertical directions to form an electromagnetic bandgap structure array; the signal connection lines 112 at corresponding positions on adjacent electromagnetic bandgap structures 110 are connected and conductive. The above-mentioned arrangement forms an array structure with a plurality of rows and columns, i.e., an electromagnetic bandgap structure array, by arranging a plurality of electromagnetic bandgap structures 110 in sequence in the horizontal and vertical directions. The electromagnetic bandgap structure array can form an equivalent circuit with the grounding layer 300. Since the structure of the metal wire 113 and the shielding groove 114 is added to the electromagnetic bandgap structure 110, the channel length of the electromagnetic bandgap structure 110 is extended, and the capacitance generated by the adjacent electromagnetic bandgap structures 110 is increased, so that the cut-off frequency depth of the noise suppression is also increased. Therefore, the equivalent circuit formed between the electromagnetic bandgap structure array after the array arrangement and the grounding layer 300 can also increase the capacitance, thereby increasing By widening the bandwidth, the cutoff frequency depth of noise suppression will also be increased, which can effectively suppress the ground bounce effect of the power layer 100, thereby reducing the effect of the ground bounce effect on signal quality and electromagnetic radiation; at the same time, through the arrangement of the signal connection line 112 in the electromagnetic bandgap structure 110, after a plurality of electromagnetic bandgap structures 110 are arranged to form an electromagnetic bandgap structure array, adjacent electromagnetic bandgap structures 110 can be connected and conducted through the signal connection line 112, which is convenient for processing. At the same time, the electromagnetic bandgap structure array can be processed on the same metal plate, and the adjacent electromagnetic bandgap structures 110 can be integrated through the signal connection line 112, which is convenient for processing and has high strength.

[0065] In some embodiments, the electromagnetic bandgap structure array is an integrated structure. Specifically, the electromagnetic bandgap structure array with an integrated structure is not only convenient for processing, but also more convenient for signal transmission and power conduction. Specifically, adjacent electromagnetic bandgap structures 110 are connected to form an integrated structure through signal connection lines 112, which can not only play a reinforcement role, but also facilitate the conduction of power and signals.

[0066] Specifically, the electromagnetic bandgap structure 110 can be applied to a multi-layer PCB circuit board, such as Figure 6 and Figure 8 As shown, a total of 9 pieces of 3X3 electromagnetic bandgap structures 110 are used, which are evenly distributed in the power layer 100 inside the circuit board. The characteristics of the electromagnetic bandgap structure 110 increase the inductance of a single peripheral metal length, and increase the capacitance between the metal line 113 and the central part 111, so that their resonant frequency can be increased, and they are used in high-frequency circuit boards; through simulation analysis to compare the loss difference between the electromagnetic bandgap structure 110 and the linear channel EBG, it can be found that because the channel length of the electromagnetic bandgap structure 110 is longer than the linear channel distance, the capacitance generated by the adjacent electromagnetic bandgap structures 110 will also be better. When the capacitance increases, the bandwidth generated will also be longer, and the cut-off frequency depth of noise suppression will also be deeper; Fig.10 The results show that the bandwidth range of the electromagnetic bandgap structure 110 has been significantly increased, extending from about 1GHz to 10GHz, with a bandwidth of about 9GHz, and the cutoff frequency depth has also been greatly improved to about -100dB; in addition, since metal wires 113 are set at the four corners of the rectangular central part 111, and four shielding slots 114 are hollowed out between the metal wires 113 and the central part 111, its capacitance has also increased, and the bandwidth for suppressing noise will be better. When this design is applied to high-speed signal PCB circuit boards, the interference of the power layer 100 can be reduced, the capacitance value of its equivalent circuit is increased, and its bandwidth can be increased, and the cutoff frequency depth and center frequency can also be moved to high frequency, and then the shielding slot 114 can isolate the noise to prevent the interference source from spreading out.

[0067] Specifically, in the first specific embodiment, the electromagnetic band gap structure 110 includes a central part 111 and a metal wire 113, both ends of the metal wire 113 are connected to and conducted with the central part 111, and a shielding groove 114 is formed between the middle of the metal wire 113 and the central part 111; the metal wire 113 is located at the periphery of the central part 111 and is spaced apart from the signal connection line 112.

[0068] In a second specific embodiment, the electromagnetic band gap structure 110 includes a central portion 111 and a metal wire 113, both ends of the metal wire 113 are connected to the central portion 111 and are conductive, and a shielding groove 114 is formed between the middle of the metal wire 113 and the central portion 111; the metal wire 113 is located at the periphery of the central portion 111 and is spaced apart from the signal connection line 112; the central portion 111 is rectangular, and a metal wire 113 is provided at each of the four corners of the central portion 111, and the metal wire 113 includes a first connection line 1131, a second connection line 1132, a third connection line 1133 and a fourth connection line 1134, and the first connection line 1131 is connected to the metal wire 1132. The first connecting line 1131 and the fourth connecting line 1134 are both connected to the central part 111, the first connecting line 1131 and the fourth connecting line 1134 are respectively perpendicular to the extension direction of the side connecting line of the central part 111 at the corresponding position, the second connecting line 1132 is perpendicular to the first connecting line 1131, the third connecting line 1133 is perpendicular to the second connecting line 1132, and the fourth connecting line 1134 is perpendicular to the third connecting line 1133; the shielding groove 114 is L-shaped, the first side of the shielding groove 114 is used to form the first connecting line 1131 and the second connecting line 1132, and the second side of the shielding groove 114 is used to form the third connecting line 1133 and the fourth connecting line 1134.

[0069] In a third specific embodiment, the electromagnetic bandgap structure 110 includes a central portion 111 and a metal wire 113, both ends of the metal wire 113 are connected to and conducted with the central portion 111, and a shielding groove 114 is formed between the middle of the metal wire 113 and the central portion 111; the metal wire 113 is located at the periphery of the central portion 111 and is spaced apart from the signal connection line 112; the central portion 111 is rectangular, the metal wire 113 is arc-shaped, and a metal wire 113 is provided at each of the four corners of the central portion 111.

[0070] In addition to the above-mentioned electromagnetic bandgap structure 110, the present invention further provides a circuit board including a power layer 100 and a ground layer 300, such as Fig. 9 As shown, the power layer 100 includes several electromagnetic bandgap structures 110, the ground layer 300 is located on one side of the power layer 100, and the power layer 100 and the ground layer 300 can be connected through a connecting column 200. For the structures of other parts of the circuit board, please refer to the relevant technology, which will not be described in detail herein.

[0071] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0072] The electromagnetic bandgap structure provided by the present invention is introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method and core ideas of the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the present invention.

Claims

1. An electromagnetic bandgap structure, characterized in that: include: center section (111); A signal connection line (112), connected to the central portion (111) and extending in a direction away from the central portion (111); A metal wire (113) is located at the periphery of the central portion (111), the metal wire (113) and the signal connection wire (112) are spaced apart, both ends of the metal wire (113) are connected to the central portion (111), and a shielding groove (114) is formed between the metal wire (113) and the central portion (111).

2. The electromagnetic bandgap structure according to claim 1, characterized in that: The central portion (111) is square in shape, and each of the four sides of the central portion (111) is connected to at least one signal connection line (112), and the signal connection line (112) extends in a straight line.

3. The electromagnetic bandgap structure according to claim 2, characterized in that: Each of the four corners of the central part (111) is connected to a metal wire (113), and the metal wire (113) extends from one side of the corner of the central part (111) to the other side of the corner.

4. The electromagnetic bandgap structure according to claim 2, characterized in that: The metal wire (113) is in an arc shape, and two ends of the metal wire (113) are respectively connected to two adjacent side edges of the central part (111).

5. The electromagnetic bandgap structure according to claim 2, characterized in that: The central portion (111) is rectangular, and the center positions of the two long sides and the two short sides of the central portion (111) are each connected to a signal connection line (112), and the distance between the signal connection line (112) and its adjacent metal line (113) is the same; The metal wire (113) comprises a first connection wire (1131), a second connection wire (1132), a third connection wire (1133) and a fourth connection wire (1134) which are connected in sequence, the first connection wire (1131) and the fourth connection wire (1134) are both connected to the central part (111), the first connection wire (1131) and the fourth connection wire (1134) are respectively perpendicular to the extension direction of the side connection wire of the central part (111) at the corresponding position, the second connection wire (1132) is perpendicular to the first connection wire (1131), the third connection wire (1133) is perpendicular to the second connection wire (1132), and the fourth connection wire (1134) is perpendicular to the third connection wire (1133); The second connection line (1132) and the third connection line (1133) have the same length, the length of the first connection line (1131) is shorter than the length of the signal connection line (112) at an adjacent position, and the length of the fourth connection line (1134) is shorter than the length of the signal connection line (112) at an adjacent position; and the first connection line (1131) is connected to the short side of the central part (111), and the second connection line (1132) is connected to the long side of the central part (111), and the length of the first connection line (1131) is shorter than the length of the second connection line (1132); The shielding groove (114) is L-shaped, the first side of the shielding groove (114) is used to form the first connecting line (1131) and the second connecting line (1132), and the second side of the shielding groove (114) is used to form the third connecting line (1133) and the fourth connecting line (1134); the first side width of the shielding groove (114) is greater than the second side width of the shielding groove (114).

6. The electromagnetic bandgap structure according to claim 1, characterized in that: The electromagnetic band gap structure (110) is a centrally symmetrical structure.

7. The electromagnetic bandgap structure according to claim 1, characterized in that: The line width of the signal connection line (112) is the same as the line width of the metal line (113).

8. The electromagnetic bandgap structure according to any one of claims 1 to 7, characterized in that: There are a plurality of electromagnetic bandgap structures (110), and the electromagnetic bandgap structures (110) are sequentially arranged in the horizontal and vertical directions to form an electromagnetic bandgap structure array; the signal connection lines (112) at corresponding positions on adjacent electromagnetic bandgap structures (110) are connected and conducted.

9. The electromagnetic bandgap structure according to claim 8, characterized in that: The electromagnetic band gap structure array is an integrated structure.

10. A circuit board, characterized in that: The invention comprises a power layer (100) and a ground layer (300), wherein the power layer (100) comprises the electromagnetic band gap structure (110) according to any one of claims 1 to 9; and the ground layer (300) is located on one side of the power layer (100).

Images