CN100496187C - Transmission line for cross groove structure - Google Patents
Transmission line for cross groove structure Download PDFInfo
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- CN100496187C CN100496187C CNB2006100834827A CN200610083482A CN100496187C CN 100496187 C CN100496187 C CN 100496187C CN B2006100834827 A CNB2006100834827 A CN B2006100834827A CN 200610083482 A CN200610083482 A CN 200610083482A CN 100496187 C CN100496187 C CN 100496187C
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- line
- transmission line
- transmission
- width
- cross
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- 230000005540 biological transmission Effects 0.000 title claims abstract description 62
- 230000000694 effects Effects 0.000 abstract description 3
- 239000003990 capacitor Substances 0.000 abstract description 2
- 230000001965 increasing effect Effects 0.000 description 8
- 238000010586 diagram Methods 0.000 description 5
- 230000001939 inductive effect Effects 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
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Abstract
A design of transmission line used in cross-trench structure, taking use of the conception of impedance matching, optimizes the length and width of part of the transmission line which connects to the cross-trench structure. Thus the part of transmission line shows low-impedance characteristic as a capacitor, and accomplishes the impedance matching at designed frequency points, which will improve the discontinuous effect caused by the high-impedance characteristic of the transmission line on cross-trench structure.
Description
Technical Field
The present invention relates to a transmission line, and more particularly, to a transmission line for a trench-crossing structure.
Background
The wiring (Layout) is one of the designs of a Printed Circuit Board (PCB). The performance of the whole system is directly influenced by the quality of the wiring, and most design theories of high-speed circuits are realized and verified through the wiring finally, so that the wiring is very important in the design of a high-speed printed circuit board.
In the design of the multi-layer printed circuit board, since the wiring of the whole board must be completed with a smaller number of layers to save the cost, different voltage levels must be cut on the limited power supply layers, so that if the transmission line crosses these different voltage cutting surfaces, a cross-slot (overlay Plane) structure is formed.
Referring to fig. 1A and 1B, fig. 1A is a schematic diagram 10 of a conventional transmission line cross-slot structure, and fig. 1B is a top view 11 of the conventional transmission line cross-slot structure, as shown in the figure, a printed circuit board 101 has a cut slot 102, a transmission line 103 is used for transmitting signals and crosses the slot 102, wherein a line width of the transmission line 103 is W. However, since the transmission line 103 crossing over the trench 102 has no signal reference plane, the partial line segment exhibits inductive high impedance characteristic, which causes discontinuity of the impedance of the transmission line, i.e. signal reflection occurs when the signal is transmitted to the partial line segment. In view of this, the solution of the prior art is to add capacitors on the two dividing surfaces to allow the current on the transmission line to flow back on the two dividing surfaces, so as to reduce the signal reflection phenomenon. However, although the prior art can solve the signal reflection problem, it increases the manufacturing cost and has to face the problem of reducing the wiring space due to the increase of the capacitance.
Disclosure of Invention
In order to solve the above problems, the present invention discloses a transmission line for a cross-trench structure, which utilizes the concept of impedance matching, and utilizes a Smith Chart (Smith Chart) to adjust the optimized line length and line width of a single transmission line according to a desired frequency, so as to change the width of a line segment connected to a portion of the transmission line of the cross-trench structure, thereby enabling the line segment to exhibit a capacitive low impedance characteristic, achieving impedance matching at a designed frequency point, further improving the discontinuous effect caused by the inductive high impedance characteristic of the transmission line on the cross-trench structure, and improving the signal reflection loss.
The invention is described in detail below with reference to the drawings and specific examples, but the invention is not limited thereto.
Drawings
FIG. 1A is a schematic diagram of a conventional cross-slot structure;
FIG. 1B is a top view of a prior art cross-slot structure;
FIG. 2A is a schematic diagram of changing the line length and the line width of a transmission line according to the present invention;
FIG. 2B is a top view of the present invention showing the change of line length and line width of a transmission line portion;
FIG. 3 is a graph of the present invention of compensating for impedance mismatch by increasing the line width of the transmission line and the reflection loss before uncompensation; and
FIG. 4 is a graph showing the compensation of impedance mismatch and uncompensated states with increasing line width of transmission lines in accordance with the present invention.
Wherein the reference numerals
10 schematic representation of a conventional cross-slot structure
11 top view of a prior art cross-slot structure
20 schematic diagram of changing line length and line width of transmission line part of the invention
21 top view of the present invention for changing the line length and line width of transmission line
30 line width compensation impedance mismatch and reflection loss curve chart before uncompensation of transmission line by increasing transmission line of the invention
40 display of the invention using increased line width of transmission line to compensate for impedance mismatch and uncompensated
101, 201 printed circuit board
102, 202 trough
103 transmission line
203 first line segment
204 second line segment
301 compensation signal reflection loss curve
302 reflection loss curve of uncompensated transmission line signal
303, 304 resonance point
Display of 401 compensated signal
402 display of signal of uncompensated transmission line
L2 second line length
W line width
W1 first linewidth
W2 second linewidth
Detailed Description
The detailed features and advantages of the present invention are described in detail in the following embodiments, which are sufficient for anyone skilled in the art to understand the technical content of the present invention and to implement the present invention, and the related objects and advantages of the present invention can be easily understood by anyone skilled in the art according to the disclosure, claims and drawings of the present specification.
The invention uses the concept of impedance matching to change the width of the transmission line, so that part of the line segment of the transmission line crossing the groove of the printed circuit board presents capacitive low impedance characteristic, thereby achieving the impedance matching of the designed frequency point and further improving the impedance discontinuous effect of the transmission line caused by inductive high impedance characteristic.
Referring to fig. 2A and 2B, fig. 2A is a schematic diagram 20 of changing the line length and the line width of the transmission line portion of the present invention, fig. 2B is a top view 21 of changing the line length and the line width of the transmission line portion of the present invention, according to an embodiment of the present invention, a Smith Chart (Smith Chart) is used to adjust the optimized line length and line width of the single transmission line according to a desired frequency to achieve impedance matching, for example, a first line length L1 (not shown) and a first line width W1 are provided on a first line segment 203 of the transmission line on an outer layer of the printed circuit board 201, and if a line segment with the first line width W1 of the first line segment 203 crosses the slot 202, the transmission line above the slot 202 exhibits an impedance-mismatched inductive high-impedance characteristic with the originally designed transmission line. Therefore, the line width of the transmission line above the trench 202 is increased to overcome the impedance discontinuity, i.e. the second line segment 204 having the second line length L2 and the second line width W2, the second line segment 204 with the increased line width extends toward at least one end of the transmission line from the center of the groove 202, according to an embodiment of the present invention, for example, the line width of the first line segment 203 is implemented by 7 mils, and the width of the groove 202 is 20 mils, the second line segment 204 extends toward two ends of the transmission line by 75 mils respectively to form a line segment with the second line length L2 of 150 mils and the second line width W2 of 14 mils. The length and width of the line segment with increased line width are not intended to limit the scope of the present invention, and those skilled in the art can change the first line length L1 and/or the first line width W1 of the groove 202 and the first line segment 203 of the transmission line, and further change the second line length L2 and/or the second line width W2 to be added to the second line segment 204 of the transmission line above the groove 202.
Referring to fig. 3, a graph 30 of the present invention using the line width of the transmission line 203 to compensate for impedance mismatch and reflection loss before uncompensation is shown, a smith chart is used to obtain the line length and line width of the transmission line with the frequency of 2 to 8GHz (gigahertz), a reflection loss curve 301 of the compensated signal is measured and compared with a reflection loss curve 302 of the uncompensated signal, as shown in the figure, two resonance points 303, 304 can be generated at 2GHz and 6.5GHz after compensation, and the reflection loss can be greatly reduced at the frequencies near the two resonance points 303, 304.
Referring to fig. 4, the graph 40 of the present invention before compensating impedance mismatch and uncompensation by increasing the line width of the transmission line 203, using the smith chart to obtain the line length and line width of the transmission line with the frequency of 3GHz, measuring the graph 401 of the compensated signal and comparing with the graph 402 of the uncompensated signal, as shown, the graph 402 of the uncompensated signal is more distorted.
The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it should be understood that various changes and modifications can be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (4)
1. A transmission line for crossing a trench structure, the crossing trench structure is a trench disposed on a printed circuit board, the transmission line crosses the trench, the transmission line has a first line length and a first line segment with a first line width, and the transmission line is characterized in that:
the transmission line is provided with a second line length and a second line section with a second line width above the groove, the second line section extends from the center position of the corresponding groove to at least one end of the transmission line and is connected with the first line section: wherein,
the second line width is larger than the first line width.
2. The transmission line for a cross-slot structure of claim 1 wherein the transmission line is for single-ended transmission.
3. The transmission line for a cross-slot structure of claim 1, which is for differential mode transmission.
4. The transmission line for a cross-trench structure of claim 1 wherein the second line length is 150 mils and the second line width is 14 mils.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2006100834827A CN100496187C (en) | 2006-05-30 | 2006-05-30 | Transmission line for cross groove structure |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2006100834827A CN100496187C (en) | 2006-05-30 | 2006-05-30 | Transmission line for cross groove structure |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101083871A CN101083871A (en) | 2007-12-05 |
| CN100496187C true CN100496187C (en) | 2009-06-03 |
Family
ID=38913072
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2006100834827A Expired - Fee Related CN100496187C (en) | 2006-05-30 | 2006-05-30 | Transmission line for cross groove structure |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN100496187C (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104039075A (en) * | 2014-06-13 | 2014-09-10 | 杭州华三通信技术有限公司 | Pcb circuit |
| CN104797078A (en) * | 2015-04-10 | 2015-07-22 | 福州瑞芯微电子有限公司 | Method for reducing impedance mismatching degree under condition of discontinuous returning path |
| CN104733823A (en) * | 2015-04-14 | 2015-06-24 | 上海安费诺永亿通讯电子有限公司 | Bendable flat transmission line |
| CN112867229A (en) * | 2020-12-25 | 2021-05-28 | 广州朗国电子科技有限公司 | Signal routing structure across division gaps and signal impedance optimization method |
-
2006
- 2006-05-30 CN CNB2006100834827A patent/CN100496187C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CN101083871A (en) | 2007-12-05 |
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| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20090603 Termination date: 20160530 |