KR102174480B1 - Asymmetric coupling line capable of reducing the noise of a bent line and method of forming the same - Google Patents

Abstract

An asymmetric coupling line according to an embodiment of the present application includes a first line that is bent and extended at a predetermined angle and a second line that is bent and extended at the same angle as the first line, and is disposed parallel to the first line, The length of the second line is longer than that of the first line, and the width of the second line is narrower than that of the first line.

Description

An asymmetric coupling line that can reduce the noise of a curved line and its formation method {ASYMMETRIC COUPLING LINE CAPABLE OF REDUCING THE NOISE OF A BENT LINE AND METHOD OF FORMING THE SAME}

The present application relates to an asymmetric coupling line and a method for forming the same, and more particularly, to an asymmetric coupling line for forming a narrow width of a long line in a bent differential line, and a method of forming the same.

Recently, digital systems are developing rapidly with the aim of realizing high physical compressibility and high data transmission speed, and the data transmission speed is expected to exceed 20 Gbps in the next generation. Due to these developments, the problem of signal interference due to electromagnetic noise in a circuit board has emerged as an important issue.

In particular, it is very important to maintain signal integrity in a digital system, and in order to solve signal interference due to electromagnetic noise, a differential line technology is used. More specifically, the differential line technology is a technology for transmitting by maintaining a phase difference between transmission signals by 180°.

On the other hand, the actual circuit of the digital system is difficult to maintain 180° phase difference between transmission signals due to an asymmetric structure. In particular, in the bent differential line, since the inner line is shorter in length than the outer line, due to this difference in length, the signal transmission speed of the outer line is delayed in phase compared to the signal transmission speed of the inner line and may be transmitted slowly. This phase difference may eventually lead to common mode noise.

A conventional technique for solving this problem compensates for a difference in transmission time by adding an inductance implemented through a flat capacitor, a surface mount device (SMD) capacitor, or a shorted coupling line to an inner line. However, since the technology compensates for the transmission time based on a specific frequency, there is a problem in that the available bandwidth is narrow and the physical space of the inner line is narrow.

An object of the present application is to provide an asymmetric coupling line capable of compensating the phase speed of a bent differential transmission line in a wide bandwidth and securing a narrow space of an inner line as a free space, and a method of forming the same.

An asymmetric coupling line according to an embodiment of the present application includes a first line that is bent and extended at a predetermined angle and a second line that is bent and extended at the same angle as the first line, and is disposed parallel to the first line, The length of the second line is longer than that of the first line, and the width of the second line is narrower than that of the first line.

In an embodiment, as the width of the second line decreases, the difference in length between the first and second lines decreases.

In an embodiment, as the width of the first line decreases, the difference in length between the first and second lines decreases.

In an embodiment, the second line is arranged to be spaced apart a predetermined distance from the first line, and as the separation distance between the second line and the first line is shorter, the difference in length between the first and second lines is Decreases.

In an embodiment, the separation distance is proportional to the differential mode impedance formed along the first and second lines.

In an embodiment, as the angle changes from 0 degrees to 90 degrees, the difference in length between the first and second lines decreases.

In an embodiment, as the angle changes from 90 degrees to 0 degrees, the difference in length between the first and second lines increases.

In an embodiment, as the length of the second line decreases, the difference in length between the first and second lines decreases.

In an embodiment, as the width of any one of the first line or the second line increases, the difference in length between the first and second lines increases.

In an embodiment, the length of the second line is calculated through the following formula (1),

이고, The above calculation formula (1) is:

ego,

Here, ιi is the length of the first line, ω _i is the width of the first line, ω _o is the width of the second line, s is the separation distance between the first and second lines, θ Is the bent angle.

이며, 여기서, V는

계산식(3)을 통해 계산되는 파라미터이고, D는

계산식(4)를 통해 계산되는 파라미터이며, 이때, υ_o는 상기 제1 선로의 위상속도이고, υ_i는 상기 제2 선로의 위상속도이다.In an embodiment, the length of the first line is calculated through the following calculation formula (2), and the calculation formula (2),

Is, where V is

It is a parameter calculated through formula (3), and D is

It is a parameter calculated through the formula (4), where υ _o is the phase speed of the first line, and υ _i is the phase speed of the second line.

In an embodiment, the phase speed of the second line is compensated based on the length ratio of the first and second lines and the phase speed of the first line.

이고, 여기서, Li는 상기 제1 선로의 인덕턴스이며, Ci는 상기 제1 선로의 커패시턴스이다. In an embodiment, the phase velocity of the first line is determined through the following equation (5), and the equation (5) is

Where Li is the inductance of the first line, and Ci is the capacitance of the first line.

In an embodiment, the phase speed of the first line is inversely proportional to the first effective dielectric constant, and the phase speed of the second line is inversely proportional to the second effective dielectric constant.

In an embodiment, the effective dielectric constant of the first line is smaller than the effective dielectric constant of the second line, and the effective dielectric constant of the second line is proportional to the width of the second line.

As a method of forming an asymmetric coupling line according to an embodiment of the present application, when the width and the bent angle of the first line are determined, forming the first line on a differential signal transmission substrate, according to the width of the first line, the Setting a narrow width of a second line, extracting and setting a separation distance corresponding to a reference impedance from a preset differential mode impedance list according to the widths of the first and second lines, and setting the width of the first line , Calculating a phase speed of the first line and a phase speed of the second line using the width of the second line and the separation distance, based on a difference in phase speed between the first and second lines, And determining at least one of the width of the second line, the separation distance, and the bent angle, and forming the second line on one surface of the differential signal transmission board based on the at least one.

The asymmetric coupling line and the method of forming the same according to the exemplary embodiment of the present application have an effect of minimizing generation of common mode noise in a wide bandwidth by compensating the phase speed of the bent differential line.

In addition, since the structure is simple, there is an effect of making it easily applicable to the field of signal integrity.

1 is a structural diagram of an asymmetric coupling line for transmitting a differential signal according to an embodiment of the present application.
2 is an embodiment of a differential signal transmission board to which the asymmetric coupling line of FIG. 1 is applied.
3 is an embodiment of a conventional differential signal transmission board.
FIG. 4 is a graph showing a difference in phase speed between the first and second lines that change according to the width of the second line of FIG.
5 is a graph showing a change in differential mode impedance according to a separation distance between first and second lines.
6 is a simulation graph showing common mode noise noise characteristics of the asymmetric coupling line of FIG. 1.
7 is a graph showing transmission characteristics of a differential signal for an asymmetric coupling line of FIG. 1.
8 is a graph comparing eye-diagrams measured according to the type of FIG. 6.
9 is an operation process of a differential line forming apparatus for forming an asymmetric coupling line of FIG. 1 on a differential signal transmission board.

Specific structural or functional descriptions of the embodiments according to the concept of the present application disclosed in the present specification are exemplified only for the purpose of describing the embodiments according to the concept of the present application, and the embodiments according to the concept of the present application are It may be implemented in various forms and is not limited to the embodiments described herein.

Since the embodiments according to the concept of the present application can apply various changes and have various forms, the embodiments will be illustrated in the drawings and described in detail in the present specification. However, this is not intended to limit the embodiments according to the concept of the present application to specific disclosed forms, and includes all changes, equivalents, or substitutes included in the spirit and scope of the present application.

Terms such as first or second may be used to describe various elements, but the elements should not be limited by the terms. The terms are only for the purpose of distinguishing one component from other components, for example, without departing from the scope of the rights according to the concept of the present application, the first component may be named as the second component, and similarly The second component may also be referred to as a first component.

When a component is referred to as being "connected" or "connected" to another component, it is understood that it may be directly connected or connected to the other component, but other components may exist in the middle. Should be. On the other hand, when a component is referred to as being "directly connected" or "directly connected" to another component, it should be understood that there is no other component in the middle. Other expressions describing the relationship between components, such as "between" and "just between" or "adjacent to" and "directly adjacent to" should be interpreted as well.

The terms used in this specification are only used to describe specific embodiments, and are not intended to limit the present application. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present specification, terms such as "comprise" or "have" are intended to designate the presence of implemented features, numbers, steps, actions, components, parts, or a combination thereof, but one or more other features or numbers It is to be understood that the possibility of addition or presence of, steps, actions, components, parts, or combinations thereof is not preliminarily excluded.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Terms as defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and should not be interpreted as an ideal or excessively formal meaning unless explicitly defined in this specification. Does not.

Hereinafter, the present application will be described in detail by describing a preferred embodiment of the present application with reference to the accompanying drawings.

1 is a structural diagram of an asymmetric coupling line 10 for transmitting a differential signal according to an embodiment of the present application.

Referring to FIG. 1, the asymmetric coupling line 10 may include a first line 100 and a second line 200.

First, the first line 100 may be bent and extended at a predetermined angle θ. Here, the first line 100 may be a line for transmitting a positive signal among differential signals. For example, it may be formed on the differential signal transmission board 50 in a thin metal pattern of a conductor material. The differential signal transmission board 50 will be described in detail in FIG. 2 below. In this case, the metal pattern may be formed as a microstrip type coupled line.

Next, the second line 200 may be bent and extended at the same angle θ as the first line 200 and may be disposed to be parallel to the first line 200. Here, the second line 200 may be a line for transmitting a negative signal among differential signals. For example, the second line 200 is arranged to face the first line 200, is formed in the same shape as the arrangement of the first line 100, and transmits a differential signal in a thin metal pattern of a conductor material. It may be formed on the substrate 50.

In addition, the second line 200 is a line located outside the first line 100 with respect to the bent angle θ, and the length lo of the second line 200 is the length of the first line 100 ( can be formed longer than li). For example, since the first track 100 is an inner track located inside the bent direction, and the second track 200 is an outside track located outside the bent direction, the second track 200 corresponding to the outside track The length lo of may be formed to be longer than the length li of the first line 100 corresponding to the inner line. Accordingly, the phase speed of the negative signal of the second line 200 may be delayed than the phase speed of the positive signal of the first line 100.

In addition, the width ω _o of the second line 200 may be formed to be narrower than the width ω _i of the first line 100. That is, in order to compensate for the delay in the phase speed of the second line 200 caused by the difference in length between the first and second lines 100 and 200, the width ω _o of the second line 200 is 1 It may be formed narrower than the width (ω _i ) of the line 100.

Here, the phase speed ratio of the first line 100 and the second line 200 is based on the same transmission time in the π transmission mode, and the length ratio (li, lo) between the first and second lines 100 and 200 Can correspond to For example, as the phase speed ratio of the first line 100 and the second line 200 increases, the length ratio (li, lo) between the first and second lines 100 and 200 increases, and the first line As the ratio of the phase velocity between the (100) and the second line 200 decreases, the length ratio (li, lo) between the first and second lines 100 and 200 may decrease.

In this case, the length lo of the second line 200 may be calculated through the following calculation equation (1).

이고, Here, the calculation formula (1),

ego,

Here, li is the length li of the first line 100, ω _i is the width of the first line 100, ω _o is the width of the second line 200, and s is the first line 100 ) Is a separation distance between the second line 200 and θ may be a bent angle.

For example, the width of the first line 100 (ω _i ), the width of the second line 200 (ω _o ), the distance between the first line 100 and the second line 200 (s) Is determined, and when the bent angle θ of the first line 100 and the second line 200 is 90 degrees, the length lo of the second line 200 can be calculated through the following calculation formula (1). I can. Here, the length lo of the second line 200 may be longer than the length li of the first line 100.

More specifically, the length (lo) of the second line (200) is the length (li) of the first line (100), the separation distance (s) between the first line (100) and the second line (200), and bent Based on the length (li) of the first line 100 according to at least one of the angle θ, the width of the first line 100 (ω _i ), or the width of the second line 200 (ω _o ) It can be formed long.

That is, the difference in length between the first and second lines 100 and 200 is the separation distance s between the first line 100 and the second line 200, the bent angle θ, and the first line 100 ) May increase according to at least one of the width (ω _i ) or the width (ω _o ) of the second line 200.

According to an embodiment, the length lo of the second line 200 is determined according to the separation distance s between the first line 100 and the second line 200, and the length of the first line 100 ( It is formed long based on li), so that the difference in length between the first and second lines 100 and 200 may increase. Here, the second line 200 may be disposed to be spaced apart from the first line 100 by a predetermined distance.

More specifically, as the separation distance (s) between the first track 100 and the second track 200 is longer, the length lo of the second track 200 is the length li of the first track 100 Since it is formed long as a reference, the difference in length between the first and second lines 100 and 200 may increase. In addition, as the separation distance s between the first line 100 and the second line 200 is shorter, the length lo of the second line 200 is based on the length li of the first line 100 As it is formed short, the difference in length between the first and second lines 100 and 200 may be reduced.

In the present application, that the length lo of the second line 200 is formed short based on the length li of the first line 100 means that the length lo of the second line 200 is the first It is not formed shorter than the length (li) of the line 100, but is formed longer than the length (li) of the first line 100, and is formed gradually shorter based on the length (li) of the first line 100 Can mean

In this case, the differential mode impedance formed between the first line 100 and the second line 200 may be changed according to the separation distance s between the first line 100 and the second line 200. Here, the differential mode impedance means the sum of impedances between the impedance of the first line 100 and the impedance of the second line 200 for the differential signal transmitted through the first line 100 and the second line 200. I can.

In addition, the differential mode impedance formed between the first line 100 and the second line 200 may be proportional to the separation distance s between the first line 100 and the second line 200. That is, as the separation distance (s) decreases, the differential mode impedance formed between the first line 100 and the second line 200 gradually decreases, and as the separation distance (s) increases, the first line 100 and the second line The differential mode impedance formed between the lines 200 may gradually increase.

According to another embodiment, the length lo of the second line 200 is determined according to the bent angle θ of the first line 100 and the second line 200, and the length of the first line 100 is li ) Is formed to be long, so that the difference in length between the first and second lines 100 and 200 may increase.

More specifically, as the bent angle θ of the first line 100 and the second line 200 changes from 0 degrees to 90 degrees, the length lo of the second line 200 is the first line 100 ) Is formed to be longer based on the length li of ), so that the difference in length between the first and second lines 100 and 200 may increase. In addition, as the bent angle θ of the first line 100 and the second line 200 changes from 90 degrees to 180 degrees, the length lo of the second line 200 is equal to that of the first line 100. Since it is formed short based on the length li, the difference in length between the first and second lines 100 and 200 may be reduced.

According to another embodiment, the length lo of the second line 200 is the first line according to the width ω _i of the first line 100 or the width ω _o of the second line 200 Since the length (li) of (100) is formed to be long, a difference in length between the first and second lines (100, 200) may increase. In this case, the width ω _o of the second line 200 may be formed to be narrower than the width ω _i of the first line 100.

More specifically, as the width ω _i of the first line 100 is wider, the length lo of the second line 200 is formed to be longer based on the length li of the first line 100. The difference in length between the first and second lines 100 and 200 may increase. In addition, as the width ω _i of the first line 100 is narrower, the length lo of the second line 200 is formed shorter based on the length li of the first line 100, and thus the first and The difference in length between the second lines 100 and 200 may increase.

In addition, as the width ω _o of the second line 200 is wider, the length lo of the second line 200 is formed longer based on the length li of the first line 100, and thus the first and The difference in length between the second lines 100 and 200 may increase. In addition, as the width ω _o of the second line 200 is narrower, the length lo of the second line 200 is formed to be shorter based on the length li of the first line 100, so that the first and The difference in length between the second lines 100 and 200 may be reduced.

That is, the length lo of the second line 200 is the length li of the first line 100, the width ω _i of the first line 100, and the width ω _o of the second line 200 ), according to at least one of a separation distance (s) and a bent angle (θ) between the first line 100 and the second line 200, the length based on the length (li) of the first line 100 Can be formed. At this time, the length lo of the second line 200 is formed longer than the length li of the first line 100, and the width ω _o of the second line 200 is of the first line 100 It may be formed narrower than the width (ω _i ).

In addition, the length li of the first line 100 may be calculated through the following equations (2) to (4).

이며, The following formula (2) is:

Is,

(3)을 통해 계산되는 파라미터이고, D는

(4)를 통해 계산되는 파라미터이며, 이때, υ_i는 제1 선로(100)의 위상속도이고, υ_i는 제2 선로(200)의 위상속도일 수 있다. Where V is

(3) is a parameter calculated through, D is

This parameter is calculated through (4), where υ _i may be the phase speed of the first line 100 and υ _i may be the phase speed of the second line 200.

More specifically, the length (li) of the first line (100) is the width (ω _i ) of the first line (100), the width (ω _o ) of the second line (200), and the first line (100) According to at least one of the separation distances s between the second lines 200, it may be formed to be short based on the length lo of the second lines 200.

That is, the difference in length between the first line 100 and the second line 200 is the width of the first line 100 (ω _i ) and the width of the second line 200 (ω _o ), and the first line ( It may increase according to at least one of the separation distance (s) between the 100) and the second line 200.

According to an embodiment, the narrower the width ω _i of the first line 100 is, the shorter the length li of the first line 100 is based on the length lo of the second line 200. , The difference in length between the first line 100 and the second line 200 may increase. In addition, as the width ω _{i of} the first line 100 is longer, the length li of the first line 100 is formed longer based on the length lo of the second line 200, so that the first line ( The difference in length between the 100) and the second line 200 may be reduced.

In the present application, it means that the length (li) of the first line (100) is formed longer based on the length (lo) of the second line (200), the length (li) of the first line (100) is the second It is not formed longer than the length (lo) of the line 200, but is formed smaller than the length (lo) of the second line 200, and is formed gradually longer based on the length (lo) of the second line 200 Can mean

According to another embodiment, the narrower the width ω _o of the second line 200 is, the shorter the length li of the first line 100 is based on the length lo of the second line 200. , The difference in length between the first line 100 and the second line 200 may increase. In addition, as the width ω _o of the second line 200 is longer, the length li of the first line 100 is formed longer based on the length lo of the second line 200, and thus the first line ( The difference in length between the 100) and the second line 200 may be reduced.

According to another embodiment, as the separation distance s between the first line 100 and the second line 200 is shorter, the length li of the first line 100 is the length of the second line 200 Since it is formed short based on (lo), a difference in length between the first line 100 and the second line 200 may increase. In addition, as the separation distance (s) between the first track 100 and the second track 200 is longer, the length li of the first track 100 is based on the length lo of the second track 200. Since it is formed long, a difference in length between the first line 100 and the second line 200 may be reduced.

In addition, the phase velocity (υ _o ) of the second line 200 is the ratio between the length li of the first line 100 and the length lo of the second line 200 and the phase of the first line 100 Based on the speed (υ _i ), it can be compensated.

For example, as the ratio (lo/li) of the length (lo) of the second line 200 to the length (li) of the first line 100 increases, the phase speed (υ _o ) of the second line 200 ) Is largely compensated for the phase speed (υ _i ) of the first line 100, and the ratio of the length (lo) of the second line 200 to the length (li) of the first line 100 (lo/li As) is smaller, the phase speed υ _o of the second line 200 may be compensated to be smaller in the phase speed υ _i of the first line 100.

In this case, the phase speed υ _i of the first line 100 may be determined through the following calculation equation (5).

이고, 여기서, Li는 제1 선로(100)의 단위길이당 인덕턴스이며, Ci는 제1 선로(100)의 단위길이당 커패시턴스일 수 있다. The following formula (5) is

Wherein, Li may be an inductance per unit length of the first line 100, and Ci may be a capacitance per unit length of the first line 100.

For example, as a differential signal is transmitted, a first impedance including an inductance per unit length and a capacitance per unit length is formed in the first line 100, and the inductance per unit length and unit length are formed in the second line 200. A second impedance including capacitance per length may be formed. In this case, the sum of the first impedance and the second impedance may be a differential mode impedance.

That is, the first impedance includes inductance per unit length of the first line 100 and capacitance per unit length, and the second impedance includes inductance per unit length of the second line 200 and capacitance per unit length. have. In this case, the product of the inductance per unit length of the first line 100 included in the first impedance and the capacitance per unit length may be greater than the product of the inductance per unit length of the second line 200 included in the second impedance and the capacitance. have. This is because the phase speed (υ _o ) of the second line 200 is compensated based on the phase speed (υ _i ) of the first line 100, so that the second line 200 included in the second impedance The product of the inductance per unit length and the capacitance per unit length may be smaller than the product of the inductance per unit length and the capacitance per unit length of the first line 100 included in the first impedance.

According to an embodiment, the phase speed (υ _i ) of the first line 100 is inversely proportional to the effective dielectric constant (ε _e1 ) for the first line 100, and the phase speed (υ _o ) of the second line 200 May be in inverse proportion to the effective dielectric constant ε _e2 for the second line 200.

At this time, the effective dielectric constant (ε _e ) for the first line 100 is calculated through the following equation (6),

이고, Here, the formula (6) is

ego,

Here, ε _r is the relative dielectric constant of the substrate on which the first line 100 is stacked, h is the height of the substrate on which the first line 100 is stacked, and ω may be the width of the first line 100. In addition, the effective dielectric constant (ε _e ) for the second line 200 may be calculated in the same manner through the above calculation equation (6).

That is, the first line effective permittivity for the 100 (ε _e) has a first width (ω _i), the effective dielectric constant (ε _e) of proportion to, and in the second line 200 of the line 100 is the second It may be proportional to the width (ω _o ) of the line 200. Accordingly, since the phase velocity (υ _o ) of the second line 200 is compensated faster than the phase velocity (υ _i ) of the first line 100, the effective dielectric constant (ε _e2 ) for the second line 200 May be smaller than the effective dielectric constant ε _e1 for the first line 100 based on an inverse proportional relationship between the phase speed and the effective dielectric constant.

The asymmetric coupling line 10 for transmitting the differential signal according to the embodiment of the present application is bent and extended at the same angle θ as the first line 100 bent and extended at a predetermined angle θ. And, it may include a second line 200 arranged to be parallel to the first line 100. At this time, the length lo of the second line 200 is longer than the length li of the first line 100, and the width ω _o of the second line 200 is the width of the first line 100 ( Since it is formed narrower than ω _i ), the phase speed υ _o of the second line 200 can be compensated without adding a capacitor or inductor for delaying the phase speed υ _i of the first line 100. . In addition, since the asymmetric coupling line 10 can compensate for the phase speed (υ _o ) of the second line 200 without structural deformation of the first line 100 in the bent differential line, not only a specific band, but also Common mode noise generation over a wide bandwidth can be minimized.

2 is an embodiment of the differential signal transmission board 50 to which the asymmetric coupling line of FIG. 1 is applied, and FIG. 3 is an embodiment of the conventional differential signal transmission board 51.

1 to 3, the differential signal transmission board 50 includes a plurality of asymmetric coupling lines 10_1 to 10_N, transmission terminals 20_1 to 20_N, and reception terminals 30_1 to 30_N on one surface. can do.

First, the plurality of asymmetric coupling lines 10_1 to 10_N may be formed in different metal patterns or in the same metal pattern shape. At this time, the plurality of asymmetric coupling lines 10_1 to 10_N may be connected to the transmitting terminals 20_1 to 20_N at one side, and electrically connected to the receiving terminals 30_1 to 30_N at the other side. That is, the plurality of asymmetric coupling lines 10_1 to 10_N may electrically connect the transmission terminals 20_1 to 20_N and the reception terminals 30_1 to 30_N to each other.

Next, the transmission terminals 20_1 to 20_N may generate a differential signal and transmit it to the reception terminals 30_1 to 30_N through a plurality of asymmetric coupling lines 10_1 to 10_N.

For example, the first transmission terminal 20_1 transmits a positive signal among differential signals to the first line (eg, 100_1) of the first asymmetric coupling line 10_1, and the second transmission terminal 20_2 is the first asymmetric A negative signal among the differential signals may be transmitted to the second line (eg, 200_1) of the coupling line 10_1.

Next, the receiving terminals 30_1 to 30_N may receive a differential signal from the transmitting terminals 20_1 to 20_N through a plurality of asymmetric coupling lines 10_1 to 10_N. For example, the receiving terminals 30_1 to 30_N may be via contacts for transmitting differential signals to the outside.

As shown in FIG. 3, the conventional differential signal transmission board 51 includes a first line (201_5) of a first line (101_5) of an asymmetric coupling line (11_5) and a second line (201_5) of the asymmetric coupling line (11_5). A part of 101_5) may be extended by protruding in one direction, and the phase speed may be compensated for in a specific band. At this time, the first line 101_5 and the second line 201_5 are arranged in different shapes, the length of the first line 101_5 is formed longer than the second line 201_5, and the first line 101 The physical spare area located in) may be formed in one direction to be narrower than in the other direction. In addition, the width ω _i of the first line 101 and the width ω _o of the second line 201 may be formed to have the same size.

In the differential signal transmission board 50 according to the embodiment of the present application, unlike the conventional differential signal transmission board 51, the width ω _o of the second line 200_5 of the asymmetric coupling line 10_5 is first It may be formed to be narrower than the width ω _i of the line 100_5. Accordingly, the use of the metal pattern can be reduced compared to the prior art, and the phase speed can be compensated.

In addition, in the differential signal transmission board 50, unlike the conventional differential signal transmission board 51, the second line 200 is arranged in parallel in the same shape as the arrangement of the first line 100, so that the first line Physical spare areas located on 100 and the second line 200 may be formed identically. Accordingly, the differential signal transmission substrate 50 can secure a wider physical margin area of the first line 100 compared to the conventional one. Accordingly, the differential signal transmission substrate 50 facilitates a manufacturing process such as pattern stacking of the asymmetric coupling line 10 and minimizes the generation of common mode noise in a wide bandwidth as well as a specific band.

Hereinafter, characteristics according to the measurement result of the asymmetric coupling line 10 of FIG. 1 will be described with reference to FIGS. 4 to 8. For this measurement, the relative dielectric constant (ε _r ) of the differential signal transmission board 50 is set to 4.4, the height (h) is set to 1.6 mm, and the first line 100 and the second line 200 have a preset angle. It was set to 90 degrees.

In addition, in order to compare the widths of the first and second lines 100 and 200 on the basis of the same, the width ω _i of the first line 100 and the width ω of the second line 200 _o ) is 1.6mm, the separation distance (s) between the first line 100 and the second line 200 is 0.75mm, the length (li) of the first line 100 is 55mm, and the second line 200 The length (lo) of was set to 59.7 mm. Then, the width ω _i of the first line 100 of the asymmetric coupling line 10 to be measured is 1.6 mm, and the separation distance s between the first line 100 and the second line 200 is 0.75 mm was set, and the width (ω _o ) of the second line 200 was varied and measured.

FIG. 4 is a graph showing a difference in phase speed between the first and second lines 100 and 200 that change according to the width ω _o of the second line 201 of FIG. 1.

1 to 4, the width (ω _o ) of the second line 200 in the asymmetric coupling line 10 based on when the widths of the first and second lines 100 and 200 are the same It represents the difference in phase speed between the first and second lines 100 and 200 measured as this is changed.

At this time, compared to the case where the widths of the first and second lines 100 and 200 are the same, the width ω _o of the second line 200 is greater than the width ω _i of the first line 100 The narrower it is, the greater the difference in phase speed between the first and second lines 100 and 200 may be changed.

As shown in FIG. 4, as the width (ω _o ) of the second line 200 is narrower than the width (ω _i ) of the first line 100, the phase speed (υ _o ) of the second line 200 Is getting faster, the phase speed (υ _i ) of the first line 100 may gradually become slower, and the width (ω _o ) of the second line 200 is greater than the width (ω _i ) of the first line 100 As the width increases, the phase speed υ _o of the second line 200 gradually decreases, and the phase speed υ _i of the first line 100 may gradually increase.

Table 1 below shows the separation distance s, parameters V and D, and the length li of the first line 100 according to the change in the width ω _o of the second line 200.

ω _o (mm) s(mm) V D(mm) li(mm) 0.25 0.13 26.3 2.11 55 0.4 0.2 30 2.4 75.5 0.55 0.25 33.1 2.65 87.8 0.7 0.3 43 2.9 125 0.85 0.34 51.7 3.13 162 One 0.39 57.8 3.38 195

That is, the asymmetric coupling line 10 formed to have a width (ω _o ) of the second line 200 narrower than the width (ω _i ) of the first line 100 is zero with respect to the phase velocity of the first line 100. 2 The phase speed of the line 200 can be compensated at a high speed. Meanwhile, in the asymmetric coupling line 10, as the width ω _o of the second line 200 decreases, the differential mode impedance may increase. Such an increase in differential mode impedance may cause a problem of suppressing signal integrity.

Hereinafter, with reference to FIG. 4, it is described that in the asymmetric coupling line 10 of FIG. 1, the problem of increasing the differential mode impedance can be solved through the separation distance s between the first and second lines 100 and 200. do.

5 is a graph showing a change in differential mode impedance according to the separation distance s between the first and second lines 100 and 200.

1 to 3 and 5, the optimum value of the differential mode impedance is 100 ohms, the separation distance s between the first and second lines 100 and 200 is 0.75 mm, and the first line 100 ) width (ω _i) is a 1.6mm, a width (ω _o) in this case reduced to 0.25mm, the differential mode impedance of the second line 200 of the indicates that the increase to 150 ohms. Here, the optimal value of the differential mode impedance is 1.6 mm in which the width (ω _i ) of the first line 100 and the width (ω _o ) of the second line 200 are the same, and the separation distance (s) is 0.75 mm It may be a differential mode impedance formed when.

At this time, as shown in FIG. 5, the width ω _i of the first line 100 is 1.6 mm, the width ω _o of the second line 200 is 0.25 mm, and the first and second lines It indicates that as the separation distance (s) between (100, 200) decreases, the differential mode impedance decreases.

For example, the width ω _i of the first line 100 is 1.6 mm, the width ω _o of the second line 200 is 0.25 mm, and between the first and second lines 100 and 200 When the separation distance (s) of is reduced from 0.25mm to 0.13mm, the differential mode impedance in the asymmetric coupling line 10 may be reduced to an optimum value of 100 ohms.

6 is a simulation graph showing common mode noise noise characteristics of the asymmetric coupling line 10 of FIG. 1.

As shown in Fig. 6, in the case of type A and type B corresponding to the conventional coupling line, common mode noise noise of -20 DB or more appears in the 1.1 GHz frequency band, and -20 DB or more is common from the 5 GHz frequency band to 9 GHz frequency band Mode noise noise may appear.

In the case of the type C corresponding to the asymmetric coupling line 10 of the present application, it can be seen that a common mode noise noise of -20 DB or less from DC to 15 GHz appears.

In addition, in the case of type A, the transmission characteristic (Sdd21) has a characteristic of -3DB or less from about 6GHz frequency band, and in the case of type B, the transmission characteristic (Sdd21) has a characteristic of -3DB or less from about 9GHz frequency band. On the other hand, in the case of type C, it can be confirmed that the transmission characteristic (Sdd21) maintains -3DB or more from DC to 15GHz.

That is, the asymmetric coupling line 10 of FIG. 1 can reduce common mode noise noise compared to conventional coupling lines such as type A and type B, while maintaining a higher transmission characteristic Sdd21.

7 is a graph showing transmission characteristics of a differential signal for the asymmetric coupling line 10 of FIG. 1.

6 and 7, in the case of type C corresponding to the asymmetric coupling line 10 of the present application, the common mode noise noise (Scd21) indicates that the common mode noise noise (Scd21) is maintained below -20 DB from DC to 15 GHz, and transmission characteristics It can be seen that (Sdd21) maintains more than -3DB from DC to 15GHz.

At this time, it can be seen that the impedance characteristic Sdd11 maintains -12DB or less from DC to 15GHz.

8 is a graph comparing eye-diagrams measured according to the type of FIG. 6.

As shown in FIG. 8, in the case of type C corresponding to the asymmetric coupling line 10 of the present application, it can be seen that generation of common mode noise in a wide bandwidth as well as a specific band of a differential signal can be minimized. .

At this time, the bit rate was set to 8Gb/s and 14Gb/s, and the rise time was set to 50ps at 10% to 90% edge rate, and the eye diagram was measured.

Table 2 below shows variables extracted from the type A eye diagram and the type C eye diagram.

Eye opening (mV) Eye width (ps) Jitter (ps) Daechill combined track (Type A) 644 113.2 5.9 Asymmetric coupling line 653 115.2 6.25

As shown in Table 2, in the case of Type C corresponding to the asymmetric coupling line 10 of the present application, compared to Type A, the eye-opening increases by 9mV and the eye-width increases by 2ps. And, since jitter increases or decreases by 0.35 ps, it can be seen that generation of common mode noise in a wide bandwidth can be minimized.

9 is an operation process of the differential line forming apparatus 1000 for forming the asymmetric coupling line 10 of FIG. 1 on the differential signal transmission board 50.

First, in step S110, when the width (ω _i ) and the bent angle (θ) of the first line 100 are determined, the differential line forming apparatus 1000 provides the first line 100 to the differential signal transmission board 50. ) Can be formed. Here, the first line 100 may be a line for transmitting a position signal from the differential signal transmission board 50. For example, the differential line forming apparatus 1000 receives the size of the width ω _i of the first line 100 and the bent angle θ from the manager, and the differential signal transmission board 50 receives the first line (100) can be formed.

Then, in step S120, the differential line forming apparatus 1000 determines the first size of the width ω _o of the second line 200 according to the size of the width ω _i of the first line 100 It can be set to be narrower than the width ω _i of the line 100. Here, the second line 200 may be a line for transmitting a negative signal from the differential signal transmission board 50. For example, the differential line forming apparatus 1000 is a section of the size of the width ω _i of the first line 100 from 0, and the size of the width ω _o of the second line 200 is the first line It can be set narrower than the width (ω _i ) of (100).

At this time, in step S130, the differential line forming apparatus 1000 is based on the previously stored differential mode impedance list according to the width ω _i of the first line 100 and the width ω _o of the second line 200 It can be set by extracting the separation distance (s) corresponding to the impedance. Here, in the previously stored differential mode impedance list, according to the width (ω _i ) of the first line 100 and the width (ω _o ) of the second line 200, the differential mode impedance is listed for each separation distance (s). Is a list, and the separation distance (s) may be a distance between the first line 100 and the second line 200.

Table 3 below is an example of a previously stored differential mode impedance list when the width (ω _i ) of the first line 100 is 1.6 mm and the width (ω _o ) of the second line 200 is 0.25 mm to be.

Separation distance(s) Differential mode impedance (Z _diff ) 0.1 95 0.13 100 0.2 114 0.3 123 0.4 132 0.5 140 .
.
. .
.
.

As shown in Table 3, the separation distance s between the first line 100 and the second line 200 may be proportional to the differential mode impedance.

For example, when the width (ω _i ) of the first line 100 is formed to be 1.6 mm, the width (ω _o ) of the second line 200 is set to 0.25 mm, and the reference impedance is 100 ohms, the differential line The furnace forming apparatus 1000 may extract a separation distance (s) of 0.13 mm corresponding to the reference impedance from the previously stored differential mode impedance list.

Then, in step S140, the differential line forming apparatus 1000 is the width of the first line 100 (ω _i ), the width of the second line 200 (ω _o ), and the first line 100 2 Using the separation distance s between the lines 200, the phase speed υ _i of the first line 100 and the phase speed υ _o of the second line 200 may be calculated.

Then, in step S150, the differential line forming apparatus 1000 based on the speed difference between the phase speed (υ _i ) of the first line 100 and the phase speed (υ _o ) of the second line 200, At least one of a width ω _o of the second line 200, a separation distance s between the first line 100 and the second line 200, and a bent angle θ may be determined.

Thereafter, in step S160, the differential line forming apparatus 1000 includes the width (ω _o ) of the second line 200, the separation distance s between the first line 100 and the second line 200, and bent The second line 200 may be formed on one surface of the differential signal transmission substrate 50 based on at least one of the angles θ.

Although the present application has been described with reference to the exemplary embodiment illustrated in the drawings, this is only exemplary, and those of ordinary skill in the art will appreciate that various modifications and equivalent other exemplary embodiments are possible therefrom. Therefore, the true technical protection scope of the present application should be determined by the technical idea of the attached registration claims.

10: asymmetric coupling line
50: differential signal transmission board
100: first track
200: second track
1000: differential signal transmission board

Claims (16)

A first line bent at a predetermined angle and extended; And
It includes a second line bent and extended at the same angle as the first line, and arranged to be parallel to the first line,
The length of the second line is longer than the length of the first line, the width of the second line is narrower than the width of the first line,
The separation distance between the first line and the second line is proportional to the differential mode impedance formed along the first and second lines,
The separation distance is set by extracting a separation distance corresponding to a reference impedance from a previously stored differential mode impedance list according to the width of the first line and the width of the second line,
The length of the first line is calculated through the following formula (2),
The above calculation formula (2) is:

Is,
Where V is

It is a parameter calculated through formula (3), and D is

It is a parameter calculated through formula (4),
Here, υo is the phase speed of the first line, υi is the phase speed of the second line, ω _i is the width of the first line, ω _o is the width of the second line, and s is the extracted It is a separation distance between the first and second lines,
The length of the second line is calculated through the following formula (1),
The above calculation formula (1) is:

ego,
Here, ι _i is the length of the first line, and θ is an asymmetric coupling line where the angle is bent. The method of claim 1,
As the width of the second line decreases, the difference in length between the first and second lines decreases. The method of claim 1,
As the width of the first line decreases, the difference in length between the first and second lines decreases. The method of claim 1,
The second line is disposed to be spaced a predetermined distance from the first line,
As the distance between the second line and the first line decreases, the difference in length between the first and second lines decreases. delete The method of claim 1,
As the angle changes from 0 degrees to 90 degrees, the difference in length between the first and second lines decreases. The method of claim 6,
As the angle changes from 90 degrees to 0 degrees, the length difference between the first and second lines increases. The method of claim 1,
As the length of the second line decreases, the difference in length between the first and second lines decreases. Following paragraph 1,
As the width of either the first line or the second line is wider, the difference in length between the first and second lines increases. delete delete The method of claim 1,
The phase speed of the second line is compensated based on the length ratio of the first and second lines and the phase speed of the first line. The method of claim 1,
The phase speed of the first line is determined through the following equation (5),
The above calculation formula (5) is

ego,
Here, Li is the inductance of the first line, and Ci is the capacitance of the first line. The method of claim 1,
The phase speed of the first line is inversely proportional to the first effective dielectric constant, and the phase speed of the second line is inversely proportional to the second effective dielectric constant. The method of claim 14,
The effective dielectric constant of the first line is smaller in magnitude than the effective dielectric constant of the second line,
An asymmetric coupling line in which the effective dielectric constant of the second line is proportional to the width of the second line. As a method of forming an asymmetric coupling line for forming an asymmetric coupling line,
Forming the first line on the differential signal transmission board when the width and the bent angle of the first line are determined;
Setting the width of the second line to be narrow according to the width of the first line;
Extracting and setting a separation distance corresponding to a reference impedance from a preset differential mode impedance list according to the widths of the first and second lines;
Calculating a phase velocity of the first line and a phase velocity of the second line using the width of the first line, the width of the second line, and the separation distance;
Determining at least one of a width of the second line, a separation distance, and a bent angle based on a difference in phase speed between the first and second lines; And
Based on the at least any one, comprising the step of forming the second line on one surface of the differential signal transmission substrate,
The separation distance between the first line and the second line is proportional to the differential mode impedance formed along the first and second lines,
The separation distance is set by extracting a separation distance corresponding to a reference impedance from a previously stored differential mode impedance list according to the width of the first line and the width of the second line,
The length of the first line is calculated through the following formula (2),
The above calculation formula (2) is:

Is,
Where V is

It is a parameter calculated through formula (3), and D is

It is a parameter calculated through formula (4),
Here, υo is the phase speed of the first line, υi is the phase speed of the second line, ω _i is the width of the first line, ω _o is the width of the second line, and s is the extracted It is a separation distance between the first and second lines,
The length of the second line is calculated through the following formula (1),
The above calculation formula (1) is:

ego,
Here, ι _i is the length of the first line, θ is a bent angle, the method of forming an asymmetric coupling line.

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