Circuit board and electronic equipment
By setting the transition structure and wire area between the signal layer and the reference layer of the circuit board and adjusting the width and distance of the transition structure, the problem of impedance discontinuity of pads and signal lines in RF circuits or high-speed circuits is solved, improving circuit performance and reducing costs.
Patent Information
- Application Number
- CN202422105534.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-28
- Publication Date
- 2025-07-22
- Estimated Expiration
- 2034-08-28
AI Technical Summary
There is a problem of impedance discontinuity between the pads and signal lines of RF circuits or high-speed circuits, resulting in poor circuit performance.
A circuit board is designed to adjust the characteristic impedance of the transition structure by providing a transition structure between the signal layer and the multiple reference layers, so that the width of the transition structure gradually decreases along the pad to the signal line direction, and a wire area and hollow area are provided on the reference layer to change the distance between the transition structure and the reference layer, thereby adjusting the characteristic impedance of the transition structure.
It effectively reduces the impedance discontinuity problem between the pad and the signal line, improves the performance of the circuit, and reduces the manufacturing cost of the circuit board.
Smart Images
Figure CN223142203U_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to the technical field of electronic devices, and particularly to a circuit board and an electronic device. Background Art
[0002] When an alternating current passes through a conductor, an alternating electromagnetic field will be formed around the conductor, which is called an electromagnetic wave. When the frequency of the electromagnetic wave is higher than 100 kHz, the electromagnetic wave can propagate in the air and be reflected by the ionosphere on the outer edge of the atmosphere, forming a long-distance transmission ability. We call this high-frequency electromagnetic wave with long-distance transmission ability RF (Radio Frequency).
[0003] In the related art, there is a problem of impedance discontinuity between the pads and signal lines of RF circuits or high-speed circuits, resulting in a large reflection coefficient and poor performance of the circuit. As Figure 6 and Figure 7 shown, currently, a transition structure 30 is used to connect the pad 10 and the signal line 20 on the signal layer to reduce the problem of impedance discontinuity. Although the transition structure 30 can achieve continuity in width between the pad 10 and the signal line 20, there is still a large impedance discontinuity problem in the signal layer. Summary of the Utility Model
[0004] The present disclosure provides a circuit board to reduce the impedance discontinuity problem of the signal layer.
[0005] The circuit board of the present disclosure includes a signal layer and a plurality of reference layers. The signal layer includes a pad, a transition structure, and a signal line connected in sequence. The width of the transition structure gradually decreases along the direction from the pad to the signal line. At least one of the reference layers includes a wire area and a hollowed-out area. The hollowed-out area is provided corresponding to at least a part of the transition structure, so that the distance from the transition structure to the reference layer gradually decreases along the direction from the pad to the signal line.
[0006] Optionally, the plurality of reference layers are provided on the same side of the signal layer in the thickness direction of the circuit board.
[0007] Optionally, the transition structure is symmetrically arranged along the width direction of the circuit board.
[0008] Optionally, the orthographic projection of the transition structure in the thickness direction of the circuit board is an isosceles triangle.
[0009] Optionally, the plurality of reference layers are provided on the same side of the signal layer in the thickness direction of the circuit board;
[0010] The wire area has a wire end close to the hollowed-out area, and the connection line of the wire ends of the plurality of reference layers is a straight line.
[0011] Optionally, the side edges of the transition structure on both sides in the width direction of the circuit board are arc-shaped.
[0012] Optionally, a plurality of the reference layers are disposed on the same side of the signal layer in the thickness direction of the circuit board;
[0013] The wire region has a wire end close to the hollowed-out region, and the connection line of the wire ends of the plurality of reference layers is an arc.
[0014] Optionally, the number of the reference layers is ~.
[0015] Optionally, the pad, the transition structure, and the signal line are integrally formed.
[0016] The present disclosure also provides an electronic device.
[0017] The electronic device of the present disclosure includes the circuit board in any of the above embodiments.
[0018] For the circuit board of the present disclosure, by gradually reducing the width of the transition structure in the direction from the pad to the signal line, not only the continuity in width between the pad and the signal line is achieved, but also when taking the width of the transition structure as a reference, the characteristic impedance of the transition structure gradually decreases in the direction from the pad to the signal line; by providing a wire region and a hollowed-out region in at least one reference layer, the distance from the transition structure to the reference layer gradually decreases in the direction from the pad to the signal line, so that when taking the distance from the transition structure to the reference layer as a reference, the characteristic impedance of the transition structure gradually increases in the direction from the pad to the signal line. Thus, the difference in the characteristic impedance of the transition structure in the direction from the pad to the signal line is small, reducing the impedance discontinuity problem between the pad and the signal line, that is, reducing the impedance discontinuity problem of the signal layer. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 is a top view of a circuit board according to an embodiment of the present disclosure.
[0020] Figure 2 is a front view of a circuit board according to an embodiment of the present disclosure.
[0021] Figure 3 is a front view of a circuit board according to another embodiment of the present disclosure.
[0022] Figure 4 is a top view of a circuit board according to still another embodiment of the present disclosure.
[0023] Figure 5 is a comparison diagram of the effects of the circuit board according to an embodiment of the present disclosure and the circuit board in the related art.
[0024] Figure 6 is a top view of the circuit board in the related art.
[0025] Figure 7 It is the front view of a circuit board in the related art.
[0026] Reference numerals:
[0027] 1. Signal layer; 11. Pad; 12. Transition structure; 13. Signal line;
[0028] 2. Reference layer; 21. Conductor area; 211. Conductor end; 22. Cut-out area; 201. First reference layer; 202. Second reference layer; 203. Third reference layer; 204. Fourth reference layer;
[0029] 10. Pad;
[0030] 20. Signal line;
[0031] 30. Transition structure;
[0032] 40. Reference layer. Detailed implementation manners
[0033] This application is made based on the inventor's discovery and recognition of the following facts and problems:
[0034] In the related art, as Figure 6 and Figure 7 shown, a transition structure 30 is used to connect between the pad 10 and the signal line 20. The transition structure 30 can achieve continuity in width between the pad 10 and the signal line 20, and reduce the impedance discontinuity problem between the pad 10 and the signal line 20. However, the reference layer of each segment of the transition structure 30 is the same, that is, the distance from each segment of the transition structure 30 to the reference layer 40 is equal, which results in a relatively large impedance discontinuity problem still existing between the pad 10 and the signal line 20, affecting the performance of the circuit.
[0035] Since the characteristic impedance is inversely proportional to the width of the transition structure and directly proportional to the distance from the transition structure to the reference layer, when the width of the transition structure is determined, by changing the distance from each segment of the transition structure to the reference layer, the characteristic impedance of each segment of the transition structure can be changed, thereby reducing the impedance discontinuity problem of the signal layer 1. For this reason, the present disclosure proposes a circuit board. By hollowing out some reference layers, that is, hollowing out the conductors of the reference layer, the distance from each segment of the transition structure to the reference layer is made different, so as to change the characteristic impedance of each segment of the transition structure from the reference layer, thereby reducing the impedance discontinuity problem existing between the pad 10 and the signal line 20, that is, reducing the impedance discontinuity problem of the signal layer.
[0036] The embodiments of the present disclosure will be described in detail below. The examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present disclosure, and should not be construed as a limitation to the present disclosure.
[0037] As shown Figures 1 to 4 in the figure, the circuit board of the embodiment of the present disclosure includes a signal layer 1 and a plurality of reference layers 2. The signal layer 1 includes a pad 11, a transition structure 12, and a signal line 13 that are connected in sequence. The width of the transition structure 12 gradually decreases along the direction from the pad 11 to the signal line 13. At least one reference layer 2 includes a wire area 21 and a hollowed-out area 22. The hollowed-out area 22 is provided corresponding to at least a part of the transition structure 12, so that the distance from the transition structure 12 to the reference layer 2 gradually decreases along the direction from the pad 11 to the signal line 13.
[0038] Among them, the reference layer 2 is connected to the ground and is used as the reference level of the signal. The wire area 21 can be understood as an area where wires are arranged. For example, a copper foil is arranged on a part of the reference layer 2, and the copper foil forms a wire; the hollowed-out area 22 can be understood as an area where no wires are arranged. For example, a part of the copper foil of the reference layer 2 is removed to form the hollowed-out area 22.
[0039] In the circuit board of the embodiment of the present disclosure, by gradually decreasing the width of the transition structure 12 along the direction from the pad 11 to the signal line 13, not only the continuity in width between the pad 11 and the signal line 13 is achieved, but also when taking the width of the transition structure 12 as a reference, the characteristic impedance of the transition structure 12 gradually decreases along the direction from the pad 11 to the signal line 13; by providing the wire area 21 and the hollowed-out area 22 in at least one reference layer 2, the distance from the transition structure 12 to the reference layer 2 gradually decreases along the direction from the pad 11 to the signal line 13, so that when taking the distance from the transition structure 12 to the reference layer 2 as a reference, the characteristic impedance of the transition structure 12 gradually increases along the direction from the pad 11 to the signal line 13. Thus, the difference in the characteristic impedance of the transition structure 12 along the direction from the pad 11 to the signal line 13 is small, reducing the impedance discontinuity problem between the pad 11 and the signal line 13, that is, reducing the impedance discontinuity problem of the signal layer 1.
[0040] Optionally, the circuit board is a radio frequency circuit board or a high-speed circuit board, that is, the signal line 20 is used to transmit radio frequency signals or high-frequency signals.
[0041] In some embodiments, the plurality of reference layers 2 are arranged on the same side of the signal layer 1 in the thickness direction of the circuit board.
[0042] By arranging the plurality of reference layers 2 on the same side of the signal layer 1 in the thickness direction of the circuit board, it is convenient to connect each reference layer 2 to the ground, thereby facilitating the processing and manufacturing of the circuit board and being beneficial to reducing the manufacturing cost of the circuit board.
[0043] To make the technical solution of the present disclosure easier to understand, the following further describes the technical solution of the present disclosure by taking the thickness direction of the circuit board as consistent with the up and down directions as an example. Among them, the up and down directions are as Figure 2 andFigure 3 as shown
[0044] For example, as Figure 2 and Figure 3 shown, the signal layer 1 is disposed on the uppermost side, and each reference layer 2 is disposed on the lower side of the signal layer 1.
[0045] In some embodiments, as Figure 1 and Figure 4 shown, the transition structure 12 is symmetrically arranged along the width direction of the circuit board.
[0046] By symmetrically arranging the transition structure 12 along the width direction of the circuit board, it is convenient for the processing and manufacturing of the transition structure 12, thereby facilitating the processing and manufacturing of the circuit board and helping to reduce the manufacturing cost of the circuit board.
[0047] To make the technical solutions of the present disclosure easier to understand, the following takes the width direction of the circuit board being consistent with the left - right direction as an example to further describe the technical solutions of the present disclosure. Among them, the left - right direction is as Figure 1 and Figure 4 shown.
[0048] For example, as Figure 1 and Figure 4 shown, the transition structure 12 is symmetrically arranged along the left - right direction.
[0049] In some embodiments, as Figure 1 and Figure 4 shown, the orthographic projection of the transition structure 12 in the thickness direction of the circuit board is an isosceles triangle.
[0050] For example, the orthographic projection of the transition structure 12 in the up - down direction is an isosceles triangle.
[0051] By setting the orthographic projection of the transition structure 12 in the thickness direction of the circuit board as an isosceles triangle, it is convenient for the processing and manufacturing of the transition structure 12, thereby facilitating the processing and manufacturing of the circuit board and helping to reduce the manufacturing cost of the circuit board.
[0052] Optionally, as Figure 2 and Figure 3 shown, the wire region 21 has a wire end 211 close to the hollowed - out region 22, and the connection line of the wire ends 211 of the plurality of reference layers 2 is a straight line.
[0053] It can be understood that when the positive projection of the transition structure 12 in the thickness direction of the circuit board is an isosceles triangle, with the width of the transition structure 12 as a reference, the characteristic impedance of the transition structure 12 decreases linearly along the direction from the pad 11 to the signal line 13; by setting the connection of the wire ends 211 of the plurality of reference layers 2 as a straight line, the distance from the transition structure 12 to the reference layer 2 decreases linearly along the direction from the pad 11 to the signal line 13, so that when the distance from the transition structure 12 to the reference layer 2 is used as a reference, the characteristic impedance of the transition structure 12 increases linearly along the direction from the pad 11 to the signal line 13.
[0054] Thus, it is convenient to make the characteristic impedance of the transition structure 12 increase linearly along the direction from the pad 11 to the signal line 13, effectively reducing the impedance discontinuity problem of the signal layer 1.
[0055] To make the technical solution of the present disclosure easier to understand, the following takes the case where the length direction of the circuit board is consistent with the front-back direction as an example to further describe the technical solution of the present disclosure. Among them, the front-back direction is as Figures 1 to 4 shown.
[0056] For example, as Figure 2 and Figure 3 shown, the hollow area 22 is arranged at the rear side of the wire area 21, the rear end of the wire area 21 is the wire end 211, and the connection of the rear ends of the wire areas 21 of the plurality of reference layers 2 is a straight line.
[0057] In some embodiments, as Figure 4 shown, the sides of the transition structure 12 on both sides in the width direction of the circuit board are both arc-shaped.
[0058] By setting the sides of the transition structure 12 on both sides in the width direction of the circuit board as arc-shaped, the stress concentration problem at each part of the transition structure 12 can be reduced, and the reliability of the circuit board can be improved.
[0059] Optionally, the wire area 21 has a wire end 211 close to the hollow area 22, and the connection of the wire ends 211 of the plurality of reference layers 2 is an arc.
[0060] It can be understood that when both the side of the transition structure 12 close to the reference layer 2 and the side of the transition structure 12 far from the reference layer 2 are arc-shaped, with the width of the transition structure 12 as a reference, the characteristic impedance of the transition structure 12 decreases non-linearly along the direction from the pad 11 to the signal line 13; by setting the connection of the wire ends 211 of the plurality of reference layers 2 as an arc, the distance from the transition structure 12 to the reference layer 2 decreases non-linearly along the direction from the pad 11 to the signal line 13, so that when the distance from the transition structure 12 to the reference layer 2 is used as a reference, the characteristic impedance of the transition structure 12 increases non-linearly or linearly along the direction from the pad 11 to the signal line 13.
[0061] Thus, it is convenient to make the characteristic impedance of the transition structure 12 increase non-linearly or linearly in the direction from the pad 11 to the signal line 13, effectively reducing the impedance discontinuity problem of the signal layer 1.
[0062] Optionally, the number of the reference layers 2 is 3 to 15.
[0063] For example, as Figure 3 shown, the number of the reference layers 2 is four. The four reference layers 2 are respectively a first reference layer 201, a second reference layer 202, a third reference layer 203 and a fourth reference layer 204. Among them, the first reference layer 201 is arranged between the signal layer 1 and the second reference layer 202, and the third reference layer 203 is arranged between the second reference layer 202 and the fourth reference layer 204.
[0064] It can be understood that when the number of the reference layers 2 is too large, it is not only inconvenient for the processing and manufacturing of the circuit board, but also causes the circuit board to be too thick, increasing the cost of the circuit board; when the number of the reference layers 2 is too small, there is still a large impedance discontinuity problem between the pad 11 and the signal line 13. By setting the number of the reference layers 2 to 3 to 15, the impedance discontinuity problem between the pad 11 and the signal line 13 can be effectively reduced under the condition of low cost of the circuit board.
[0065] Optionally, the pad 11, the transition structure 12 and the signal line 13 are integrally formed.
[0066] For example, the pad 11, the transition structure 12 and the signal line 13 are integrally etched.
[0067] By setting the pad 11, the transition structure 12 and the signal line 13 to be integrally formed, it is beneficial to reduce the manufacturing cost of the circuit board.
[0068] In the circuit board of the embodiment of the present disclosure, by hollowing out the reference layer 2 at the transition structure 12, each section of the transition structure 12 has a different reference layer 2, thereby reducing the impedance discontinuity problem of the signal layer 1. Thus, while reducing reflection and optimizing return loss, no additional components are introduced, the cost of the circuit board is not increased, and the design flexibility is not decreased.
[0069] Taking the total number of layers of the signal layer 1 and the reference layer 2 of the circuit board as ten layers as an example, the simulation results are as follows. It can be seen that by comparison, the overall is optimized by 6 dB and 2.5 dB compared with the solutions in the related art.
[0070] The electronic device of the embodiment of the present disclosure includes the circuit board described in any one of the above embodiments. Among them, the electronic device can be a mobile phone, a tablet computer, a notebook computer, a wearable electronic device, etc.
[0071] Since the circuit board according to the embodiments of the present disclosure can reduce the impedance discontinuity problem of the signal layer 1, the performance of the circuit board can be improved, and thus the performance of the electronic device can be improved.
[0072] Although the embodiments of the present disclosure have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present disclosure. Any changes, modifications, substitutions, and variations made by those of ordinary skill in the art to the above embodiments are within the scope of protection of the present disclosure.
Claims
1. A circuit board, characterized in that, Comprising: A signal layer, the signal layer including a pad, a transition structure, and a signal line connected in sequence, the width of the transition structure gradually decreasing in the direction from the pad to the signal line; A plurality of reference layers, at least one of the reference layers including a wire region and a hollowed-out region, the hollowed-out region being provided corresponding to at least a part of the transition structure, so that the distance from the transition structure to the reference layer gradually decreases in the direction from the pad to the signal line.
2. The circuit board according to claim 1, characterized in that, A plurality of the reference layers are provided on the same side of the signal layer in the thickness direction of the circuit board.
3. The circuit board according to claim 1, wherein, The transition structure is symmetrically arranged along the width direction of the circuit board.
4. The circuit board according to claim 3, characterized in that, The orthographic projection of the transition structure in the thickness direction of the circuit board is an isosceles triangle.
5. The circuit board according to claim 4, characterized in that, A plurality of the reference layers are provided on the same side of the signal layer in the thickness direction of the circuit board; The wire region has a wire end close to the hollowed-out region, and the connection line of the wire ends of the plurality of reference layers is a straight line.
6. The circuit board according to claim 3, wherein The side edges on both sides of the transition structure in the width direction of the circuit board are both arc-shaped.
7. The circuit board according to claim 6, characterized in that, A plurality of the reference layers are provided on the same side of the signal layer in the thickness direction of the circuit board; The wire region has a wire end close to the hollowed-out region, and the connection line of the wire ends of the plurality of reference layers is an arc.
8. The circuit board according to any one of claims 1-7, characterized in that The number of the reference layers is 3 to 15.
9. The circuit board according to any one of claims 1-7, characterized in that, The pad, the transition structure, and the signal line are integrally formed.
10. An electronic device, characterized in that, A circuit board according to any one of claims 1-9.