Circuit board structure for optimizing radio frequency circuit pad stub line

Abstract

The utility model discloses a circuit board structure for optimizing a radio frequency circuit pad stub line in the field of circuit board design, which comprises a plurality of pad groups arranged on a circuit board and a copper sheet, and each pad group comprises a first pad and a second pad which are oppositely arranged; the first bonding pad is provided with a first side edge opposite to the second bonding pad, the first side edge is flush with one end of the corresponding copper sheet, the second bonding pad is provided with a second side edge opposite to the first bonding pad, and the second side edge is flush with one end of the corresponding copper sheet. According to the utility model, the problem that stub lines are formed on the inner sides of the pads of a small-size package device in the existing radio frequency circuit is solved, the impedance requirement is met, stub lines are prevented from being formed on the inner sides of the first pad and the second pad, the impedance discontinuity is reduced, the signal reflection degree is reduced, the signal transmission path is optimized, and the signal transmission efficiency is improved. Therefore, the signal quality is improved, and the performance of the radio frequency circuit is improved.

Description

Technical Field

[0001] This utility model relates to the field of circuit board design technology, specifically to a circuit board structure that optimizes the residual traces of RF circuit pads. Background Technology

[0002] Radio frequency (RF) circuits play a crucial role in modern wireless communication systems, and their performance directly impacts communication quality and system stability. In RF circuit design, impedance matching and signal integrity of transmission lines are critical factors. To ensure signal transmission quality, RF transmission lines typically require a relatively wide linewidth to reduce transmission loss and reflection.

[0003] However, with the trend of miniaturization of electronic devices, small-sized packaged devices such as 0402 are widely used in radio frequency circuits. The pad width of these devices is usually smaller than the line width of the radio frequency transmission line, resulting in a residual stud line that cannot be matched with the impedance of the transmission line on the inner side of the device pad. The residual stud line will introduce impedance discontinuity, causing signal reflection, which in turn affects the performance of the radio frequency circuit, such as increasing insertion loss, reducing return loss, and causing signal distortion.

[0004] The above-mentioned defects urgently need to be addressed. Utility Model Content

[0005] To address the issue of residual traces forming inside the pads of small-sized packaged devices in existing RF circuits, this invention provides a circuit board structure that optimizes the residual traces on RF circuit pads.

[0006] The technical solution of this utility model is as follows:

[0007] A circuit board structure for optimizing residual traces on RF circuit pads includes several pad groups and copper foil disposed on the circuit board, wherein the pad groups include a first pad and a second pad disposed opposite to each other.

[0008] The first pad has a first side disposed opposite to the second pad, the first side being flush with one end of the copper strip corresponding to it. The second pad has a second side disposed opposite to the first pad, the second side being flush with one end of the copper strip corresponding to it.

[0009] According to the present invention based on the above scheme, the width of the first pad and the width of the second pad are both smaller than the width of the corresponding copper pad.

[0010] According to the present invention based on the above scheme, the length of the first pad and the length of the second pad are both less than the length of the corresponding copper pad.

[0011] According to the above-described scheme of this utility model, both the first pad and the second pad are square in shape.

[0012] According to the above-described scheme of this utility model, the width of the first pad and the width of the second pad are both 19mil to 22mil, and the length of the first pad and the length of the second pad are both 19mil to 22mil.

[0013] According to the present invention based on the above scheme, a first silkscreen frame is provided around the first solder pad, and a second silkscreen frame is provided around the second solder pad.

[0014] According to the above-described scheme of this utility model, the first screen printing frame and the second screen printing frame are symmetrically arranged.

[0015] According to the above-described scheme of this utility model, one end of the first screen printing frame is flush with the first side, and the second screen printing frame is flush with the second side.

[0016] According to the above-described scheme of this utility model, the width of the copper sheet is 25mil to 30mil.

[0017] According to the above-described scheme of this utility model, the impedance of the copper foil is 50 ohms.

[0018] The advantages of this utility model based on the above solution are as follows:

[0019] In the circuit board structure of the above-mentioned optimized RF circuit pad residual traces, the first side of the first pad is flush with one end of its corresponding copper layer, and the second side of the second pad is flush with one end of its corresponding copper layer. This satisfies the impedance requirements, prevents residual traces from forming on the inner side of the first pad and the inner side of the second pad, reduces impedance discontinuity, reduces the degree of signal reflection, optimizes the signal transmission path, thereby improving signal quality and enhancing the performance of the RF circuit. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of this utility model without copper foil;

[0021] Figure 2 This is a schematic diagram of the structure of this utility model;

[0022] Figure 3 This is a schematic diagram of the structure when no copper foil is set on the pad group;

[0023] Figure 4 A schematic diagram of the structure when copper is set on the pad group.

[0024] In the diagram, 1 is the pad group; 11 is the first pad; 111 is the first side; 12 is the second pad; 121 is the second side; 2 is the copper sheet; 3 is the first silkscreen frame; and 4 is the second silkscreen frame. Detailed Implementation

[0025] To make the technical problem to be solved, the technical solution, and the beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model.

[0026] Radio frequency (RF) circuits are a core component of modern wireless communication systems, and their performance directly determines communication quality and the stability of the entire system. Impedance matching and signal integrity are two critical factors in RF circuit design. To ensure high-quality signal transmission, RF transmission lines typically require a wide linewidth to minimize transmission loss and signal reflection. However, with the continuous miniaturization of electronic devices, small-package devices such as 0402 are increasingly used in RF circuits. The pad width of these devices is often smaller than the linewidth of the RF transmission line, resulting in a residual stud that cannot be impedance-matched to the transmission line inside the device pads. This residual stud causes impedance discontinuity, leading to signal reflection and negatively impacting the performance of the RF circuit, such as increasing insertion loss, reducing return loss, and even causing signal distortion.

[0027] like Figures 1 to 4 As shown, in order to solve the above-mentioned technical problems, this utility model provides a circuit board structure for optimizing residual traces on RF circuit pads, including several pad groups 1 and copper traces 2 disposed on the circuit board. The pad group 1 includes a first pad 11 and a second pad 12 disposed opposite to each other. The first pad 11 has a first side 111 disposed opposite to the second pad 12, and the first side 111 is flush with one end of the corresponding copper trace 2. The second pad 12 has a second side 121 disposed opposite to the first pad 11, and the second side 121 is flush with one end of the corresponding copper trace 2. This satisfies the impedance requirements, prevents residual traces from forming on the inner side of the first pad 11 and the inner side of the second pad 12, improves the continuity of impedance, reduces the degree of signal reflection, thereby improving signal quality and thus improving the performance of the RF circuit.

[0028] In this embodiment, the first side 111 of the first pad 11 is flush with one end of its corresponding copper strip 2, and the second side 121 of the second pad 12 is flush with one end of its corresponding copper strip 2. During signal transmission from the copper strip 2 to the pad group 1 and from the pad group 1 to other devices, the signal can propagate in a more continuous impedance environment, thereby reducing signal reflection. For example, in high-frequency signal transmission, reduced signal reflection allows the received signal waveform to be closer to the original waveform transmitted by the transmitter, improving signal integrity.

[0029] In this embodiment, the first side 111 of the first pad 11 is flush with one end of its corresponding copper strip 2, and the second side 121 of the second pad 12 is flush with one end of its corresponding copper strip 2. This prevents residual pins from forming on the inner sides of the first pad 11 and the second pad 12, ensuring relatively stable impedance matching throughout the transmission path. This allows for more efficient signal transmission between the copper strip 2 and the pad group 1, reducing energy loss due to impedance mismatch. Taking radio frequency signal transmission in a wireless communication system as an example, the reduction in transmission loss results in less energy attenuation during transmission, maintaining sufficient signal strength over greater distances, thereby improving the coverage and reliability of the communication system.

[0030] In traditional circuits, signal reflection and transmission loss caused by residual wires lead to significant fluctuations in signal strength, making them susceptible to external interference. The optimized circuit board structure in this embodiment, by addressing the residual wire issue, results in more stable signal transmission. The signal strength within the circuit remains at a relatively stable level, allowing the RF circuit to better resist external interference and maintain normal operation even in complex electromagnetic environments. For example, in mobile devices, this stable RF circuit ensures communication stability and reduces issues such as call interruptions and data transmission errors when the device is in different signal environments.

[0031] like Figure 4 As shown, in this embodiment, the width of the first pad 11 and the width of the second pad 12 are both smaller than the length of the corresponding copper foil 2. This allows for precise matching of the width requirements of pads for components such as 0402 capacitors, ensuring that these small-sized components can be securely soldered onto the circuit board and guaranteeing the reliability of the electrical connection. For example, in a high-frequency signal processing circuit module, 0402 capacitors need to be accurately connected to the circuit to achieve filtering. A pad group 1 of suitable size ensures a good connection between the capacitor and the circuit, thereby effectively exerting its filtering function. Furthermore, the lengths of the first pad 11 and the second pad 12 are both smaller than the length of the corresponding copper foil 2, meeting the requirements for signal transmission and making signal transmission between the copper foil 2 and the pad group 1 more efficient.

[0032] like Figure 3As shown, in this embodiment, both the first pad 11 and the second pad 12 are square. Square pads have a regular geometric shape, which, compared to other irregular shapes, promotes a more uniform distribution of the electric field on the pad surface during radio frequency signal transmission. At high frequencies, when a signal is transmitted through the pad, the uniform electric field reduces signal distortion and loss. Furthermore, the four sides of the square first pad 11 and the second pad 12 are of equal length, making impedance matching easier when connected to the corresponding copper traces 2. Compared to pads of other shapes, this effectively reduces signal reflection at the connection point. Additionally, when using surface mount technology (SMT) to solder devices such as 0402, the square first pad 11 and the second pad 12 facilitate precise control of solder distribution and soldering temperature by soldering equipment (such as reflow ovens and wave soldering equipment). The symmetry of the four corners also helps the solder flow uniformly around the pad, reducing soldering defects such as cold solder joints and bridging, thereby greatly improving soldering reliability.

[0033] In this embodiment, the width of the first pad 11 and the width of the second pad 12 are both 19mil to 22mil. It can be designed that the width of the first pad 11 and the width of the second pad 12 are any values ​​in the range of 19mil, 19.2mil, 19.4mil, 19.6mil, 19.68mil, 20mil, 20.2mil, 20.4mil, 20.6mil, 20.8mil, 21mil, 21.2mil, 21.4mil, 21.6mil, 21.65mil, 21.8mil, and 22mil. Of course, in actual design, the width of the first pad 11 and the width of the second pad 12 can be designed according to the actual situation. Furthermore, the lengths of the first pad 11 and the second pad 12 are both between 19mil and 22mil. They can be designed to be any value within the range of 19mil, 19.2mil, 19.4mil, 19.6mil, 19.68mil, 20mil, 20.2mil, 20.4mil, 20.6mil, 20.8mil, 21mil, 21.2mil, 21.4mil, 21.6mil, 21.65mil, 21.8mil, and 22mil. Of course, in actual design, the lengths of the first pad 11 and the second pad 12 can be designed according to the actual situation.

[0034] like Figure 3As shown, in this embodiment, a first silkscreen frame 3 is provided around the first pad 11, and a second silkscreen frame 4 is provided around the second pad 12. The first silkscreen frame 3 and the second silkscreen frame 4 provide clear visual references for the soldering equipment. When performing component placement, the high-precision pick-and-place machine can accurately position the pad group 1 based on the outlines of the first silkscreen frame 3 and the second silkscreen frame 4, ensuring that small-sized resistors, capacitors, and other components such as 0402 are accurately placed on their corresponding pad groups 1. This improves the accuracy and efficiency of component placement, reduces soldering defects caused by component placement deviations, and thus increases the overall yield of the circuit board production. Furthermore, the first silkscreen frame 3 and the second silkscreen frame 4 help operators quickly and accurately align the printing template with the pads, ensuring precise solder paste printing.

[0035] like Figure 3 , Figure 4 As shown, in this embodiment, the first silkscreen frame 3 and the second silkscreen frame 4 are symmetrically arranged, which allows key processes such as solder paste printing and component mounting to use consistent parameters. Taking solder paste printing as an example, since the first silkscreen frame 3 and the second silkscreen frame 4 are symmetrical, the printer does not need to adjust parameters such as squeegee pressure and printing speed for different shapes or positions. Solder paste printing on symmetrical pad areas can be completed with a single adjustment, which greatly improves printing efficiency, reduces printing quality fluctuations caused by frequent parameter adjustments, and ensures that the solder paste is evenly and accurately distributed on each pad, laying the foundation for good subsequent soldering results.

[0036] like Figure 3 , Figure 4 As shown, in this embodiment, one end of the first silkscreen frame 3 is flush with the first side 111, and the second silkscreen frame 4 is flush with the second side 121, providing a precise visual reference for automated equipment such as pick-and-place machines. When the robotic arm of the pick-and-place machine picks up a component and moves it above the pad for placement, the flush silkscreen frame helps the equipment to more accurately identify the position and boundary of the pad, ensuring that the component can be accurately placed on the pad and avoiding soldering defects such as cold solder joints and short circuits caused by positional deviations.

[0037] In this embodiment, the width of copper sheet 2 is 25mil to 30mil. The width of copper sheet 2 can be designed to be any value in the range of 25mil, 25.2mil, 25.4mil, 25.6mil, 25.8mil, 26mil, 26.2mil, 26.4mil, 26.6mil, 26.8mil, 27mil, 27.2mil, 27.4mil, 27.6mil, 27.8mil, 28mil, 28.2mil, 28.4mil, 28.6mil, 28.8mil, 29mil, 29.2mil, 29.4mil, 29.6mil, 29.8mil, and 30mil. In actual design, the width of copper sheet 2 can be designed according to actual needs.

[0038] In this embodiment, the impedance of copper foil 2 is 50 ohms, which meets the impedance requirements of the radio frequency circuit and ensures good impedance matching when the signal is connected to other circuit components (such as chips, antennas, etc.). When the impedance of copper foil 2 matches the overall circuit impedance, resistance loss, dielectric loss, etc., during signal transmission can be controlled at a low level. Of course, in actual design, the impedance of copper foil 2 can be designed according to actual needs.

[0039] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

[0040] The present utility model patent has been described above with reference to the accompanying drawings. Obviously, the implementation of the present utility model patent is not limited to the above-described manner. Any improvements made by adopting the inventive concept and technical solution of the present utility model patent, or the direct application of the inventive concept and technical solution of the present utility model patent to other occasions without modification, are all within the protection scope of the present utility model.

Claims

1. A circuit board structure for optimizing the stub line of a radio frequency circuit pad, characterized by, The copper sheet is arranged on the circuit board, and the circuit board comprises a plurality of pad groups arranged on the circuit board, wherein the pad groups comprise oppositely arranged first pads and second pads; The first pad has a first side edge opposite to the second pad, and the first side edge is flush with one end of the corresponding copper sheet; the second pad has a second side edge opposite to the first pad, and the second side edge is flush with one end of the corresponding copper sheet.

2. The circuit board structure for optimizing the stub line of a radio frequency circuit pad according to claim 1, wherein, The width of the first pad and the width of the second pad are both less than the width of the corresponding copper sheet.

3. The circuit board structure for optimizing the stub line of a radio frequency circuit pad according to claim 1, wherein, The length of the first pad and the length of the second pad are both less than the length of the corresponding copper sheet.

4. The circuit board structure for optimizing the stub line of a radio frequency circuit pad according to claim 1, wherein The shape of the first pad and the shape of the second pad are both square.

5. The circuit board structure for optimizing the stub line of a radio frequency circuit pad according to claim 4, wherein The width of the first pad and the width of the second pad are both 19 mil-22 mil, and the length of the first pad and the length of the second pad are both 19 mil-22 mil.

6. The circuit board structure for optimizing the stub line of a radio frequency circuit pad according to claim 1, wherein The first pad is provided with a first silk screen frame on the periphery, and the second pad is provided with a second silk screen frame on the periphery.

7. The circuit board structure for optimizing the stub line of a radio frequency circuit pad according to claim 6, wherein The first silk screen frame and the second silk screen frame are symmetrically arranged.

8. The circuit board structure for optimizing the stub line of a radio frequency circuit pad according to claim 6, wherein One end of the first silk screen frame is flush with the first side edge, and the second silk screen frame is flush with the second side edge.

9. The circuit board structure for optimizing the stub line of a radio frequency circuit pad according to claim 1, wherein, The width of the copper sheet is 25 mil-30 mil.

10. The circuit board structure for optimizing the stub line of a radio frequency circuit pad according to claim 1, wherein, The impedance of the copper sheet is 50 ohms.

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