High frequency transmission line and high frequency board

• US 20040257178A1
• Filed: 04/12/2004
• Published: 12/23/2004
• Est. Priority Date: 04/11/2003
• Status: Active Grant

• Current Assignee: TDK Corporation
• Original Assignee: TDK Corporation
• Inventors: Shimoda, Hideaki
• Granted Patent: US 7,193,490 B2
• Time in Patent Office: Days
• US Class Current: 333/238
• CPC Class Codes: H01P 5/08 for linking dissimilar lines or devices H01P1/16, H01P5/04 take precedence; linking lines of the same kind but with different dimensions H01P5/02
• CPC Class Codes: H05K 1/0219 Printed shielding conductors for shielding around or between signal conductors, e.g. coplanar or coaxial printed shielding conductors
• CPC Class Codes: H05K 1/0222 for shielding around a single via or around a group of vias, e.g. coaxial vias or vias surrounded by a grounded via fence
• CPC Class Codes: H05K 1/0251 related to vias or transitions between vias and transmission lines
• CPC Class Codes: H05K 1/115 Via connections; Lands around holes or via connections H05K1/112 takes precedence
• CPC Class Codes: H05K 2201/09618 Via fence, i.e. one-dimensional array of vias
• CPC Class Codes: H05K 2201/0979 Redundant conductors or connections, i.e. more than one current path between two points
• CPC Class Codes: H05K 2201/09845 Stepped hole, via, edge, bump or conductor

Abstract

Since a width of an edge portion of a signal line of a first high frequency transmission line is changed with respect to a width of another portion thereof, a deviation of impedances in a connection portion of the first and second high frequency transmission lines can be suppressed, so that signal reflections occurred in the connection portion can be lowered and a signal passing characteristic is improved.

Claims

1. A high frequency transmission line comprising:

a first high frequency transmission line having a signal line, a width of an edge portion thereof being different from a width of another portion thereof; and

a second high frequency transmission line different from said first high frequency transmission line, having a signal line which is connected to the edge portion of said signal line of the first high frequency transmission line.

2. A high frequency transmission line as claimed in claim 1, wherein said first and second high frequency transmission lines own the signal lines in different layers of a dielectric substrate respectively;

the edge portion of the signal line of said first high frequency transmission line is arranged to overlap with the signal line of said second high frequency transmission line; and

a connection conductor is provided to connect said edge portion of said first high frequency transmission line to said edge portion of said second high frequency transmission line.

3. A high frequency transmission line as claimed in claim 2 wherein said edge portion of the second high frequency transmission line has a width which is different from a width of another portion thereof.

4. A high frequency transmission line as claimed in claim 2 further comprising a conductor for shortening a distance between a ground conductor and said signal line of said first high frequency transmission line.

5. A high frequency transmission line comprising:

a first high frequency transmission line having a signal line in a layer of a dielectric substrate;

a second high frequency transmission line having a signal line in a different layer of a dielectric substrate;

a third signal line which is provided in a layer between said first signal line of said first high frequency transmission line and said second signal line of said second high frequency transmission line, and which is formed in such a manner that one edge of said third signal line is overlapped with said first signal line and another edge thereof is overlapped with said second signal line;

a first connection conductor for connecting said first signal line to said one edge of said third signal line; and

a second connection conductor for connecting said second signal line to said another edge of said third signal line.

6. A high frequency transmission line as claimed in claim 5, wherein an edge portion of said first signal line connected to said first connection conductor owns a line width different from a line width of another portion thereof.

7. A high frequency transmission line as claimed in claim 6 wherein an edge portion of said second signal line connected to said second connection conductor owns a line width different from a line width of another portion thereof.

8. A high frequency transmission line as claimed in claim 5 wherein a width of said third signal line is-set between said first signal line and said second signal line.

9. A high frequency transmission line as claimed in claim 5 wherein said third signal line is arranged in a step form in such a manner that one edge of said third signal line is overlapped with a line of an upper layer and another edge of said third signal line is overlapped with a line of a lower layer, and owns at least one, or more lines, the overlapped portions of which are connected to each other;

a line width of a partial line within said lines is defined between a width of said first signal line and a width of said second signal line; and

the line width is changed in a step manner among the lines.

10. A high frequency transmission line as claimed in claim 5, further comprising:

a conductor for shortening a distance between said first signal line and a ground conductor.

11. A high frequency transmission line comprising:

a first high frequency transmission line having a signal line in a layer of a dielectric substrate;

a second high frequency transmission line having a signal line in a different layer of a dielectric substrate, the edge portion being overlapped with said signal line of said first high frequency line;

a connection conductor for connecting said signal line of said first high frequency transmission line to said edge portion of said second high frequency transmission line; and

a conductor for shortening a distance between said signal line of said first high frequency transmission line and a ground conductor.

12. A high frequency board for conducting a high frequency signal to a high frequency circuit via a high frequency transmission line which contains a first high frequency line and a second high frequency line different from said first high frequency line, wherein the high frequency transmission line comprises:

a first high frequency transmission line having a signal line, a width of an edge portion thereof being different from a width of another portion thereof; and

a second high frequency transmission line different from said first high frequency transmission line, having a signal line which is connected to the edge portion of said signal line of the first high frequency transmission line.

13. A high frequency board as claimed in claim 12, wherein said first and second high frequency transmission lines own the signal lines in different layers of a dielectric substrate respectively;

the edge portion of the signal line of said first high frequency transmission line is arranged to overlap with the signal line of said second high frequency transmission line; and

a connection conductor is provided to connect said edge portion of said first high frequency transmission line to said edge portion of said second high frequency transmission line.

14. A high frequency board which conducts a high frequency signal to a high frequency circuit via a high frequency transmission line containing signal lines in different layers of a dielectric substrate, wherein the high frequency transmission line comprising:

a first high frequency transmission line having a signal line in a layer of a dielectric substrate;

a second high frequency transmission line having a signal line in a different layer of a dielectric substrate;

a third signal line which is provided in a layer between said first signal line of said first high frequency transmission line and said second signal line of said second high frequency transmission line, and which is formed in such a manner that one edge of said third signal line is overlapped with said first signal line and another edge thereof is overlapped with said second signal line;

a first connection conductor for connecting said first signal line to said one edge of said third signal line; and

a second connection conductor for connecting said second signal line to said another edge of said third signal line.

15. A high frequency board which conducts a high frequency signal to a high frequency circuit via a high frequency transmission line containing signal lines in different layers of a dielectric substrate, wherein the high frequency transmission line comprising:

a first high frequency transmission line having a signal line in a layer of a dielectric substrate;

a second high frequency transmission line having a signal line in a different layer of a dielectric substrate, the edge portion being overlapped with said signal line of said first high frequency line;

a connection conductor for connecting said signal line of said first high frequency transmission line to said edge portion of said second high frequency transmission line; and

a conductor for shortening a distance between said signal line of said first high frequency transmission line and a ground conductor.