Multi-medium SCX frequency band signal integrity design method

Abstract

The invention belongs to the technical field of high-frequency circuit signal integrity design, and particularly relates to a multi-medium SCX frequency band signal integrity design method, which comprises the following steps: S1, theoretical analysis and key parameter calculation: firstly, carrying out comprehensive analysis on a whole signal transmission link; through theoretical analysis, simulation verification and adjustment based on actual processing capacity, the signal integrity can be effectively improved in different medium environments, a reliable and efficient solution is provided for high-frequency circuit design, the method has remarkable technical advantages and wide application prospects, and in actual application, the method has good application prospects. The design method can be flexibly applied according to specific circuit requirements and medium environments, the optimal signal transmission effect is achieved, and meanwhile along with continuous development of the electronic technology, the design method can be further expanded and perfected so as to meet the signal integrity design requirements under the higher-frequency and more complex medium environments.

Description

Technical Field

[0001] The invention belongs to the technical field of high-frequency circuit signal integrity design, and in particular relates to a SCX frequency band signal integrity design method through multiple media. Background Art

[0002] In the research and design of high-frequency circuits, signal integrity has always been a key issue. With the continuous development of electronic technology, signal frequency continues to increase. In the process of high-frequency signal transmission, we often face the dilemma of out-of-tolerance index parameters. The fundamental reason why high-frequency signal indicators do not meet the requirements is that the signal integrity is destroyed, which is directly manifested in changes in the signal's S parameters, increased losses, and slower signal propagation rates.

[0003] The guarantee of signal integrity plays a vital role in the design of high-frequency and high-speed signal circuits. Ensuring that the signal can be transmitted from the source to the receiving end without distortion is the core point of the design. In a circuit environment where multiple media coexist, the signal integrity problem is more complicated. Different media have different electrical properties, such as dielectric constant, magnetic permeability, etc. These differences will cause reflection, refraction, scattering and other phenomena in the signal transmission process, thereby affecting the signal quality.

[0004] At present, although there are some conventional design methods and analysis means to deal with signal integrity issues, there are still many limitations when facing high frequency bands such as the SCX band and complex multi-media environments. For example, some design methods have poor adaptability to media and it is difficult to achieve effective signal integrity optimization in media of different forms and states; some traditional analysis methods may not be able to accurately locate and solve signal discontinuity problems caused by vias and other factors in multi-media environments. Therefore, there is an urgent need for a signal integrity design method specifically for the SCX band of multi-media to meet the growing demand for high-frequency circuit design.

[0005] Therefore, we propose a SCX band signal integrity design method through multiple media to solve the above problems. Summary of the invention

[0006] The object of the present invention is to provide a method for designing SCX band signal integrity through multiple media in view of the above problems.

[0007] To achieve the above object, the present invention provides the following technical solution: a method for designing SCX frequency band signal integrity through multiple media, comprising the following steps: S1. Theoretical analysis and calculation of key parameters First, the entire signal transmission link is comprehensively analyzed to determine the key factors affecting signal integrity, and a signal integrity analysis model is constructed. Theoretical studies are conducted on factors such as transmission lines, devices, and vias. For transmission lines, the characteristic impedance is calculated based on their physical structure and material properties using electromagnetic theory and transmission line theory. Taking into account the influence of copper foil, material, line width and other factors on the characteristic impedance, professional impedance calculation software is used to calculate the impedance values ​​of microstrip lines and strip lines under different conditions by inputting relevant parameters such as the dielectric constant of the medium, copper foil thickness, line width, etc. It is calculated that the characteristic impedance matching is in a better state when it is 50Ω. S2. Simulation verification and optimization improvement After completing the theoretical calculation, the design scheme is simulated and verified with the help of advanced simulation software. The calculated transmission line parameters, via structure and other design elements are input into the simulation software to build a simulation model that is highly similar to the actual circuit environment. Regarding the key factor of vias, since the surrounding medium in the mixed-pressure printed circuit board is changeable, it is easy to cause signal discontinuity. In the simulation, we focus on the electromagnetic field distribution, signal reflection and transmission loss at the vias. By changing the parameters such as the size, shape and connection method of the vias with the transmission line, we observe the changes in the signal integrity indicators. According to the simulation results, the design scheme is optimized and improved. If it is found that the signal has large loss or reflection in certain frequency bands, the signal quality can be improved by adjusting the via parameters and transmission line layout. For example, the aperture size and pad size of the via can be adjusted, and the transition area between the via and the microstrip line or stripline can be optimized. At the same time, the simulation results under different optimization schemes are compared, and the optimal design scheme is selected to ensure that the integrity of the signal in a multi-media environment is effectively improved; S3. Adjustment based on actual processing capacity When determining the final design plan, fully consider the limitations of actual processing capabilities to ensure that the via size, transmission line width and other parameters used in the design plan can be achieved under the current processing technology level. For example, some via sizes that are too small may cause excessive processing difficulty or high cost. At this time, it is necessary to make appropriate adjustments to the design parameters while ensuring signal integrity.

[0008] In the above-mentioned SCX band signal integrity design method through multiple media, the S1 performs a routine check on the characteristics of the device to ensure that it meets the design requirements.

[0009] In the above-mentioned SCX band signal integrity design method through multiple media, the line width of the microstrip line used as the coplanar waveguide in S1 is 1.12 mm, and the line width of the stripline is 0.94 mm.

[0010] Compared with the prior art, the present invention provides a method for designing SCX frequency band signal integrity through multiple media, which has the following beneficial effects: The SCX band signal integrity design method through multiple media is not limited by the form and state of the media, and can achieve signal integrity optimization in an environment with a variety of different media combinations. Whether it is a single medium or a complex multi-media structure, the method can be used to effectively design and adjust, while the existing technology is often targeted at specific media or media combinations and has poor adaptability. By combining theoretical analysis with simulation verification, the signal integrity is comprehensively evaluated and optimized. Theoretical calculation provides an accurate basis for design, and simulation verification can fully test and improve the design scheme before actual production, avoiding errors caused by traditional design methods based on experience or a single means, greatly improving the accuracy of product design. In the design stage, through precise calculation and simulation optimization, potential problems can be discovered and solved in advance, reducing repeated debugging and modification in the actual production process. At the same time, adjustments based on actual processing capabilities avoid processing difficulties and cost increases caused by unreasonable design, thereby effectively reducing product development costs. The focus is on detailed analysis and optimization of vias, a key factor that easily causes signal discontinuity in a multi-media environment. Through precise calculation and simulation, a more reasonable via structure and connection method can be designed, which can effectively improve the electromagnetic field distribution around the vias, reduce signal reflection and loss, and improve signal integrity. However, the existing technology has relatively limited effect when dealing with via problems in a multi-media environment. DETAILED DESCRIPTION

[0011] The following examples are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0012] Embodiment 1 S1. According to the parameters such as the dielectric constant of FR-4 medium (assumed to be 4.5) and the thickness of copper foil (assumed to be 35 μm), the characteristic impedance of the microstrip line and the strip line is calculated using impedance calculation software. According to the calculation method of the present invention, when the microstrip line is used as a coplanar waveguide, the line width should be designed to be about 1.12 mm, and the line width of the strip line should be about 0.94 mm, so as to achieve characteristic impedance matching at 50Ω; S2. Construct a circuit model using FR-4 as the medium and including the transmission line parameters calculated above in the simulation software, simulate the transmission of the signal in the model, and observe the signal's S parameters, loss and other indicators; S3. The simulation results show that there are some problems with signal integrity, such as a large reflection coefficient at certain frequency points. The layout of the microstrip line or stripline can be fine-tuned, such as adjusting the line length and line spacing, and the simulation verification can be performed again until the signal integrity meets the design requirements; S4. According to the finalized design scheme, the circuit board is manufactured and actually tested. The test results show that through the design method of the present invention, in a single medium environment, the transmission quality of the signal in the SCX frequency band is significantly improved, and all indicators meet expectations.

[0013] Embodiment 2 S1. Calculate the characteristic impedance of microstrip line and stripline for different dielectric regions. For FR-4 dielectric region, calculate the parameters according to the above FR-4 dielectric parameter calculation method. For Rogers dielectric region (assuming the dielectric constant is 3.5), use impedance calculation software and copper foil thickness and other parameters to calculate the appropriate line width to achieve characteristic impedance matching at 50Ω. S2. When designing vias, take full account of their impact on the transition area between different media. Use simulation software to simulate the process of signal transmission from one medium to another through vias, and analyze the electromagnetic field changes, signal reflection and loss at the vias. S3. Adjust the parameters of the via, such as the aperture, pad size, and the position of the via in different dielectric layers. For example, try different aperture sizes to observe their impact on signal integrity. After multiple simulations and optimizations, determine the optimal via design to minimize signal transmission loss and reflection in a multi-media mixed-pressure printed circuit board. S4. After the design is completed, actual production and testing are carried out. The test results show that in a multi-media mixed-pressure printed circuit board environment, the signal can be transmitted stably and with high quality in the SCX frequency band, proving the effectiveness of the design method of the present invention in a complex multi-media environment.

[0014] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for designing signal integrity of SCX band through multiple media, characterized by: The steps include: S1. Theoretical analysis and calculation of key parameters First, the entire signal transmission link is comprehensively analyzed to determine the key factors affecting signal integrity, and a signal integrity analysis model is constructed. Theoretical studies are conducted on factors such as transmission lines, devices, and vias. For transmission lines, the characteristic impedance is calculated based on their physical structure and material properties using electromagnetic theory and transmission line theory. Taking into account the influence of copper foil, material, line width and other factors on the characteristic impedance, professional impedance calculation software is used to calculate the impedance values ​​of microstrip lines and strip lines under different conditions by inputting relevant parameters such as the dielectric constant of the medium, copper foil thickness, line width, etc. It is calculated that the characteristic impedance matching is in a better state when it is 50Ω. S2. Simulation verification and optimization improvement After completing the theoretical calculation, the design scheme is simulated and verified with the help of advanced simulation software. The calculated transmission line parameters, via structure and other design elements are input into the simulation software to build a simulation model that is highly similar to the actual circuit environment. Regarding the key factor of vias, since the surrounding medium in the mixed-pressure printed circuit board is changeable, it is easy to cause signal discontinuity. In the simulation, we focus on the electromagnetic field distribution, signal reflection and transmission loss at the vias. By changing the parameters such as the size, shape and connection method of the vias with the transmission line, we observe the changes in the signal integrity indicators. According to the simulation results, the design scheme is optimized and improved. If it is found that the signal has large loss or reflection in certain frequency bands, the signal quality can be improved by adjusting the via parameters and transmission line layout. For example, the aperture size and pad size of the via can be adjusted, and the transition area between the via and the microstrip line or stripline can be optimized. At the same time, the simulation results under different optimization schemes are compared, and the optimal design scheme is selected to ensure that the integrity of the signal in a multi-media environment is effectively improved; S3. Adjustment based on actual processing capacity When determining the final design plan, fully consider the limitations of actual processing capabilities to ensure that the via size, transmission line width and other parameters used in the design plan can be achieved under the current processing technology level. For example, some via sizes that are too small may cause excessive processing difficulty or high cost. At this time, it is necessary to make appropriate adjustments to the design parameters while ensuring signal integrity.

2. The method for designing SCX frequency band signal integrity through multiple media according to claim 1, characterized in that: The S1 is to perform a routine check on the characteristics of the device to ensure that it meets the design requirements.

3. The method for designing SCX frequency band signal integrity through multiple media according to claim 1, characterized in that: The line width of the microstrip line used as a coplanar waveguide in S1 is 1.12 mm, and the line width of the strip line is 0.94 mm.