Artificial surface plasmon microstrip transmission line with crosstalk suppression effect

Abstract

The invention discloses an artificial surface plasmon microstrip transmission line with a crosstalk suppression effect. The transmission line conduction band is provided with a periodic internal notch groove structure which is used for transmitting microwave artificial surface plasmons with strong local field constraint performance. The periodic notch grooves can be S-shaped, spiral, T-shaped, cross-shaped, KoCh-shaped, Moore Curve-shaped and other forms and are distributed in the microstrip conduction band, and the width of the conduction band is not increased, so that the remarkable inhibition effect that the far-end crosstalk is lower than-30dB is realized on the premise that the size of the microstrip line is not changed. The microstrip transmission line has the low-pass characteristic, the frequency response falling edge is steep, the cut-off frequency can be flexibly adjusted by adjusting the notch groove width and the number of iterations, and application requirements of different frequency bands can be met by scaling. The structure is simple, the size is compact, inter-line crosstalk can be effectively suppressed, the signal transmission quality is improved, the strict signal integrity requirement is met, and the high-frequency and high-speed signal transmission and functional devices are widely applied, and the wide application prospect is achieved.

Description

Technical Field

[0001] The present invention belongs to the field of microwave microstrip transmission lines, and in particular relates to an artificial surface plasmon microstrip transmission line with a crosstalk suppression effect, which can effectively suppress far-end crosstalk in high-speed signal transmission. Background Art

[0002] Microstrip line is a transmission line structure widely used in high-frequency and microwave circuit design. It has the advantages of simple structure, easy production and stable performance. It is widely used in microwave integrated circuits, devices, antennas and system design. With the rapid development of modern high-speed digital circuits and microwave communication systems, signal frequency, transmission rate and PCB signal line density are growing geometrically, and the signal integrity and electromagnetic compatibility requirements in circuit design are becoming more and more serious. In this environment, the crosstalk problem of traditional microstrip transmission lines is becoming increasingly prominent.

[0003] Crosstalk refers to the phenomenon that during the signal transmission process, an electrical signal in a signal transmission line induces an undesired voltage or current in an adjacent signal line through electromagnetic coupling. This phenomenon is mainly caused by electromagnetic coupling. Specifically, when the signal propagates along the transmission line, there is an outward-extending edge electromagnetic field between the signal path and the return path. The electromagnetic coupling caused by this is the root cause of crosstalk. As the transmission rate increases, the crosstalk problem will lead to signal loss, increased noise, and increased interference, thereby reducing the signal-to-noise ratio, seriously affecting the accuracy and reliability of data transmission, and becoming one of the bottlenecks limiting the improvement of system performance.

[0004] Artificial surface plasmon is a new technology that can effectively control microwave, millimeter wave and terahertz transmission by artificially designing subwavelength periodic structures on metal surfaces. Compared with free space electromagnetic waves, artificial surface plasmon has the following advantages: ① Higher local field confinement. Artificial surface plasmon is a subwavelength localized surface wave that can improve the confinement of the guided wave mode of the transmission line, effectively compress the spatial extension of the edge electromagnetic field, and thus reduce the coupling crosstalk between transmission lines. ② Unique and precisely controllable slow wave dispersion characteristics. Through the characteristic parameters of the unit structure, its dispersion characteristics can be precisely controlled, and even the customization of dispersion curves with different trends can be achieved, so it has a stronger electromagnetic guided wave control capability. ③ Shorter waveguide wavelength, larger wave vector, and higher unit structure design freedom. The waveguide wavelength of artificial surface plasmon is significantly smaller than that of free space waves and conventional guided waves, which is conducive to the miniaturization of circuits and antennas; its wave vector mismatch can avoid co-frequency electromagnetic interference; its flexible unit structure design enables it to be integrated with lumped components, active chips and systems in microwave and millimeter wave circuit and antenna applications.

[0005] In order to solve the crosstalk problem of traditional microstrip transmission lines, the present invention combines artificial surface plasmon technology and incorporates subwavelength periodic structures into the design of PCB microstrip transmission lines, which can significantly enhance the spatial constraints of the electromagnetic field and effectively reduce the impact of crosstalk on signals. This new type of microstrip transmission line not only has obvious advantages in transmission performance and crosstalk suppression capabilities, but also provides a solution with important potential for the design of future microwave high-speed circuit systems. Summary of the invention

[0006] The main purpose of the present invention is to solve the crosstalk problem existing in the prior art and propose an artificial surface plasmon microstrip transmission line with crosstalk suppression effect. By introducing a periodic internal groove structure on the microstrip guide, the structure can effectively transmit microwave artificial surface plasmons with strong local field binding characteristics, thereby significantly suppressing far-end crosstalk without increasing the width of the original microstrip guide.

[0007] In order to achieve the above object, the present invention adopts the following technical scheme:

[0008] The invention discloses an artificial surface plasmon microstrip transmission line with a crosstalk suppression effect. The main structure of the artificial surface plasmon microstrip transmission line is a microstrip transmission line. A periodic internal groove structure is arranged on a conductive strip of the microstrip transmission line for transmitting microwave artificial surface plasmons with extremely strong local field confinement performance. The periodic internal groove structure is in one or a combination of S-shaped, spiral, T-shaped, cross-shaped, KoCh-shaped, and Moore Curve-shaped forms, and is distributed inside the microstrip conductive strip, without increasing the conductive strip width, thereby achieving a good crosstalk suppression effect without changing the size of the microstrip conductive strip. The artificial surface plasmon transmission line has a low-pass characteristic, and its frequency response has a steep falling edge. The cutoff frequency can be flexibly adjusted by changing the side width of the internal groove and the number of iterations. By enlarging or reducing the size and the number of iterations of the internal groove, the invention is suitable for electromagnetic wave transmission in microwave, millimeter wave, or even terahertz bands, as well as active and passive device design.

[0009] Compared with the prior art, the present invention has the following beneficial effects:

[0010] (1) The present invention adopts a microstrip line internal groove structure. Compared with the traditional artificial surface plasmon unit structure with branches loaded on both sides of the microstrip line, it greatly saves wiring space and has a lower 3W line spacing, which is particularly suitable for high-density, narrow line spacing and complex stacked structure PCB boards.

[0011] (2) The artificial surface plasmon microstrip transmission line proposed in the present invention has a simulated transmission coefficient of less than -30 dB at far-end crosstalk in the range of 0 to 10 GHz, which is significantly better than the average far-end crosstalk level of about -10 dB in conventional microstrip designs of the same specifications. This enables the present invention to effectively suppress crosstalk, improve signal transmission quality, and meet stringent signal integrity requirements.

[0012] (3) The present invention introduces a groove structure into the interior of a microstrip line for the first time, and is used to design a novel internally grooved artificial surface plasmon transmission line with strong electromagnetic wave confinement performance and small structural size. This internally grooved structure can achieve good transmission characteristics and crosstalk suppression levels while being miniaturized, and has great application potential.

[0013] (4) The transmission line of the present invention has a typical low-pass characteristic, and its frequency response has a steep falling edge. The cutoff frequency can be adjusted flexibly by changing the overall width of the side of the internal groove and the number of iterations, and different frequency bands can be moved by scaling, so as to meet the application requirements of different frequency bands.

[0014] (5) The present invention has a simple structure, compact size, low processing cost, is easy to implement large-scale production and processing, and has good commercial prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings illustrate embodiments and together with the description serve to explain the principles of the invention.Other embodiments and many of the intended advantages of the embodiments will be readily appreciated as they become better understood by reference to the following detailed description.

[0016] Figure 1 This is a schematic diagram of the structure of an artificial surface plasmon microstrip transmission line unit in Example 1;

[0017] Figure 2 is a dispersion curve diagram of the artificial surface plasmon microstrip transmission line unit of Example 1;

[0018] Figure 3 Schematic diagram of an artificial surface plasmon microstrip transmission line with a transition structure according to Example 2;

[0019] Figure 4 The simulation results of the artificial surface plasmon microstrip transmission lines S11 and S21 with transition structures of Example 2;

[0020] Figure 5 Schematic diagram of the structure of the parallel coupled artificial surface plasmon microstrip transmission line of Example 3;

[0021] Figure 6 This is a diagram of experimental measurement results of parallel coupled artificial surface plasmon microstrip transmission lines S11 and S21 of Example 3;

[0022] Figure 7 This is a diagram of the experimental measurement results of the parallel-coupled artificial surface plasmon microstrip transmission line S41 of Example 3. DETAILED DESCRIPTION

[0023] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer and more understandable, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0024] In the present invention, the terms "first", "second", "third", etc. are only used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence, nor can they be understood as indicating or implying relative importance. In the description, the directions or positional relationships indicated by "upper", "lower", "left", "right", "front", and "back" are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and are not intended to indicate or imply that the device referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present invention. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0025] Example 1

[0026] The present invention discloses an artificial surface plasmon microstrip transmission line (SSPPMS) with crosstalk suppression effect, wherein the dielectric substrate material is Rogers RT5880, the dielectric constant is 2.2, the thickness is 0.508 mm, and the transmission loss angle is 0.0009. The metal ground and the conducting strip material of the transmission line are both copper, and the conducting strip is provided with periodic S-shaped grooves. The SSPPMS unit structure is as follows: Figure 1 As shown. Among them, the period length p of the unit is 2mm, the width C of the groove hollow area is 0.1mm, and the length range is 0.525mm~3.6mm. By analyzing with the eigenmode solver of the full-wave simulation software, the dispersion curve of the unit structure of the present embodiment 1 can be obtained, that is, the corresponding relationship between frequency (Frequency) and phase (Phase), as shown in FIG. Figure 2 As shown. The results show that the dispersion curve of the unit structure deviates significantly from the light, and the asymptotic (cut-off) frequency is 18.5GHz, showing the typical dispersion characteristics of artificial surface plasmons. In addition, it can be seen from the artificial surface plasmon dispersion curve that the present invention has a low-pass characteristic. By adjusting the unit structure parameters, the asymptotic frequency value can be adjusted, thereby designing an artificial surface plasmon microstrip line that meets the application of a specific frequency band.

[0027] Example 2

[0028] Using the SSPPMS unit structure in Example 1, an artificial surface plasmon microstrip line with a transition structure can be designed, such as Figure 3 As shown. In this embodiment, the dielectric substrate material of the artificial surface plasmon transmission line with a transition structure is Rogers RT5880, with a dielectric constant of 2.2, a thickness of 0.508mm, and a transmission loss angle of 0.0009; the metal ground and the periodic S-shaped groove material are selected as copper. Specifically, the width C of the hollow area is 0.1mm, and the length ranges from 0.525mm to 3.6mm; the two end areas are transition unit areas (contains transition units 1 to 11 with a gradient groove length), and the remaining middle area is the S-shaped groove main unit; the period length p of the transmission line unit is 2mm. Using full-wave simulation, it can be obtained that S11 and S21 of the artificial surface plasmon microstrip line with a transition structure are as shown in Figure 4 As shown, S11 is lower than -20dB in the range of 0 to 10GHz, and S21 is about -0.27dB, indicating that good transmission characteristics can be achieved in this frequency band.

[0029] Example 3

[0030] In order to illustrate that the artificial surface plasmon microstrip transmission line of the present invention has good crosstalk suppression characteristics, this embodiment uses two artificial surface plasmon microstrip lines with transition structures described in Example 2 to form a parallel coupled artificial surface plasmon microstrip transmission line structure, such as Figure 5 As shown. The dielectric substrate material of the parallel coupled artificial surface plasmon transmission line is Rogers RT5880, with a dielectric constant of 2.2, a thickness of 0.508mm, and a transmission loss angle of 0.0009; the metal ground and the periodic S-shaped groove material are selected as copper. The dimensions are selected as follows: the width C of the hollow area is 0.1mm, and the length range is 0.525mm~3.6mm; the two transmission lines are axisymmetric structures, units 1 to 11 are transition units, and unit 12 is the main unit; the distance s between the two parallel coupled transmission lines is 0.4mm; the period length p of the transmission line unit is 2mm. For comparative analysis, by processing conventional parallel coupled traditional microstrip transmission lines (MS) and the parallel coupled artificial surface plasmon microstrip transmission lines (SSPPMS) samples of this embodiment, the basic structural parameters of the two are consistent except that the guide strips of this embodiment have grooves. The network analyzer is used for measurement, and the experimentally measured S11 and S21 parameter results are shown as follows Figure 6 As shown. It can be seen that the S11 of the present invention is lower than -10dB in the 0-10GHz working frequency band, and the reflection is very small; S21 is close to the microstrip line in the 0-10GHz working frequency band, and has very low insertion loss; the comparison results of the far-end coupling coefficient S41 of the parallel coupled transmission line obtained by simulation are shown as follows Figure 7As shown, it can be seen that the S41 of the parallel-coupled artificial surface plasmon microstrip transmission line (SSPPMS) of the present invention is around -30 dB in the 0-10 GHz operating frequency band, which is much lower than the S41 of the conventional parallel-coupled traditional microstrip transmission line (MS), showing a good far-end crosstalk suppression effect.

[0031] The above describes the specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can make several improvements within the technical scope disclosed in the present application without departing from the principle of the present invention, and these improvements should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. An artificial surface plasmon microstrip transmission line with crosstalk suppression effect, characterized in that: Its main structure is a microstrip transmission line, and a periodic internal groove structure is arranged on the guide strip of the microstrip transmission line, which is used to transmit microwave artificial surface plasmons with extremely strong local field confinement performance; the periodic internal groove structure adopts one or a combination of S-shape, spiral shape, T-shape, cross shape, KoCh shape, and Moore Curve shape, and is distributed inside the microstrip guide strip, and will not increase the guide strip width, thereby achieving a significant suppression effect of far-end crosstalk below -30dB without changing the size of the microstrip guide strip; the microstrip transmission line has a low-pass characteristic, a steep falling edge of the frequency response, and the cutoff frequency can be flexibly adjusted by adjusting the groove width and the number of iterations, and can adapt to the application requirements of different frequency bands through scale scaling.

2. The artificial surface plasmon microstrip transmission line with crosstalk suppression effect as claimed in claim 1, characterized in that: The metal layers of the microstrip transmission line are located on the upper and lower sides of the substrate, with the metal line on the upper side and the metal ground on the lower side, both with a thickness of 0.018mm. The substrate material is Rogers RT5880 with a thickness of 0.508mm. To achieve 50Ω impedance matching, the width of the microstrip line is 1.56mm, and a transition structure is introduced between the microstrip line and the main unit.

3. The artificial surface plasmon microstrip transmission line with crosstalk suppression effect as claimed in claim 1, characterized in that: The periodic internal grooves are distributed inside the microstrip conductor, which greatly saves wiring space compared to the traditional artificial surface plasmon unit structure with branches loaded on both sides of the microstrip line, has a lower 3W line spacing, and is particularly suitable for high-density, narrow line spacing, and complex stacked structure PCB boards. The artificial surface plasmon microstrip transmission line with an internal groove structure as claimed in claim 1, characterized in that: It has a simple structure and compact size. It can effectively suppress crosstalk between lines, improve signal transmission quality, and meet stringent signal integrity requirements. It is widely used in high-frequency and high-speed signal transmission and passive, active and other functional device designs, and has broad application prospects.

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