Electromagnetic bandgap structure, circuit board

Abstract

The application discloses an electromagnetic bandgap structure and a circuit board, and is applied to the field of high-frequency circuits.The electromagnetic bandgap structure comprises a center part, a signal connecting line connected with the center part and extending away from the center part, and metal wires located at the periphery of the center part, the metal wires being spaced apart from the signal connecting line, both ends of the metal wires being connected with the center part, and a shielding groove being formed between the metal wires and the center part.The electromagnetic bandgap structure provided by the application increases the noise suppression cutoff frequency depth, can effectively suppress the ground bounce effect of a power layer, and further reduces the effect of the ground bounce effect on signal quality and electromagnetic radiation; the shielding groove can avoid the diffusion of a signal interference source, so as to ensure the integrity of signal transmission.

Description

Technical Field

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

[0002] In recent years, due to the increasingly faster signal transmission speed in high-frequency digital circuits, signals are subject to interference from many factors during transmission. Therefore, signal integrity becomes particularly important. When a signal is transmitted from the transmitting end to the receiving end, the waveform may be disrupted by interference, leading to signal distortion. Factors affecting this include signal timing issues, signal ringing, signal reflection, near-end and far-end crosstalk, switching noise, ground bounce and power supply bounce, attenuation, capacitive loads, electromagnetic radiation, and battery interference. Therefore, reducing noise is the best way to maintain a stable 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 noise suppression is often relatively small, which can affect the integrity of signal transmission.

[0004] Therefore, ensuring the integrity of signal transmission in high-frequency circuits is a technical problem that needs to be solved by those skilled in the art. Summary of the Invention

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

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] An electromagnetic bandgap structure, comprising:

[0008] Central part;

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

[0010] A metal wire is located around the periphery of the central portion. The metal wire and the signal connection line are distributed at intervals. Both ends of the metal wire are connected to the central portion, and a shielding groove is formed between the metal wire and the central portion.

[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 signal connection line, which extends in a straight line.

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

[0013] On the other hand, the metal wire is arc-shaped, and its two ends are respectively connected to the two adjacent sides of the central portion.

[0014] On the other hand, the central portion is rectangular, and a signal connection line is connected to the center of each of the two long sides and the two short sides of the central portion, and the signal connection line is equidistant from the adjacent metal wires.

[0015] The metal wire includes a first connecting line, a second connecting line, a third connecting line, and a fourth connecting line connected in sequence. The first connecting line and the fourth connecting line are both connected to the central portion. The first connecting line and the fourth connecting line are perpendicular to the extension direction of the side connecting line of the central portion at the corresponding position. The second connecting line is perpendicular to the first connecting line, the third connecting line is perpendicular to the second connecting line, and the fourth connecting line is perpendicular to the third connecting line.

[0016] The second connecting line and the third connecting line have the same length. The length of the first connecting line is less than the length of the signal connecting line at the adjacent position. The length of the fourth connecting line is less than the length of the signal connecting line at the adjacent position. The first connecting line is connected to the short side of the central portion, and the second connecting line is connected to the long side of the central portion. The length of the first connecting line is less than the length of the second connecting 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 width of the first side of the shielding groove is greater than the width of the second side of the shielding groove.

[0018] On the other hand, the electromagnetic bandgap 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 wire.

[0020] On the other hand, there are multiple electromagnetic bandgap structures, and each electromagnetic bandgap structure is arranged sequentially along 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 conduction is performed.

[0021] On the other hand, the electromagnetic bandgap structure array is an integral structure.

[0022] The present invention also provides a circuit board comprising the electromagnetic bandgap structure described in any one of the preceding claims.

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

[0024] The electromagnetic bandgap structure provided by this invention has the following advantages: By improving the linear electromagnetic bandgap structure in related technologies to an electromagnetic bandgap structure with a central portion and metal wires arranged around the periphery of the central portion, and by connecting the two ends of the metal wires to the central portion, the channel length of the electromagnetic bandgap structure is extended. This increases the capacitance generated by adjacent electromagnetic bandgap structures. In other words, the capacitance of the equivalent circuit formed between the power layer and ground layer with this electromagnetic bandgap structure increases. As the capacitance increases, the bandwidth range increases accordingly, and the cutoff frequency depth for noise suppression also increases. This effectively suppresses the ground bounce effect of the power layer, thereby reducing the impact of ground bounce on signal quality and electromagnetic radiation. The electromagnetic bandgap structure can directly increase the number of electromagnetic bandgap structure units by cutting channels on the existing power layer without adding an additional power layer, thus achieving the effect of increasing capacitance. It is easy to operate and has low manufacturing cost. Furthermore, since the shielding groove is formed between the metal line and the central part, and the shielding groove is a closed groove, the formation of the shielding groove creates a certain gap between the metal line and the central part, thereby increasing the length of the metal line. Due to the increased length of the metal line, 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 prevent the signal interference source from spreading, thereby ensuring the integrity of signal transmission. It can be used on multilayer PCB circuit boards.

[0025] In one embodiment, multiple electromagnetic bandgap structures are arranged sequentially in the horizontal and vertical directions to form an array structure with several rows and columns, namely an electromagnetic bandgap structure array. This electromagnetic bandgap structure array can form an equivalent circuit with the ground layer. Because the electromagnetic bandgap structure incorporates metal wires and shielding grooves, the channel length of the electromagnetic bandgap structure is extended, increasing the capacitance generated by adjacent electromagnetic bandgap structures. This increases the cutoff frequency depth for noise suppression. Therefore, the equivalent circuit formed between the arrayed electromagnetic bandgap structure array and the ground layer also increases capacitance. This increases the bandwidth range and the noise suppression cutoff frequency depth, effectively suppressing the ground bounce effect of the power layer and reducing its impact on signal quality and electromagnetic radiation. Furthermore, the signal connection lines in the electromagnetic bandgap structure allow adjacent structures to be connected and conductive via these lines after forming an electromagnetic bandgap structure array. This facilitates fabrication. Additionally, the electromagnetic bandgap structure array can be fabricated on the same metal plate, and adjacent structures can be integrated via the signal connection lines, resulting in convenient fabrication and 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 the corresponding technical effects. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the electromagnetic bandgap structure in related technologies;

[0029] Figure 2 This is an equivalent circuit model for high-impedance surface structures in related technologies;

[0030] Figure 3 This is a schematic diagram of the electromagnetic bandgap structure of a linear channel in related technologies;

[0031] Figure 4 This is the equivalent circuit model for linear channel structures in related technologies;

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

[0033] Figure 6 for Figure 5 The diagram shows the structure of the electromagnetic bandgap structure after it is arrayed.

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

[0035] Figure 8 for Figure 7 The diagram shows the structure of the electromagnetic bandgap structure after it is arrayed.

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

[0037] Figure 10 This is a comparison chart of simulation results of the electromagnetic bandgap structure provided by this invention and electromagnetic bandgap structures in related technologies.

[0038] Figure label:

[0039] Power layer 100; electromagnetic bandgap structure 110; central part 111; signal connection line 112; metal wire 113; first connection line 1131; second connection line 1132; third connection line 1133; fourth connection line 1134; shielding groove 114; connecting post 200; grounding layer 300. Detailed Implementation

[0040] The core of this 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 for noise suppression.

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] With the development of technological products towards higher speeds, smaller sizes, and lower voltages, especially with the increasing speed of high-performance servers, the impact of GBN (Ground Bounce Noise) on systems is becoming more significant, making the suppression of GBN crucial. Utilizing a PBG (Photonic bandgap) structure to form a parallel plate waveguide structure between the power plane and the complete ground plane (Electromagnetic bandgap) is a method known as EBG (Electromagnetic bandgap waveguide). The bandgap (electromagnetic bandgap structure 110) 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, with a high-order band-stop filter connected in parallel to suppress the ground bounce noise (GBN) effect. A series LC circuit, also known as an LC series resonant circuit, is a circuit composed of an inductor (L) and a capacitor (C) connected in series. A high-order band-stop filter, also known as a high-order band-stop filter or high-order notch filter, is a frequency-selective circuit that can block or at least severely attenuate the frequency band within two cutoff frequencies. The following are some key characteristics and applications of series LC circuits:

[0043] The name "electromagnetic bandgap structure" originally came from "High Impedance surface" (HIS), and it was initially used primarily in antenna design. The characteristic of this special structure is its ability to effectively block surface currents, attenuating electromagnetic waves and hindering their propagation. Its initial structural form consisted of a square metal patch with a grounding via 200 pins. These patches were arranged in a periodic geometric pattern, with a dielectric material filling the space between the patch and the grounding layer 300. This three-layer structure creates an omnidirectional cutoff band in specific frequency ranges, effectively blocking electromagnetic wave propagation. The overall structure is as follows: Figure 1 As shown.

[0044] The way this structure blocks electromagnetic wave propagation can be understood through the use of lumped element circuits; such as... Figure 2 As shown, this is the equivalent circuit model of the HIS structure. The high-impedance surface in the equivalent circuit is as follows: Figure 2As shown in section A, the resulting circuit is an LC parallel circuit. The capacitance (C) is generated between the two metal patches, while the inductance (L) is generated by the metal patch, the connecting post 200, and the ground layer 300. When this equivalent circuit resonates, it acts as a high-impedance propagation path, making propagation difficult. Therefore, it creates a cutoff band for electromagnetic waves, and the center frequency of this cutoff band is the resonant frequency of the equivalent circuit. This structure was initially used only in antenna design. Later, its principle was applied to PCB printed circuit boards to achieve noise suppression. Research has confirmed its good noise suppression effect. Its main purpose is to increase the noise suppression bandwidth and reduce manufacturing costs. Therefore, many different types of electromagnetic bandgap structures have emerged to date.

[0045] Depending on the type of EBG structure applied to the PCB, it can be divided into several forms. This article introduces the design of a linear channel electromagnetic bandgap (Coplanar EBG) structure, which is constructed by making regular shape cuts only on the power layer 100. For example... Figure 3 As shown, Figure 3 This is a schematic diagram of a linear channel electromagnetic bandgap structure 110. Its noise suppression principle can be explained using its equivalent circuit model, such as... Figure 4 As shown, Figure 4 The equivalent circuit model for a linear channel structure mainly consists of a parallel circuit formed by an inductor (L) and a capacitor (C1). Under specific bandwidth conditions, a resonance effect occurs, causing its input impedance to approach infinity. Figure 4 The capacitor (C2) shown refers to the capacitor formed between the power layer 100 and the ground layer 300. The equivalent capacitance generated by stacking two circuit board layers can be imagined as two metal layers stacked one on top of the other, resulting in capacitor C2. Therefore, for noise, this straight channel is equivalent to a high-impedance propagation path, so noise is not easily transmitted.

[0046] Based on the structural analysis of the linear channel above, it can be found that the key factors affecting the design of the EBG structure are: 1. noise suppression bandwidth, 2. center frequency, 3. cutoff frequency depth, and 4. signal integrity (SI). These four characteristics serve as the benchmark for judgment. Therefore, these four characteristics must be considered when designing a new structure. However, the results of previous linear channel coplanar structures show that the first three characteristics have been significantly improved. Only the signal integrity is affected by the increased gap between the basic unit and the gap between the basic unit and the central body of the channel, which causes incompleteness of the power plane. Therefore, it is necessary to consider designing and developing a new structure to increase the noise suppression bandwidth in exchange for signal integrity. In the past, the linear channel was hollowed out in related technologies. However, simulation results showed that the signal integrity was affected. Therefore, different EBG structures were designed to improve the integrity of signal transmission.

[0047] In this implementation, please refer to Figure 5 and Figure 6 The electromagnetic bandgap structure 110 includes:

[0048] Central section 111;

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

[0050] Metal wire 113 is located around the center portion 111. Metal wire 113 and signal connection line 112 are distributed at intervals. Both ends of metal wire 113 are connected to the center portion 111, and a shielding groove 114 is formed between metal wire 113 and the center portion 111.

[0051] Specifically, the central part 111, the signal connection line 112, and the metal wire 113 can be processed by cutting a 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 together with the central part 111 constitute the metal sheet of the electromagnetic bandgap structure 110.

[0052] The electromagnetic bandgap structure 110 improves upon the linear electromagnetic bandgap structure 110 in the related art by having a central portion 111 and a metal wire 113 disposed around 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 increases. In other words, the capacitance value of the equivalent circuit formed between the power layer 100 and the ground layer 300 with the electromagnetic bandgap structure 110 increases. When the capacitance increases, the bandwidth range is correspondingly increased, and the cutoff frequency depth for noise suppression is also increased. This effectively suppresses the ground bounce effect of the power layer 100, thereby reducing the effect of the ground bounce effect on signal quality and electromagnetic radiation. The electromagnetic bandgap structure 110 can directly increase the number of units of the electromagnetic bandgap structure 110 by making channel cuts on the existing power layer 100 without adding an additional power layer 100, thus achieving the effect of increasing capacitance. It is easy to operate and has low manufacturing cost. Furthermore, since a shielding groove 114 is formed between the metal line 113 and the central part 111, the shielding groove 114 is a closed groove. The formation of the shielding groove 114 creates a certain gap between the metal line 113 and the central part 111, thereby increasing the length of the metal line 113. Due to the increased length of the metal line 113, 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 prevent the signal interference source from spreading, thereby ensuring the integrity of signal transmission. It can be used on multi-layer PCB circuit boards.

[0053] In some embodiments, the central portion 111 is square, for example, it can be a rectangular structure. The length of the central portion 111 is 23-27mm, or 25mm, and the width can be set as needed. Each of the four sides of the central portion 111 is connected to at least one signal connection line 112. The signal connection lines 112 extend in a straight line. Specifically, the signal connection lines 112 extend in a direction away from the sides of the central portion 111. In order to facilitate the connection and conduction between adjacent central portions 111 and at the same time reduce the length of the signal connection lines 112, the extension direction of the signal connection lines 112 can be perpendicular to the central portion. With the side extension direction corresponding to the position on 111 set in this way, after the two adjacent electromagnetic bandgap structures 110 are turned on, the signal connection lines 112 on the two electromagnetic bandgap structures 110 can be easily connected and turned on, making the processing more convenient; of course, if conditions permit, the extension direction of the signal connection line 112 can also be set at an angle 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 bandgap structures 110 should correspond to ensure that the two adjacent electromagnetic bandgap structures 110 can be turned on smoothly and ensure the reliability of signal transmission.

[0054] In some embodiments, a metal wire 113 is connected to each of the four corners of the central portion 111, and the metal wire 113 extends from one corner of the central portion 111 to the other corner. Specifically, for example... Figure 5 As shown, by setting a metal line 113 at each of the four corners of the central part 111, the metal sheet formed by the central part 111 and the metal lines 113 at the four corners has a longer channel length than the distance of a straight channel. The capacitance generated by the metal sheet through the adjacent electromagnetic bandgap structure 110 is also better. When the capacitance increases, the bandwidth generated is also longer. In addition, the cutoff frequency depth for noise suppression is also deeper.

[0055] In some implementation methods, please refer to Figure 7 and Figure 8 The metal wire 113 is arc-shaped, and its two ends are connected to the two adjacent sides of the central portion 111, respectively. Specifically, the metal wire 113 can extend in an arc shape, forming a shielding groove 114 between the arc-shaped metal wire 113 and the central portion 111, which can also suppress noise sources and reduce the generation of signal interference sources. Specifically, the metal wire 113 can be arc-shaped, which is easy to process and is conducive to increasing the channel length, thereby increasing the capacitance 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 of each of the two long sides and the two short sides of the central portion 111. That is, the signal connection line 112 is located in the middle of the corresponding side of the central portion 111. This arrangement can ensure the stability of the electromagnetic bandgap structure 110, facilitate processing, and ensure that the distance between the signal connection line 112 and its adjacent metal line 113 is the same. Specifically, a metal line 113 can be arranged on each side of the signal connection line 112. The metal lines 113 on both sides of the signal connection line 112 are symmetrically arranged with respect to the signal connection line 112, which facilitates processing and results in a uniform structure.

[0057] Furthermore, the metal wire 113 includes a first connecting wire 1131, a second connecting wire 1132, a third connecting wire 1133, and a fourth connecting wire 1134 connected in sequence. The first connecting wire 1131 and the fourth connecting wire 1134 are both connected to the central portion 111. The second connecting wire 1132 and the third connecting wire 1133 are connected between the first connecting wire 1131 and the fourth connecting wire 1134 in sequence. The first connecting wire 1131 and the fourth connecting wire 1134 are perpendicular to the extension direction of the side connecting wires of the central portion 111 at their respective positions. 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. That is to say, the second connecting line 1132 and the third connecting line 1133 connect the first connecting line 1131 and its extension, as well as the fourth connecting line 1134 and its extension, and together they can form a square structure. The extensions of the first connecting line 1131 and the fourth connecting line 1134 are both located on the central part 111.

[0058] Furthermore, the second connecting line 1132 and the third connecting line 1133 are of the same length. That is, the second connecting line 1132 and the third connecting line 1133, connecting the first connecting line 1131 and its extension, as well as the fourth connecting line 1134 and its extension, can collectively communicate a square structure. Specifically, the length of the first connecting line 1131 is less than the length of the adjacent signal connecting line 112, and the length of the fourth connecting line 1134 is less than the length of the adjacent signal connecting line 112. This arrangement ensures that after multiple electromagnetic bandgap structures 110 are arranged to form an array structure, the metal wires 113 on adjacent electromagnetic bandgap structures 110 will not contact each other; adjacent electromagnetic bandgap structures 110 are connected and conductive only through the signal connecting line 112. The first connecting line 1131 is connected to the central portion 11. On the short side of 1, the second connecting line 1132 connects 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. Since the structure of the central part 111 is rectangular, the length of the first connecting line 1131 must be less than the length of the second connecting line 1132 to ensure that the lengths of the second connecting line 1132 and the third connecting line 1133 are the same. That is, the first connecting line 1131 starts from the edge of the solid area of ​​the central part, extends away from the short side of the central part 111, and turns at a predetermined distance from the side of the central part 111, extending 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 extends to the central part 111 through the fourth connecting line 1134.

[0059] 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. 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. 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 configuration replaces the linear channel in related technologies with a metal line 113 with four connecting lines. The metal line 113 is extended by bending, thus increasing its equivalent inductance. This increases the capacitance of the equivalent circuit formed between the power layer 100 and the ground layer 300 with the electromagnetic bandgap structure 110. As the capacitance increases, the bandwidth range increases accordingly, and the cutoff frequency depth for noise suppression also increases. This effectively suppresses the ground bounce effect of the power layer 100, thereby reducing the effect of ground bounce on signal quality and electromagnetic radiation. In addition, by hollowing out the space between the metal line 113 and the center portion 111 to form a shielding groove 114, the shielding groove 114 acts as a protective wall, suppressing noise sources and preventing signal interference. In one specific embodiment, the outer wall structure of this electromagnetic bandgap structure 110 can be a square with a side length of 30mm, with a rectangle in the middle that is 25mm long and 20mm wide. Then, metal wires 113 with a width of 2mm need to be added to the four corners of the rectangle. The second connecting wire 1132 and the third connecting wire 1133 are 8mm long. Figure 5 The diagram shows the structure of an EBG cell, which is the basic unit that constitutes the electromagnetic bandgap structure 110. These cells can be periodic or aperiodic and are separated by a specific gap width. EBG cells are typically composed of metal patches printed on a substrate, which are also called cells. These cells are connected to the surface of the ground layer 300 via conductive pins, wires, or connecting posts 200.

[0061] In some embodiments, one end of the metal wire 113 extends from the edge of the central portion 111 away from the central portion 111. The metal wire 113 extends in a serpentine back-and-forth structure, or in a curved or zigzag direction. A shielding groove 114 with a bent edge is formed between the metal wire 113 and the central portion 111. The other end of the metal wire 113 extends to the central region. By extending the metal wire 113 in a zigzag or curved manner, the length of the metal wire 113 can be maximized within a limited space. This extends the channel length of the electromagnetic bandgap structure 110, increases the capacitance generated by the adjacent electromagnetic bandgap structure 110, and correspondingly increases the bandwidth range. This increases the cutoff frequency depth for noise suppression, 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 manufacture and provides a uniform increase in equivalent inductance, thereby ensuring its stable suppression of the ground bounce effect of the power layer 100; simultaneously, such as Figure 5 and Figure 7 As shown, the electromagnetic bandgap structure 110 can also be a left-right symmetrical structure or a top-bottom symmetrical structure, which is easy to process and convenient for 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 and the metal line 113 to be the same, the processing is convenient and it is beneficial to calculate the cutting position of the metal plate.

[0064] In some implementations, such as Figure 6 and Figure 8 As shown, there are multiple electromagnetic bandgap structures 110. These structures are arranged sequentially in the horizontal and vertical directions to form an electromagnetic bandgap structure array. Signal connection lines 112 at corresponding positions on adjacent electromagnetic bandgap structures 110 are connected and conductive. This arrangement, with multiple electromagnetic bandgap structures 110 arranged sequentially in the horizontal and vertical directions, forms an array structure with several rows and columns, i.e., an electromagnetic bandgap structure array. This array can form an equivalent circuit with the ground layer 300. Because the electromagnetic bandgap structure 110 incorporates metal wires 113 and shielding grooves 114, the channel length of the electromagnetic bandgap structure 110 is extended, increasing the capacitance generated by adjacent electromagnetic bandgap structures 110. This increases the cutoff frequency depth for noise suppression. Therefore, the equivalent circuit formed between the array of electromagnetic bandgap structures and the ground layer 300 also increases capacitance, thereby enhancing... Increasing the bandwidth range also increases the cutoff frequency depth for noise suppression, effectively suppressing the ground bounce effect of the power layer 100, thereby reducing the effect of ground bounce on signal quality and electromagnetic radiation. Simultaneously, the presence of signal connection lines 112 in the electromagnetic bandgap structure 110 allows adjacent electromagnetic bandgap structures 110 to be connected and conductive via these lines after forming an electromagnetic bandgap structure array. This facilitates fabrication. Furthermore, the electromagnetic bandgap structure array can be fabricated on the same metal plate, and adjacent electromagnetic bandgap structures 110 can be integrated into a single structure via signal connection lines 112, resulting in convenient fabrication and high strength.

[0065] In some embodiments, the electromagnetic bandgap structure array is an integral structure. Specifically, the integral electromagnetic bandgap structure array not only facilitates processing, but also makes signal transmission and power conduction more convenient. Specifically, adjacent electromagnetic bandgap structures 110 are connected by signal connection lines 112 to form an integral structure, which can not only provide reinforcement, but also facilitate power and signal conduction.

[0066] Specifically, the electromagnetic bandgap structure 110 can be applied to multilayer PCB circuit boards, such as... Figure 6 and Figure 8 As shown, a total of nine 3x3 electromagnetic bandgap structures 110 are evenly distributed in the power layer 100 of the circuit board. The characteristics of the electromagnetic bandgap structure 110 increase the inductance of a single peripheral metal length and the capacitance between the metal line 113 and the central portion 111, allowing for an increase in their resonant frequency and application on high-frequency circuit boards. Through simulation analysis comparing 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 that of the linear channel, the capacitance generated by adjacent electromagnetic bandgap structures 110 is better. As the capacitance increases, the resulting bandwidth is longer, and the noise suppression cutoff frequency depth is also deeper. Figure 10 The results show that the bandwidth of the electromagnetic bandgap structure 110 is significantly increased, extending from approximately 1 GHz to 10 GHz, with a bandwidth of about 9 GHz. Furthermore, the cutoff frequency depth is greatly improved to around -100 dB. Additionally, the addition of metal lines 113 at the four corners of the rectangular central portion 111, and the creation of four shielding slots 114 between the metal lines 113 and the central portion 111, increases the capacitance, resulting in better noise suppression bandwidth. Applying this design to a high-speed signal PCB circuit board reduces interference on the power layer 100, increases the capacitance of its equivalent circuit, thus increasing the bandwidth, and allows for a higher cutoff frequency depth and center frequency shift. The shielding slots 114 also isolate noise, preventing interference sources from spreading.

[0067] Specifically, in the first 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 conduct through the central portion 111. 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 around the central portion 111 and is spaced apart from the signal connection line 112.

[0068] In a second specific embodiment, the electromagnetic bandgap structure 110 includes a central portion 111 and metal wires 113. Both ends of the metal wires 113 are connected to and conductively conduct through the central portion 111. A shielding groove 114 is formed between the middle of the metal wires 113 and the central portion 111. The metal wires 113 are located around the periphery of the central portion 111 and are spaced apart from the signal connection lines 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. The metal wires 113 include a first connecting line 1131, a second connecting line 1132, a third connecting line 1133, and a fourth connecting line 1134. Both 131 and the fourth connecting line 1134 are connected to the central portion 111. The first connecting line 1131 and the fourth connecting line 1134 are perpendicular to the extension direction of the side connecting line of the central portion 111 at the corresponding positions. 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 conduct through the central portion 111. 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 around the periphery of the central portion 111 and is spaced apart from the signal connection line 112. The central portion 111 is rectangular, and the metal wire 113 is arc-shaped. A metal wire 113 is provided at each of the four corners of the central portion 111.

[0070] In addition to the electromagnetic bandgap structure 110 described above, the present invention also provides a circuit board including a power layer 100 and a ground layer 300, such as... Figure 9 As shown, the power layer 100 includes several of the aforementioned 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 by a connecting post 200. For the structure of other parts of this circuit board, please refer to relevant technologies; these details will not be elaborated upon here.

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

[0072] The electromagnetic bandgap structure provided by this invention has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and core ideas of this invention. It should be noted that those skilled in the art can make various improvements and modifications to this invention without departing from its principles, and these improvements and modifications also fall within the protection scope of this invention.

Claims

1. An electromagnetic bandgap structure, characterized in that, include: Central part (111); A signal connection line (112) is connected to the central portion (111) and extends in a direction away from the central portion (111); A metal wire (113) is located around the central portion (111). The metal wire (113) and the signal connection line (112) are distributed at intervals. 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). The central portion (111) is square, and each of the four sides of the central portion (111) is connected to at least one signal connection line (112), which extends in a straight line. A metal wire (113) is connected to each of the four corners of the central portion (111), and the metal wire (113) extends from one corner of the central portion (111) to the other corner. The electromagnetic bandgap structure (110) is a centrally symmetrical structure. A metal wire (113) is 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 arranged symmetrically with respect to the signal connection line (112).

2. The electromagnetic bandgap structure according to claim 1, characterized in that, The metal wire (113) is arc-shaped, and the two ends of the metal wire (113) are respectively connected to the two adjacent sides of the central part (111).

3. The electromagnetic bandgap structure according to claim 1, characterized in that, The central portion (111) is rectangular, and a signal connection line (112) is connected to the center of each of the two long sides and the two short sides of the central portion (111), and the signal connection line (112) is equidistant from the adjacent metal line (113); The metal wire (113) includes a first connecting line (1131), a second connecting line (1132), a third connecting line (1133), and a fourth connecting line (1134) connected in sequence. The first connecting line (1131) and the fourth connecting line (1134) are both connected to the central portion (111). The first connecting line (1131) and the fourth connecting line (1134) are perpendicular to the extension direction of the side connecting line of the central portion (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 second connecting line (1132) has the same length as the third connecting line (1133), the length of the first connecting line (1131) is less than the length of the adjacent signal connecting line (112), and the length of the fourth connecting line (1134) is less than the length of the adjacent signal connecting line (112); and the first connecting line (1131) is connected to the short side of the central portion (111), the second connecting line (1132) is connected to the long side of the central portion (111), and the length of the first connecting line (1131) is less than the length of the second connecting 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 width of the first side of the shielding groove (114) is greater than the width of the second side of the shielding groove (114).

4. 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).

5. The electromagnetic bandgap structure according to any one of claims 1 to 4, characterized in that, There are multiple electromagnetic bandgap structures (110). Each electromagnetic bandgap structure (110) is arranged in sequence along 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 conduction is performed.

6. The electromagnetic bandgap structure according to claim 5, characterized in that, The electromagnetic bandgap structure array is a single integrated structure.

7. A circuit board, characterized in that, It includes a power layer (100) and a ground layer (300), wherein the power layer (100) includes an electromagnetic bandgap structure (110) as described in any one of claims 1 to 6; and the ground layer (300) is located on one side of the power layer (100).

Images