JP2012138751A - Substrate with microstrip line, substrate with coplanar line, and substrate with differential microstrip line - Google Patents

Abstract

Provided is a substrate with a microstrip line in which dielectric loss is reduced with a simple configuration.
A substrate (100) with a microstrip line includes a substrate (102) made of a dielectric, a signal line (104) provided on one surface of the substrate (102), and the other of the substrate (102). A ground electrode (106) provided on the surface and a groove (108) provided on the substrate (102) and defining a space through which an electric field generated between the signal line (104) and the ground electrode (106) passes. Prepare.
[Selection] Figure 1

Description

  The present invention relates to a substrate with a microstrip line, a substrate with a coplanar line, and a substrate with a differential microstrip line.

A circuit board used for an electronic device is provided with a microstrip line, a coplanar line, or a differential microstrip line.
A microstrip line, a coplanar line, and a differential microstrip line are used as transmission paths for electrical signals. However, transmission loss based on dielectric loss has become a problem as the frequency of electrical signals increases.

  Therefore, in the microstrip line disclosed in Patent Document 1, the two conductor thin films as the signal line and the ground electrode are opposed to each other through air. According to this microstrip line, since the relative dielectric constant of air is lower than that of the substrate, the dielectric loss is reduced.

JP-A-3-64101

The microstrip line disclosed in Patent Document 1 has two conductor thin films provided on different substrates, and these substrates are supported by a support, and the configuration is complicated.
Further, the technique disclosed in Patent Document 1 is difficult to apply to a coplanar line in which a signal line and a ground line are provided on the same surface of a substrate.
On the other hand, in the differential microstrip line, the signal lines are adjacent to each other on the same surface of the substrate, the electric field is concentrated between the signal lines, and dielectric loss occurs due to the presence of the substrate located between the signal lines. To do. For this reason, it is difficult to sufficiently reduce the dielectric loss of the differential microstrip line by the technique disclosed in Patent Document 1.

The present invention has been made in view of the above-described circumstances, and one of its purposes is to provide a substrate with a microstrip line in which dielectric loss is reduced with a simple configuration.
Another object of the present invention is to provide a substrate with a coplanar line in which dielectric loss is reduced with a simple configuration.
Furthermore, one of the objects of the present invention is to provide a substrate with a differential microstrip line in which dielectric loss is reduced with a simple configuration.

  To achieve the above object, according to one aspect of the present invention, a substrate made of a dielectric, a signal line provided on one surface of the substrate, and a ground electrode provided on the other surface of the substrate, There is provided a substrate with a microstrip line provided on the substrate and having a groove defining a space through which an electric field generated between the signal line and the ground electrode passes.

  According to one embodiment of the present invention, the substrate is made of a dielectric, the signal line is provided on one surface of the substrate, the ground line is provided on both sides of the signal line, and the substrate is provided. There is provided a substrate with a coplanar line comprising a groove defining a space through which an electric field generated between the signal line and the ground line passes.

  Furthermore, according to one aspect of the present invention, a substrate made of a dielectric, a first signal line provided on one surface of the substrate, and a second signal line provided along the first signal line. A signal line, a ground electrode provided on the other surface of the substrate, and a space provided on the substrate for defining a space through which an electric field generated between the first signal line and the second signal line passes. A substrate with a differential microstrip line comprising a groove is provided.

ADVANTAGE OF THE INVENTION According to this invention, the board | substrate with a microstrip line by which a dielectric loss is reduced with a simple structure is provided.
In addition, according to the present invention, a substrate with a coplanar line in which dielectric loss is reduced with a simple configuration is provided.
Furthermore, according to the present invention, a substrate with a differential microstrip line in which dielectric loss is reduced with a simple configuration is provided.

It is sectional drawing which shows schematically the board | substrate with a microstrip line of 1st Embodiment. It is sectional drawing which shows schematically the board | substrate with a microstrip line of 2nd Embodiment. It is sectional drawing which shows schematically the board | substrate with a microstrip line of the modification. (A) is a figure for demonstrating the process of forming a groove | channel in a board | substrate in the manufacturing method of the board | substrate with a microstrip line of FIG. 2, (b) adheres another board | substrate to the board | substrate in which the groove | channel was formed. It is a figure for demonstrating the process to do. It is sectional drawing which shows schematically the board | substrate with a coplanar track | line of 3rd Embodiment. (A) is sectional drawing which shows schematically the board | substrate with a coplanar line of 4th Embodiment, (b) is sectional drawing which shows schematically the board | substrate with a coplanar line of a modification. It is sectional drawing which shows schematically the board | substrate with a differential microstrip line of 5th Embodiment. (A) is sectional drawing which shows schematically the board | substrate with a differential microstrip line of 6th Embodiment, (b) is sectional drawing which shows schematically the board | substrate with a differential microstrip line of a modification. is there. It is sectional drawing which shows schematically the board | substrate with a differential microstrip line of 7th Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
FIG. 1 is a schematic cross-sectional view of a substrate 100 with a microstrip line (hereinafter also simply referred to as a substrate 100 with a line) according to the first embodiment.
The board | substrate 100 with a track | line has the board | substrate 102 which consists of dielectric materials, such as a glass epoxy resin, for example. Although not shown, an electrical element such as an LSI (Large Scale Integrated circuit) or a connector is mounted on the substrate 102.

On one surface of the substrate 102, signal lines 104 are formed in a predetermined pattern in order to electrically connect the electrical elements or electrical elements and connectors. The signal line 104 is made of a conductive thin film such as copper, for example, and is formed by etching.
A ground electrode 106 is provided on the other surface of the substrate 102. The ground electrode 106 is made of, for example, a conductive thin film such as copper provided over the entire surface of the substrate 102.

  Two grooves 108 are formed in the substrate 102. These grooves 108 extend along both sides of the signal line 104 and open in the vicinity of the signal line 104. The groove 108 is formed by cutting the substrate 102 with an end mill or a drill, for example.

According to the substrate 100 with the microstrip line of the first embodiment described above, the electric field from the signal line 104 toward the ground electrode 106 passes through the grooves 108 and 108. In other words, the grooves 108 and 108 form a space in the region of the substrate 102 through which the electric field passes.
Air exists in the grooves 108 and 108, and the relative permittivity of air is lower than that of the substrate 102. For this reason, when a signal propagates through the signal line 104, dielectric loss is suppressed, and as a result, transmission loss is suppressed.

[Second Embodiment]
FIG. 2 is a schematic cross-sectional view of a substrate 120 with a microstrip line (hereinafter also simply referred to as a substrate 120 with a line) according to the second embodiment. In addition, about the structure same as previous embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted. The same applies to the descriptions of the third to seventh embodiments.

In the substrate 120 with a line, as a preferable aspect, the groove 122 penetrates the substrate 102.
Moreover, in the board | substrate 120 with a line, as a preferable aspect, the part of the board | substrate 102 directly under the signal wire | line 104 is also shaved by the groove | channel 122. FIG. Therefore, in the width direction of the groove 122, the end of the groove 122 is located below the signal line 104 beyond the end of the signal line 104. On the other surface of the substrate 102, a ground electrode 124 made of a conductive thin film such as copper and a substrate 126 made of a dielectric such as glass epoxy resin are provided.

  FIG. 3 is a schematic cross-sectional view of a modified substrate 140 with a microstrip line (hereinafter also simply referred to as a substrate 140 with a line). The groove 142 of the substrate with line 140 is open on the other surface of the substrate 102, but is not open on one surface of the substrate 102. The bottom wall 144 of the groove 142 located on one surface side of the substrate 102 is located in the vicinity of the signal line 104 and preferably has a thickness as thin as possible.

The board | substrate 120 with a line | wire of 2nd Embodiment is produced with the following manufacturing methods, for example. First, as shown in FIG. 4A, a groove 122 is formed from the other surface of the substrate 102 to one surface using a cutting tool T such as an end mill. Thereafter, as shown in FIG. 4B, the substrate with line 120 is manufactured by bonding the substrate 126 having the ground electrode 124 on one surface to the other surface of the substrate 102.
Moreover, the board | substrate 140 with a track | line can be manufactured using the manufacturing method similar to the board | substrate 120 with a track | route 120 except leaving the bottom wall 144 without letting the groove | channel 142 penetrate.

  According to the substrate 120 with a microstrip line of the second embodiment and the substrate 140 with a microstrip line of the modified example described above, the grooves 122 and 142 have the signal lines 104 compared to the substrate 100 with a microstrip line of the first embodiment. , The ratio of the electric field passing through the air out of the electric field from the signal line 104 toward the ground electrode 124 becomes higher.

  Further, since the grooves 122 and 142 reach the ground electrode 124, the ratio of the electric field passing through the air to the ground electrode 124 becomes higher. As a result, when the signal propagates through the signal line 104, the dielectric loss is further suppressed, and as a result, the transmission loss is further suppressed.

[Third Embodiment]
FIG. 5 is a schematic cross-sectional view of a substrate 200 with a coplanar line (hereinafter also simply referred to as a substrate 200 with a line) according to the third embodiment.
In the substrate 200 with a line, two ground lines 202 made of a conductive thin film such as copper are provided on one side of the substrate 102 on both sides of the signal line 201. The ground line 202 extends in parallel with the signal line 201 with a predetermined interval. The groove 108 is opened between the signal line 201 and the ground line 202.

According to the substrate 200 with a coplanar line of the third embodiment described above, the electric field from the signal line 201 toward the ground line 202 and the ground electrode 106 passes through the grooves 108 and 108. In particular, the electric field is concentrated between the signal line 201 and the ground line 202, and this concentrated electric field passes through the grooves 108 and 108. In other words, the grooves 108 and 108 form a space in the region of the substrate 102 through which the electric field passes.
Here, air exists in the grooves 108 and 108, and the relative permittivity of air is lower than that of the substrate 102. For this reason, when a signal propagates through the signal line 201, dielectric loss is effectively suppressed, and as a result, transmission loss is suppressed.

[Fourth Embodiment]
FIG. 6A is a schematic cross-sectional view of a substrate 220 with a coplanar line (hereinafter also simply referred to as a substrate with line 220) according to the fourth embodiment.
In the substrate 220 with a line, as a preferable aspect, the groove 122 penetrates the substrate 102.
Moreover, in the board | substrate 220 with a line, as a preferable aspect, the part of the board | substrate 102 just under the signal wire | line 201 and the grounding line 202 is also shaved by the groove | channel 122. Therefore, in the width direction of the groove 122, the end of the groove 122 is located below the signal line 201 and the ground line 202 beyond the end of the signal line 201 and the ground line 202. On the other surface of the substrate 102, a ground electrode 124 made of a conductive thin film such as copper and a substrate 126 made of a dielectric such as glass epoxy resin are provided.

  The board | substrate 220 with a line | wire can be manufactured using the manufacturing method similar to the board | substrate 120 with a line | wire of 2nd Embodiment.

FIG. 6B is a schematic cross-sectional view of a substrate 240 with a coplanar line (hereinafter also simply referred to as a substrate 240 with a line) according to a modification. The groove 142 of the substrate with line 240 is open on the other surface of the substrate 102, but is not open on one surface of the substrate 102. The bottom wall 144 of the groove 142 located on one surface side of the substrate 102 is located between the signal line 201 and the ground line 202 and preferably has a thickness as thin as possible.
The board | substrate 240 with a line | wire can be manufactured using the manufacturing method similar to the board | substrate 120 with a line | wire 120 of 2nd Embodiment except leaving the bottom wall 144 without letting the groove | channel 142 penetrate.

  According to the substrate 220 with a coplanar line of the fourth embodiment and the substrate 240 with a coplanar line of the modification described above, the grooves 122 and 142 have the signal line 201 and the ground line compared to the substrate 200 with a coplanar line of the third embodiment. By spreading below 202, the ratio of the electric field passing through the air out of the electric field from the signal line 201 toward the ground line 202 becomes higher.

Further, since the grooves 122 and 142 reach the ground electrode 124, the ratio of the electric field passing through the air to the ground electrode 124 becomes higher. As a result, when the signal propagates through the signal line 201, the dielectric loss is further suppressed, and as a result, the transmission loss is further suppressed.
[Fifth Embodiment]
FIG. 7 is a schematic cross-sectional view of a substrate 300 with a differential microstrip line (hereinafter also simply referred to as a substrate with a line 300) according to a fifth embodiment.
In the substrate with a line 300, a signal line (first signal line) 301 and a signal line (second signal line) 302 made of a conductive thin film such as copper are provided on one surface of the substrate 102 together with the signal line (first signal line) 301. The signal line 302 extends in parallel with the signal line 301 at a predetermined interval so as to be electromagnetically coupled to the signal line 301. The groove 108 is opened between the signal line 301 and the signal line 302.

According to the substrate 300 with the differential microstrip line of the fifth embodiment described above, the electric field from the signal line 301 toward the signal line 302 and the ground electrode 106 passes through the groove 108. In particular, the electric field is concentrated between the signal line 301 and the signal line 302, and this concentrated electric field passes through the groove 108. In other words, the grooves 108 and 108 form a space in the region of the substrate 102 through which the electric field passes.
Here, air exists in the groove 108, and the relative permittivity of air is lower than that of the substrate 102. For this reason, when the differential signal propagates through the signal line 301 and the signal line 302, the dielectric loss is effectively suppressed, and as a result, the transmission loss is suppressed.

[Sixth Embodiment]
FIG. 8A is a schematic cross-sectional view of a substrate 320 with a differential microstrip line (hereinafter also simply referred to as a substrate 320 with a line) according to the sixth embodiment.
In the substrate 320 with a line, as a preferable aspect, the groove 122 penetrates the substrate 102.
Moreover, in the board | substrate 320 with a line, as a preferable aspect, the part of the board | substrate 102 just under the signal line 301 and the signal line 302 is also shaved by the groove | channel 122. FIG. Therefore, the end of the groove 122 is positioned below the signal line 301 and the signal line 302 beyond the end of the signal line 301 and the end of the signal line 302 in the width direction of the groove 122. On the other surface of the substrate 102, a ground electrode 124 made of a conductive thin film such as copper and a substrate 126 made of a dielectric such as glass epoxy resin are provided.

  The board | substrate 320 with a line | wire can be manufactured using the manufacturing method similar to the board | substrate 120 with a line | wire of 2nd Embodiment.

FIG. 8B is a schematic cross-sectional view of a modified substrate 330 with a differential microstrip line (hereinafter also simply referred to as a substrate with line 330). The groove 142 of the substrate with line 330 is open on the other surface of the substrate 102, but is not open on one surface of the substrate 102. The bottom wall 144 of the groove 142 located on one surface side of the substrate 102 is located between the signal line 301 and the signal line 302, and preferably has a thickness as thin as possible.
The board | substrate 330 with a line | wire can be manufactured using the manufacturing method similar to the board | substrate 120 with a line | wire 120 of 2nd Embodiment except leaving the bottom wall 144 without letting the groove | channel 142 penetrate.

  According to the substrate 320 with the differential microstrip line and the substrate 330 with the differential microstrip line of the sixth embodiment described above, the grooves 122 and 142 are formed as compared with the substrate 300 with the differential microstrip line of the fifth embodiment. By spreading below the signal line 301 and the signal line 302, the ratio of the electric field passing through the air in the electric field from the signal line 301 toward the signal line 302 becomes higher.

  Further, since the grooves 122 and 142 reach the ground electrode 124, the ratio of the electric field passing through the air to the ground electrode 124 becomes higher. As a result, when the differential signal propagates through the signal line 301 and the signal line 302, the dielectric loss is further suppressed, and as a result, the transmission loss is further suppressed.

[Seventh Embodiment]
FIG. 9 is a schematic cross-sectional view of a substrate 340 with a differential microstrip line (hereinafter also simply referred to as a substrate 340 with a line) according to the seventh embodiment.
In the substrate with line 340, the grooves 108 and 108 are provided on both sides of the signal line 301 and the signal line 302, and the dielectric loss is further suppressed as compared with the substrate 300 with the differential microstrip line of the fifth embodiment, Transmission loss is suppressed.

  Finally, the present invention is not limited to the first to seventh embodiments described above, and includes forms obtained by adding various modifications to these embodiments.

100, 120 Substrate with microstrip line 102, 126 Substrate 104, 201 Signal line 106, 124 Ground electrode 108, 122 Groove 202 Ground line 301 Signal line (first signal line)
302 signal line (second signal line)
200,220 Substrate with coplanar line 300,320,330,340 Substrate with differential microstrip line

Claims (9)

A dielectric substrate;
A signal line provided on one surface of the substrate;
A ground electrode provided on the other surface of the substrate;
A substrate with a microstrip line provided on the substrate and having a groove defining a space through which an electric field generated between the signal line and the ground electrode passes. The groove extends from one surface of the substrate to the other surface,
The substrate with a microstrip line according to claim 1. The groove was dug from the other surface of the substrate toward one surface,
The board | substrate with a microstrip line of Claim 1 or 2. A dielectric substrate;
A signal line provided on one surface of the substrate;
A ground line provided on both sides of the signal line;
A substrate with a coplanar line, comprising a groove provided on the substrate and defining a space through which an electric field generated between the signal line and the ground line passes. The substrate further has a ground electrode on the other surface;
The groove extends from one surface of the substrate to the other surface,
The board | substrate with a coplanar track | line of Claim 4. The groove was dug from the other surface of the substrate toward one surface,
The board | substrate with a coplanar track | line of Claim 4 or 5. A dielectric substrate;
A first signal line provided on one surface of the substrate;
A second signal line provided along the first signal line;
A ground electrode provided on the other surface of the substrate;
A substrate with a differential microstrip line, comprising a groove provided on the substrate and defining a space through which an electric field generated between the first signal line and the second signal line passes. The groove extends from one surface of the substrate to the other surface,
The substrate with a differential microstrip line according to claim 7. The groove was dug from the other surface of the substrate toward one surface,
The substrate with a differential microstrip line according to claim 7 or 8.

Images