阅读说明：本技术 一种印刷电路板和印刷电路板的设计方法 (Printed circuit board and design method thereof ) 是由 李雅君 于 2021-09-18 设计创作，主要内容包括：本发明提出了一种印刷电路板和印刷电路板的设计方法,至少包括信号层和混合PP层；信号层按照传输的信号速率进行分区；混合PP层由损耗不同的基材拼接组成；且传输信号速率最大的分区在混合PP层对应的区域采用损耗最小的基材；除传输信号速率最大的分区之外的分区在混合PP层对应的区域分别采用相应损耗的基材。本发明还提出了一种印刷电路板的设计方法,用于设计一种印刷电路板。根据将信号层分割成不同的基材区,然后在每个信号层的上下使用不同成本的介质基材,基材进行同层混合的设计,在基材压合时,将PP水平旋转预设角度。可以极大地避免编织效应对高速信号的影响,保证信号完整性和产品性能的基础上降低PCB的基材生产成本。(The invention provides a printed circuit board and a design method thereof, which at least comprises a signal layer and a mixed PP layer; the signal layer is partitioned according to the transmission signal rate; the mixed PP layer is formed by splicing base materials with different losses; the partition with the maximum transmission signal rate adopts the base material with the minimum loss in the area corresponding to the mixed PP layer; and the subareas except the subarea with the maximum transmission signal rate respectively adopt the base materials with corresponding losses in the areas corresponding to the mixed PP layer. The invention also provides a design method of the printed circuit board, which is used for designing the printed circuit board. According to the method, a signal layer is divided into different substrate areas, then medium substrates with different costs are used above and below each signal layer, the design of mixing the same layers is carried out on the substrates, and when the substrates are laminated, PP is horizontally rotated by a preset angle. The influence of the weaving effect on the high-speed signal can be greatly avoided, and the production cost of the base material of the PCB is reduced on the basis of ensuring the integrity of the signal and the performance of the product.)

1. A printed circuit board, characterized in that it comprises at least a signal layer and a hybrid PP layer;

the signal layer is partitioned according to the transmission signal rate; the mixed PP layer is formed by splicing base materials with different losses;

the partition with the maximum transmission signal rate adopts the base material with the minimum loss in the area corresponding to the mixed PP layer; and the subareas except the subarea with the maximum transmission signal rate respectively adopt the base materials with corresponding losses in the areas corresponding to the mixed PP layer.

2. The printed circuit board of claim 1, wherein the signal layer being partitioned according to the signal rate of transmission comprises: the signal layer is divided into a first subarea, a second subarea and a third subarea according to the transmission signal rate;

the transmission rate is greater than a first rate threshold value and is a first partition; the second partition is larger than the second speed threshold and smaller than the first speed threshold; a third partition is set when the speed is smaller than the second speed threshold; wherein the first rate threshold is greater than the second rate threshold.

3. The printed circuit board of claim 2, wherein the hybrid PP layer is composed of a substrate with different loss, and further comprising: the mixed PP layer is formed by transversely splicing a first base material, a second base material and a third base material, wherein the losses of the first base material, the second base material and the third base material are sequentially increased; the first partition adopts a first base material in the area corresponding to the mixed PP layer; the second partition adopts a second base material in the area corresponding to the mixed PP layer; the third zone employs a third substrate in the area corresponding to the mixed PP layer.

4. A printed circuit board according to claim 3, wherein the hybrid PP layer is horizontally rotated by a predetermined angle with respect to the signal layer for eliminating propagation delay caused by programming effect.

5. The printed circuit board of claim 4, wherein the predetermined angle is any one of 10 degrees to 35 degrees.

6. The printed circuit board of claim 2, wherein the hybrid PP layer is composed of a substrate with different loss by splicing: the mixed PP layer is formed by vertically splicing a first base material and a second base material with sequentially-increased loss; the first partition adopts a first base material in the area corresponding to the mixed PP layer; the second subarea and the third subarea adopt second base materials in the areas corresponding to the mixed PP layers.

7. The printed circuit board of claim 6, wherein when the mixed PP layer is formed by vertically splicing a first substrate and a second substrate with sequentially higher loss, the dielectric constant of the mixed PP layer is as follows after the first substrate and the second substrate are pressed together:

wherein epsilon₁Is the dielectric constant of the first substrate; epsilon₂Is the dielectric constant of the second substrate; h is₁Is the thickness of the first substrate; h is₂Is the thickness of the first substrate.

8. A method of designing a printed circuit board for designing a printed circuit board according to any one of claims 1 to 7, comprising the steps of:

partitioning a signal layer of the printed circuit board according to the transmission rate of signals;

cutting the corresponding PP layer according to the subarea of the signal layer; and the most important subarea for transmitting signals adopts the base material with the minimum loss in the corresponding area after the mixed PP layer is cut; the subareas except the subarea which is most important for transmitting signals respectively adopt the base materials with corresponding losses in the areas corresponding to the cutting of the mixed PP layer.

9. The method of claim 8, wherein the partitioning the signal layers of the printed circuit board according to the importance of the transmitted signals comprises: dividing a signal layer of the printed circuit board into a first partition, a second partition and a third partition, wherein the importance degrees of the first partition, the second partition and the third partition are sequentially reduced according to the importance degrees of transmitted signals.

10. The method as claimed in claim 9, wherein the area with the highest transmission signal rate is formed by using a substrate with the lowest loss in the area corresponding to the mixed PP layer; the method for respectively adopting the base materials with corresponding losses in the areas corresponding to the mixed PP layer by the subareas except the subarea with the maximum transmission signal rate comprises the following steps:

the mixed PP layer is formed by transversely splicing a first base material, a second base material and a third base material which are sequentially increased in loss; the first partition adopts a first base material in the area corresponding to the mixed PP layer; the second partition adopts a second base material in the area corresponding to the mixed PP layer; the third partition adopts a third base material in the area corresponding to the mixed PP layer;

or the mixed PP layer is formed by vertically splicing a first base material and a second base material with sequentially-increased loss; the first partition adopts a first base material in the area corresponding to the mixed PP layer; the second subarea and the third subarea adopt second base materials in the areas corresponding to the mixed PP layers.

Technical Field

The invention belongs to the technical field of printed circuit board design, and particularly relates to a printed circuit board and a design method of the printed circuit board.

Background

PCB, (Printed Circuit Board) is a Printed Circuit Board. With the development of electronic technology and the increase of competitive pressure in industry, the overall server product tends to be miniaturized and the design and production cost is reduced, so that in the research and development process, research and development designers need to consider and process a plurality of problems encountered in the PCB design process more finely, and the product design and production cost is reduced on the premise of ensuring the optimal product performance.

In the existing PCB design process, in the aspect of substrate selection, the PCB substrate meeting the requirements can be selected preferentially according to the signal transmission rate and the signal loss requirements on the PCB board card, so that the signal quality of important signal lines is ensured. Taking an 8-layer PCB design as an example, a typical stack structure and substrate selection is shown in Table 1 below:

lamination of layers	Type (B)	Material	Thickness (mil)	Type of material
					top	SIGNAL	Copper	1.9	1oz+Plating
		PP	2.7	PP(1080(RC65))
					L2	GND	Copper	1.2	1oz
		Core	4.0	CORE(1*3313)
					L3	SIGNAL	Copper	1.2	1oz
		PP	15.0	PP(2116(RC61)*3)
					L4	GND/PWR	Copper	2.4	2oz
		Core	5.0	CORE(2*1078)
					L5	GND/PWR	Copper	2.4	2oz
		PP	15.0	PP(2116(RC61)*3)
					L6	SIGNAL	Copper	1.2	1oz
		Core	4.0	CORE(1*3313)
					L7	GND	Copper	1.2	1oz
		PP	2.7	PP(1080(RC65))
					bottom	SIGNAL	Copper	1.9	1oz+Plating

As can be seen from table 1, in selecting the PP and CORE substrate types, the material types are adjusted by using one entire layer as a unit, and the substrate that meets the conditions and has the lowest cost is not selected according to the actual PCB wiring condition of each layer. Although different base materials used by the board card can be adjusted according to different board card signals in the prior art, a small number of important signal lines are often arranged on a certain layer, and a whole layer of Low Loss base materials with Low Loss, good performance and high cost are used, so that the cost is not reduced very easily.

Disclosure of Invention

In order to solve the above technical problems, the present invention provides a printed circuit board and a design method of the printed circuit board. Firstly, the requirements of signal performance are met, and the production cost can be greatly reduced; by fully utilizing the substrate waste and the substrate with the size not enough for producing large materials, the utilization rate of the substrate is improved, the environment is protected, and the material cost is reduced.

In order to achieve the purpose, the invention adopts the following technical scheme:

a printed circuit board comprising at least a signal layer and a hybrid PP layer;

the signal layer is partitioned according to the transmission signal rate; the mixed PP layer is formed by splicing base materials with different losses;

the partition with the maximum transmission signal rate adopts the base material with the minimum loss in the area corresponding to the mixed PP layer; and the subareas except the subarea with the maximum transmission signal rate respectively adopt the base materials with corresponding losses in the areas corresponding to the mixed PP layer.

Further, the partitioning the signal layer according to the transmission signal rate includes: the signal layer is divided into a first subarea, a second subarea and a third subarea according to the transmission signal rate;

the transmission rate is greater than a first rate threshold value and is a first partition; the second partition is larger than the second speed threshold and smaller than the first speed threshold; a third partition is set when the speed is smaller than the second speed threshold; wherein the first rate threshold is greater than the second rate threshold.

Further, the mixed PP layer is formed by splicing base materials with different losses, and further comprises: the mixed PP layer is formed by transversely splicing a first base material, a second base material and a third base material, wherein the losses of the first base material, the second base material and the third base material are sequentially increased; the first partition adopts a first base material in the area corresponding to the mixed PP layer; the second partition adopts a second base material in the area corresponding to the mixed PP layer; the third zone employs a third substrate in the area corresponding to the mixed PP layer.

Further, the hybrid PP layer is horizontally rotated by a preset angle with respect to the signal layer, so as to eliminate transmission delay caused by programming effect.

Further, the preset angle is any one of 10 degrees to 35 degrees.

Further, the mixed PP layer is formed by splicing base materials with different losses and comprises the following steps: the mixed PP layer is formed by vertically splicing a first base material and a second base material with sequentially-increased loss; the first partition adopts a first base material in the area corresponding to the mixed PP layer; the second subarea and the third subarea adopt second base materials in the areas corresponding to the mixed PP layers.

Further, when the mixed PP layer is formed by vertically splicing a first substrate and a second substrate, which have sequentially increased losses, the dielectric constant of the mixed PP layer is as follows after the first substrate and the second substrate are pressed:

wherein，ε₁Is the dielectric constant of the first substrate; epsilon₂Is the dielectric constant of the second substrate; h is₁Is the thickness of the first substrate; h is₂Is the thickness of the first substrate.

The invention also provides a design method of the printed circuit board, which is used for designing the printed circuit board and comprises the following steps:

partitioning a signal layer of the printed circuit board according to the transmission rate of signals;

cutting the corresponding PP layer according to the subarea of the signal layer; and the most important subarea for transmitting signals adopts the base material with the minimum loss in the corresponding area after the mixed PP layer is cut; the subareas except the subarea which is most important for transmitting signals respectively adopt the base materials with corresponding losses in the areas corresponding to the cutting of the mixed PP layer.

Further, the partitioning the signal layer of the printed circuit board according to the importance degree of the transmitted signal includes: dividing a signal layer of the printed circuit board into a first partition, a second partition and a third partition, wherein the importance degrees of the first partition, the second partition and the third partition are sequentially reduced according to the importance degrees of transmitted signals.

Further, the partition with the maximum transmission signal rate adopts a base material with minimum loss in a region corresponding to the mixed PP layer; the method for respectively adopting the base materials with corresponding losses in the areas corresponding to the mixed PP layer by the subareas except the subarea with the maximum transmission signal rate comprises the following steps:

the mixed PP layer is formed by transversely splicing a first base material, a second base material and a third base material which are sequentially increased in loss; the first partition adopts a first base material in the area corresponding to the mixed PP layer; the second partition adopts a second base material in the area corresponding to the mixed PP layer; the third partition adopts a third base material in the area corresponding to the mixed PP layer; or the mixed PP layer is formed by vertically splicing a first base material and a second base material with sequentially-increased loss; the first partition adopts a first base material in the area corresponding to the mixed PP layer; the second subarea and the third subarea adopt second base materials in the areas corresponding to the mixed PP layers.

The effect provided in the summary of the invention is only the effect of the embodiment, not all the effects of the invention, and one of the above technical solutions has the following advantages or beneficial effects:

the invention provides a printed circuit board and a design method of the printed circuit board, wherein the printed circuit board at least comprises a signal layer and a mixed PP layer; the signal layer is partitioned according to the transmission signal rate; the mixed PP layer is formed by splicing base materials with different losses; the partition with the maximum transmission signal rate adopts the base material with the minimum loss in the area corresponding to the mixed PP layer; and the subareas except the subarea with the maximum transmission signal rate respectively adopt the base materials with corresponding losses in the areas corresponding to the mixed PP layer. The invention also provides a design method of the printed circuit board, which is used for designing the printed circuit board. According to the PCB wiring design of the signal layer, the signal layer is divided into different substrate areas, then the dielectric substrates with different costs are used on the upper part and the lower part of each signal layer, and the design that the substrates are mixed on the same layer is provided; small area scrap of some substrates can also be fully utilized, with the PP being rotated horizontally 10 degrees as the substrates are being laminated. The requirements of signal performance are met, and the production cost can be greatly reduced; by fully utilizing the substrate waste and the substrate with the size not enough for producing large materials, the utilization rate of the substrate is improved, the environment is protected, and the material cost is reduced. And the Layout engineer uses the design of the 10-degree wiring in the process of designing the PCB wiring, so that the Layout is more convenient, faster and easier to realize, the influence of the weaving effect on the high-speed signal can be greatly avoided, the slight change of the line width caused by the frequent corner of the wiring is avoided, and the reduction of the production cost of the base material of the PCB on the basis of ensuring the integrity of the signal and the performance of the product is facilitated.

Drawings

Fig. 1 is a schematic diagram of a substrate selection in a printed circuit board according to embodiment 1 of the present invention;

fig. 2 is a schematic diagram of a high-speed line of a signal layer of a printed circuit board according to embodiment 1 of the present invention;

fig. 3 is a schematic diagram illustrating a signal layer region division in a printed circuit board according to embodiment 1 of the present invention;

fig. 4 is a schematic diagram illustrating a variation of a cross-region line width in a printed circuit board according to embodiment 1 of the present invention;

FIG. 5 is a schematic diagram of the substrate lamination of a printed circuit board according to embodiment 1 of the present invention;

fig. 6 is a switching diagram of a horizontal pressing process of a CORE layer in a printed circuit board according to embodiment 1 of the present invention;

fig. 7 is a schematic view of horizontal press-fitting of a printed circuit board according to embodiment 1 of the present invention;

fig. 8 is a top view of a printed circuit board according to embodiment 1 of the present invention, in which a PP layer is horizontally rotated by 10 degrees;

fig. 9 is a front view of a printed circuit board according to embodiment 1 of the present invention, in which a PP layer is horizontally rotated by 10 degrees;

FIG. 10 is a schematic diagram showing the effect of the programming effect in example 1 of the present invention;

FIG. 11 is a schematic view of a vertical laminated substrate in example 2 of the present invention;

fig. 12 is a flowchart of a printed circuit board design method according to embodiment 3 of the present invention.

Detailed Description

In order to clearly explain the technical features of the present invention, the following detailed description of the present invention is provided with reference to the accompanying drawings. The following disclosure provides many different embodiments, or examples, for implementing different features of the invention. To simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Furthermore, the present invention may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. It should be noted that the components illustrated in the figures are not necessarily drawn to scale. Descriptions of well-known components and processing techniques and procedures are omitted so as to not unnecessarily limit the invention.

Example 1

Embodiment 1 of the present invention provides a printed circuit board, which can select different levels of base materials according to a wiring design of each layer of PCB signal lines, and select different areas of the same layer to use base materials with different costs for mixing. The printed circuit board at least comprises a signal layer and a mixed PP layer;

the signal layer is partitioned according to the transmission signal rate; the mixed PP layer is formed by splicing base materials with different losses; the partition with the maximum transmission signal rate adopts the base material with the minimum loss in the area corresponding to the mixed PP layer; and the subareas except the subarea with the maximum transmission signal rate respectively adopt the base materials with corresponding losses in the areas corresponding to the mixed PP layer.

The signal layer is divided into a first subarea, a second subarea and a third subarea according to the transmission signal rate; the transmission rate is greater than a first rate threshold value and is a first partition; the second partition is larger than the second speed threshold and smaller than the first speed threshold; a third partition is set when the speed is smaller than the second speed threshold; wherein the first rate threshold is greater than the second rate threshold. The mixed PP layer is formed by transversely splicing a first base material, a second base material and a third base material, wherein the losses of the first base material, the second base material and the third base material are sequentially increased. The first partition adopts a first base material in the area corresponding to the mixed PP layer; the second partition adopts a second base material in the area corresponding to the mixed PP layer; the third zone employs a third substrate in the area corresponding to the mixed PP layer.

Fig. 1 is a schematic diagram of a substrate selection in a printed circuit board according to embodiment 1 of the present invention; the PCB wiring for each signal layer is divided into a Normal (Normal region), a low loss region, and a transition region portion according to the rate of signal lines, signal importance, and the like. The Low-Loss and high-performance Ultra-Low-Loss base material is used at the critical signal line, the Normal base material (common base material) with Low Loss, general performance and Low cost is used at the non-critical signal line, and the Low-Loss base material (Low-Loss base material) is used in the transition region. Taking 16GHz, strip line as an example, the loss criteria for Normal substrate is 2.1dB/in, for Low-loss substrate is 1.49dB/in, and for Ultra Low-loss substrate is 0.96 dB/in. Fig. 1 is a schematic diagram of a substrate selection in a printed circuit board according to embodiment 1 of the present invention; fig. 2 is a schematic diagram of a high-speed line of a signal layer of a printed circuit board according to embodiment 1 of the present invention, where the signal layer includes only a few pairs of high-speed differential lines, and other portions are low-speed single-ended lines. Fig. 3 is a schematic diagram illustrating a signal layer region division in a printed circuit board according to embodiment 1 of the present invention; dividing the reference medium of the signal layer into three parts, wherein the left part has no important signal line and is a Normal area, and the reference medium of the signal layer is a Normal substrate; the right part is provided with an important signal line with high transmission rate, which is a Low loss area, and the reference medium of the important signal line is selected from an Ultra Low loss base material; a5 mm transition region was provided between the Normal region and the Low loss region, and a Low loss substrate was used. Because the dielectric constants of different substrates are different, when a signal enters a Normal region from a low-loss region through a transition region, the dielectric constant of the substrate is increased, and the line width of a signal line is reduced; taking a 50ohms impedance line as an example, the signal line is reduced from 7mil to 6.4mil at point a and from 6.4mil to 6mil at point B, as shown in fig. 4, which is a schematic diagram of the variation of the line width across the area in the printed circuit board according to embodiment 1 of the present invention, corresponding to the line width variation data in the following table two.

After the base material parts with different costs are cut, the base material selection requirement of each layer is sent to a PCB (printed Circuit Board) factory, and the PP and the CORE are processed by the PCB factory according to the base material area cutting of each layer when the materials are prepared. When pressing the CORE, different substrates need to be cut into required sizes according to a substrate area division diagram provided by a designer, for example, fig. 5 is a schematic diagram of pressing the substrates in the printed circuit board according to embodiment 1 of the present invention; and mixing the base materials with different costs in the same layer. Then, the copper foil, the mixed base material and the copper foil are pressed together at high temperature and high pressure, and fig. 6 is a switching diagram of the horizontal pressing process of the CORE layer in the printed circuit board according to embodiment 1 of the present invention; forming a hybrid CORE. And when the PCB is pressed, the copper foil, the mixed PP and the mixed CORE are pressed together under equal pressure. Fig. 7 is a schematic view of horizontal press-fitting of a printed circuit board according to embodiment 1 of the present invention; thus, a low-cost board card can be completed. The waste materials with small area of the base materials can be reused, and the utilization rate of the base materials is improved.

Before pressing the CORE and the PCB, the Ultra Low Low substrate needs to be horizontally rotated by a preset angle, and the rotation of the preset angle can be realized between 10 degrees and 35 degrees. (with the increase of the rotation angle, the board utilization rate will be reduced, so from the perspective of cost, 10 degrees is preferred, fig. 8 is a top view of the printed circuit board with the PP layer horizontally rotated by 10 degrees in the embodiment 1 of the present invention, the PCB thus manufactured does not need Layout of 10 degrees by Layout engineers in the PCB wiring process, fig. 9 is a front view of the printed circuit board with the PP layer horizontally rotated by 10 degrees in the embodiment 1 of the present invention, white is a copper plate, black is PP., fig. 10 is a comparison diagram of the programming effect influence of the embodiment 1 of the present invention, the left diagram is a normal trace, and the right diagram is a trace of 10 degrees after PP is rotated.

Example 2

Because the mixing of the same layer is complex in production and processing, a design method for directly pressing the Ultra Low Loss substrate is provided. Namely, the mixed PP layer is formed by splicing substrates with different losses and comprises the following components: the mixed PP layer is formed by vertically splicing a first base material and a second base material with sequentially-increased loss; the first partition adopts a first base material in the area corresponding to the mixed PP layer; the second subarea and the third subarea adopt second base materials in the areas corresponding to the mixed PP layers.

When the mixed PP layer is formed by vertically splicing a first substrate and a second substrate with sequentially-increased loss, the dielectric constant of the mixed PP layer is as follows after the first substrate and the second substrate are pressed:

wherein epsilon₁Is the dielectric constant of the first substrate; epsilon₂Is the dielectric constant of the second substrate; h is₁Is the thickness of the first substrate; h is₂Is the thickness of the first substrate.

When the Layout of the Layout. FIG. 11 is a schematic view of a vertical laminated substrate in example 2 of the present invention;

the dielectric constant of the directly laminated substrate is between that of the Normal substrate and that of the Ultra Low substrate, and the relationship between the dielectric constant epsilon of the directly laminated substrate and that of the Normal substrate and that of the Ultra Low substrate is as follows:

wherein epsilon₁Is the dielectric constant, ε, of a Normal substrate₂Is the dielectric constant, h, of an Ultra Low Loss substrate₁Is the thickness of the Normal substrate, h₂Is the thickness of the Ultra Low Loss substrate.

The loss of the substrate is better than that of a Normal substrate, so that the transmission quality of signals can be ensured, and the cost can be reduced.

Dividing the signal layer into different substrate areas according to the PCB wiring design of the signal layer, and then using medium substrates with different costs on the upper and lower sides of each signal layer to provide the design of mixing the substrates on the same layer; small area scrap of some substrates can also be fully utilized, and the PP is horizontally rotated by any angle of 10 to 35 degrees when the substrates are laminated. Therefore, the method is more convenient, faster and easier to realize, can greatly avoid the influence of the weaving effect on the high-speed signal, avoids the slight change of the line width caused by the frequent rotation angle of the wiring, and is favorable for reducing the production cost of the base material of the PCB on the basis of ensuring the integrity of the signal and the performance of the product.

Example 3

Based on the printed circuit board provided in embodiments 1 and 2 of the present invention, embodiment 3 of the present invention provides a method for designing a printed circuit board. Fig. 12 is a flowchart of a printed circuit board design method according to embodiment 3 of the present invention.

In step S1201, partitioning a signal layer of the printed circuit board according to a transmission rate of a signal;

the signal layer is divided into a first subarea, a second subarea and a third subarea according to the transmission signal rate; the transmission rate is greater than a first rate threshold value and is a first partition; the second partition is larger than the second speed threshold and smaller than the first speed threshold; a third partition is set when the speed is smaller than the second speed threshold; wherein the first rate threshold is greater than the second rate threshold.

In step S1202, cutting a corresponding PP layer according to the partition of the signal layer; and the most important subarea for transmitting signals adopts the base material with the minimum loss in the corresponding area after the mixed PP layer is cut; the subareas except the subarea which is most important for transmitting signals respectively adopt the base materials with corresponding losses in the areas corresponding to the cutting of the mixed PP layer.

The mixed PP layer is formed by transversely splicing a first base material, a second base material and a third base material which are sequentially increased in loss; the first partition adopts a first base material in the area corresponding to the mixed PP layer; the second partition adopts a second base material in the area corresponding to the mixed PP layer; the third partition adopts a third base material in the area corresponding to the mixed PP layer; and is

And the hybrid PP layer is horizontally rotated by a preset angle relative to the signal layer and is used for eliminating transmission time delay caused by programming effect. Wherein the preset angle is any one of 10 degrees to 35 degrees.

Or the mixed PP layer is formed by vertically splicing a first base material and a second base material with sequentially-increased loss; the first partition adopts a first base material in the area corresponding to the mixed PP layer; the second subarea and the third subarea adopt second base materials in the areas corresponding to the mixed PP layers.

When the mixed PP layer is formed by vertically splicing a first substrate and a second substrate with sequentially-increased loss, the dielectric constant of the mixed PP layer is as follows after the first substrate and the second substrate are pressed:

wherein epsilon₁Is the dielectric constant of the first substrate; epsilon₂Is the dielectric constant of the second substrate; h is₁Is the thickness of the first substrate; h is₂Is the thickness of the first substrate.

The embodiment 3 of the invention provides a pressing method of mixed CORE; horizontally rotating the base material by 10 degrees in the pressing process to avoid the design of programming effect; a design method for locally pressing an Ultra Low Loss base material. The method is simple, convenient, fast and easy to realize, can greatly avoid the influence of the weaving effect on the high-speed signal, avoids the fine change of the line width caused by the frequent corner of the wiring, and is favorable for reducing the production cost of the base material of the PCB on the basis of ensuring the integrity of the signal and the performance of the product.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Furthermore, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include elements inherent in the list. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element. In addition, parts of the above technical solutions provided in the embodiments of the present application, which are consistent with the implementation principles of corresponding technical solutions in the prior art, are not described in detail so as to avoid redundant description.

Although the embodiments of the present invention have been described with reference to the accompanying drawings, the scope of the present invention is not limited thereto. Various modifications and alterations will occur to those skilled in the art based on the foregoing description. And are neither required nor exhaustive of all embodiments. On the basis of the technical scheme of the invention, various modifications or changes which can be made by a person skilled in the art without creative efforts are still within the protection scope of the invention.