CN108112162A - Signal transmssion line and its design method, flexible printed circuit board - Google Patents
Signal transmssion line and its design method, flexible printed circuit board Download PDFInfo
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- CN108112162A CN108112162A CN201711435105.XA CN201711435105A CN108112162A CN 108112162 A CN108112162 A CN 108112162A CN 201711435105 A CN201711435105 A CN 201711435105A CN 108112162 A CN108112162 A CN 108112162A
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K1/00—Printed circuits
- H05K1/02—Details
- H05K1/0213—Electrical arrangements not otherwise provided for
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K1/00—Printed circuits
- H05K1/02—Details
- H05K1/11—Printed elements for providing electric connections to or between printed circuits
- H05K1/118—Printed elements for providing electric connections to or between printed circuits specially for flexible printed circuits, e.g. using folded portions
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/0005—Apparatus or processes for manufacturing printed circuits for designing circuits by computer
Abstract
The present invention relates to a kind of signal transmssion line and its design method, which includes the following steps：Determine the outer shape parameter of signal transmssion line；The stepped construction of modelled signal transmission line；Characteristic impedance value of the signal transmssion line in transmission objectives signal is obtained, by characteristic impedance value input and the corresponding banding line model of stepped construction, obtains the characteristic parameter of stepped construction；Corresponding signal transmssion line is designed using the characteristic parameter of outer shape parameter and stepped construction.The above method determines the stepped construction of signal transmssion line, the stepped construction of modelled signal transmission line, characteristic impedance value input with the corresponding banding line model of stepped construction is obtained to the characteristic parameter of stepped construction, utilizes outer shape parameter and the characteristic parameter modelled signal transmission line of stepped construction.The program ensure that the characteristic impedance of signal transmssion line and signal transmission matches impedances, improve the reliability and integrality of signal transmission.A kind of flexible printed circuit board is also provided.
Description
Technical Field
The invention relates to the technical field of electronic circuits, in particular to a signal transmission line, a design method thereof and a flexible printed circuit board.
Background
With the rapid development of electronic products, the functions of the electronic products become more and more complex. The functional modules in various electronic systems need to be connected with each other through signal transmission lines. The signal transmission line is generally connected to each functional module through a connector of the functional module, so that the signal transmission line and the connector of the functional module need to be matched with a signal transmission impedance to ensure the transmission quality of signals.
The characteristic impedance of the transmission conductor of the signal transmission line provided by the conventional technology is not matched with the signal transmission impedance, and as the signal transmission rate increases, the signal transmission line is easy to cause signal transmission distortion and signal strength attenuation when transmitting signals, so that the transmission quality of the signals is reduced, and the signal transmission reliability of the signal transmission line provided by the technology is low. For example, in the conventional technology, a cable or a flexible flat cable is used to connect a functional module to transmit signals, and because the transmission conductor of the cable or the flexible flat cable is not matched with the signal transmission impedance, the high-speed signal transmission is distorted, the high-speed signal transmission reliability is poor, and the transmission quality of the high-speed signal is affected.
Disclosure of Invention
In view of the above, it is necessary to provide a signal transmission line, a method for designing the same, and a flexible printed circuit board, which solve the problem of low reliability of the conventional technology.
A method for designing a signal transmission line includes the steps of:
determining the appearance parameters of the signal transmission line;
designing a laminated structure of the signal transmission line;
acquiring a characteristic impedance value of the signal transmission line when a target signal is transmitted, inputting the characteristic impedance value into a strip line model corresponding to the laminated structure, and acquiring characteristic parameters of the laminated structure of the signal transmission line;
and designing a corresponding signal transmission line by using the appearance parameters and the characteristic parameters of the laminated structure.
The method for designing the signal transmission line determines the appearance parameters of the signal transmission line, designs the laminated structure of the signal transmission line, obtains the characteristic impedance value of the signal transmission line when transmitting the target signal, inputs the characteristic impedance value into a strip line model corresponding to the laminated structure to obtain the characteristic parameters of the laminated structure of the signal transmission line, and designs the corresponding signal transmission line by using the appearance parameters and the characteristic parameters of the laminated structure. The scheme enables the characteristic parameters of the laminated structure of the signal transmission line to correspond to the characteristic impedance value when the target signal is transmitted, ensures that the characteristic impedance of the signal transmission line is matched with the signal transmission impedance, improves the reliability and the integrity of signal transmission, and also improves the electromagnetic compatibility of signal transmission.
In one embodiment, the step of designing the stacked structure of the signal transmission line includes:
sequentially constructing a TOP plane layer, a signal layer and a BOTTOM plane layer to obtain a three-layer signal transmission line structure;
and adopting the three-layer signal line structure as a laminated structure of the signal transmission line.
In one embodiment, the characteristic parameters of the laminated structure of the signal transmission line include the width and thickness of the signal layers, the dielectric constant of the filling medium, and the distance between the layers;
the three-layer transmission line structure comprises a symmetrical three-layer transmission line structure and an asymmetrical three-layer transmission line structure.
In one embodiment, the three-layered transmission line structure is a symmetric three-layered transmission line structure;
the step of inputting the characteristic impedance value into a stripline model corresponding to the laminated structure to obtain characteristic parameters of the laminated structure of the signal transmission line includes:
inputting the characteristic impedance value as a target impedance value of the symmetrical three-layer transmission line structure into a symmetrical strip line model to obtain the width and thickness of the signal layer, the dielectric constant of the filling medium and the distance between the layers; the symmetrical stripline model is as follows:
wherein, Z 0 Presentation instrumentTarget impedance value, epsilon, of the symmetrical three-layer transmission line structure r Denotes the dielectric constant of the filling medium, H denotes the distance between the TOP plane layer and the BOTTOM plane layer, W denotes the width of the signal layer and C t Representing the thickness of the signal layer.
In one embodiment, the tri-layer transmission line structure is an asymmetric tri-layer transmission line structure;
the step of inputting the characteristic impedance value into a stripline model corresponding to the laminated structure to obtain characteristic parameters of the laminated structure of the signal transmission line includes:
inputting the characteristic impedance value as a target impedance value of an asymmetric three-layer transmission line structure into an asymmetric strip line model, and acquiring the width and the thickness of a signal layer, the dielectric constant of a filling medium, a first distance between a TOP plane layer and the signal layer and a second distance between a BOTTOM plane layer and the signal layer;
the asymmetric stripline model is as follows:
wherein, Z is 1 Represents a target impedance value, ε, of the asymmetric three-layer transmission line structure r Is the dielectric constant, H, of the filling medium 1 Is the first distance, H 2 W is the width and C of the signal layer for the second distance t Is the thickness of the signal layer.
In one embodiment, the step of determining the form factor of the signal transmission line comprises:
determining the appearance parameters of the signal transmission line according to the specification parameters of the target connector; the shape parameters comprise the length, the width and the thickness of the signal transmission line, the number of connecting pads of a port of the signal transmission line, the length and the width of the connecting pads, the center distance between every two connecting pads and the length of a port supporting band of the signal transmission line;
the step of designing a corresponding signal transmission line by using the shape parameters and the characteristic parameters of the laminated structure comprises the following steps:
and manufacturing the corresponding signal transmission line shape and level on the flexible copper-clad substrate by using the shape parameters of the signal transmission line and the characteristic parameters of the laminated structure to obtain the signal transmission line.
In order to solve the problem of low reliability of the conventional technology, in one embodiment, a signal transmission line is provided, which includes a signal transmission line main body and connection parts provided at two ends of the signal transmission line main body;
the signal transmission line main body adopts a laminated structure; the characteristic parameters of the laminated structure and the characteristic impedance value have a corresponding relation; the characteristic impedance value refers to an impedance value of the signal transmission line when a target signal is transmitted;
the connecting part is used for accessing a target signal, and the transmission line main body is used for transmitting the target signal.
The signal transmission line comprises a signal transmission line main body and connecting parts arranged at two ends of the signal transmission line main body; the signal transmission line main body adopts a laminated structure, and the characteristic parameters of the laminated structure have a corresponding relation with the impedance value of the signal transmission line when transmitting a target signal; the connecting part is used for accessing a target signal, and the transmission line body is used for transmitting the target signal. The scheme enables the characteristic parameters of the laminated structure of the signal transmission line to correspond to the characteristic impedance value when the target signal is transmitted, ensures that the characteristic impedance of the signal transmission line is matched with the signal transmission impedance, improves the reliability and the integrity of signal transmission, and also improves the electromagnetic compatibility of signal transmission.
In one embodiment, the stacked structure comprises a three-layer transmission line structure; the three-layer transmission line structure comprises a symmetrical three-layer transmission line structure or an asymmetrical three-layer transmission line structure;
the three-layer transmission line structure comprises a TOP plane layer, a signal layer and a BOTTOM plane layer;
the signal layer is located between the TOP plane layer and the BOTTOM plane layer, and filling media are filled between the TOP plane layer and the BOTTOM plane layer.
In one embodiment, the sheet material of the signal transmission line body adopts a flexible copper clad substrate; the connecting part is a connecting pad; the substrate of the TOP planar layer, signal layer and BOTTOM planar layer is copper.
In response to the problem of low reliability of the conventional technology, in one embodiment, a flexible printed circuit board is provided, which includes the signal transmission line as described above.
Drawings
FIG. 1 is a flow diagram of a method of designing a signal transmission line in one embodiment;
fig. 2 is a schematic diagram illustrating an external structure of a flexible flat cable according to an embodiment;
FIG. 3 is a schematic diagram illustrating an external structure of a signal transmission line according to an embodiment;
FIG. 4 is a schematic diagram of a laminated structure of a signal transmission line in one embodiment;
FIG. 5 is a schematic diagram of a symmetric stripline model of a signal transmission line in one embodiment;
fig. 6 is a schematic diagram of an asymmetric stripline model of a signal transmission line in one embodiment.
Detailed Description
The following describes in detail a specific embodiment of the method for designing a signal transmission line according to the present invention with reference to the drawings.
In one embodiment, a method for designing a signal transmission line is provided, and referring to fig. 1, fig. 1 is a flowchart of the method for designing a signal transmission line in one embodiment, and the method for designing may include the following steps:
step S101, determining the shape parameters of the signal transmission line.
The signal transmission line is a transmission line capable of transmitting an electric signal, and is capable of transmitting a data signal of each functional module in an electronic product, for example. The shape parameter of the signal transmission line refers to a dimension parameter required for designing the shape of the signal transmission line, such as the length, width, or thickness of the signal transmission line.
The step is mainly to design the appearance structure of the signal transmission line, and the appearance size parameters of the signal transmission line can be determined according to the required appearance structure of the transmission line.
Generally, the signal transmission line is installed on a connector provided in the functional module to transmit the data signal in the functional module, so that the signal transmission line with the corresponding external size parameter can be adopted for connectors with different size structures.
In one embodiment, the form factor of the signal transmission line may be determined according to the specification parameters of the target connector.
According to the specification requirements of the connector, the length, the width and the thickness of the signal transmission line can be designed, and the specification parameters of the connection pads of the signal transmission line port can be designed, wherein the specification parameters of the connection pads comprise the number of the connection pads, the length and the width of the connection pads and the center distance among the connection pads.
The embodiment mainly designs the overall dimension parameters of the signal transmission line according to the specification requirements of the installed connector, ensures that the signal transmission line can be matched with the connector, and improves the design efficiency and the reliability of signal transmission.
When the signal transmission line is installed on the connector, the signal transmission line is usually required to be plugged and pulled out, and the signal transmission line port is also provided with a supporting belt, so that the supporting belt of the signal transmission line port can be designed according to the specification requirement of the connector. In one embodiment, the length of the supporting band of the signal transmission line port can be designed to be larger than that of the connecting PAD (namely, the connecting PAD), the connecting PAD is protected, the connecting PAD is prevented from being damaged during plugging and unplugging, and plugging and unplugging force is facilitated during installation of the signal transmission line.
In one embodiment, the outer dimension parameters of the signal transmission line to be designed may be determined according to the outer dimension parameters of the flexible flat cable. In the present embodiment, the external dimension parameters of the signal transmission line are designed according to the flexible flat cable matching the specification and size of the target connector.
Fig. 2 is a schematic diagram illustrating an external configuration of a flexible flat cable according to an embodiment, wherein external size parameters of a signal transmission line can be designed by referring to the external configuration parameters of the flexible flat cable shown in fig. 2. Specifically, the length L, width W, connection PAD length S1, and width C of the flexible flat cable shown in FIG. 2 (a) can be determined w And the center-to-center distance P, and the thickness T of the flexible flat cable and the lengths d1 and d2 of the support bands of the two connection ports shown in fig. 2 (b) are designed to correspond to the external dimension parameters of the signal transmission line.
Referring to fig. 3, fig. 3 is a schematic diagram illustrating an external structure of a signal transmission line according to an embodiment, and the length L, the width W, the connection PAD length S1, and the width C of the signal transmission line shown in fig. 3 (a) can be obtained according to the external structure parameters of the flexible flat cable shown in fig. 2 w And a center-to-center distance P, such as the thickness T of the signal transmission line shown in fig. 3 (b), the lengths d1 and d2 of the support bands of the two connection ports, etc., and fig. 3 (c) is a bottom view of the signal transmission line, it can be understood that the structural parameters shown in fig. 3 (c) correspond to the structural parameters shown in fig. 3 (a).
By adopting the scheme of the embodiment to design the appearance parameters of the signal transmission line, the design efficiency can be improved.
Step S102, designing a laminated structure of the signal transmission line.
The signal transmission line may have different laminated structures, which refer to structures constituting respective levels of the signal transmission line. Because the signal transmission lines with different laminated structures can influence the quality of signal transmission to different degrees, the step designs the detailed laminated structures of the signal transmission lines, and provides a design basis for improving the signal transmission reliability of the signal transmission lines.
In one embodiment, the stacked structure of the signal transmission line may be designed by a method including the steps of:
sequentially constructing a TOP plane layer, a signal layer and a BOTTOM plane layer to obtain a three-layer signal transmission line structure; and adopting the three-layer signal line structure as a laminated structure of the signal transmission line.
Referring to fig. 4, fig. 4 is a schematic diagram illustrating a stacked structure of a signal transmission line in an embodiment, where the stacked structure of the signal transmission line may adopt a three-layer transmission line structure; the optical fiber comprises a TOP plane layer, a signal layer and a BOTTOM plane layer; the signal layer is located between the TOP plane layer and the BOTTOM plane layer, and filling media are filled between the TOP plane layer and the BOTTOM plane layer.
In this embodiment, the laminated structure of the designed Signal transmission line may be a three-layer transmission line structure, where the three-layer transmission line structure includes a TOP plane layer L1 (Ground Reference), a Signal layer L2 (Signal line), and a BOTTOM plane layer L3 (Ground Reference).
The signal layer is typically located between the TOP plane layer and the BOTTOM plane layer. The TOP plane layer and the signal layer, and the BOTTOM plane layer and the signal layer can be filled with filling media, the signal layer is a main transmission path layer on the signal transmission line, and the TOP plane layer and the BOTTOM plane layer are reflow layers or reference layers of signals.
In general, the base material of each layer of the signal transmission line can be designed, and in order to improve the transmission quality of the signal, in one embodiment, the base material of the TOP plane layer, the signal layer and the BOTTOM plane layer can be designed to be copper.
Step S103, obtaining a characteristic impedance value of the signal transmission line when the signal transmission line transmits the target signal, inputting the characteristic impedance value into a strip line model corresponding to the laminated structure, and obtaining characteristic parameters of the laminated structure of the signal transmission line.
The signal transmission line may generate a certain impedance for the transmitted electrical signal, and the characteristic parameters of the stacked structure of the signal transmission line may be designed according to the impedance, including the relative distance between each layer, the width or the thickness of each layer, and the like.
The method mainly comprises the steps of obtaining a characteristic impedance value of a signal transmission line when a target signal is transmitted, inputting the characteristic impedance value into a strip line model to obtain characteristic parameters of a laminated structure of the signal transmission line, and designing the characteristic parameters of the laminated structure so as to match the characteristic impedance of the signal transmission line with the impedance and ensure the signal transmission quality of the signal transmission line.
The stripline model may be selected corresponding to a stacked structure of the signal transmission line, for example, a three-layer transmission line structure, which generally includes a symmetric three-layer transmission line structure and an asymmetric three-layer transmission line structure, so that different stripline models may be adopted for different stacked structures.
In one embodiment, the three-layer transmission line structure is a symmetric three-layer transmission line structure, and the step of inputting the characteristic impedance value into a stripline model corresponding to the stacked structure in step S103 and obtaining the characteristic parameters of the stacked structure of the signal transmission line may include:
inputting the characteristic impedance value serving as a target impedance value of the symmetrical three-layer transmission line structure into a symmetrical strip line model, and acquiring the width and thickness of a signal layer, the dielectric constant of a filling medium and the distance between layers; the symmetric stripline model is:
wherein, Z 0 Representing a target impedance value, ε, of the symmetrical three-layer transmission line structure r Denotes the dielectric constant of the filling medium, H denotes the distance between the TOP plane layer and the BOTTOM plane layer, W denotes the width of the signal layer and C t Denotes the thickness of the signal layer, and pi denotes the circumferential ratio.
In this embodiment, referring to fig. 5, fig. 5 is a schematic diagram of a symmetric stripline model of a signal transmission line in an embodiment, when distances from a signal layer to a TOP plane and a BOTTOM plane are equal, a symmetric PCB stripline model is used to obtain characteristic parameters of a stacked structure of the transmission line according to characteristic impedance values.
Assuming that the width of the signal layer is W and the thickness is C t The thickness is generally copper thickness, and the dielectric constant of the filling medium between the TOP plane layer and the BOTTOM plane layer is epsilon r The reference plane distance between the TOP plane layer and the BOTTOM plane layer is H, and the trace is located in the middle of the two reference planes, so that the impedance of the signal transmission line can be calculated by the above model.
From the symmetrical stripline model, Z is known 0 Can be prepared from H, C t W and ε r Four variables determine, Z 0 Proportional to H, C t W and ε r Is inversely proportional, generally when W/H< 0.35 and C t /H&0.25, Z can be calculated using the above stripline model 0 . Therefore, when it is required to design the target impedance as Z 0 When the signal transmission line is used, other quantities can be calculated through the model, and also can be calculated through a two-dimensional field simulation tool, and the calculated parameters guide the signal transmission line such as board selection of PCB design, line width of PCB wiring rule or copper thickness design and the like.
In an embodiment, the three-layer transmission line structure is an asymmetric three-layer transmission line structure, and the step of inputting the characteristic impedance value into a stripline model corresponding to the stacked structure in step S103 to obtain the characteristic parameter of the stacked structure of the signal transmission line may include:
the characteristic impedance value can be used as a target impedance value of an asymmetric three-layer transmission line structure, an asymmetric strip line model is input, and the width and the thickness of a signal layer, the dielectric constant of a filling medium, a first distance between a TOP plane layer and the signal layer and a second distance between a BOTTOM plane layer and the signal layer are obtained; the asymmetric stripline model is as follows:
wherein, Z is 1 Representing the asymmetric three-layer transmission lineTarget impedance value of structure, epsilon r Is the dielectric constant of the filling medium, H 1 Is the first distance, H 2 W is the width of the signal layer and C is the second distance t Is the thickness of the signal layer.
In this embodiment, referring to fig. 6, fig. 6 is a schematic diagram of an asymmetric stripline model of a signal transmission line in an embodiment, when distances from a signal layer to a TOP plane and a BOTTOM plane are not equal, a characteristic parameter of a stacked structure of the transmission line is obtained according to a characteristic impedance value by using the asymmetric PCB stripline model. For a signal transmission layer with width W and thickness C t Dielectric constant of the filling medium between the TOP plane and the BOTTOM plane layer is epsilon r The distance between the TOP plane layer and the signal layer is H 1 The distance between the BOTTOM plane layer and the signal layer is H 2 Of signal transmission line of impedance Z 1 Can be calculated from the asymmetric stripline model described above.
Therefore, when it is required to design the target impedance as Z 1 The other parameters can be used for guiding the board selection of PCB design, the line width of PCB wiring rule, copper thickness design and the like.
Step S104, designing a corresponding signal transmission line by using the appearance parameters and the characteristic parameters of the laminated structure.
In this step, the form of the signal transmission line corresponding to the form parameter and the levels corresponding to the feature parameter of the stacked structure can be designed by using the form parameter and the feature parameter of the stacked structure obtained in the above steps, thereby completing the design of the signal transmission line.
In one embodiment, the external form parameters of the signal transmission line and the characteristic parameters of the laminated structure can be used for designing the corresponding external form and level of the signal transmission line on the flexible copper-clad foil substrate to obtain the signal transmission line.
In the embodiment, a corresponding signal transmission line is designed on the flexible copper clad substrate according to the appearance parameters and the characteristic parameters of the laminated structure. The specific type or specification of the flexible copper clad laminate is not particularly limited, as long as the flexibility of the flexible copper clad laminate meets the bending requirement of a signal transmission line to be replaced, such as a flexible flat cable, during normal installation and maintenance of a product.
The technical scheme of the embodiment ensures the flexibility of the signal transmission line, so that the signal transmission line is not easy to damage when in use, and the signal integrity and reliability of the signal transmission line are further improved.
The method for designing a signal transmission line according to any one of the embodiments includes determining an external form parameter of the signal transmission line, designing a stacked structure of the signal transmission line, obtaining a characteristic impedance value of the signal transmission line when a target signal is transmitted, inputting the characteristic impedance value into a stripline model corresponding to the stacked structure to obtain a characteristic parameter of the stacked structure of the signal transmission line, and designing the corresponding signal transmission line by using the external form parameter and the characteristic parameter of the stacked structure. The scheme enables the characteristic parameters of the laminated structure of the signal transmission line to correspond to the characteristic impedance value when the target signal is transmitted, ensures that the characteristic impedance of the signal transmission line is matched with the signal transmission impedance, improves the reliability and the integrity of signal transmission, and improves the electromagnetic compatibility of signal transmission.
In order to overcome the problem of low signal transmission reliability and integrity of the signal transmission line provided by the conventional technology, in one embodiment, a signal transmission line is provided, which can be designed by using the signal transmission method described in any one of the above embodiments, and comprises a signal transmission line main body and connecting parts arranged at two ends of the signal transmission line main body;
the signal transmission line main body adopts a laminated structure; the characteristic parameters of the laminated structure and the characteristic impedance value have a corresponding relation; the characteristic impedance value refers to an impedance value of the signal transmission line when a target signal is transmitted;
the connecting part is used for accessing a target signal, and the transmission line main body is used for transmitting the target signal.
The signal transmission line provided by the above embodiment includes a signal transmission line main body and connecting parts arranged at two ends of the signal transmission line main body; the signal transmission line main body adopts a laminated structure, and the characteristic parameters of the laminated structure have a corresponding relation with the impedance value of the signal transmission line when transmitting a target signal; the connecting part is used for accessing a target signal, and the transmission line main body is used for transmitting the target signal. The scheme enables the characteristic parameters of the laminated structure of the signal transmission line to correspond to the characteristic impedance value when the target signal is transmitted, ensures that the characteristic impedance of the signal transmission line is matched with the signal transmission impedance, improves the reliability and the integrity of signal transmission, and also improves the electromagnetic compatibility of signal transmission.
In one embodiment, the stacked structure comprises a three-layer transmission line structure; the three-layer transmission line structure comprises a symmetrical three-layer transmission line structure or an asymmetrical three-layer transmission line structure;
the three-layer transmission line structure comprises a TOP plane layer, a signal layer and a BOTTOM plane layer;
the signal layer is located between the TOP plane layer and the BOTTOM plane layer, and filling media are filled between the TOP plane layer and the BOTTOM plane layer.
In one embodiment, the plate of the signal transmission line body adopts a flexible copper clad substrate; the connecting part is a connecting pad; the substrate of the TOP, signal and BOTTOM planar layers is copper.
In one embodiment, there is also provided a flexible printed circuit board including the signal transmission line as described in any one of the above embodiments.
The present embodiment provides an ultra-thin flexible printed circuit board, that is, a flexible PCB, which can have flexibility of a flexible flat cable and can perform impedance control on a high-speed signal. The flexible printed circuit board has the functions of shielding and controlling the impedance of the signal line, can be used for replacing a flexible flat cable used in a transmission technology to carry out signal transmission, can reduce signal distortion, improves the integrity and reliability of signals, and meets the requirements of signal transmission quality, thereby improving the overall electromagnetic compatibility of products.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent should be subject to the appended claims.
Claims (10)
1. A signal transmission line is characterized by comprising a signal transmission line main body and connecting parts arranged at two ends of the signal transmission line main body;
the signal transmission line main body adopts a laminated structure; the characteristic parameters of the laminated structure and the characteristic impedance value have a corresponding relation; the characteristic impedance value refers to an impedance value of the signal transmission line when a target signal is transmitted;
the connecting part is used for accessing a target signal, and the transmission line main body is used for transmitting the target signal.
2. The signal transmission line of claim 1, wherein the stacked structure comprises a three-layer transmission line structure; the three-layer transmission line structure comprises a symmetrical three-layer transmission line structure or an asymmetrical three-layer transmission line structure;
the three-layer transmission line structure comprises a TOP plane layer, a signal layer and a BOTTOM plane layer;
the signal layer is located between the TOP plane layer and the BOTTOM plane layer, and filling media are filled between the TOP plane layer and the BOTTOM plane layer.
3. The signal transmission line according to claim 1 or 2, wherein the board of the signal transmission line body is a flexible copper clad substrate; the connecting part is a connecting pad; the substrate of the TOP planar layer, signal layer and BOTTOM planar layer is copper.
4. A flexible printed circuit board characterized by comprising the signal transmission line of any one of claims 1 to 3.
5. A method for designing a signal transmission line according to any one of claims 1 to 3, comprising the steps of:
determining the appearance parameters of the signal transmission line;
designing a laminated structure of the signal transmission line;
acquiring a characteristic impedance value of the signal transmission line when a target signal is transmitted, inputting the characteristic impedance value into a strip line model corresponding to the laminated structure, and acquiring characteristic parameters of the laminated structure of the signal transmission line;
and designing a corresponding signal transmission line by using the appearance parameters and the characteristic parameters of the laminated structure.
6. The method of claim 5, wherein the step of designing the laminated structure of the signal transmission line comprises:
sequentially constructing a TOP plane layer, a signal layer and a BOTTOM plane layer to obtain a three-layer signal transmission line structure;
and adopting the three-layer signal line structure as a laminated structure of the signal transmission line.
7. The method according to claim 6, wherein the characteristic parameters of the laminated structure of the signal transmission line include the width and thickness of the signal layers, the dielectric constant of the filling medium, and the distance between the layers;
the three-layer transmission line structure comprises a symmetrical three-layer transmission line structure and an asymmetrical three-layer transmission line structure.
8. The method of claim 7, wherein the three-layered transmission line structure is a symmetrical three-layered transmission line structure;
the step of inputting the characteristic impedance value into a stripline model corresponding to the laminated structure to obtain characteristic parameters of the laminated structure of the signal transmission line includes:
inputting the characteristic impedance value as a target impedance value of the symmetrical three-layer transmission line structure into a symmetrical strip line model to obtain the width and thickness of the signal layer, the dielectric constant of the filling medium and the distance between the layers; the symmetrical stripline model is as follows:
wherein Z is 0 Representing a target impedance value, ε, of the symmetrical three-layer transmission line structure r Denotes the dielectric constant of the filling medium, H denotes the distance between the TOP and BOTTOM planar layers, W denotes the width of the signal layer and C t Representing the thickness of the signal layer.
9. The method of claim 7, wherein the tri-layer transmission line structure is an asymmetric tri-layer transmission line structure;
the step of inputting the characteristic impedance value into a stripline model corresponding to the laminated structure to obtain characteristic parameters of the laminated structure of the signal transmission line includes:
inputting the characteristic impedance value as a target impedance value of an asymmetric three-layer transmission line structure into an asymmetric strip line model, and acquiring the width and the thickness of a signal layer, the dielectric constant of a filling medium, a first distance between a TOP plane layer and the signal layer and a second distance between a BOTTOM plane layer and the signal layer;
the asymmetric stripline model is as follows:
wherein, Z is 1 Representing a target impedance value, ε, of the asymmetric three-layer transmission line structure r Is composed ofDielectric constant of the filling medium, H 1 Is the first distance, H 2 W is the width and C of the signal layer for the second distance t Is the thickness of the signal layer.
10. The method of any one of claims 5 to 9, wherein the step of determining the profile parameters of the signal transmission line comprises:
determining the appearance parameters of the signal transmission line according to the specification parameters of the target connector; the shape parameters comprise the length, the width and the thickness of the signal transmission line, the number of connecting pads of a port of the signal transmission line, the length and the width of the connecting pads, the center distance between every two connecting pads and the length of a port supporting band of the signal transmission line;
the step of designing a corresponding signal transmission line using the form parameter and the characteristic parameter of the stacked structure includes:
and manufacturing the corresponding signal transmission line shape and level on the flexible copper-clad substrate by using the shape parameters of the signal transmission line and the characteristic parameters of the laminated structure to obtain the signal transmission line.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711435105.XA CN108112162A (en) | 2017-12-26 | 2017-12-26 | Signal transmssion line and its design method, flexible printed circuit board |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201711435105.XA CN108112162A (en) | 2017-12-26 | 2017-12-26 | Signal transmssion line and its design method, flexible printed circuit board |
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| CN109327969A (en) * | 2018-11-30 | 2019-02-12 | 安庆华璟电子科技有限公司 | A kind of design method of high-frequency resistance and the matched wiring board of loss |
| CN112654135A (en) * | 2020-12-11 | 2021-04-13 | 珠海景旺柔性电路有限公司 | FPC flat coaxial line and manufacturing method thereof |
| CN114744389A (en) * | 2022-04-14 | 2022-07-12 | 浙江大学 | Flexible circuit high-frequency transmission line based on dielectric groove and dielectric support |
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| CN109327969A (en) * | 2018-11-30 | 2019-02-12 | 安庆华璟电子科技有限公司 | A kind of design method of high-frequency resistance and the matched wiring board of loss |
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| CN112654135A (en) * | 2020-12-11 | 2021-04-13 | 珠海景旺柔性电路有限公司 | FPC flat coaxial line and manufacturing method thereof |
| CN114744389A (en) * | 2022-04-14 | 2022-07-12 | 浙江大学 | Flexible circuit high-frequency transmission line based on dielectric groove and dielectric support |
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Application publication date: 20180601 |