CN118921835A - Printed circuit board for suppressing transmission line crosstalk - Google Patents

Abstract

The present application relates to the field of electronic information technology, and specifically discloses a printed circuit board for suppressing transmission line crosstalk. The printed circuit board includes: a substrate; a grounding layer arranged on the substrate; a transmission line arranged on the substrate, the transmission line including an interfering line and a disturbed line; an anti-interference line, the anti-interference line is arranged on the substrate and both ends are connected to the grounding layer, the anti-interference line, the interfering line and the disturbed line are arranged in parallel, and the anti-interference line is used to suppress the crosstalk between the interfering line and the disturbed line. For the crosstalk between the disturbed line and the interfering line on the printed circuit board that uses the grounding layer as the signal return channel, the present invention adds an anti-interference line arranged in parallel with the two, so that the magnetic field on the interfering line is coupled to the anti-interference line, thereby suppressing the magnetic field coupling between the interfering line and the disturbed line, and at the same time, the electric field on the interfering line is coupled to the anti-interference line, thereby suppressing the electric field coupling between the interfering line and the disturbed line.

Description

A printed circuit board for suppressing transmission line crosstalk

Technical Field

The present application relates to the field of electronic information technology, and in particular to a printed circuit board for suppressing transmission line crosstalk.

Background Art

The rapid development of contemporary electronic information technology has led to a closer distribution of electronic components and transmission lines within the limited space on printed circuit boards. At the same time, the increase in signal rate has made the electromagnetic environment around the transmission lines more complex, which has led to electromagnetic compatibility problems such as crosstalk between transmission lines. These problems not only affect the efficiency and quality of signal transmission, but in severe cases may cause the entire electronic system to malfunction.

In particular, the continuous progress of integrated circuit manufacturing technology in the past half century has made the size of chips smaller and smaller, the layout of electronic components on printed circuit boards more compact, and the density between transmission lines is increasing. The clock frequency of digital circuits is also getting faster and faster, most of which are above megahertz (MHz), and the clock frequency of some CPU chips can reach 3.5GHz. These factors together lead to crosstalk problems between transmission lines on printed circuit boards, resulting in signal distortion and increased bit error rate, and in severe cases, even causing electronic equipment to fail to work properly. Especially in high-speed digital circuits, the impact of crosstalk is more significant.

Due to factors such as the size and manufacturing process of printed circuit boards, it is difficult to suppress crosstalk between transmission lines on printed circuit boards, especially between the same chip or adjacent chips, by using shielded housings or shielded wires. Using magnetic beads or bypass capacitors to suppress crosstalk will affect the impedance of the transmission line and impose many design restrictions; on the other hand, it is difficult to achieve broadband suppression.

At present, the commonly used transmission line crosstalk suppression method is to increase the distance between the interfering line and the disturbed line. For crosstalk suppression between signal transmission lines on printed circuit boards, the commonly used method is the 3W principle, where W is the trace width, that is, the distance between transmission lines is set to more than 3 times the trace width to reduce the electromagnetic coupling between the two.

However, the main problem with using the traditional 3W principle to reduce crosstalk between transmission lines on printed circuit boards is that under the demand for miniaturization of equipment, there is usually not enough space to meet the long-distance conditions between the interfering line and the disturbed line. In addition, as the signal frequency continues to increase, the coupling between transmission lines continues to increase, so that in some cases, even if the spacing between the interfering line and the disturbed line meets the 3W principle, the occurrence of crosstalk cannot be avoided.

Summary of the invention

In view of this, the present application proposes a printed circuit board for suppressing transmission line crosstalk, aiming to solve the problem that crosstalk is easily generated between transmission lines of the existing printed circuit board.

The present application proposes a printed circuit board for suppressing transmission line crosstalk, the printed circuit board comprising: a substrate; a grounding layer arranged on the substrate; a transmission line arranged on the substrate, the transmission line comprising an interfering line and a disturbed line; an anti-interference line, the anti-interference line being arranged on the substrate and having both ends connected to the grounding layer, the anti-interference line, the interfering line and the disturbed line being arranged in parallel, and the anti-interference line being used to suppress crosstalk between the interfering line and the disturbed line.

Furthermore, in the above-mentioned printed circuit board for suppressing transmission line crosstalk, the crosstalk includes inductive coupling and capacitive coupling; when the interference line sends a signal, the magnetic field on the interference line is coupled to the anti-interference line in an inductive coupling manner, and the magnetic field generated by the induced current on the anti-interference line partially offsets the magnetic field on the interference line, thereby reducing the inductive coupling between the interference line and the disturbed line; when the interference line sends a signal, the electric field on the interference line is coupled to the anti-interference line in a capacitive coupling manner, and the capacitive coupling voltage of the anti-interference line is zero due to grounding, thereby reducing the capacitive coupling between the interference line and the disturbed line.

Furthermore, in the above-mentioned printed circuit board for suppressing transmission line crosstalk, the anti-interference line, the interference line and the disturbed line are arranged in parallel with each other.

Furthermore, in the above-mentioned printed circuit board for suppressing transmission line crosstalk, the anti-interference line is arranged between the interfering line and the disturbed line.

Furthermore, in the above-mentioned printed circuit board for suppressing transmission line crosstalk, the distance from the anti-interference line to the interference line is equal to the distance from the anti-interference line to the disturbed line.

Furthermore, in the above-mentioned printed circuit board for suppressing transmission line crosstalk, the distance from the anti-interference line to the interference line is greater than the distance from the anti-interference line to the disturbed line.

Furthermore, in the above-mentioned printed circuit board for suppressing transmission line crosstalk, the anti-interference line is arranged on a side of the interfering line away from the disturbed line.

Furthermore, in the above-mentioned printed circuit board for suppressing transmission line crosstalk, the anti-interference line is arranged on a side of the disturbed line away from the interfering line.

Furthermore, in the above-mentioned printed circuit board for suppressing transmission line crosstalk, there is at least one anti-interference line, and each anti-interference line can be arranged at any position between the interfering line and the disturbed line, on the side of the interfering line away from the disturbed line, and on the side of the disturbed line away from the interfering line.

Furthermore, the above-mentioned printed circuit board for suppressing transmission line crosstalk also includes: at least one conductive layer, each of the conductive layers is arranged parallel to the substrate, and the anti-interference line, the interference line and the disturbed line are all arranged in the same conductive layer.

It can be seen that for the crosstalk between the disturbed line and the interfering line on the printed circuit board using the ground layer as the signal return channel, the present invention adds an anti-interference line arranged in parallel with the two, so that the magnetic field on the interfering line is coupled to the anti-interference line, thereby suppressing the magnetic field coupling between the interfering line and the disturbed line, and at the same time, the electric field on the interfering line is coupled to the anti-interference line, thereby suppressing the electric field coupling between the interfering line and the disturbed line. In addition, since the present invention suppresses the crosstalk between the interfering line and the disturbed line by adding an anti-interference line, and thus has no restrictions on the length of the interfering line and the disturbed line and the distance between the two, it saves space for the printed circuit board and allows the printed circuit board to be more miniaturized.

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

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the present application will become more apparent through a more detailed description of exemplary embodiments of the present application in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the present application.

FIG1 is a schematic structural diagram of a printed circuit board for suppressing transmission line crosstalk provided in an embodiment of the present application;

FIG2 is an equivalent circuit diagram of crosstalk between parallel transmission lines on a printed circuit board for suppressing transmission line crosstalk in the related art;

FIG3 is an equivalent circuit diagram of the anti-crosstalk principle of a printed circuit board for suppressing transmission line crosstalk provided in an embodiment of the present application;

FIG4 is a cross-sectional view of a printed circuit board for suppressing transmission line crosstalk provided by an embodiment of the present application;

FIG5 is another cross-sectional view of a printed circuit board for suppressing transmission line crosstalk provided by an embodiment of the present application;

FIG6 is another cross-sectional view of a printed circuit board for suppressing transmission line crosstalk provided by an embodiment of the present application;

FIG7 is another cross-sectional view of a printed circuit board for suppressing transmission line crosstalk provided by an embodiment of the present application;

FIG8 is an anti-crosstalk curve diagram of the printed circuit board for suppressing transmission line crosstalk shown in FIG7;

FIG9 is another cross-sectional view of a printed circuit board for suppressing transmission line crosstalk provided by an embodiment of the present application;

FIG10 is an anti-crosstalk curve diagram of the printed circuit board for suppressing transmission line crosstalk shown in FIG9 ;

FIG11 is another cross-sectional view of a printed circuit board for suppressing transmission line crosstalk provided by an embodiment of the present application;

FIG. 12 is an anti-crosstalk curve diagram of the printed circuit board for suppressing transmission line crosstalk shown in FIG. 11 .

DETAILED DESCRIPTION

The preferred embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although the preferred embodiments of the present application are shown in the accompanying drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the present application more thorough and complete, and to fully convey the scope of the present application to those skilled in the art.

The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The singular forms of "a", "said" and "the" used in this application and the appended claims are also intended to include plural forms unless the context clearly indicates other meanings. It should also be understood that the term "and/or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

It should be understood that although the terms "first", "second", "third", etc. may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of this application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

In the description of the present application, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

Unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

The technical solution of the embodiments of the present application is described in detail below with reference to the accompanying drawings.

1 , a printed circuit board 10 for suppressing transmission line crosstalk according to an embodiment of the present application includes a substrate (not shown), a ground layer 110 , a transmission line, and an anti-interference line 120 .

The substrate is the base layer of the printed circuit board 10 that suppresses transmission line crosstalk and serves as a physical basis for carrying other parts of the printed circuit board. The substrate is usually made of insulating materials, such as epoxy resin glass fiber cloth, polyimide and the like.

The ground plane 110 is disposed on the substrate and is usually connected to a common reference point of the circuit for stabilizing voltage and reducing electromagnetic interference.

It can be understood that the printed circuit board 10 for suppressing the crosstalk of the transmission line should also include a conductive layer, and the transmission line is arranged on the conductive layer. Continuing to refer to Figure 1, the transmission line includes an interfering line 130 and a disturbed line 140. Unintentional electromagnetic coupling is prone to occur between transmission lines that are close to each other. This coupling belongs to near-field coupling and is called crosstalk. Among them, the wire that releases energy to the outside is called the interfering line 130, and the wire that passively receives energy is called the disturbed line 140. In order to suppress the crosstalk problem between the interfering line 130 and the disturbed line 140, the anti-interference line 120 is added in this embodiment.

It should be understood that the transmission line in this embodiment refers to any line on the printed circuit board where crosstalk may occur. For example, the conductive path connecting various electronic components in the circuit. The main function of the transmission line is to transmit electrical signals, including voltage and current, from one part of the circuit to another. It can also connect electronic components (such as resistors, capacitors, integrated circuits, etc.) to form the required circuit configuration. The transmission line can also realize signal distribution, power distribution, etc.

In specific implementation, the anti-interference line 120 is also arranged on the substrate. Both ends of the anti-interference line 120 are connected to the ground layer 110. The anti-interference line 120 is a wire, and both ends are connected to the ground layer 110 and short-circuited to the ground. The anti-interference line 120 is arranged in parallel with the interference line 130 and the disturbed line 140 to suppress the crosstalk between the interference line 130 and the disturbed line 140. Preferably, the anti-interference line 120, the interference line 130 and the disturbed line 140 are arranged in parallel.

In this embodiment, crosstalk includes inductive coupling and capacitive coupling. When the magnetic field on the interference line 130 is coupled to the anti-interference line 120 in an inductive coupling manner, the magnetic field generated by the induced current on the anti-interference line 120 partially offsets the magnetic field on the interference line 130 to reduce the inductive coupling between the interference line 130 and the disturbed line 140. When the electric field on the interference line 130 is coupled to the anti-interference line 140 in a capacitive coupling manner, the capacitive coupling voltage of the anti-interference line 140 is zero due to grounding, so as to reduce the capacitive coupling between the interference line 130 and the disturbed line 140.

It should be noted that, in a specific implementation, the anti-interference line 120 is arranged near the interference line 130 and the disturbed line 140, and the distance between the three can be determined according to actual conditions. As long as the magnetic field and electric field on the interference line 130 can be coupled to the anti-interference line 120, this embodiment does not impose any limitation on its specific value.

Compared with the method of increasing the length and spacing of the transmission line to prevent crosstalk in the related art, since the present embodiment suppresses the crosstalk between the interfering line 130 and the disturbed line 140 by adding the anti-interference line 120, there is no restriction on the length of the interfering line 130 and the disturbed line 140 and the spacing between the two, which saves space for the printed circuit board, makes it easier to miniaturize the printed circuit board, and also reduces the cost and is easy to implement. In addition, the frequency range of crosstalk suppression in the present embodiment is relatively wide. According to experiments, the present embodiment can effectively suppress crosstalk between transmission lines within a frequency range of 100KHz to 300MHz.

It can be seen that for the crosstalk between the disturbed line 140 and the interfering line 130 on the printed circuit board 100 that use the ground layer 110, i.e., the ground plane, as the signal return channel, this embodiment adds an anti-interference line 120 parallel to the disturbed line 140 and the interfering line 130, i.e., a wire with both ends short-circuited to the ground, so that the magnetic field on the interfering line 130 is coupled to the anti-interference line 120 in an inductive coupling and/or capacitive coupling manner, thereby suppressing the coupling between the interfering line 130 and the anti-interference line 140.

The basic principle of this embodiment is described in more detail below in conjunction with FIG. 2 and FIG. 3 .

Referring to FIG. 2 , FIG. 2 is an equivalent circuit diagram of crosstalk between parallel transmission lines in the related art. There are distributed inductance L _m and distributed capacitance C _m between the interfering line 130 and the disturbed line 140. If the frequency of the signal or noise in the interfering line 130 is high, the interference will be coupled to the loop where the disturbed line 140 is located through the distributed inductance L _m and the distributed capacitance C _m . This process is called inductive and capacitive coupling, which can also be called magnetic field and electric field coupling. FIG. 2 shows an equivalent circuit model of crosstalk between the interfering line 130 and the disturbed line 140, wherein _VS is the interference voltage of the interfering line, _RS is the source impedance of the interfering line, _CG is the capacitance to ground of the interfering line, _LG is the self-inductance of the interfering line, and _RL is the load impedance of the interfering line. _RNE is the near-end load impedance of the disturbed line, _RFE is the far-end load impedance of the disturbed line, _CR is the capacitance to ground of the disturbed line, and _LR is the self-inductance of the disturbed line. _Cm is the mutual capacitance between the interfering line and the disturbed line, and _Lm is the mutual inductance between the interfering line and the disturbed line.

If the interference voltage coupled on the near-end load impedance R _NE of the disturbed loop is V _NE , and the interference voltage coupled on the far-end load impedance R _FE is V _FE , then the crosstalk between the disturbing loop and the disturbed loop can be defined as the ratio of the disturbed loop V _NE or V _FE to the input voltage V _S , where V _NE /V _S is the near-end crosstalk and V _FE /V _S is the far-end crosstalk. Their expressions are:

The first term of the above two equations is inductive coupling, and the second term is capacitive coupling. It can be seen that both near-end crosstalk and far-end crosstalk will decrease with the decrease of _Lm or _Cm .

Referring again to FIG. 3 , FIG. 3 shows an equivalent circuit diagram of an embodiment in which a short-circuited wire parallel to the interference wire 130 and the disturbed wire 140 is added between the interference wire 130 and the disturbed wire 140. The short-circuited wire may be referred to as an “anti-interference wire”. L _m1 is the mutual inductance between the interference wire and the sacrificial wire, C _m1 is the mutual capacitance between the interference wire 130 and the anti-interference wire 120, and C _m2 is the mutual capacitance between the anti-interference wire 120 and the disturbed wire 140.

When the magnetic field of the high-frequency signal or noise current on the interference line 130 is coupled to the anti-interference line 120 through L _m1 in an inductive coupling manner, an induced electromotive force is generated on the anti-interference line 120. Since the anti-interference line 120 is short-circuited to the ground, a large induced current is generated on the anti-interference line 120. According to Lenz's law, the magnetic field of the induced current on the anti-interference line 120 will partially offset the magnetic field of the high-frequency signal or noise current on the interference line, thereby reducing the magnetic flux of the interference line 130 on the disturbed line 140, and correspondingly, the inductive coupling between the two is reduced.

When the high-frequency signal or noise voltage on the interference line 130 is capacitively coupled to the anti-interference line 120 through C _m1 , since the anti-interference line 120 is short-circuited to the ground, the capacitive coupling voltage on the anti-interference line 120 is 0, and theoretically no AC voltage will be coupled to the disturbed line through C _m2 . At the same time, due to the existence of the anti-interference line 120, the mutual capacitance C _m between the interference line 130 and the disturbed line 140 is greatly reduced, and accordingly, the capacitive coupling between the two is reduced.

As described above, in this embodiment, for the crosstalk between the disturbed line 130 and the interfering line 140 on the printed circuit board using the ground plane as the signal return channel, an anti-interference line 120 parallel to the disturbed line 140 and the interfering line 130 and short-circuited to the ground at both ends is added between the disturbed line 140 and the interfering line 130 to achieve crosstalk suppression between the disturbed line 140 and the interfering line 130. This embodiment can reduce the inductive coupling and capacitive coupling between the disturbed line 140 and the interfering line 130 on the printed circuit board 100 using the ground plane as the return channel.

In some embodiments, referring to Fig. 4, the anti-interference line 120 is disposed between the interfering line 130 and the disturbed line 140. Furthermore, the distance from the anti-interference line 120 to the interfering line 130 is equal to the distance from the anti-interference line 120 to the disturbed line 140, that is, the anti-interference line 120 is placed in the middle of the interfering line 130 and the disturbed line 140, so as to further improve the suppression effect of crosstalk.

In a specific implementation, the distance between the anti-interference line 120 and the interference line 130 , and the distance between the anti-interference line 120 and the disturbed line 140 may be one time the line width w.

5 , the anti-interference line 120 is disposed on a side of the interference line 130 away from the disturbed line 140. Specifically, the spacing between the anti-interference line 120 and the interference line 130, and between the interference line 130 and the disturbed line 140 can be one time the line width w.

6 , the anti-interference line 120 is disposed on a side of the disturbed line 140 away from the disturbed line 130. Specifically, the spacing between the disturbed line 130 and the disturbed line 140, and between the disturbed line 140 and the anti-interference line 120 can also be one time the line width w.

It should be noted that in the implementation schemes shown in Figures 4, 5 and 6, the spacing between the interference line 130, the anti-interference line 120 and the disturbed line 140 is only schematically shown as one times the routing width. In specific implementations, the spacing between the three can also be any value less than 3w and greater than 1w, for example, 2w, etc. This embodiment does not impose any limitation on its specific value.

In some embodiments, there is one anti-interference line 120 , and the anti-interference line 120 can be set at any position between the interfering line 130 and the disturbed line 140 , on the side of the interfering line 130 away from the disturbed line 140 , or on the side of the disturbed line 140 away from the interfering line 130 .

Further, in some embodiments, when the anti-interference line 120 is placed between the interfering line 130 and the disturbed line 140, the distance from the anti-interference line 120 to the interfering line 130 is greater than the distance from the anti-interference line 120 to the disturbed line 140. In other words, the anti-interference line 120 is placed close to the disturbed line 140 to further improve the anti-crosstalk effect.

Of course, in some other embodiments, there may be two or more anti-interference wires 120 . In this case, each anti-interference wire 120 may be arranged in any one of the three positions mentioned above.

For example, there are two anti-interference lines. The anti-interference line 120 can be set on the left side of the interfering line 130 and the right side of the disturbed line 140. The two anti-interference lines 120 can also be set on the left side of the interfering line 130 or on the right side of the disturbed line 140. The two anti-interference lines 120 can also be set between the interfering line 130 and the disturbed line 140 to further improve the anti-crosstalk effect.

In some embodiments, the printed circuit board 100 is provided with at least one conductive layer, each conductive layer is provided in parallel with the substrate, and the anti-interference line 120, the interference line 130 and the disturbed line 140 are all provided in the same conductive layer.

During specific implementation, the line widths of the anti-interference line 120 , the interference line 130 , and the disturbed line 140 may be the same or different, and this embodiment does not impose any limitation thereto.

In a specific application, the relative positions of the anti-interference line 120, the interfering line 130 and the disturbed line 140 will affect the crosstalk suppression effect. The following experiment illustrates the anti-crosstalk effect of the anti-interference line 120 when the disturbed line 140 and the interfering line 130 are at different intervals.

The parameters used in the following experiments are: transmission line length: 20cm, that is, the length of the interference line 130 and the disturbed line 140 are both 20cm; the length of the anti-interference line 120 is 20cm; the thickness of the substrate: 0.5mm; the thickness of the ground layer 110: 0.035mm; the width of the copper wire: 0.254mm, that is, the width of the anti-interference line 120, the interference line 130 and the disturbed line 140, that is, the trace width W; the termination load of the interference line 130 and the disturbed line 140: 50Ω.

Experiment 1: When the distance between the interfering line 130 and the disturbed line 140 is 1 times the line width, the anti-interference line 120 is placed on the left side of the interfering line 130 or on the right side of the disturbed line 140, as shown in Figure 7. The anti-interference line 120 can be placed at position A or position B as shown in the figure, where position A is located at 1 times the line width on the left side of the interfering line 130, and position B is located at 1 times the line width on the right side of the disturbed line 140. It should be noted that the left and right here are relative to the state shown in Figure 7.

Curve a, curve b and curve c shown in Fig. 8 are crosstalk curves between the interference line 130 and the disturbed line 140 when the anti-interference line 120 is located at position A, at position B, and when no anti-interference line 120 is provided between the interference line 130 and the disturbed line 140. In the figure, the horizontal axis is the frequency of the interference signal emitted by the interference line 130, and the vertical axis is the crosstalk coefficient.

It can be seen from Figure 8 that when the distance between the interfering line 130 and the disturbed line 140 is 1 times the routing width, when the anti-interference line 120 is located at position A and position B respectively, it has a suppressing effect on crosstalk within the frequency of 100KHz to 300MHz, and when the anti-interference line 120 is placed at position B, that is, at one times the line width outside the disturbed line 140, the best crosstalk suppression effect can be achieved.

Experiment 2: When the distance between the interfering line 130 and the disturbed line 140 is 3 times the line width, the anti-interference line 120 can be placed on the left side of the interfering line 130, or on the right side of the disturbed line 140, or between the interfering line 130 and the disturbed line 140, as shown in Figure 9. Among them, position A shown in Figure 9 is located at one line width on the left side of the interfering line 130, position B is located at one line width on the right side of the disturbed line 140, and position C is located in the middle of the interfering line and the disturbed line. It should be noted that the left and right here are relative to the state shown in Figure 9.

Curve a, curve b, curve c and curve d in Fig. 10 are respectively the crosstalk curves between the interference line 130 and the disturbed line 140 when the anti-interference line 120 is located at position A, position B, position C, and when the anti-interference line 120 is not provided between the interference line 130 and the disturbed line 140. In the figure, the horizontal axis is the frequency of the interference signal emitted by the interference line 130, and the vertical axis is the crosstalk coefficient.

It can be seen from Figure 10 that when the distance between the interfering line 130 and the disturbed line 140 is 3 times the routing width, when the anti-interference line 120 is located at position A, position B and position C respectively, it has a suppressing effect on crosstalk within the frequency of 100KHz to 300MHz, and when the anti-interference line 120 is placed at position C, that is, the middle position between the interfering line 130 and the disturbed line 140, the suppressing effect on crosstalk within the frequency of 100KHz to 300MHz is the best.

Experiment 3: When the distance between the interfering line 130 and the disturbed line 140 is greater than 3 times the line width, an example is given in which the distance between the interfering line 130 and the disturbed line 140 is 5 times the line width.

From the analysis in Experiment 2, it can be seen that the crosstalk suppression effect is best when the anti-interference line 120 is set between the interfering line 130 and the disturbed line 140. Therefore, in the case where there is a 5-fold trace width between the interfering line 130 and the disturbed line 140, the position where the anti-interference line 120 can play a good suppression effect should be located between the interfering line 130 and the disturbed line 140. Position C, Position D, and Position E shown in Figure 11 are the placement positions of the anti-interference line 120 in this experiment; among them, Position C is located at one trace width on the right side of the interfering line 130, Position D is located at one trace width on the left side of the disturbed line 140, and Position E is located in the middle of the interfering line 130 and the disturbed line 140.

When the anti-interference line 120 is located at the above three positions respectively, and when there is no anti-interference line 120 , the crosstalk curve between the interfering line 130 and the disturbed line 140 is shown in FIG. 12 .

Curve a, curve b, curve c and curve d in Fig. 12 are crosstalk curves between the interference line 130 and the disturbed line 140 when the anti-interference line 120 is located at position C, position D, position E, and when no anti-interference line 120 is provided between the interference line 130 and the disturbed line 140. In the figure, the horizontal axis is the frequency of the interference signal emitted by the interference line 130, and the vertical axis is the crosstalk coefficient.

As can be seen from FIG. 12, when the distance between the interference line 130 and the disturbed line 140 is 5 times the routing width, when the anti-interference line 120 is located at position C, position D and position E, the crosstalk within the frequency range of 100KHz to 300MHz is inhibited, and when the anti-interference line 120 is placed at position E, that is, the middle position between the interference line 130 and the disturbed line 140, the crosstalk within the frequency range of 100KHz to 300MHz is best inhibited. In addition, it can be seen from FIG. 12 that when the anti-interference line 120 is placed between the interference line 130 and the disturbed line 140, the distance from the anti-interference line 120 to the interference line 130 is greater than the distance from the anti-interference line 120 to the disturbed line 140, that is, when the anti-interference line 120 is arranged close to the disturbed line 140, the anti-crosstalk effect is better.

In summary, this embodiment reduces the crosstalk between transmission lines on the printed circuit board by setting a wire adjacent to and parallel to the transmission line and short-circuiting the two ends to the ground, i.e., an anti-interference wire. Compared with the related art method of suppressing crosstalk by increasing the distance between the interfering wire and the disturbed wire, using magnetic beads or bypass capacitors, and using shielded cables, the embodiment of the present invention has the advantages of convenient setting, low cost, and a wide frequency range (100KHz to 300MHz) for suppressing crosstalk in practical applications.

Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims (10)

1. A printed circuit board for suppressing transmission line crosstalk, comprising:

A substrate;

a ground layer disposed on the substrate;

The transmission line is arranged on the substrate and comprises an interference line and a disturbed line;

The anti-interference line is arranged on the substrate, two ends of the anti-interference line are connected to the ground layer, the anti-interference line, the interference line and the interfered line are arranged in parallel, and the anti-interference line is used for inhibiting crosstalk between the interference line and the interfered line.

2. The printed circuit board for suppressing transmission line crosstalk of claim 1,

The crosstalk includes inductive coupling and capacitive coupling;

When the interference line sends a signal, a magnetic field on the interference line is coupled to the anti-interference line in an inductive coupling mode, and the magnetic field generated by the induced current on the anti-interference line partially counteracts the magnetic field on the interference line, so that the inductive coupling between the interference line and the interfered line is reduced;

When the interference line sends a signal, an electric field on the interference line is coupled to the anti-interference line in a capacitive coupling mode, and the anti-interference line is grounded so that the capacitive coupling voltage is zero, thereby reducing the capacitive coupling between the interference line and the interfered line.

3. The printed circuit board for suppressing transmission line crosstalk of claim 1,

The anti-interference line, the interference line and the disturbed line are arranged in parallel.

4. The printed circuit board for suppressing transmission line crosstalk of claim 1,

The anti-interference line is arranged between the interference line and the interfered line.

5. The printed circuit board for suppressing transmission line crosstalk of claim 4,

And the distance from the anti-interference line to the interference line is equal to the distance from the anti-interference line to the interfered line.

6. The printed circuit board for suppressing transmission line crosstalk of claim 4,

The distance from the anti-interference line to the interference line is larger than the distance from the anti-interference line to the interfered line.

7. The printed circuit board for suppressing transmission line crosstalk of claim 1,

The anti-interference line is arranged on one side of the interference line far away from the interfered line.

8. The printed circuit board for suppressing transmission line crosstalk of claim 1,

The anti-interference line is arranged on one side of the interfered line far away from the interference line.

9. The printed circuit board for suppressing transmission line crosstalk of claim 1,

The number of the anti-interference lines is at least one, and each anti-interference line can be arranged at any position among the position between the interference line and the interfered line, the position of the interference line away from the side of the interfered line and the position of the interfered line away from the side of the interference line.

10. The printed circuit board for suppressing transmission line crosstalk according to any of claims 1 to 8, further comprising:

and each conductive layer is arranged in parallel with the substrate, and the anti-interference line, the interference line and the disturbed line are arranged on the same conductive layer.