Microstrip line structure based on stub line shape
By designing a microstrip line structure with a stub shape, the problem of microstrip line crosstalk in the high-frequency band was solved, realizing the requirements of high-frequency performance improvement and miniaturization, reducing costs, and facilitating industrialization.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-26
- Publication Date
- 2026-03-13
AI Technical Summary
Existing technologies struggle to effectively suppress crosstalk between microstrip lines at high frequencies, leading to signal distortion and timing jitter. Furthermore, traditional methods often sacrifice wiring density or increase costs.
Design a microstrip line structure based on a stub shape, including a metal ground plane, a dielectric substrate, a first conductor strip and a second conductor strip, with stubs placed between them, and optionally centrally periodic or strip-integrated stubs, suitable for the DC-90GHz frequency band.
It effectively suppresses crosstalk over a wide frequency band, improves near/far-end crosstalk suppression by more than 10dB, reduces insertion loss, maintains good impedance matching, adapts to miniaturization requirements, and is low-cost, making it easy to industrialize.
Smart Images
Figure CN121663144A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of passive electronic devices for microwave and millimeter waves, and more particularly to a microstrip line structure based on a stub shape. Background Technology
[0002] In the context of rapid development in modern electronic technology, microstrip lines, as an indispensable transmission line form in microwave and radio frequency systems, are widely used in high-speed digital circuits and communication systems. However, during high-frequency signal transmission, crosstalk between microstrip lines has become a key factor restricting system performance. When high-speed signals propagate along microstrip lines, they generate strong electromagnetic fields. These electromagnetic fields not only induce mutual inductance and capacitance between adjacent microstrip lines but also couple to other transmission lines through spatial radiation, thus causing crosstalk. This interference leads to signal waveform distortion, timing jitter, and increased bit error rate, seriously threatening the reliability of high-speed digital communication and circuit applications.
[0003] As electronic devices continue to evolve towards miniaturization and high performance, the spacing between microstrip lines is forced to shrink, further exacerbating crosstalk. To address this issue, the industry has proposed various traditional crosstalk suppression methods, mainly including increasing line spacing, shortening coupling length, inserting grounding guard lines, or using differential structures. However, these methods often have significant drawbacks: increasing line spacing and shortening coupling length sacrifice wiring density, making it difficult to meet the miniaturization requirements of devices; using differential structures or inserting grounding guard lines increases manufacturing complexity and cost, which does not meet the low-cost requirements of modern integrated circuits.
[0004] Therefore, there is an urgent need for a microstrip line structure design that can effectively suppress crosstalk over a wide frequency range (especially the high-frequency band) without sacrificing wiring density or significantly increasing manufacturing costs, so as to meet the comprehensive requirements of modern electronic devices for high performance, miniaturization, and low cost. Summary of the Invention
[0005] The purpose of this application is to provide a microstrip line structure based on a stub shape, which addresses the problem that existing solutions are unable to effectively suppress microstrip line crosstalk in a wide high-frequency band (DC-90GHz), and solves the performance degradation problems such as signal distortion and timing jitter caused by crosstalk in high-frequency and miniaturized scenarios.
[0006] To achieve the above objectives, this application adopts the following technical solution:
[0007] This application provides a microstrip line structure based on a stub shape, comprising a metal ground plane, a dielectric substrate, a first conductor strip, a second conductor strip, and a stub, wherein:
[0008] The first conductor strip and the second conductor strip are respectively placed at the center of the upper surface of the dielectric substrate, and a gap is left between the first conductor strip and the second conductor strip;
[0009] The stub is placed within the interval between the first conductor strip and the second conductor strip;
[0010] The metal ground plane is placed on the lower surface of the dielectric substrate.
[0011] Optionally, the stub is a centrally periodically spaced stub, periodically placed within the interval, and its left and right ends are at a certain distance from the first conductor strip and the second conductor.
[0012] Optionally, the stub is an integrated stub, periodically placed within the interval, with one end connected to the first conductor strip or the second conductor.
[0013] Optionally, it also includes a first port, a second port, a third port, and a fourth port, which are respectively located on both sides of the microstrip line structure and are symmetrical about the center, for electrical measurement of the transmission line.
[0014] Optionally, the first, second, third, and fourth ports are connected to a 1mm coaxial test head for direct matching with electrical testing equipment.
[0015] Optionally, the dielectric substrate can be any low-loss, flexible material.
[0016] Optionally, the first conductor strip and the second conductor strip have the same size.
[0017] Optionally, the stub is rectangular in shape.
[0018] Optionally, the metal ground plane is made of copper-clad metal.
[0019] Optionally, the height of the metal grounding plates is 0.035 mm.
[0020] Based on the above technical solution, this application can achieve the following technical effects:
[0021] To address the challenge of effectively suppressing microstrip line crosstalk across a wide high-frequency band (DC-90GHz) using existing solutions, a novel microstrip line structure adapted to this band is designed to resolve performance degradation issues such as signal distortion and timing jitter caused by crosstalk in high-frequency, miniaturized scenarios. This meets the core requirements of modern integrated circuits: miniaturization, low cost, and high integration. Specifically, this includes:
[0022] 1. Structural Innovation: A differentiated stub structure design is proposed. Addressing the two major requirements of "insertion loss optimization" and "crosstalk suppression," two stub microstrip line structures are proposed: a microstrip line with spaced stubs and a microstrip line with integrated stubs, ensuring effectiveness across the DC-90GHz wideband.
[0023] 2. Short stubs do not require additional substrate layers, ground vias, or periodic arrays. They can be fabricated simultaneously with microstrip lines without occupying additional wiring space, solving the problem of "sacrificing density and increasing cost" in traditional solutions and adapting to the miniaturization requirements of integrated circuits.
[0024] 3. The dielectric substrate can be made of any low-loss flexible material, such as Kapton material, liquid crystal polymer, polyimide, or new low-loss materials for millimeter-wave / terahertz bands in the future.
[0025] 4. Both ends of the transmission line can be connected to 1mm coaxial test heads, which can be directly matched with electrical test equipment. For example, if a vector network analyzer is used for testing, no additional conversion structure is required, which facilitates integration and testing.
[0026] Compared with the prior art, this application has the following beneficial effects:
[0027] 1. Superior high-frequency performance: Within the DC-90GHz wide frequency band, the integrated stub solution improves near / far-end crosstalk suppression by more than 10dB (<-25dB / -30dB respectively), and the spacing stub solution reduces insertion loss by 2dB at 90GHz, while maintaining good impedance matching of |S11|<-13dB, solving the problems of high-frequency failure and high loss.
[0028] 2. Adaptable to miniaturization: Short-cut cables, through the spacing between wires or integrated design, do not occupy additional wiring space and do not require increasing the spacing between wires or adding lines, meeting the needs of high integration and miniaturization of equipment.
[0029] 3. Low cost and easy implementation: Short stubs and microstrip lines are processed simultaneously without the need for additional layers, arrays, or holes. It is compatible with existing design processes, has low material and processing costs, and is easy to industrialize. Attached Figure Description
[0030] Figure 1 This is a schematic diagram of a microstrip line coupling structure provided in an embodiment of this application, including a three-dimensional view, an xoz cross-sectional view, and an xoy cross-sectional view;
[0031] Figure 2 This is a schematic diagram of a microstrip line coupling structure with spaced stubs provided in an embodiment of this application, including a three-dimensional view, an xoz cross-sectional view, and an xoy cross-sectional view;
[0032] Figure 3This is a schematic diagram of a microstrip line coupling structure with integrated stubs provided in an embodiment of this application, including a three-dimensional view, an xoz cross-sectional view, and an xoy cross-sectional view;
[0033] Figure 4 This application provides an embodiment of a microstrip line coupling structure, a microstrip line coupling structure with spaced stubs, and a microstrip line coupling structure with integrated stubs. 11 Simulation results;
[0034] Figure 5 This application provides an embodiment of a microstrip line coupling structure, a microstrip line coupling structure with spaced stubs, and a microstrip line coupling structure with integrated stubs. 21 Simulation results;
[0035] Figure 6 This application provides an embodiment of a microstrip line coupling structure, a microstrip line coupling structure with spaced stubs, and a microstrip line coupling structure with integrated stubs. 31 Simulation results;
[0036] Figure 7 This application provides an embodiment of a microstrip line coupling structure, a microstrip line coupling structure with spaced stubs, and a microstrip line coupling structure with integrated stubs. 41 Simulation results. Detailed Implementation
[0037] The present application will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present application will become clearer from the following description and claims. It should be noted that the drawings are all in a very simplified form and are not to scale, and are only used to facilitate and clarify the illustration of the embodiments of the present application.
[0038] It should be noted that, in order to clearly illustrate the content of this application, several embodiments are provided to further explain the different implementations of this application. These embodiments are enumerated rather than exhaustive. Furthermore, for the sake of brevity, content mentioned in the preceding embodiments is often omitted in the following embodiments. Therefore, content not mentioned in the following embodiments can be referred to in the preceding embodiments.
[0039] Example 1
[0040] like Figure 1The diagram shows a schematic representation of a microstrip line coupling structure in the prior art, including a three-dimensional view, an xoz cross-sectional view, and an xoy cross-sectional view. The microstrip line coupling structure includes a metal ground plane A1, a dielectric substrate A2, a first conductor strip (signal line) A3 at the center of the upper surface of the dielectric substrate, and a second conductor strip (signal line) A4. The first and second conductor strips are respectively positioned at the center of the upper surface of the dielectric substrate, with a gap between them; the metal ground plane is located on the lower surface of the dielectric substrate. Figure 1 The first conductor strip (signal line) A3 and the second conductor strip (signal line) A4 on the upper surface of the dielectric substrate have the same dimensions, with a width of 0.6 mm and a spacing of 10 mm; the dielectric substrate A2 has a width of 30 mm, a length of 20 mm, and a height of 0.254 mm; the metal ground plane A1 has a width of 30 mm, a length of 20 mm, and a height of 0.035 mm.
[0041] This embodiment, based on existing technology, further provides a microstrip line coupling structure with spaced short stubs, such as... Figure 2 As shown, the structure includes a metal ground plane B1, a dielectric substrate B2, a first conductor strip (signal line) B3 and a second conductor strip (signal line) B4 at the center of the upper surface of the dielectric substrate, and a stub with spacing B5. The first and second conductor strips are respectively positioned at the center of the upper surface of the dielectric substrate, with a gap between them; the stub is placed within the gap between the first and second conductor strips; the metal ground plane is positioned on the lower surface of the dielectric substrate. The stub is a centrally periodically spaced stub, periodically placed within the gap, and its left and right ends are at a certain distance from the first and second conductor strips.
[0042] In one specific embodiment, Figure 2 The structure is a microstrip line coupled with spaced short stubs. The first conductor strip (signal line) B3 and the second conductor strip (signal line) B4 on the upper surface of the dielectric substrate have the same dimensions, with a width of 0.6 mm and a spacing of 10 mm. The central periodic spaced short stub B5 has a length of 0.6 mm, a width of 0.2 mm, and a period of 0.4 mm. The dielectric substrate B2 has a width of 30 mm, a length of 20 mm, and a height of 0.254 mm. The metal ground plane B1 has a width of 30 mm, a length of 20 mm, and a height of 0.035 mm.
[0043] This embodiment, based on existing technology, further provides a microstrip line coupling structure with integrated stubs, such as... Figure 3As shown, the structure includes a metal ground plane C1, a dielectric substrate C2, a first conductor strip (signal line) C3 and a second conductor strip (signal line) C4 at the center of the upper surface of the dielectric substrate, and a microstrip line integrated stub C5. The first and second conductor strips are respectively positioned at the center of the upper surface of the dielectric substrate, with a gap between them; the stub is placed within the gap between the first and second conductor strips; the metal ground plane is located on the lower surface of the dielectric substrate. The stub is a strip-integrated stub, periodically placed within the gap, with one end connected to either the first or second conductor strip.
[0044] In one specific embodiment, Figure 3 The structure is a microstrip line coupled with an integrated stub. The first conductor strip (signal line) C3 and the second conductor strip (signal line) C4 on the upper surface of the dielectric substrate have the same size and a width of 0.6 mm. The microstrip line integrated stub C5 is closely adjacent to the center conductor strip (signal line) C3 / C4 on the upper surface of the dielectric substrate. C5 has a length of 0.33 mm, a width of 0.2 mm, and a period of 0.4 mm. The distance between C3 and C4 is 10 mm.
[0045] In one embodiment, the metal ground plane is made of copper-clad metal, and the height of the copper-clad ground plane is 0.035mm.
[0046] In one embodiment, the structure further includes a first port, a second port, a third port, and a fourth port, respectively located on both sides of the microstrip line structure and symmetrical about the center, for electrical measurements of the transmission line. The first port, second port, third port, and fourth port are connected to a 1mm coaxial test head for direct matching with electrical testing equipment.
[0047] In one specific embodiment, such as Figure 1 , 2 As shown in Figures 1 and 3, test ports 1, 2, 3, and 4 are located on both sides of the microstrip line coupled structure, the microstrip line coupled structure with spaced stubs, and the microstrip line coupled structure with integrated stubs, respectively, and are symmetrical about the center, responsible for the electrical measurement of the transmission line; the transmission line uses a four-port excitation form, with one port set at each of the four end interfaces, namely the first port, the second port, the third port, and the fourth port; test ports 1, 2, 3, and 4 can be connected to a coaxial test head, such as a 1mm coaxial head (covering up to 110GHz).
[0048] In one embodiment, the dielectric substrate can be made of any low-loss flexible material, such as Kapton material, liquid crystal polymer, polyimide, or future novel low-loss materials for millimeter-wave / terahertz bands.
[0049] In one specific embodiment, the dielectric substrate is made of Rogers 5880 material with a relative permittivity of 2.2, a loss tangent of 0.0009, and a thickness of 0.254 mm.
[0050] In one embodiment, simulations were performed on the microstrip line coupling structure, the microstrip line coupling structure with spaced stubs, and the microstrip line coupling structure with integrated stubs provided in this embodiment. The simulation results are as follows:
[0051] Figure 4 S represents a microstrip line coupled structure, a microstrip line coupled structure with spaced stubs, and a microstrip line coupled structure with integrated stubs. 11 Simulation results. The addition of the stub significantly enhances the impedance matching of the coupled microstrip line, with the |S11| value remaining below -13dB across the entire frequency range, indicating good impedance matching.
[0052] Figure 5 S represents a microstrip line coupled structure, a microstrip line coupled structure with spaced stubs, and a microstrip line coupled structure with integrated stubs. 21 Simulation results show that the integrated stub effectively reduces the insertion loss of microstrip lines. Comparative analysis reveals that introducing stubs between microstrip lines ensures that the |S21| (dB) value does not fall below -2dB in the DC-90GHz frequency range. In contrast, the attenuation of the conventional structure increases significantly, reaching -4dB. These results confirm that the application of stubs greatly reduces insertion loss. However, compared to microstrip lines with stubs, the further reduction in insertion loss is relatively small.
[0053] Figure 6 S represents a microstrip line coupled structure, a microstrip line coupled structure with spaced stubs, and a microstrip line coupled structure with integrated stubs. 31 Simulation results. Figure 6 The near-end coupling performance (S31) of the transmission line structure is shown. The improvement in near-end coupling between the microstrip line and the microstrip line with spaced stubs is small, while the microstrip line with stubs exhibits satisfactory near-end coupling performance with an S31 value below -25 dB.
[0054] Figure 7 S represents a microstrip line coupled structure, a microstrip line coupled structure with spaced stubs, and a microstrip line coupled structure with integrated stubs. 41 Simulation results. Figure 7 The far-end coupling performance (S41) is shown. Similar to near-end coupling, the improvement in far-end coupling between the microstrip line and the microstrip line with spaced stubs is small. However, the microstrip line with stubs exhibits superior far-end coupling performance, with an S31 value below -30 dB and a far-end crosstalk reduction of approximately 10 dB.
[0055] In summary, to address the challenge of effectively suppressing microstrip line crosstalk across a wide high-frequency band (DC-90GHz) using existing solutions, a novel microstrip line structure adapted to this band was designed. This solves the performance degradation issues caused by crosstalk, such as signal distortion and timing jitter, in high-frequency, miniaturized scenarios. It meets the core requirements of modern integrated circuits: miniaturization, low cost, and high integration. Compared with existing technologies, it possesses the following significant advantages:
[0056] 1. Superior high-frequency performance: Within the DC-90GHz wide frequency band, the integrated stub solution improves near / far-end crosstalk suppression by more than 10dB (<-25dB / -30dB respectively), and the spacing stub solution reduces insertion loss by 2dB at 90GHz, while maintaining good impedance matching of |S11|<-13dB, solving the problems of high-frequency failure and high loss.
[0057] 2. Adaptable to miniaturization: Short-cut cables, through the spacing between wires or integrated design, do not occupy additional wiring space and do not require increasing the spacing between wires or adding lines, meeting the needs of high integration and miniaturization of equipment.
[0058] 3. Low cost and easy implementation: Short stubs and microstrip lines are processed simultaneously without the need for additional layers, arrays, or holes. It is compatible with existing design processes, has low material and processing costs, and is easy to industrialize.
[0059] The above description is merely an embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this application should be included within the scope of the claims of this application.
Claims
1. A microstrip line structure based on a stub shape, characterized in that, It includes a metal ground plane, a dielectric substrate, a first conductor strip, a second conductor strip, and a stub, wherein: The first conductor strip and the second conductor strip are respectively placed at the center of the upper surface of the dielectric substrate, and a gap is left between the first conductor strip and the second conductor strip; The stub is placed within the interval between the first conductor strip and the second conductor strip; The metal ground plane is placed on the lower surface of the dielectric substrate.
2. The microstrip line structure according to claim 1, characterized in that, The stub is a centrally periodic stub with intervals, periodically placed within the intervals, and its left and right ends are at a certain distance from the first conductor strip and the second conductor.
3. The microstrip line structure according to claim 1, characterized in that, The stub is an integrated stub, periodically placed within the interval, with one end connected to the first conductor strip or the second conductor.
4. The microstrip line structure according to claim 1, characterized in that, It also includes a first port, a second port, a third port, and a fourth port, which are respectively located on both sides of the microstrip line structure and are symmetrical about the center, for electrical measurement of the transmission line.
5. The microstrip line structure according to claim 4, characterized in that, The first, second, third, and fourth ports are connected to a 1mm coaxial test head for direct matching with electrical testing equipment.
6. The microstrip line structure according to claim 1, characterized in that, The dielectric substrate can be any low-loss, flexible material.
7. The microstrip line structure according to claim 1, characterized in that, The first conductor strip and the second conductor strip have the same dimensions.
8. The microstrip line structure according to claim 1, characterized in that, The stub is rectangular in shape.
9. The microstrip line structure according to claim 1, characterized in that, The metal ground plane is made of copper-clad metal.
10. The microstrip line structure according to claim 9, characterized in that, The height of all the metal grounding plates is 0.035mm.