TWM483552U - Low crosstalk high frequency transmission differential pair microstrip line - Google Patents

Description

Low crosstalk high frequency transmission differential pair microstrip line

A transmission line, and more particularly to a differential pair microstrip line with low crosstalk high frequency transmission.

In recent years, in digital systems, as the signal transmission rate has increased and the size of electronic products has become smaller and smaller, the design of electronic circuits has become more and more dense. Therefore, the phenomenon of crosstalk between lines is becoming more and more serious. . The so-called crosstalk is caused by the influence of the electromagnetic coupling on the adjacent transmission line when the signal is transmitted in the transmission channel, and the coupling voltage and the coupling current are generated on the interfered transmission line. Excessive crosstalk will affect the efficiency of the system operation, causing the circuit to be triggered by mistakes, and the system will not work properly. In addition, in the motherboard or high-speed circuit, if the electronic circuit needs to be turned according to the actual design, often increase the interval between the microstrip lines or increase the rise and fall times of the digital signal to suppress crosstalk, but still can not effectively solve the crosstalk problem. .

In view of the fact that the traditional method does not effectively solve the crosstalk problem between lines, it is urgent to propose a novel low-crosstalk high-frequency transmission differential pair microstrip line structure, which can be used to suppress the occurrence of crosstalk and reduce the conversion of differential mode to common mode. effect.

This creation mainly uses the microstrip line of the transmitted signal. When there is a signal, the surface current is mainly distributed at the edge of the microstrip line, that is, the edge of the conduction band has a very high current density. If the sub-wavelength periodic ripple is etched at the edge of the microstrip line, the edge current is introduced The groove forms an approximately closed loop, which is beneficial to enhance the self-inductance of the circuit itself and constrain the magnetic field to the vicinity of its own wire, thereby effectively reducing crosstalk caused by mutual inductance of adjacent circuits. As the structure and depth of the interior of the groove will have different constraints on the magnetic field.

In the prior art, the microstrip circuit has a periodic structure for the purpose of band-stop filtering, but it is often used in practical circuits because the structure is too long. Moreover, another use of the periodic structure in the prior art is to form a suitable R-L architecture for coupling to adjacent circuits. Therefore, the concept of this creation is different from the views of the above two conventional techniques. The two deep-rooted views of the periodic structure based on the periodic structure are such that it is quite difficult for professional staff to think of using the periodic structure to transmit the signal. In addition, the circuit design software used by professionals is quite difficult. This type of line is not supported, and it is unimaginable to use a periodic line to make a signal line. At present, there are two methods commonly used to suppress crosstalk. The first one is to reduce crosstalk by multiple turns of differential lines or single-ended lines. For differential pairs, it will cause an increase in common-mode signals, which is not conducive to the overall wire. The operation of the circuit. The second method is to use a grounding wire between the adjacent circuit, which causes two obvious defects. The area of the first loop cannot be effectively reduced. The second is that the ground line only blocks the electric field, and the effect of suppressing the mutual inductance between the lines is not significant. This creation uses a path traced on the surface of the conductor to make the edge current form a quasi-loop in such a loop, effectively restraining the magnetic field and suppressing crosstalk caused by mutual inductance. Such constraints have a better effect on the higher frequency signals. Since the period length is much smaller than the wavelength, its operating frequency is far from the band gap, and the main function is to transmit signals instead of reflected signals. No., the application is not the same concept as the filter. The applicable fields are high-frequency microwave circuits and high-speed circuits, especially in dense lines, which can effectively isolate mutual interference between signal lines. The difference between the main transmission complementary signal and the single-ended transmission line is that it has strong anti-interference ability, but in use, the circuit will use more signal lines than the single-ended transmission line, and the circuit area will be relatively large. some. In order to reduce the area of the circuit, the differential pair will be too close to other transmission lines, and the effect of crosstalk and differential signal conversion to a common mode signal becomes extremely serious. It is necessary to separate from the traditional differential microstrip line and use a completely new concept transmission line. To replace. In the transmission of the signal, the differential pair is composed of two transmission lines, both of which transmit signals, but the signals of the two lines are 180° out of phase, which is a significant difference from the single-ended transmission line.

One of the aims of the present invention is to provide a differential pair microstrip line with low crosstalk high frequency transmission, comprising: a first microstrip line transmitting a first transmission signal, the first microstrip line having a periodic arrangement a plurality of grooves; and a second microstrip line parallel to the first microstrip line and configured to transmit a second transmission signal, the second transmission signal and the first transmission signal system having a phase difference of 180 a complementary signal of the second microstrip line having a plurality of periodically arranged grooves; wherein the plurality of grooves are periodically arranged on the outer side of the first microstrip line in a subwavelength manner, and On the outer side of the second microstrip line, the sub-wavelength is the length of the arrangement period of the plurality of grooves, which is smaller than the wavelength of the transmitted first transmission signal and the second transmission signal, and the plurality of grooves provide enhancement Subwavelength confinement of electromagnetic waves.

Another object of the present invention is to further include: a first port, which is a port of the first microstrip line and the second microstrip line, and a complementary input signal; and a second port, which is the first a microstrip line and the second microstrip line, and the individual outputs complementary signals a port; wherein the plurality of grooves arranged along an edge of the microstrip line reduce a differential mode to common mode conversion effect when a complementary signal is transmitted from the first port to the second port. The plurality of grooves reduce the energy crosstalk effect of a single microstrip line or a differential pair adjacent to each other when the complementary signal is transmitted from the first port to the second port.

The plurality of grooves, in a subwavelength arrangement, further includes: a plurality of grooves symmetrically on the outer side of the first microstrip line, and periodically arranged on the inner side of the first microstrip line And a plurality of grooves symmetrically on the outer side of the second microstrip line, and periodically arranged inside the second microstrip line.

The effect achieved by this creation is to provide a low-crosstalk high-frequency transmission differential pair microstrip line structure, which is used to solve the problem of crosstalk and common mode conversion effects in high-speed circuits, and improve signal transmission quality and reduce board size. .

Another effect achieved by the present invention is to provide a differential pair microstrip line structure with low crosstalk high frequency transmission, a periodic groove differential pair microstrip line with sub-wavelength size, and the shape and size of the groove can be practical according to the actual The design is adjusted accordingly, and the mode of the artificial surface plasma polaron is highly constrained to the electromagnetic energy on the groove microstrip line.

11‧‧‧First microstrip line

12‧‧‧Second microstrip line

13‧‧‧First port

14‧‧‧second port

15‧‧‧ rectangular concave body

16‧‧‧Rigid convex body

17‧‧‧First Extension

18‧‧‧Second extension

20‧‧‧Z-shaped convex body

21‧‧‧Substrate

22‧‧‧ third port

23‧‧‧fourth port

Fig. 1 is a schematic diagram of a grooved differential pair on the outer side of a subwavelength periodic structure.

Fig. 2 is a schematic diagram of a coupling circuit of a conventional open differential pair of sub-wavelength periodic structures.

Figure 3 Outside open grooved differential centering S _{dd 21} represents the signal transmission capability, and S _{dd 41} represents the crosstalk of the differential pair and the adjacent conventional differential pair.

Fig. 4 The outer open groove type differential centering S _{cd 21} represents the conversion effect of the differential mode signal and the common mode signal.

Figure 5 is a schematic diagram of the outer hairpin differential pair of the subwavelength periodic structure.

Figure 6. Schematic diagram of the outer hairpin differential pair detail of the subwavelength periodic structure.

Fig. 7 is a schematic diagram of a coupling circuit of a conventional hairpin differential pair and a conventional differential pair of a subwavelength periodic structure.

Figure 8 The outer hairpin differential pairing S _{dd 21} represents the signal transmission capability, and S _{dd 41} represents the crosstalk of the differential pair and the adjacent conventional differential pair.

Figure 9 External hairpin differential centering S _{cd 21} represents the conversion effect of the differential mode signal and the common mode signal.

Figure 10 is a schematic diagram of the grooved differential pair on the outer side of the subwavelength periodic structure.

Figure 11 is a schematic diagram of a coupling circuit of a differential differential pair of a sub-wavelength periodic structure and a conventional differential pair.

Figure 12 Outer grooved differential centering S _{dd 21} represents the signal transmission capability, and S _{dd 41} represents the crosstalk of the differential pair and the adjacent conventional differential pair.

Figure 13 The outer groove type differential alignment S _{cd 21} represents the conversion effect of the differential mode signal and the common mode signal.

Figure 14 is a schematic diagram of a double-side open groove differential pair of sub-wavelength periodic structures.

Fig. 15 is a schematic diagram of a coupling circuit of a sub-wavelength periodic structure double-sided open groove differential pair and a conventional differential pair.

Figure 16 Double-sided open groove differential pairing S _{dd 21} represents the signal transmission capability, and S _{dd 41} represents the crosstalk of the differential pair and the adjacent conventional differential pair.

Figure 17 Double-sided open groove differential centering S _{cd 21} represents the conversion effect of the differential mode signal and the common mode signal.

Figure 18 is a schematic diagram of a double-sided grooved differential pair of sub-wavelength periodic structures.

Figure 19 is a schematic diagram of a sub-wavelength periodic structure double-sided recessed differential pair and a single-ended microstrip line coupling circuit.

Figure 20 Subwavelength period double-sided grooved differential pairing S _{dd 21} represents the signal transmission capability, and S _{sd 41} represents the crosstalk of the differential pair and the adjacent single-ended microstrip line.

Figure 21 Subwavelength period double-sided grooved differential pairing S _{cd 21} represents the conversion effect of the differential mode signal and the common mode signal.

Figure 22 is a schematic diagram of a two-side hairpin differential pair of subwavelength periodic structures.

Figure 23 is a schematic diagram of a sub-wavelength periodic structure of a double-sided hairpin differential pair detail.

Figure 24 is a schematic diagram of a sub-wavelength periodic structure with a double-sided hairpin differential pair and a single-ended microstrip line coupling circuit.

Figure 25 Periodic double-sided hairpin differential pair S _{dd 21} represents the signal transmission capability, and S _{sd 41} represents the crosstalk of the differential pair and the adjacent single-ended microstrip line.

Figure 26 Periodic double-sided hairpin differential pairing S _{cd 21} represents the conversion effect of the differential mode signal and the common mode signal.

As shown in FIG. 1 , the present invention provides the outer open groove type differential pair of the first embodiment. The two sub-wavelength periodic microstrip lines form a differential pair, and the signal is input by the first port 13 and the output is the second port 14 . One is that the first microstrip line 11 sends a signal, and the other is that the second microstrip line 12 sends a signal with a phase difference of 180° (two complementary signals), and the complex number in the structure of the outer open groove type differential pair a recessed structure having a rectangular recess 15 in combination with a rectangular projection 16 having a continuous periodic structure, and at each opening of the recess, each rectangular projection 16 has a Two first extensions 17 extending in parallel in the center of each groove.

Width of the microstrip line is w, the interval is two microstrip lines w _1, the thickness of the two metal microstrip line is t, the thickness of the substrate 21 to cycle length h, the cycle of the microstrip line is d, periodic microstructures The groove depth of the strip line is b , and the dielectric constant of the medium of the substrate 21 is ε _r . When a single-ended microstrip line or another differential pair appears next to the conventional smooth grooveless differential pair, there are two distinct Effect, the first effect is that a significant differential mode to common mode effect will occur from the first port 13 to the second port 14. The second effect is that the complementary signal input by the first port 13 will generate crosstalk adjacent to another microstrip line or differential pair, in order to prove that the sub-wavelength periodic differential pair has suppression of crosstalk between adjacent microstrip lines, And can effectively reduce the conversion effect between the differential mode and the common mode, you can consider the numerical analysis of the coupled circuit structure of Figure 2.

As shown in FIG. 2, it is a set of sub-wavelength periodic opening grooves, and the first microstrip line 11 and the second microstrip line 12 are combined with another conventional differential pair (the width of each microstrip line is w ₄ ). Coupling circuit. The differential signal is input by the first port 13, and the output of the second port 14 is analyzed, that is, S _{dd 21} can understand the transmission capability of the differential pair. Input from the first port 13 analyzes the output of the fourth port 23 to understand the crosstalk between the differential pair and the adjacent conventional differential pair. The interval between the first set of differential pairs and the second set of differential pair microstrip lines is w ₂ , the differential pair signal is entered by the first port 13, and the transmission capability output by the second port 14 is represented by the S parameter is S _{dd 21} , the differential pair The signal is entered by the first port 13, and the crosstalk effect output by the fourth port 23 of the conventional differential pair is represented by the S parameter as S _{dd 41} and the differential pair signal is entered by the first port 13. The effect of the differential mode to common mode output by the second port 14 is represented by the S parameter as S _{cd 21} , where conventionally the effect of transmission and crosstalk of the two smooth sets of differential pairs is indicated by a solid line, where the dashed line indicates One group is a sub-wavelength periodic structure differential pair, and the other group is the effect of transmission and crosstalk of a conventional differential pair. As shown in Fig. 3 and Fig. 4, the simulated parameters are: w = w ₁ = w ₂ = w ₃ = w ₄ = 1.2 mm, the total length of the microstrip line is 10 cm, the material of the substrate 21 is RO4003, and the thickness of the metal film is t = 0.0175 mm, plate thickness h = 0.508 mm, groove depth b = 0.6 w , cycle length d = 1.0 mm, analysis range from 200 MHz to 12 GHz. In FIG. 2, the first port 13 is a differential input signal for two microstrip lines; the second port 14 is the receiving end of the differential pair, the third port 22 is the near end of the conventional differential pair, and the fourth port 23 is the conventional differential. The far end of the pair, where S _{dd 21 of} FIG. 3 represents the signal transmission capability of the differential pair, and S _{dd 41} represents the crosstalk of the differential pair and the adjacent another differential pair, where S _{cd 21 of} FIG. 4 represents the differential mode signal and the common mode. Signal conversion effect.

The first embodiment shows the results of the conventional differential pair as shown in the solid lines of Figs. 3 and 4. As shown in FIG. 3, the transmission capability of the conventional differential pair signal from the first port 13 to the second port 14 is represented by the S parameter: S _{dd 21.} At a frequency of 200 MHz, S _{dd 21} = -0.08821 dB at a frequency of 12 GHz. Lower S _{dd 21} = -2.32492dB. As shown in FIG. 3, the crosstalk effect of the conventional differential differential pair signal from the first port 13 to the output of the conventional differential pair fourth port 23 is represented by the S parameter: S _{dd 41} , S _{dd 41} = -48.55245 at 200 MHz, at 12 GHz S _{dd 41} = -9.38157dB. As shown in FIG. 4, the effect of the differential pair signal entering the differential mode common mode output by the first port 13 from the second port 14 is represented by the S parameter: S _{cd 21} at 12 GHz S _{cd 21} = -12.37439.

In the first embodiment, one set is a sub-wavelength period outer open groove type differential pair and the other set is a conventional differential pair result, as shown by the dashed lines in FIGS. 3 and 4. As shown in FIG. 3, the transmission capability of the differential pair signal from the first port 13 to the second port 14 is represented by the S parameter: S _{dd 21} , S _{dd 21} = -0.07573 dB at a frequency of 200 MHz, at a frequency of 12 GHz. S _{dd 21} = -1.21404dB. As shown in FIG. 3, the crosstalk effect of the differential pair signal entering from the first port 13 by the conventional differential pair fourth port 23 is represented by the S parameter: S _{dd 41} , S _{dd 41} = -60.6408 dB at 200 MHz, at 12 GHz S _{dd 41} = -29.62501 dB, and the maximum crosstalk from 1 GHz to 10 GHz is S _{dd 41} = -34.538 dB at 5.1 GHz. As shown in FIG. 4, the effect of the differential pair signal entering the differential mode common mode output by the first port 13 from the second port 14 is represented by the S parameter: S _{cd 21} at 12 GHz S _{cd 21} = -27.66008 dB.

The comprehensive comparison results of the outer open groove type differential pair and the conventional differential pair in the first embodiment are shown in Figs. 3 and 4 . As shown in Fig. 3, at 12 GHz, the conventional differential pair S _{dd 21} = -3.22492 dB, and the sub-wavelength periodic differential pair S _{dd 21} = -1.21404 dB, the transmission capability is significantly improved in the case of high frequency signals. As shown in FIG. 3, the crosstalk S _{dd 41} = -9.38157 dB between the conventional differential pairs of 12 GHz and the subwavelength period differential pair S _{dd 41} = -29.62501 dB, and the crosstalk is remarkably suppressed. As shown in Fig. 4, the effect of the conventional differential-difference mode-to-common mode at 12 GHz is 12 GHz S _{cd 21} = -12.37439 dB, and the sub-wavelength period difference pair S _{cd 21} = -27.66008 dB, and the differential mode-to-common mode effect is suppressed. Auxiliary Description: Figure 3 is the S-parameter calculation result of the coupling circuit of Figure 2. Considering the numerical results of Figure 3, the S _{dd 21 of the} conventional differential pair is represented by a solid line, which is -0.08821 dB at 200 MHz and -3.22492 dB at 12 GHz. The sub-wavelength period outside the open groove type differential pair S _{dd 21} is indicated by a broken line, which is -0.07573dB at 200MHz and -1.21404dB at 12GHz. It is obvious that the subwavelength periodic structure has better transmission capability and better for electromagnetic fields. constraint. Due to this strong constraint on the electromagnetic field, the open-difference differential pair on the outer side of the sub-wavelength period will obviously have lower interference for the adjacent microstrip line. As the frequency increases, crosstalk becomes more and more obvious. At 12 GHz, the crosstalk of the conventional differential structure to another conventional differential pair S _{dd 41} is -9.38157 dB, while the subwavelength period outside the grooved differential pair and the traditional differential pair crosstalk S _{dd 41 is} only -29.62501dB, which has obvious crosstalk resistance. Figure 4 shows the variation of the differential mode to common mode with frequency in the coupled circuit. As the frequency increases, the effect of differential mode to common mode is more pronounced. However, if the differential pair is engraved with a sub-wavelength period outside the open groove type corrugation, the effect of the conversion can be effectively suppressed. The effect of the differential mode to common mode signal of the conventional differential pair is S _{cd 21} = -12.37439 dB at 12 GHz, and the effect of the differential mode to common mode signal of the open differential groove pair on the outer side of the subwavelength period is only S _{cd 21} =- 27.66008dB, it is obvious that the sub-wavelength periodic structure can effectively suppress the conversion efficiency of the differential mode to the common mode.

The present invention provides the subwavelength period outer hairpin differential pair of the second embodiment, as shown in FIG. 5, two The sub-wavelength periodic microstrip line forms a differential pair, the signal is input by the first port 13, and the output is the second port 14, one of which is the first microstrip line 11 sends the signal, and the other is the second differential of the same differential pair. The strip line 12 is fed with a phase difference of 180° signal (two complementary signals), and the outer hairpin differential pair structure has a continuous z-shaped protrusion 20 having a continuous periodic structure, and the plurality of Z-shaped protrusions 20, a first extension portion 17 is attached to each of the openings of the recess, and extends to a center of each of the recesses, a first extension portion 17; and a second extension portion 18, which is attached to each of the recesses The middle portion of the Z-shaped convex body 20 extends in parallel to the center of each of the grooves; wherein the first extending portion 17 and the second extending portion 18 extend in opposite directions.

The width of the microstrip line: w , the spacing of the two microstrip lines: w ₁ , the thickness of the metal: t , the thickness of the substrate 21 is: h , the period length of the periodic microstrip line: d , the groove depth of the periodic microstrip line : b , dielectric constant of the substrate 21 medium: ε _r , other structural parameters a ₁ , a ₂ (width of the outer opening groove), a ₃ (width of the inner opening groove), b ₁ (width of the metal strip), b ₂ (interval of thin metal strips). When a single-ended microstrip line or another differential pair appears next to this traditional (smooth) differential pair, there are two distinct effects, the first effect being apparent from the first port 13 to the second port 14. The effect of differential mode to common mode. The second effect is that the complementary signal input by the first port 13 will crosstalk on another microstrip line or differential pair. In order to prove that this sub-wavelength periodic differential pair has the effect of suppressing the crosstalk between adjacent microstrip lines and effectively reducing the conversion effect between the differential mode and the common mode, the numerical analysis of the coupling circuit structure of FIG. 7 can be considered. Figure 7 is a set of sub-wavelength periodic hairpin differential pairs and a conventional differential pair. The differential signal is input by the first port 13, and the second port 14 output is analyzed, that is, S _{dd 21} can understand the transmission capability of the differential pair. It is input by the first port 13. Analysis of the output of the fourth port 23 can be used to understand the crosstalk between the differential pair and the conventional differential pair. The edge spacing of the two sets of differential pairs: w ₂ , the differential pair signal is entered by the first port 13, and the transmission capability output by the second port 14 is represented by the S parameter: S _{dd 21} , the differential pair signal is entered by the first port 13 by the conventional The crosstalk effect of the differential pair fourth port 23 output is represented by the S parameter: S _{dd 41} , the effect of the differential pair signal entering the differential mode common mode output by the first port 13 from the second port 14 is represented by the S parameter: S _{cd 21} The effect of conventionally representing the transmission and crosstalk between all smooth paired pairs is indicated by the solid line. The dotted line indicates the effect of transmission and crosstalk of the sub-wavelength periodic structure differential pair. Simulated parameters: w = w ₁ = w ₂ = w ₃ = w ₄ = 1.2 mm, the total length of the microstrip line is 10 cm, the material of the substrate 21 is made of RO4003, the thickness of the metal film is t = 0.0175 mm, and the thickness of the plate is h = 0.508 Mm, groove depth b = 0.6 w , cycle length d = 1.0 mm, analysis range from 200 MHz to 12 GHz. In Figure 7, a complementary differential signal is input to the two microstrip lines of the first port 13, the second port 14 is the receiving end of the differential pair, the third port 22 is the proximal end of the conventional differential pair, and the fourth port 23 represents the conventional The far end of the differential pair. In Figure 8, the simulated parameters are: w = w ₁ = w ₂ = w ₃ = w ₄ = 1.2 mm, the total length of the microstrip line is 10 cm, the material of the substrate 21 is made of RO4003, the thickness of the metal film is t = 0.0175 mm, the plate Thickness h = 0.508 mm, groove depth b = 0.6 w , period length d = 1.0 mm, analysis range from 200 MHz to 12 GHz, S _{dd 21} indicates signal transmission capability, and S _{dd 41} indicates sub-wavelength periodic differential pair and conventional difference The crosstalk. In Figure 9, the simulated parameters are: w = w ₁ = w ₂ = w ₃ = w ₄ = 1.2 mm, the total length of the microstrip line is 10 cm, the material of the substrate 21 is made of RO4003, the thickness of the metal film is t = 0.0175 mm, the plate Thickness h =0.508 mm, groove depth b = 0.6 w , period length d = 1.0 mm, analysis range from 200 MHz to 12 GHz, S _{cd 21} represents the conversion effect of differential mode signal and common mode signal.

The results of the coupling circuit of the two sets of conventional differential pairs of the second embodiment are shown by solid lines in Figs. 8 and 9. As shown in FIG. 8, where the differential pair signal is entered by the first port 13, the transmission capability output by the second port 14 is represented by the S parameter: S _{dd 21} . At a frequency of 200MHz S _{dd 21} = -0.08821dB, at a frequency of 12GHz S _{dd 21} = -2.32492dB. As shown in FIG. 8, where the differential pair signal is entered by the first port 13, the crosstalk effect output by the conventional differential pair fourth port 23 is represented by the S parameter: S _{dd 41} , S _{dd 41} = -48.55245 dB at 200 MHz, 12 GHz Lower S _{dd 41} = -9.38157dB. As shown in FIG. 9, the effect of the differential pair signal being input from the first port 13 into the differential mode common mode output by the second port 14 is represented by the S parameter: S _{cd 21} at 12 GHz S _{cd 21} = -12.37439 dB.

In the second embodiment, one set is the sub-wavelength period outer hairpin differential pair and the other set is the result of the conventional differential pair, as shown by the dashed lines in FIGS. 8 and 9.

As shown by the dashed line in Fig. 8, where the differential pair signal is entered by the first port 13, the output capability output by the second port 14 is represented by the S parameter: S _{dd 21.} At a frequency of 200 MHz, S _{dd 21} = -0.09344 dB, at S _{dd 21} = -1.20989 dB at a frequency of 12 GHz. As shown in FIG. 8, where the differential pair signal is entered by the first port 13, the crosstalk effect output by the conventional differential pair fourth port 23 is represented by the S parameter: S _{dd 41} , S _{dd 41} = -63.57423 dB at 200 MHz, 12 GHz Lower S _dd41 = -33.33179dB. As shown in FIG. 9, the effect of the differential pair signal being input from the first port 13 into the differential mode common mode output by the second port 14 is represented by the S parameter: S _{cd 21} , S _{cd 21} = -35.91338 dB at 12 GHz.

The comparison result between the conventional differential pair and the sub-wavelength period outer hairpin differential pair of the second embodiment is shown in Figs. As shown in FIG. 8, in the 12 GHz group, S _{dd 21} = -3.22492 dB of the conventional differential pair, and the sub-wavelength period differential pair S _{dd 21} = -1.20989 dB. Transmission capacity is significantly improved in the case of high frequency signals. As shown in FIG. 8, where the crosstalk of the conventional differential pair at 12 GHz and another conventional differential pair S _{dd 41} = -9.38157 dB, the crosstalk of the subwavelength period differential pair to the conventional differential pair S _{dd 41} = -33.33179 dB, crosstalk Significant inhibition is obtained. As shown in Figure 9, where the conventional differential-difference mode-to-common mode effect at 12 GHz has an effect of 12 GHz S _{cd 21} = -12.37439 dB, sub-wavelength periodic differential pair S _{cd 21} = -35.91338 dB, differential mode to common mode The effect is suppressed. Auxiliary Description: Figure 8 is the S-parameter calculation result of the coupling circuit of Figure 7. Considering the numerical results of Fig. 8, the Sd _{dd 21 of the} conventional differential pair is indicated by a solid line, which is -0.08821 dB at 200 MHz and -3.22492 dB at 12 GHz. The S _{dd 21 of the} outer pair of hairpin differential pairs of the sub-wavelength period is indicated by a broken line, which is -0.09344 dB at 200 MHz and -1.20989 dB at 12 GHz. The conventional differential pair has a slightly superior transmission capability at a lower frequency. However, as the frequency increases, the transmission capacity of the subwavelength periodic structure is better, and the electromagnetic field has better constraints. Due to this strong constraint on the electromagnetic field, the sub-wavelength period outer hairpin differential pair will obviously have lower interference for the adjacent microstrip line. As the frequency increases, crosstalk becomes more and more obvious. The crosstalk S _{dd 41} of the conventional differential structure for another conventional differential pair at 12 GHz is -9.38157 dB. The crosstalk between the outer side of the subwavelength period and the crosstalk of another conventional differential pair S _{dd 41 is} only -33.33179dB, which has obvious crosstalk resistance. Figure 9 is a graph showing the variation of the differential mode to common mode with frequency in the coupled circuit. As the frequency increases, the effect of differential mode to common mode is more obvious. However, if the differential pair is engraved with the outer wave clip ripple of the sub-wavelength period, the effect of the conversion can be effectively suppressed. The differential mode of the conventional differential pair is common mode. The effect of the signal is -12.37439dB at 12GHz, and the effect of the differential-mode common-mode signal on the outer-band differential pair of sub-wavelength period is only -35.91338dB. Obviously, the sub-wavelength periodic structure can effectively suppress the differential mode to common mode. Conversion efficiency.

The present invention provides the outer groove differential pair of the third embodiment. As shown in FIG. 10, the two sub-wavelength periodic microstrip lines form a differential pair, and the signal is input by the first port 13, and the output is the second port 14, wherein the first The microstrip line 11 feeds the signal, and the other is that the second microstrip line 12 sends a phase difference of 180° signal (two complementary signals), and the outer groove differential pair structure, the structure of the plurality of grooves The structure has a rectangular concave body 15 combined with a rectangular convex body 16 in a continuous periodic structure, and the distance between adjacent rectangular convex bodies 16 is the periodic arrangement length of the plurality of concave grooves. The width of the microstrip line: w , the spacing of the two microstrip lines: w ₁ , the thickness of the metal: t , the thickness of the substrate 21 is: h , the period length of the periodic microstrip line: d , the groove depth of the periodic microstrip line : b , the dielectric constant of the substrate 21 medium: ε _r , when there is a single-ended microstrip line or another set of differential pairs next to this traditional (smooth) differential pair, there are two distinct effects, the first effect A significant differential mode to common mode effect will occur from the first port 13 to the second port 14. The second effect is that the complementary signal input by the first port 13 will crosstalk on another microstrip line or differential pair.

In order to prove that the sub-wavelength periodic differential pair has suppression of crosstalk between adjacent microstrip lines or differential pairs, and can effectively reduce the conversion effect between the differential mode and the common mode, the numerical analysis of the coupling circuit structure of FIG. 11 can be considered. 11 is a coupling circuit of a pair of sub-wavelength period outer groove differential pairs and a conventional differential pair, the differential signal is input by the first port 13, and the second port 14 output is analyzed, that is, S _{dd 21} can understand the transmission capability of the differential pair. . The input from the first port 13 analyzes the output of the fourth port 23 to understand the crosstalk between the differential pair and the adjacent conventional differential pair. As shown in FIG. 11, the sub-wavelength periodic microstrip line is spaced from the edge of the conventional differential pair: w ₂ , the differential pair signal is entered by the first port 13, and the transmission capability output by the second port 14 is represented by the S parameter: S _{dd 21} The crosstalk effect of the differential pair signal entering from the first port 13 by the conventional differential pair fourth port 23 is represented by the S parameter: S _{dd 41} , the differential pair signal is entered by the first port 13 and the differential mode output by the second port 14 The effect of the common mode is represented by the S parameter: S _{cd 21} , where conventional means that the transmission and crosstalk effects of the two pairs of all smooth differential pairs are indicated by solid lines, wherein the dashed line indicates the transmission capability of the differential pair of sub-wavelength periodic structures. And the crosstalk effect with the traditional differential pair, the simulated parameters: w = w ₁ = w ₂ = w ₃ = w ₄ = 1.2mm, the total length of the microstrip line is 10cm, the material of the substrate 21 is RO4003, the thickness of the metal film t = 0.0175 mm, plate thickness h = 0.508 mm, groove depth b = 0.6 w , cycle length d = 1.0 mm, analysis range from 200 MHz to 12 GHz, first port 13 is differential pair of two microstrip line inputs complementary Differential signal, the second port 14 is a differential pair receiving , The proximal third port 22 represents a conventional differential pair, the distal end of the fourth port 23 represents a conventional differential pair. Figure 12 shows the simulated parameters: w = w ₁ = w ₂ = w ₃ = w ₄ = 1.2 mm, the total length of the microstrip line is 10 cm, the material of the substrate 21 is RO4003, and the thickness of the metal film is t = 0.0175 mm. The plate thickness h = 0.508 mm, the groove depth b = 0.6 w , the cycle length d = 1.0 mm, and the analysis ranged from 200 MHz to 12 GHz. S _{dd 21} represents the transmission capability of the signal, and S _{dd 41} represents the crosstalk of the differential pair and the adjacent conventional differential pair. Figure 13, the simulated parameters: w = w ₁ = w ₂ = w ₃ = w ₄ = 1.2mm, the total length of the microstrip line is 10cm, the substrate 21 is made of RO4003 material, the thickness of the metal film is t = 0.0175mm, The plate thickness h = 0.508 mm, the groove depth b = 0.6 w , the cycle length d = 1.0 mm, and the analysis ranged from 200 MHz to 12 GHz. S _{cd 21} represents the conversion effect of the differential mode signal and the common mode signal.

The present invention provides the results of the two pairs of conventional differential pair coupling circuits of the third embodiment as shown by the solid lines in FIGS. 12 and 13. As shown in FIG. 12, in which the differential pair signal is entered by the first port 13, the transmission capability output by the second port 14 is represented by the S parameter: S _{dd 21.} At a frequency of 200 MHz, S _{dd 21} = -0.08821 dB, at the frequency S _{dd 21} = -2.32492 dB at 12 GHz. As shown in FIG. 12, the crosstalk effect of the differential pair signal entering from the first port 13 by the conventional differential pair fourth port 23 is represented by the S parameter: S _{dd 41} , S _{dd 41} = -48.55245 dB at 200 MHz, at 12 GHz S _{dd 41} = -9.38157dB. As shown in FIG. 13, the effect of the differential pair signal being input from the first port 13 into the differential mode common mode output by the second port 14 is represented by the S parameter: S _{cd 21} at 12 GHz S _{cd 21} = -12.37439 dB.

The present invention provides the result of the coupling circuit of the outer groove differential pair and the conventional differential pair of the third embodiment as shown by the dashed lines in FIGS. 12 and 13. As shown in FIG. 12, the transmission capability of the differential pair signal from the first port 13 to the second port 14 is represented by the S parameter: S _{dd 21.} At a frequency of 200 MHz, S _{dd 21} = -0.07265 dB at a frequency of 12 GHz. Lower S _{dd 21} = -1.14271dB. As shown in FIG. 12, the crosstalk effect of the differential pair signal entering from the first port 13 by the conventional differential pair fourth port 23 is represented by the S parameter: S _{dd 41} , S _{dd 41} = -61.53771 dB at 200 MHz, at 12 GHz Lower S _{dd 41} = -36.11641 dB, and the maximum crosstalk from 1 GHz to 10 GHz is S _{dd 41} = -32.2849 dB at 5.36 GHz. As shown in FIG. 13, where the differential pair signal is entered by the first port 13, the effect of the differential mode to common mode output by the second port 14 is represented by the S parameter: S _{cd 21} at 12 GHz S _{cd 21} = -19.69095 dB.

This creation provides a comparison result between the outer groove differential pair of the third embodiment and the conventional differential pair, as shown in FIGS. 12 and 13. As shown in FIG. 12, where the conventional differential pair S _{dd 21} = -2.32492 dB at 12 GHz and the sub-wavelength periodic differential pair S _{dd 21} = -1.114271 dB, the transmission capability is significantly improved in the case of high frequency signals. As shown in FIG. 12, in which the crosstalk S _{dd 41} = -9.38157 dB between the two pairs of conventional differential pairs at 12 GHz, the sub-wavelength periodic differential pair and the conventional differential pair S _{dd 41} = -36.11641 dB, the crosstalk is significantly suppressed. . As shown, where S 12GHz 12GHz when a conventional differential effects of differential mode to common mode of transfer _cd 13 ₂₁ = _-12.37439dB, subwavelength periodic differential pair S _{cd 21} = -19.69095dB, common mode differential mode switch The effect is suppressed. Auxiliary Description: Figure 12 is the S-parameter calculation result of the coupling circuit of Figure 11. Considering the numerical results of Figure 12, the traditional differential pair S _{dd 21} is represented by a solid line, which is -0.08821dB at 200MHz and -3.22492dB at 12GHz. The S _{dd 21 of the} differential pair of grooves outside the wavelength period is indicated by a broken line, which is -0.07265dB at 200MHz and -1.114271dB at 12GHz. At lower frequencies, the subwavelength period differential pairs have a slightly better transmission capability, and With the increase of frequency, the transmission capacity of sub-wavelength periodic structure is better, and it has better constraints on electromagnetic field. Due to this strong constraint on electromagnetic field, the differential pair of outer-wavelength periodic sub-wavelength is smooth for adjacent microstrip lines or traditional The differential pair will obviously have lower interference. As the frequency increases, crosstalk becomes more and more obvious. At 12 GHz, the traditional differential structure has a crosstalk S _{dd 41} of -9.38157 dB for another conventional differential pair, while the subwavelength period is concave outside. The crosstalk between the slot differential pair and the traditional differential pair S _{dd 41 is} only -36.11641dB, which has obvious anti-crosstalk effect. Figure 13 shows the variation of the differential mode to common mode with frequency in the coupled circuit. As the frequency increases, the difference Modular common mode effect Is becoming increasingly obvious, however, if differential pair engraved outer groove subwavelength periodic corrugation, the effect of conversion can be effectively suppressed. Conventional differential rotation of the differential-mode effects in the common-mode signal is 12GHz S _{cd 21} = -12.37439dB, However, the effect of the differential mode to common mode signal of the differential pair on the outer side of the subwavelength period is only S _{cd 21} = -19.69095 dB. Obviously, the subwavelength periodic structure can effectively suppress the conversion efficiency of the differential mode to the common mode.

The present invention provides a double-sided open groove differential pair of the fourth embodiment, as shown in FIGS. 14 and 15. The two sub-wavelength periodic microstrip lines form a differential pair, the signal is input by the first port 13, and the output is the second port 14, one of which is the first microstrip line 11 sends the signal, and the other is the second microstrip. The line 12 is fed with a phase difference of 180° signal (two complementary signals), and in the structure of the double-sided open groove type differential pair, the structure of the plurality of grooves has a rectangular concave body 15 combined with one The rectangular protrusions 16 have a continuous periodic structure, and at each opening of the groove, each of the rectangular protrusions 16 has two first extensions 17 extending in parallel to the center of each of the grooves. width of the microstrip line is w, the interval is two microstrip lines w _1, the thickness of the two metal microstrip line is t, the thickness of the substrate 21 to cycle length h, the cycle of the microstrip line is d, periodic microstructures The groove depth of the strip line is b , and the dielectric constant of the medium of the substrate 21 is ε _r . When a single-ended microstrip line or another differential pair appears next to the conventional smooth grooveless differential pair, there are two distinct Effect, the first effect is that there will be significant differential mode to common mode effect from the first port 13 to the second port 14. . The second effect is that the complementary signal input by the first port 13 will cause crosstalk on the other microstrip line or differential pair, in order to prove that the sub-wavelength periodic differential pair has suppression of crosstalk between adjacent microstrip lines, And can effectively reduce the conversion effect between the differential mode and the common mode, you can consider the coupling circuit structure of Figure 15 for numerical analysis.

As shown in FIG. 15, it is a coupling circuit of a set of sub-wavelength periodic double-sided open grooves, a first microstrip line 11 and a second microstrip line 12 and a conventional differential pair. The differential signal is input by the first port 13, and the second port 14 output is analyzed, that is, S _{dd 21} can understand the transmission capability of the differential pair. Input from the first port 13, analyzing the output of the fourth port 23, can be used to understand the crosstalk between the differential pair and the adjacent conventional differential pair. The interval between the conventional differential pair and the edge of the second microstrip line 12 is w ₂ , and the transmission capability of the differential pair signal from the first port 13 to the output by the second port 14 is represented by the S parameter as S _{dd 21} , and the differential pair signal is The crosstalk effect of a port 13 entering the output of the fourth port 23 by the conventional differential pair is represented by the S parameter as S _{dd 41} , and the differential pair signal is input from the first port 13 into the differential mode of the common mode output by the second port 14 by S. The parameter is denoted as S _{cd 21} , where conventionally the effect of transmission and crosstalk of all smooth differential pairs is indicated by a solid line, where the dashed line represents the effect of transmission and crosstalk of sub-wavelength periodic structure differential pairs. As shown in Fig. 16 and Fig. 17, the simulated parameters are: w = w ₁ = w ₂ = w ₃ = w ₄ = 1.2 mm, the total length of the microstrip line is 10 cm, the material of the substrate 21 is RO4003, and the thickness of the metal film t = 0.0175 mm, plate thickness h = 0.508 mm, groove depth on both sides is b = 0.3 w , cycle length d = 1.0 mm, and the range of analysis is from 200 MHz to 12 GHz. In Figure 15, the first port 13 is a differential input signal for two microstrip lines; the second port 14 is the receiving end of the differential pair, the third port 22 is the near end of the conventional differential pair, and the fourth port 23 is the conventional differential. The far end of the pair, where S _{dd 21 of} Fig. 16 represents the transmission capability of the signal, and S _{dd 41} represents the crosstalk of the differential pair and the adjacent conventional differential pair, wherein S _{cd 21 of} Fig. 17 represents the conversion of the differential mode signal and the common mode signal. effect.

In the fourth embodiment, the results of the two sets of differential pairs being the conventional differential pair are shown by the solid lines in FIGS. 16 and 17. As shown in FIG. 16, the transmission capability in which the differential pair signal is input from the first port 13 to the second port 14 is represented by an S parameter: S _{dd 21} . At a frequency of 200MHz S _{dd 21} = -0.08821dB, at a frequency of 12GHz S _{dd 21} = -2.32492dB. As shown in FIG. 16, the crosstalk effect of the differential pair signal entering from the first port 13 by the conventional differential pair fourth port 23 is represented by the S parameter: S _{dd 41} , S _{dd 41} = -48.55245 dB at 200 MHz, at 12 GHz S _{dd 41} = -9.38157dB. As shown in FIG. 17, the effect of the differential pair signal being input from the first port 13 into the differential mode common mode output by the second port 14 is represented by the S parameter: S _{cd 21} , S _{cd 21} = -12.37439 dB at 12 GHz.

The results of the sub-wavelength double-sided open groove differential pair and the conventional differential pair coupling circuit of the fourth embodiment are shown by the broken lines in Figs. As shown in FIG. 16, the transmission capability of the differential pair signal from the first port 13 to the second port 14 is represented by the S parameter: S _{dd 21.} At a frequency of 200 MHz, S _{dd 21} = -0.07977 dB at a frequency of 12 GHz. Lower S _{dd 21} = - 1.0001 dB. As shown in FIG. 16, the crosstalk effect of the differential pair signal entering from the first port 13 by the conventional differential pair fourth port 23 is represented by the S parameter: S _{dd 41} , S _{dd 41} = -49.2638 dB at 200 MHz, at 12 GHz Lower S _{dd 41} = -30.72547 dB, and the maximum crosstalk from 1 GHz to 10 GHz is S _{dd 41} = -24.5046 dB at 5.26 GHz. As shown in FIG. 17, the effect of the differential pair signal being input from the first port 13 into the differential mode to the common mode by the second port 14 is represented by the S parameter: S _{cd 21} , S _{cd 21} = -28.37445 dB at 12 GHz.

The comparison results of the sub-wavelength double-sided open groove type differential pair and the conventional differential pair of the fourth embodiment are shown in Figs. 16 and 17 . As shown in FIG. 16, where the conventional differential pair S _{dd 21} = -3.22492 dB at 12 GHz and the sub-wavelength periodic differential pair S _{dd 21} = - 1.0001 dB, the transmission capability is significantly improved in the case of high frequency signals. As shown in Figure 16, where the crosstalk between the 12 GHz conventional differential pair and another conventional differential pair S _{dd 41} = -9.38157 dB, the crosstalk between the subwavelength periodic differential pair and the conventional differential pair S _{dd 41} = -30.72547 dB, crosstalk is clearly suppressed. As shown in Figure 17, the effect of the conventional differential-difference-mode common-mode at 12 GHz is 12 GHz S _{cd 21} = -12.37439 dB, and the sub-wavelength period differential pair S _{cd 21} = -28.37445 dB, and the differential mode-to-common mode effect is suppressed. . Auxiliary Description: Figure 16 is the S-parameter calculation result of the coupling circuit of Figure 15. Considering the numerical results of Fig. 16, the S _{dd 21 of the} conventional differential pair is indicated by a solid line, which is -0.08821 dB at 200 MHz and -3.22492 dB at 12 GHz. The sub-wavelength period double-sided open-groove differential pair S _{dd 21} is indicated by a broken line, which is -0.07977dB at 200MHz and -1.0001dB at 12GHz. Obviously, the sub-wavelength periodic structure has better transmission capability and better electromagnetic field. Constraint. Due to this strong constraint on the electromagnetic field, the sub-wavelength periodic double-sided open groove differential pair will obviously have lower interference for adjacent microstrip lines. As the frequency increases, crosstalk becomes more and more obvious. At 12 GHz, the traditional differential structure has a crosstalk S _{dd 41} of -9.38157 dB for another conventional differential structure, while the subwavelength period has a double-sided open groove differential pair and a conventional differential structure. Crosstalk S _{dd 41 is} only -30.72547dB with obvious crosstalk immunity. Figure 17 is a graph showing the variation of the differential mode to common mode with frequency in the coupled circuit. As the frequency increases, the effect of differential mode to common mode is more pronounced. However, if the differential pair is engraved with a sub-wavelength period double-sided open groove corrugation, the effect of the conversion can be effectively suppressed. The effect of differential mode to common mode signal of traditional differential pair is S _{cd 21} =-12.37439dB at 12GHz, while the effect of differential mode to common mode signal of sub-wavelength period double-sided open groove differential pair is only S _{cd 21} = -28.37445dB, it is obvious that the sub-wavelength periodic structure can effectively suppress the conversion efficiency of the differential mode to the common mode.

In the fifth embodiment, the sub-wavelength period double-sided groove type differential pair, as shown in FIG. 18, the two sub-wavelength periodic microstrip lines form a differential pair, the signal is input by the first port 13, and the output is the second port 14, wherein One is that the first microstrip line 11 sends a signal, and the other is that the second microstrip line 12 sends a signal with a phase difference of 180° (two complementary signals), in a double-sided groove differential pair structure, The structure of the plurality of grooves has a rectangular concave body 15 combined with a rectangular convex body 16 having a continuous periodic structure, and the distance between the adjacent rectangular convex bodies 16 is a periodic arrangement of the plurality of concave grooves. length. The width of the microstrip line: w , the spacing of the two microstrip lines: w ₁ , the thickness of the metal: t , the thickness of the substrate 21 is: h , the period length of the periodic microstrip line: d , the groove depth of the periodic microstrip line : b , dielectric constant of the substrate 21 medium: ε _r , groove width: a . When a single-ended microstrip line or another differential pair appears next to this traditional (smooth) differential pair, there are two distinct effects, the first effect being apparent from the first port 13 to the second port 14 The effect of differential mode to common mode. The second effect is that the complementary signal input by the first port 13 will crosstalk on another microstrip line or differential pair. In order to prove that this sub-wavelength periodic differential pair has the effect of suppressing the crosstalk between adjacent microstrip lines and effectively reducing the conversion effect between the differential mode and the common mode, the numerical analysis of the coupling circuit structure of FIG. 19 can be considered. A set of sub-wavelength period double-sided groove type differential pair and single-ended microstrip line coupling circuit, the differential signal is input by the first port 13, and the second port 14 output is analyzed, that is, S _{dd 21} can understand the transmission of the differential pair ability. The input from the first port 13 analyzes the output of the fourth port 23 to understand the crosstalk between the differential pair and the adjacent single-ended microstrip line. As shown in FIG. 19, the interval between the single-ended microstrip line and the differential pair: w ₂ , the transmission capability of the differential pair signal from the first port 13 to the second port 14 is represented by the S parameter: S _{dd 21} , differential pair signal The crosstalk effect outputted by the first port 13 into the fourth port 23 of the single-ended microstrip line is represented by the S parameter: S _{sd 41} , the differential pair signal is entered by the first port 13 into the differential mode common mode output by the second port 14. The effect is represented by the S parameter: S _{cd 21} , where conventionally indicates that the transmission and crosstalk effects of all smooth differential pairs are represented by solid lines, where the dashed lines represent the effects of transmission and crosstalk of subwavelength periodic differential pairs, simulating Parameters: w = w ₁ = w ₂ = w ₃ = 1.2 mm, the total length of the microstrip line is 10 cm, the material of the substrate 21 is RO4003, the thickness of the metal film is t = 0.0175 mm, the thickness of the plate is h = 0.508 mm, and the groove depth is b = 0.3 w , the period length d = 1.0 mm, the range of analysis is from 200 MHz to 12 GHz, the first port 13 is a complementary differential signal input by two microstrip lines, the second port 14 is the receiving end of the differential pair, and the third Port 22 represents the near end of the single-ended microstrip line, and fourth port 23 represents the single-ended micro The far end with the line. Figure 20 shows the simulated parameters: w = w ₁ = w ₂ = w ₃ = 1.2 mm, the total length of the microstrip line is 10 cm, the material of the substrate 21 is RO4003, the thickness of the metal film is t = 0.0175 mm, and the thickness h =0.508 mm, groove depth b = 0.3 w , cycle length d = 1.0 mm, analysis range from 200 MHz to 12 GHz. S _{dd 21} represents the transmission capability of the signal, and S _{sd 41} represents the crosstalk of the differential pair and the adjacent single-ended microstrip line. Figure 21 shows the simulated parameters: w = w ₁ = w ₂ = w ₃ = 1.2 mm, the total length of the microstrip line is 10 cm, the material of the substrate 21 is RO4003, the thickness of the metal film is t = 0.0175 mm, and the thickness h =0.508 mm, groove depth b = 0.3 w , cycle length d = 1.0 mm, d = 2a, analysis range from 200 MHz to 12 GHz. S _{cd 21} represents the conversion effect of the differential mode signal and the common mode signal.

The results of the present invention providing the conventional differential pair and single-ended microstrip line coupling circuit of the fifth embodiment are shown by the solid lines in FIGS. 20 and 21. As shown in FIG. 20, the transmission capability of the differential pair signal from the first port 13 to the second port 14 is represented by the S parameter: S _{dd 21.} At a frequency of 200 MHz, S _{dd 21} = -0.0679 dB at a frequency of 12 GHz. Lower S _{dd 21} = -2.336253 dB. As shown in FIG. 20, the crosstalk effect of the differential pair signal entering from the first port 13 to the fourth port 23 outputted by the single-ended microstrip line is represented by the S parameter: S _{sd 41} , S _{sd 41} = -42.63854 dB at 200 MHz, S _{sd 41} = -6.55742 dB at 12 GHz. As shown in FIG. 21, the effect of the differential pair signal being input from the first port 13 into the differential mode common mode output by the second port 14 is represented by the S parameter: S _{cd 21} , S _{cd 21} =-12.96263 dB at 12 GHz.

The present invention provides the results of the double-sided groove type differential pair and the single-ended microstrip line coupling circuit of the fifth embodiment as shown by the dotted lines in FIGS. 20 and 21. As shown in FIG. 20, the transmission capability of the differential pair signal from the first port 13 to the second port 14 is represented by the S parameter: S _{dd 21.} At a frequency of 200 MHz, S _{dd 21} = -0.10201 dB at a frequency of 12 GHz. Lower S _{dd 21} = -1.18541dB. As shown in FIG. 20, the crosstalk effect of the differential pair signal input from the first port 13 into the fourth port 23 of the single-ended microstrip line is represented by the S parameter: S _{sd 41} , S _{sd 41} = -42.82679 dB at 200 MHz, S _{sd 41} = -13.93195 dB at 12 GHz. As shown in FIG. 21, the effect of the differential pair signal being input from the first port 13 into the differential mode common mode output by the second port 14 is represented by the S parameter: S _{cd 21} , S _{cd 21} = -23.28997 dB at 12 GHz.

The present invention provides a comparison result between the double-sided groove type differential pair and the single-ended microstrip line of the fifth embodiment, as shown in FIGS. 20 and 21. As shown in FIG. 20, in the conventional differential pair S _{dd 21} = -2.336253 dB at 12 GHz, the sub-wavelength periodic differential pair S _{dd 21} = -1.18541 dB, and the transmission capability is significantly improved in the case of high frequency signals. As shown in FIG. 20, in which the crosstalk of the conventional differential pair of 12 GHz and the single-ended microstrip line S _{sd 41} = -6.55742 dB, and the sub-wavelength period differential pair S _{sd 41} = -13.93195 dB, crosstalk is remarkably suppressed. As shown in Figure 21, the conventional differential-difference mode-to-common mode effect at 12 GHz has an effect of 12 GHz S _{cd 21} = -12.96263 dB, sub-wavelength periodic differential pair S _{cd 21} = -23.28997 dB, differential mode common mode effect. Obtained inhibition. Auxiliary Description: Figure 20 is the S-parameter calculation result of the coupling circuit of Figure 19. Considering the numerical results of Fig. 20, S _{dd 21 of the} conventional differential pair is indicated by a solid line, which is -0.0679 dB at 200 MHz and -2.36253 dB at 12 GHz. The sub-wavelength period double-sided grooved differential pair S _{dd 21} is indicated by a broken line, which is -0.10201dB at 200MHz and -1.18541dB at 12GHz. At lower frequencies, the conventional differential pair has a slightly better transmission capability. As the frequency increases, the transmission capacity of the subwavelength periodic structure is better, and the electromagnetic field has better constraints. Due to this strong constraint on the electromagnetic field, the sub-wavelength periodic double-sided grooved differential pair will obviously have lower interference for adjacent microstrip lines. As the frequency increases, the crosstalk becomes more and more obvious. At 12 GHz, the crosstalk of the traditional differential structure for the single-ended microstrip line S _{sd 41} is -6.55742 dB, while the sub-wavelength period double-sided grooved differential pair and single-ended microstrip line The crosstalk S _{sd 41 is} only -13.93195 dB, which has obvious crosstalk resistance. Figure 21 is a graph showing the variation of the differential mode to common mode with frequency in the coupled circuit. As the frequency increases, the effect of differential mode to common mode is more pronounced. However, if the differential pair is engraved with a sub-wavelength period double-sided groove type corrugation, the effect of the conversion can be effectively suppressed. The effect of differential mode to common mode signal of traditional differential pair is -12.96263dB at 12GHz, while the effect of differential mode to common mode signal of sub-wavelength period double-sided grooved differential pair is only -23.28997dB. It is obvious that the sub-wavelength periodic structure can effectively suppress the conversion efficiency of the differential mode to the common mode.

The present invention provides a sub-wavelength periodic double-side hairpin differential pair according to the sixth embodiment. As shown in FIG. 22, two sub-wavelength periodic microstrip lines form a differential pair, and the signal is input by the first port 13 and the output is the second port. 14, one of which is that the first microstrip line 11 of the first differential pair feeds the signal, and the other is that the second microstrip line 12 sends a signal with a phase difference of 180° (two complementary signals), both sides The hairpin differential pair structure has a structure in which the plurality of Z-shaped protrusions 20 have a continuous periodicity, and the plurality of Z-shaped protrusions 20, a first extension portion 17, is attached to the opening of each of the grooves, to each a first extending portion 17 extending in parallel with the center of the groove; and a second extending portion 18 extending at a middle portion of each of the Z-shaped protrusions 20, extending in parallel to the center of each of the grooves; wherein The extending directions of the first extending portion 17 and the second extending portion 18 are opposite. The width of the microstrip line: w , the spacing of the two microstrip lines: w ₁ , the thickness of the metal: t , the thickness of the substrate 21 is: h , the period length of the periodic microstrip line: d , the groove depth of the periodic microstrip line : b , dielectric constant of the substrate 21 medium: ε _r , other structural parameters a ₁ , a ₂ (width of the outer opening groove), a ₃ (width of the inner opening groove), b ₁ (width of the metal strip), b ₂ (interval of thin metal strips). When a single-ended microstrip line or another differential pair appears next to this traditional (smooth) differential pair, there are two distinct effects, the first effect being apparent from the first port 13 to the second port 14. The effect of differential mode to common mode. The second effect is that the complementary signal input by the first port 13 will crosstalk on another microstrip line or differential pair. In order to prove that this sub-wavelength periodic differential pair has the effect of suppressing the crosstalk between adjacent microstrip lines and effectively reducing the switching effect between the differential mode and the common mode, the numerical analysis of the coupling circuit structure of FIG. 24 can be considered. Figure 24 is a coupling circuit of a set of sub-wavelength periodic hairpin differential pairs and single-ended microstrip lines. The differential signal is input by the first port 13, and the second port 14 output is analyzed, that is, S _{dd 21} can understand the transmission capability of the differential pair. It is input by the first port 13. Analysis of the output of the fourth port 23 can be used to understand the crosstalk between the differential pair and the single-ended microstrip line. The spacing between the single-ended microstrip line and the differential pair: w ₂ , the transmission capability of the differential pair signal from the first port 13 to the second port 14 is represented by the S parameter: S _{dd 21} , the differential pair signal is entered by the first port 13 The crosstalk effect output by the single-ended microstrip line fourth port 23 is represented by the S parameter: S _{sd 41} , the effect of the differential pair signal entering the differential mode common mode output by the first port 13 from the second port 14 is represented by the S parameter : S _{cd 21} , where conventionally indicates that the effects of transmission and crosstalk of all smooth differential pairs are indicated by solid lines. The dotted line indicates the effect of transmission and crosstalk of the sub-wavelength periodic structure differential pair. Simulated parameters: w = w ₁ = w ₂ = w ₃ = 1.2 mm, the total length of the microstrip line is 10 cm, the material of the substrate 21 is RO4003, the thickness of the metal film is t = 0.0175 mm, the thickness of the plate is h = 0.508 mm, the groove Deep b = 0.3 w , period length d = 1.0 mm, and the range of analysis is from 200 MHz to 12 GHz. In FIG. 24, two microstrip lines of the first port 13 input complementary differential signals, the second port 14 is a receiving end of the differential pair, the third port 22 is a near end of the single-ended microstrip line, and the fourth port 23 represents a single The distal end of the microstrip line. In Fig. 25, the simulated parameters are: w = w ₁ = w ₂ = w ₃ = 1.2 mm, the total length of the microstrip line is 10 cm, the material of the substrate 21 is made of RO4003, the thickness of the metal film is t = 0.0175 mm, and the thickness h = 0.508mm, groove depth b = 0.3 w ,, cycle length = 1.0mm d, 200MHz from the scope of the analysis to 12GHz, S _{dd 21} represents the signal transmission capability, S _{sd 41} represents subwavelength periodic differential pair and single ended microstrip line Crosstalk between other parameters a ₁ =0.1 d , a ₂ =0.2 d , a ₃ =0.7 d , b ₁ = b ₂ =0.25 b . In Fig. 26, the simulated parameters are: w = w ₁ = w ₂ = w ₃ = 1.2 mm, the total length of the microstrip line is 10 cm, the material of the substrate 21 is made of RO4003, the thickness of the metal film is t = 0.0175 mm, and the thickness h = 0.508mm, groove depth b = 0.3 w ,, cycle length d = 1.0mm, the range of 200MHz to analysis by 12GHz, S _cd transitions ₂₁ represents a differential mode signals and common-mode signals.

The results of the conventional differential pair and single-ended microstrip line coupling circuit of the sixth embodiment are shown by solid lines in Figs. 25 and 26. As shown in FIG. 25, the transmission capability of the differential pair signal from the first port 13 to the second port 14 is represented by the S parameter: S _{dd 21.} At a frequency of 200 MHz, S _{dd 21} = -0.0679 dB at a frequency of 12 GHz. Lower S _{dd 21} = -2.336253 dB. As shown in FIG. 25, the crosstalk effect in which the differential pair signal is input from the first port 13 into the fourth port 23 of the single-ended microstrip line is represented by the S parameter: S _{sd 41} , S _{sd 41} = -42.63854 dB at 200 MHz, S _{sd 41} = -6.55742 dB at 12 GHz. As shown in FIG. 26, the effect of the differential pair signal being input from the first port 13 into the differential mode common mode output by the second port 14 is represented by the S parameter: S _{cd 21} , S _{cd 21} =-12.96263 dB at 12 GHz.

The results of the sub-wavelength periodic double-side hairpin differential pair and the single-ended microstrip line coupling circuit of the sixth embodiment are shown by the broken lines in Figs. 25 and 26. As shown in FIG. 25, the transmission capability of the differential pair signal from the first port 13 to the second port 14 is represented by an S parameter: S _{dd 21.} At a frequency of 200 MHz, S _{dd 21} = -0.11412 dB at the frequency. S _{dd 21} =-1.1716 dB at 12 GHz. As shown in FIG. 25, the crosstalk effect in which the differential pair signal is input from the first port 13 to the fourth port 23 outputted by the single-ended microstrip line is represented by an S parameter: S _{sd 41} , S _{sd 41} = -43.8893 dB at 200 MHz, S _{sd 41} = -23.45903 dB at 12 GHz. As shown in FIG. 26, the effect of the differential pair signal being input from the first port 13 into the differential mode common mode output by the second port 14 is represented by the S parameter: S _{cd 21} , S _{cd 21} = -36.05781 dB at 12 GHz.

The comparison result of the conventional differential pair and the sub-wavelength period double-sided hairpin differential pair of the sixth embodiment is as shown in FIGS. 25 and 26. 25, wherein in the 12GHz conventional differential pair S _{dd 21} = -2.36253dB, the subwavelength periodic differential pair S _{dd 21} drops to only -1.1716dB, there are significant transmission capacity in the case of high-frequency signal Improvement. As shown in Figure 25, where the crosstalk of the traditional differential pair and the single-ended microstrip line at 12 GHz is S _{sd 41} = -6.55742 dB, the crosstalk between the sub-wavelength periodic differential pair and the single-ended microstrip line is S _{sd 41} = -23.45903 With dB dB, crosstalk is clearly suppressed. As shown in Fig. 26, the effect of the traditional differential-difference mode-to-common mode at 12 GHz is 12 GHz S _{cd 21} = -12.96263 dB, and the sub-wavelength periodic differential pair is S _{cd 21} = -36.05781 dB, differential mode common mode effect. Obtained inhibition. Auxiliary Description: Figure 25 is the S parameter calculation result of the coupling circuit of Figure 24. Considering the numerical results of Fig. 25, the S _{dd 21 of the} conventional differential pair is indicated by a solid line, which is -0.0679 dB at 200 MHz and -2.36253 dB at 12 GHz. The sub-wavelength periodic double-side hairpin differential pair S _{dd 21} is indicated by a dashed line, which is -0.11412dB at 200MHz and -1.1716dB at 12GHz. At lower frequencies, the conventional differential pair has a slightly better transmission capability. As the frequency increases, the transmission capacity of the subwavelength periodic structure is better, and the electromagnetic field has better constraints. Due to this strong constraint on the electromagnetic field, the sub-wavelength periodic double-sided hairpin differential pair will obviously have lower interference for adjacent microstrip lines. As the frequency increases, crosstalk becomes more and more obvious. At 12 GHz, the crosstalk of the traditional differential structure for the single-ended microstrip line S _{sd 41} is -6.55742 dB, while the sub-wavelength period double-sided hairpin differential pair and single-ended microstrip line The crosstalk S _{sd 41 is} only -23.45903dB, which has obvious crosstalk resistance. Figure 26 is a graph showing the variation of the differential mode to common mode with frequency in the coupled circuit. As the frequency increases, the effect of differential mode to common mode is more pronounced. However, if the differential pair is engraved with a sub-wavelength periodic double-sided hairpin ripple, the effect of the conversion can be effectively suppressed. The effect of the differential mode to common mode signal of the conventional differential pair is -12.96263 dB at 12 GHz, while the sub-wavelength period is bilaterally distributed. The effect of the differential mode to common mode signal of the clip differential pair is only S _{cd 21} -36.05781dB. Obviously, the subwavelength periodic structure can effectively suppress the conversion efficiency of the differential mode to the common mode.

The present invention provides a low-crosstalk high-frequency transmission differential pair microstrip line, such as the fourth embodiment, the fifth embodiment, and the sixth embodiment, the plurality of grooves are arranged in a sub-wavelength manner, as shown in the figure. 14. Figure 18, and Figure 22, further comprising: a plurality of grooves symmetrically on the outer side of the first microstrip line 11, and periodically arranged inside the first microstrip line 11; and symmetrical The plurality of grooves are on the outer side of the second microstrip line 12 and are periodically arranged inside the second microstrip line 12. The distance between the inner side of the first microstrip line 11 and the inner side of the second microstrip line 12 is the distance w ₁ as shown in FIGS. 14 , 18 , and 22 . Therefore, in the fourth embodiment, the fifth embodiment, and the sixth embodiment, the two sides of the first microstrip line 11 and the two sides of the second microstrip line 12 are arranged along the edge of the microstrip line. A plurality of grooves have a periodic sub-wavelength arrangement.

The present invention provides a grooved differential pair structure, as shown in FIG. 10 and FIG. 18, wherein the structure of the plurality of grooves, such as the third embodiment and the fifth embodiment, has a rectangular concave body 15 combined. A rectangular protrusion 16 has a continuous periodic structure, and the distance between adjacent rectangular protrusions 16 is the periodic arrangement length of the plurality of grooves.

The present invention provides an open-groove differential pair structure, as shown in FIG. 1 and FIG. 14 , wherein the structure of the plurality of grooves, as in the first embodiment and the fourth embodiment, has a rectangular recess 15 . In combination with a rectangular protrusion 16 having a continuous periodic structure, and at the opening of each groove, each of the rectangular protrusions 16 has two first extensions extending in parallel to the center of each of the grooves. 17.

The present invention provides a hairpin differential pair structure, as shown in FIG. 5 and FIG. 22, wherein the structure of the plurality of grooves, as in the second embodiment and the sixth embodiment, has a plurality of Z-shaped protrusions 20 a continuous periodic structure, at each opening of the recess, each of the Z-shaped projections 20 has a first extension 17 extending in parallel to the center of each of the grooves, and for each Z-shaped projection At the middle of the portion 20, there is a second extension portion 18 extending in parallel to the center of each of the grooves, and the first extension portion 17 and the second extension portion 18 extend in opposite directions.

The above descriptions are merely illustrative of the preferred embodiments or examples of the technical means employed to solve the problems, and are not intended to limit the scope of the invention. Any change or modification that is consistent with the scope of the patent application scope of this creation or the scope of the patent creation is covered by the scope of the creation patent.

11‧‧‧First microstrip line

12‧‧‧Second microstrip line

13‧‧‧First port

14‧‧‧second port

17‧‧‧First Extension

18‧‧‧Second extension

20‧‧‧Z-shaped convex body

21‧‧‧Substrate

a, b, d, h, w, w ₁ , ε _r ‧‧‧ dimensions

Claims (7)

A low crosstalk high frequency transmission differential pair microstrip line, comprising: a first microstrip line transmitting a first transmission signal, the first microstrip line having a plurality of periodically arranged grooves; a second microstrip line parallel to the first microstrip line and configured to transmit a second transmission signal, the second transmission signal and the first transmission signal being complementary to each other by a phase difference of 180° The second microstrip line has a plurality of grooves arranged periodically; wherein the plurality of grooves are periodically arranged on the outer side of the first microstrip line and on the outer side of the second microstrip line in a subwavelength manner The sub-wavelength mode is a periodic arrangement length of the plurality of grooves smaller than the transmitted first transmission signal and the second transmission signal, and the plurality of grooves provide a sub-wavelength constraint for enhancing electromagnetic waves. The low-crosstalk high-frequency transmission differential pair microstrip line as described in claim 1, further comprising: a first port, wherein the first microstrip line and the second microstrip line are complementary to individual inputs a port of the signal; and a second port, the first microstrip line and the second microstrip line, the ports for outputting complementary signals; wherein the plurality of grooves arranged along the edge of the microstrip line When the complementary signal is transmitted from the first port to the second port, the conversion effect of the differential mode to the common mode is reduced. The low-crosstalk high-frequency transmission differential pair microstrip line as described in claim 2, wherein the plurality of grooves are arranged in a sub-wavelength manner, and further comprising: symmetrically to the first microstrip line a plurality of grooves on the outer side, and periodically arranged inside the first microstrip line; and symmetrical to the plurality of grooves on the outer side of the second microstrip line, and periodically arranged in the first The inside of the second microstrip line. The low-crosstalk high-frequency transmission differential pair microstrip line according to claim 3, further comprising: a substrate, the first microstrip line and the second microstrip line being on the substrate . The low-crosstalk high-frequency transmission differential pair microstrip line according to claim 4, wherein the plurality of grooves have a rectangular concave body combined with a rectangular convex body in a continuous periodicity The structure, adjacent to the distance between the rectangular protrusions, is the length of the arrangement period of the plurality of grooves. The low-crosstalk high-frequency transmission differential pair microstrip line according to claim 4, wherein the plurality of grooves have a rectangular concave body combined with a rectangular convex body in a continuous periodic manner. And at each of the openings of the recesses, each of the rectangular projections has two first extensions extending in parallel to the center of each of the recesses. The low-crosstalk high-frequency transmission differential pair microstrip line according to claim 4, wherein the plurality of grooves have a structure in which a plurality of Z-shaped protrusions have a continuous periodic structure, and the plurality of structures The Z-shaped convex body comprises: a first extending portion which is fastened to the opening of each of the grooves, a first extending portion extending in parallel to the center of each of the grooves; and a second extending portion And extending to the center of each of the grooves at the middle of each of the Z-shaped protrusions; wherein the extending directions of the first extending portion and the second extending portion are opposite.