Coplanar waveguide structure

Abstract

The coplanar waveguide structure comprises a top-layer covering film, a base material and a bottom-layer covering film which are attached in sequence, and a microstrip line area stratum reference stratum is embedded in the top-layer covering film; the bottom layer covering film is embedded with a microstrip line area bottom layer stratum; the microstrip line area stratum reference ground layer comprises a microstrip line area line, a first coplanar waveguide area line, a second coplanar waveguide area line, a coplanar waveguide area edge reference ground line and a coplanar waveguide area middle reference ground line. The coplanar waveguide area edge reference ground wires are located on the two sides of the top-layer covering film; the microstrip line area differential line, the first coplanar waveguide area line and the second coplanar waveguide area line are located among the coplanar waveguide area edge reference ground line; the microstrip line area differential lines are located at the two ends of the top-layer covering film and are divided into two parts in the middle direction of the top-layer covering film to form a first coplanar waveguide area line and a second coplanar waveguide area line. Transition ground holes are formed in the two ends of the coplanar waveguide area middle reference ground wire. The coplanar waveguide structure provided by the invention can enhance line-to-line coupling.

Description

Technical Field

[0001] The invention relates to the field of flexible circuit boards, and in particular to a coplanar waveguide structure. Background Art

[0002] With the popularity of foldable screens and AR, VR, MR and other devices, the bending and transmission performance of flexible circuit boards at the hinges are getting higher and higher.

[0003] Currently, the mainstream solutions to improve the bending problem of flexible circuit boards are: air gap structure and coplanar waveguide structure.

[0004] 1. The air gap structure weakens the effect between layers by removing the adhesive between different layers, and the effect is close to that of a single-layer board. The coplanar waveguide structure is directly a single-layer board. The high-speed signal and all reference grounds are wired on the same layer. Compared with the air gap structure, the coplanar waveguide has better bending performance in theory and a higher lifespan when used in products. However, the problems of insufficient wiring space and unstable signals have always hindered the promotion of the coplanar waveguide structure.

[0005] 2. Coplanar waveguides have the problem of insufficient wiring space. In addition to the crowded wiring space caused by its single-layer structure, coplanar waveguides have no upper and lower signal reference layers. In order to increase capacitance and reduce inductance, they can only increase the line width as much as possible. The line width is usually several times or even dozens of times that of microstrip lines. In addition, coplanar waveguides also have the problem of unstable signals. Also, due to the lack of upper and lower reference layers, a large part of the electric field of the coplanar waveguide structure diverges outside the circuit board, similar to a capacitive sensor. When a large dielectric constant material or metal such as a human hand approaches, its capacitance will increase significantly, causing a significant decrease in impedance, that is, the impedance is easy to change with the use environment, resulting in unstable signals; in addition, the divergence of the electric field also leads to poor isolation, which is prone to electromagnetic interference problems.

[0006] There is currently an improved structure that can reduce the signal instability problem to a certain extent by cutting the signal line away from the reference ground, but it is still far inferior to microstrip lines and strip lines; and it does not solve the problem of occupying wiring space. Summary of the invention

[0007] In order to overcome the above technical defects, the present invention provides a coplanar waveguide structure, which can enhance the coupling between lines.

[0008] In order to solve the above problems, the present invention is implemented according to the following technical solutions:

[0009] A coplanar waveguide structure, comprising: a top cover film, a substrate, and a bottom cover film which are laminated in sequence, wherein the top cover film is inlaid with a microstrip line region stratum reference stratum; the bottom cover film is inlaid with a microstrip line region bottom stratum;

[0010] The microstrip line area ground layer reference ground layer includes: a microstrip line area line, a first coplanar waveguide area line, a second coplanar waveguide area line, a coplanar waveguide area edge reference ground line, and a coplanar waveguide area middle reference ground line;

[0011] The reference ground lines at the edge of the coplanar waveguide region are located on both sides of the top cover film;

[0012] The microstrip line area differential line, the first coplanar waveguide area line, and the second coplanar waveguide area line are located between the reference ground lines at the edge of the coplanar waveguide area;

[0013] The microstrip line area differential line is located at two ends of the top cover film, and is divided into two along the middle direction of the top cover film to form the first coplanar waveguide area line and the second coplanar waveguide area line;

[0014] The middle reference ground line of the coplanar waveguide area is located between the first coplanar waveguide area line and the second coplanar waveguide area line, and transition ground holes are provided at both ends of the middle reference ground line of the coplanar waveguide area;

[0015] The transition ground hole is arranged to penetrate the middle reference ground line of the coplanar waveguide area, the substrate, and the bottom ground layer of the microstrip line area.

[0016] As a further improvement of the present invention, the coplanar waveguide region edge reference ground line comprises: a first section and a second section, and a connection between the first section and the second section is configured as an arc shape;

[0017] The first section is located outside the microstrip line area differential line, and the second section is located outside the first coplanar waveguide area line and the second coplanar waveguide area line;

[0018] A plurality of microstrip line area reference ground vias are arranged near the microstrip line area differential line of the first section. The microstrip line area reference ground vias are arranged to penetrate the first section, the substrate, and the bottom layer of the microstrip line area.

[0019] As a further improvement of the present invention, a group of the microstrip line area stratum reference stratum is provided, the first coplanar waveguide area line is a first coplanar waveguide area signal line, and the second coplanar waveguide area line is a second coplanar waveguide area signal line;

[0020] The coplanar waveguide area edge reference ground line, the first coplanar waveguide area signal line, the coplanar waveguide area middle reference ground line, the second coplanar waveguide area signal line, and the coplanar waveguide area edge reference ground line are arranged at intervals.

[0021] As a further improvement of the present invention, the connection between the microstrip line area differential line and the first coplanar waveguide area signal line and the second coplanar waveguide area signal line is configured to be in an arc shape.

[0022] As a further improvement of the present invention, two groups of microstrip line area stratum reference strata are provided, the first coplanar waveguide area lines are first coplanar waveguide area differential lines, and the second coplanar waveguide area lines are second coplanar waveguide area differential lines;

[0023] The coplanar waveguide area edge reference ground line, the first coplanar waveguide area differential line, the coplanar waveguide area middle reference ground line, the second coplanar waveguide area differential line, the coplanar waveguide area edge reference ground line, the first coplanar waveguide area differential line, the coplanar waveguide area middle reference ground line, the second coplanar waveguide area differential line, and the coplanar waveguide area edge reference ground line are arranged at intervals.

[0024] As a further improvement of the present invention, the connection between the microstrip line area differential line and the first coplanar waveguide area line is configured to be in an arc shape.

[0025] As a further improvement of the present invention, the radius of the transition hole is smaller than W G1 / 2, where W G1 is the line width of the reference ground line in the middle of the coplanar waveguide area.

[0026] As a further improvement of the present invention, the line width of the reference ground line in the middle of the coplanar waveguide area is less than or equal to the line width of the line in the first coplanar waveguide area.

[0027] As a further improvement of the present invention, the two ends of the reference ground line in the middle of the coplanar waveguide region are set to be semicircular, and the radius of the semicircle is equal to (W G1 / 2+S1), wherein S1 is the distance between the first coplanar waveguide area line and the middle reference ground line of the coplanar waveguide area.

[0028] As a further improvement of the present invention, it is characterized in that W S2 / (S2+W S2 )≤0.5, where W S2 is the line width of the first coplanar waveguide area line, and S2 is the distance between the first coplanar waveguide area line and the middle reference ground line of the coplanar waveguide area.

[0029] Compared with the prior art, the present invention has the following beneficial effects: coupling can be strengthened by using the reference ground line in the middle of the coplanar waveguide area, and the differential line in the microstrip line area is divided into two to form a first coplanar waveguide area line and a second coplanar waveguide area line to reduce the line width, thereby reducing the waste caused by the area with low electromagnetic intensity due to the large line width, making the electric field more concentrated, and at the same time solving the problems of line width occupying space, crosstalk, and signal instability. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The specific embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings, wherein:

[0031] Figure 1 An exploded view of the coplanar waveguide structure described in Example 1;

[0032] Figure 2 This is a schematic structural diagram of the substrate described in Example 1;

[0033] Figure 3 A schematic diagram of the structure of the bottom stratum of the microstrip line area described in Example 1;

[0034] Figure 4 This is a schematic diagram of the structure of the microstrip line region stratum reference stratum described in Example 1;

[0035] Figure 5 It is a partial enlarged view of the microstrip line region stratum reference stratum described in Example 1;

[0036] Figure 6 This is the electromagnetic intensity distribution diagram of the conventional coplanar waveguide in Example 1;

[0037] Figure 7 This is a comparison diagram of the electric field strength at 5 μm above the signal line in Example 1;

[0038] Figure 8 This is a comparison diagram of the electric field strength at 60 μm above the signal line in Example 1;

[0039] Fig. 9 An exploded view of the coplanar waveguide structure described in Example 2;

[0040] Fig.10 This is a schematic structural diagram of the substrate described in Example 2;

[0041] Fig.11 A schematic diagram of the structure of the bottom stratum of the microstrip line area described in Example 2;

[0042] Fig.12 This is a schematic diagram of the structure of the microstrip line region stratum reference stratum described in Example 2;

[0043] Fig.13 A local enlarged view of the microstrip line region stratum reference stratum described in Example 2;

[0044] Fig.14 It is a TDR comparison diagram between the present invention and the prior art structure;

[0045] Fig.15 It is a comparison diagram of insertion loss between the structure of the present invention and the prior art;

[0046] Fig.16 A comparison diagram of the isolation between the present invention and the prior art structure;

[0047] Fig.17This is a comparison diagram of impedance between the structure of the present invention and the prior art after interference from a 3mm*3mm grounded metal block appears 20μm above;

[0048] Fig.18 Insertion loss comparison diagram between the structure of the present invention and the prior art after interference by a 3mm*3mm grounded metal block appears 20μm above.

[0049] Description of reference numerals:

[0050] Embodiment 1: 101, top covering film; 102, substrate; 103, bottom covering film; 104, microstrip line area stratum reference stratum; 1041, microstrip line area line; 1042, first coplanar waveguide area signal line; 1043, second coplanar waveguide area signal line; 1044, coplanar waveguide area edge reference ground line; 10441, first section; 10442, second section; 10443, microstrip line area reference ground via; 1045, coplanar waveguide area middle reference ground line; 105, microstrip line area bottom stratum; 106, transition ground hole.

[0051] Embodiment 2: 201, top covering film; 202, substrate; 203, bottom covering film; 204, microstrip line area stratum reference stratum; 2041, microstrip line area line; 2042, first coplanar waveguide area differential line; 2043, second coplanar waveguide area differential line; 2044, coplanar waveguide area edge reference ground line; 20441, first section; 20442, second section; 20443, microstrip line area reference ground via; 2045, coplanar waveguide area middle reference ground line; 205, microstrip line area bottom stratum; 206, transition ground hole. DETAILED DESCRIPTION

[0052] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0053] Example 1

[0054] The present invention provides a coplanar waveguide structure, which is a single-ended coplanar waveguide structure, such as Figures 1 to 3As shown, it includes: a top cover film 101, a substrate 102, and a bottom cover film 103 which are laminated in sequence, the top cover film 101 is inlaid with a microstrip line area stratum reference stratum 104; the bottom cover film 103 is inlaid with a microstrip line area bottom stratum 105; the microstrip line area stratum reference stratum 104 includes: a microstrip line area line 1041, a first coplanar waveguide area line, a second coplanar waveguide area line, a coplanar waveguide area edge reference ground line 1044, and a coplanar waveguide area middle reference ground line 1045; the coplanar waveguide area edge reference ground line 1044 is located on both sides of the top cover film 101; the microstrip line area differential line, the first coplanar waveguide area line, the second coplanar waveguide area line, the coplanar waveguide area edge reference ground line 1044, and the coplanar waveguide area middle reference ground line 1045. The waveguide area line and the second coplanar waveguide area line are located between the reference ground line 1044 at the edge of the coplanar waveguide area; the microstrip line area differential line is located at both ends of the top cover film 101, and is divided into two along the middle direction of the top cover film 101 to form the first coplanar waveguide area line and the second coplanar waveguide area line; the middle reference ground line 1045 of the coplanar waveguide area is located between the first coplanar waveguide area line and the second coplanar waveguide area line, and transition ground holes are set at both ends of the middle reference ground line 1045 of the coplanar waveguide area; the transition ground hole is set to penetrate the middle reference ground line 1045 of the coplanar waveguide area, the substrate 102, and the bottom layer 105 of the microstrip line area.

[0055] like Figure 4 As shown, the coplanar waveguide area edge reference ground line 1044 includes: a first section 10441 and a second section 10442, and the connection between the first section 10441 and the second section 10442 is set in an arc shape; the first section 10441 is located on the outside of the microstrip line area differential line, and the second section 10442 is located on the outside of the first coplanar waveguide area line and the second coplanar waveguide area line; the first section 10441 is close to the microstrip line area differential line, and a plurality of microstrip line area reference ground vias 10443 are set, and the microstrip line area reference ground vias 10443 are set through the first section 10441, the substrate, and the microstrip line area bottom layer 105 to ensure the signal return of the coplanar waveguide edge ground.

[0056] In this embodiment, a group of microstrip line area stratum reference stratum 104 is set, the first coplanar waveguide area line is the first coplanar waveguide area signal line 1042, and the second coplanar waveguide area line is the second coplanar waveguide area signal line 1043; the coplanar waveguide area edge reference ground line 1044, the first coplanar waveguide area signal line 1042, the coplanar waveguide area middle reference ground line 1045, the second coplanar waveguide area signal line 1043, and the coplanar waveguide area edge reference ground line 1044 are arranged at intervals.

[0057] In this embodiment, a group of coplanar waveguide region edge reference ground lines 1044 are added at both side edges, so that the signal lines at both ends of the coplanar waveguide structure are wrapped by the ground (return path).

[0058] Specifically, the first coplanar waveguide area signal line 1042 and the second coplanar waveguide area signal line 1043 are arranged in parallel, the impedance of the first coplanar waveguide area signal line 1042 is Z1, and the impedance of the second coplanar waveguide area signal line 1043 is Z2. Among them, Z0 is the characteristic impedance required by the transmission line. Considering the symmetry of the overall structure, Z1=Z2=2Z0 is generally taken.

[0059] like Figure 5 As shown, the connection between the microstrip line area differential line and the first coplanar waveguide area signal line 1042 and the second coplanar waveguide area signal line 1043 is set to be arc-shaped. Specifically, the connection is realized by using a double transition arc. The microstrip line area differential line first expands outward through the first transition arc, and then retracts inward through the second transition arc. The radius of the first transition arc R1=W G1 +S1+W S2 , the radius of the second transition arc R1 = W G1 +S1+W S2 .

[0060] The radius of the transition hole 106 is smaller than W G1 / 2, where W G1 is the line width of the reference ground line in the middle of the coplanar waveguide area.

[0061] The line width of the reference ground line 1045 in the middle of the coplanar waveguide area is smaller than the line width of the line in the first coplanar waveguide area, which facilitates the processing of the transition ground hole 106 hole plate.

[0062] The two ends of the reference ground line 1045 in the middle of the coplanar waveguide region are set to be semicircular, and the radius of the semicircle is equal to (W G1 / 2+S1), where S1 is the distance between the signal line of the first coplanar waveguide area and the reference ground line in the middle of the coplanar waveguide area, and is evenly coupled with the transition ground hole plate.

[0063] In this embodiment, W S2 :W S3 :W G3 ≈1:1:1:1, S1:S2:S3:S4: In order to concentrate the electric field, W S2 / (S2+W S2 )≤0.5, at this time, the metal utilization rate reaches a maximum value. S2 is the line width of the signal line 1042 in the first coplanar waveguide region, W S3 is the line width of the signal line in the first coplanar waveguide region, W G3is the line width of the second section 10442 of the reference ground line 1044 at the edge of the coplanar waveguide area, S2 is the distance between the first coplanar waveguide area line and the middle reference ground line 1045 in the coplanar waveguide area, S1 is the distance between the middle reference ground line 1045 in the coplanar waveguide area and the signal line 1043 in the second coplanar waveguide area, S3 is the distance between the second coplanar waveguide area signal line 1043 and the second section 10442 of the reference ground line 1044 at the edge of the coplanar waveguide area, and S4 is the distance between the second coplanar waveguide area signal line 1043 and the second section 10442 of the reference ground line 1044 at the edge of the coplanar waveguide area.

[0064] The effective electric field of the coplanar waveguide structure is mainly concentrated between the signal line and the ground. The impedance gain of increasing or decreasing the line width at other locations is relatively small. From the perspective of capacitance, the farther away from the reference layer, the larger the spacing between the capacitor plates. If the spacing between a point on the signal line and the reference layer is x, then the capacitance change rate increases with the increase of x. (a is a constant), starting from close to 0, 0 As x increases, f(x)' decreases rapidly, and the decrease in characteristic impedance depends on the increase in capacitance, resulting in a line width increase of x1 required to reduce 10Ω, and a line width x2>>x1 required to reduce 20Ω: Figure 6 As shown. The same rule can be seen from the calculation of electric field strength. Obviously, although the line width of the coplanar waveguide is large, the largest influence on the signal or impedance is only a small part that is directly opposite to the signal line, that is, the part inside the box: What we need to solve is to increase the proportion of the electric field strength of the partial structure of the box. For example, increasing the copper thickness is the most direct way, but it is not suitable for products that need to be resistant to bending. It is also not suitable to reduce the etching capacity limitations caused by reducing the line spacing: In the end, the best way left is to reduce the part with weak electric field strength and increase the number of parts with strong electric field. The electric field strength formed between the two points (where ΔU is the potential difference between the two points, and Δd is the distance between the two points). Δd at A is constant because E is relatively constant. E at B is Close to a proportional relationship, when Δd increases, E decreases rapidly, but the electric field strength decreases to 1 / 2 of the original value, that is, if the line width continues to increase, the occupied area will be too large and the impedance change will be small. At this time, Δd=S+W S ≈2S, so the ideal design is

[0065] As the line width increases at the coplanar waveguide port, the impedance usually decreases. It is necessary to reduce the line width of the lead-out ground line to reduce the parasitic capacitance of the coplanar waveguide port while retaining the effect of the return path. The line width can be slightly smaller than the signal line spacing S.

[0066] like Figure 7 and Figure 8As shown, when close to the signal line, the design of the present invention has a greater electric field strength than the traditional design, and a little further away, the electric field strength of the traditional coplanar waveguide is greater, indicating that the electric field of the traditional coplanar waveguide is more radiative, and the design of the present invention has a minimum electric field strength of about half of the maximum electric field strength when close to the signal line, which is in line with the design expectations, that is, by adjusting the line width to meet the second requirement, the utilization rate of the line width is close to the maximum, and the electric field changes can also be concentrated inside the PCB, which can improve the stability of the signal line and reduce crosstalk between signal lines.

[0067] Example 2

[0068] This embodiment provides another coplanar waveguide structure, which is a coplanar waveguide structure with a differential structure, such as Figures 9 to 11 As shown, it includes: a top cover film 201, a substrate 202, and a bottom cover film 203 which are laminated in sequence, the top cover film 201 is inlaid with a microstrip line area stratum reference stratum 204; the bottom cover film 203 is inlaid with a microstrip line area bottom stratum 205; the microstrip line area stratum reference stratum 204 includes: a microstrip line area line 2041, a first coplanar waveguide area line, a second coplanar waveguide area line, a coplanar waveguide area edge reference ground line 2044, and a coplanar waveguide area middle reference ground line 2045; the coplanar waveguide area edge reference ground line 2044 is located on both sides of the top cover film 201; the microstrip line area differential line, the first coplanar waveguide area line, the second coplanar waveguide area line, the coplanar waveguide area edge reference ground line 2044, and the coplanar waveguide area middle reference ground line 2045. The waveguide area line and the second coplanar waveguide area line are located between the reference ground line 2044 at the edge of the coplanar waveguide area; the microstrip line area differential line is located at both ends of the top cover film 201, and is divided into two along the middle direction of the top cover film 201 to form the first coplanar waveguide area line and the second coplanar waveguide area line; the middle reference ground line 2045 of the coplanar waveguide area is located between the first coplanar waveguide area line and the second coplanar waveguide area line, and transition ground holes are set at both ends of the middle reference ground line 2045 of the coplanar waveguide area; the transition ground hole is set to penetrate the middle reference ground line 2045 of the coplanar waveguide area, the substrate 202, and the bottom layer 205 of the microstrip line area.

[0069] like Fig.12 and Fig.13 As shown, the coplanar waveguide area edge reference ground line 2044 includes: a first section 20441 and a second section 20442, and the connection between the first section 20441 and the second section 20442 is set in an arc shape; the first section 20441 is located on the outside of the microstrip line area differential line, and the second section 20442 is located on the outside of the first coplanar waveguide area line and the second coplanar waveguide area line; the first section 20441 is close to the microstrip line area differential line, and a plurality of microstrip line area reference ground vias 20443 are set, and the microstrip line area reference ground vias 20443 are set through the first section 20441, the substrate, and the microstrip line area bottom stratum 205.

[0070] In this embodiment, two groups of microstrip line area stratum reference strata 204 are provided, the first coplanar waveguide area line is the first coplanar waveguide area differential line 2042, and the second coplanar waveguide area line is the second coplanar waveguide area differential line 2043; the coplanar waveguide area edge reference ground line 2044, the first coplanar waveguide area differential line 2042, the coplanar waveguide area middle reference ground line 2045, the second coplanar waveguide area differential line 2043, the coplanar waveguide area edge reference ground line 2044, the first coplanar waveguide area differential line 2042, the coplanar waveguide area middle reference ground line 2045, the second coplanar waveguide area differential line 2043, and the coplanar waveguide area edge reference ground line 2044 are arranged at intervals.

[0071] The connection between the microstrip line area differential line and the first coplanar waveguide area differential line is set to be an arc shape. Specifically, the connection is realized by using a double transition arc. The microstrip line area differential line first expands outward through the first transition arc, and then retracts inward through the second transition arc. The radius of the first transition arc is R1=W G1 +S1+W S2 , the radius of the second transition arc R1 = W G1 +S1+W S2 .

[0072] The radius of the transition hole 206 is smaller than W G1 / 2, where W G1 is the line width of the reference ground line in the middle of the coplanar waveguide area.

[0073] The line width of the reference ground line 2045 in the middle of the coplanar waveguide area is smaller than the line width of the line in the first coplanar waveguide area, which facilitates the processing of the transition ground hole 206 hole plate.

[0074] The two ends of the reference ground line 2045 in the middle of the coplanar waveguide region are set to be semicircular, and the radius of the semicircle is equal to (W G1 / 2+S1), where S1 is the distance between the signal line of the first coplanar waveguide area and the reference ground line in the middle of the coplanar waveguide area, and is evenly coupled with the transition ground hole plate.

[0075] In this embodiment, W S2 :W S3 :W G3 ≈1:1:1:1, S1:S2:S3:S4: In order to concentrate the electric field, W S2 / (S2+W S2 )≤0.5, at this time, the metal utilization rate reaches a maximum value. S2 is the line width of the differential line in the first coplanar waveguide region, W S3 is the line width of the differential line 2042 in the first coplanar waveguide region, W G3is the line width of the second section of the reference ground line at the edge of the coplanar waveguide area, S2 is the distance between the first coplanar waveguide area line and the middle reference ground line 2045 of the coplanar waveguide area, S1 is the distance between the middle reference ground line 2045 of the coplanar waveguide area and the second coplanar waveguide area differential line 2043, S3 is the distance between the second coplanar waveguide area differential line 2043 and the second section 20442 of the reference ground line 2044 at the edge of the coplanar waveguide area, and S4 is the distance between the second coplanar waveguide area differential line 2043 and the second section 20442 of the reference ground line 2044 at the edge of the coplanar waveguide area.

[0076] For other implementations of this embodiment, please refer to Example 1, which will not be described in detail here.

[0077] like Figures 14 to 18 As shown, the present invention has the following beneficial effects:

[0078] 1. The line width is significantly reduced: Under the same impedance and line spacing conditions, the total occupancy of the present invention is only 1 / 10 to 1 / 7 of that of the traditional coplanar waveguide.

[0079] 2. Low crosstalk between lines: The isolation of this design is 20-30dB greater than that of conventional designs. Fig.16 shown.

[0080] 3. Strong anti-interference ability: Under non-interference conditions, the insertion loss performance is slightly worse than that of ordinary designs (due to the small line width and large conductor loss, this shortcoming is difficult to avoid); under external interference conditions, such as a 3mm*3mm grounded metal block interference at 20μm above, see below Fig.17 and Fig.18 , the TDR mutation and insertion loss of this design are much smaller than those of traditional coplanar waveguide, which is of great significance for the use and promotion of coplanar waveguide products.

[0081] 4. The lines of this design are consistent with those of traditional coplanar waveguides, and the required etching capability is close to that of traditional coplanar waveguides, which will not significantly increase the process cost.

[0082] 5. The metal layer and the dielectric can be made thinner, ensuring signal stability while having good bending ability.

[0083] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A coplanar waveguide structure, characterized in that: include: A top cover film, a substrate, and a bottom cover film are laminated in sequence, wherein the top cover film is inlaid with a microstrip line area stratum reference stratum; The bottom cover film is inlaid with a bottom stratum of a microstrip line area; The microstrip line area ground layer reference ground layer includes: a microstrip line area line, a first coplanar waveguide area line, a second coplanar waveguide area line, a coplanar waveguide area edge reference ground line, and a coplanar waveguide area middle reference ground line; The reference ground lines at the edge of the coplanar waveguide region are located on both sides of the top cover film; The microstrip line area differential line, the first coplanar waveguide area line, and the second coplanar waveguide area line are located between the reference ground lines at the edge of the coplanar waveguide area; The microstrip line area differential line is located at two ends of the top cover film, and is divided into two along the middle direction of the top cover film to form the first coplanar waveguide area line and the second coplanar waveguide area line; The middle reference ground line of the coplanar waveguide area is located between the first coplanar waveguide area line and the second coplanar waveguide area line, and transition ground holes are provided at both ends of the middle reference ground line of the coplanar waveguide area; The transition ground hole is arranged to penetrate the middle reference ground line of the coplanar waveguide area, the substrate, and the bottom ground layer of the microstrip line area.

2. The coplanar waveguide structure according to claim 1, characterized in that: The coplanar waveguide region edge reference ground line comprises: a first section and a second section, wherein the connection between the first section and the second section is configured as an arc shape; The first section is located outside the microstrip line area differential line, and the second section is located outside the first coplanar waveguide area line and the second coplanar waveguide area line; A plurality of microstrip line area reference ground vias are arranged near the microstrip line area differential line of the first section. The microstrip line area reference ground vias are arranged to penetrate the first section, the substrate, and the bottom layer of the microstrip line area.

3. The coplanar waveguide structure according to claim 1, characterized in that: A set of microstrip line area stratum reference stratum is provided, the first coplanar waveguide area line is a first coplanar waveguide area signal line, and the second coplanar waveguide area line is a second coplanar waveguide area signal line; The coplanar waveguide area edge reference ground line, the first coplanar waveguide area signal line, the coplanar waveguide area middle reference ground line, the second coplanar waveguide area signal line, and the coplanar waveguide area edge reference ground line are arranged at intervals.

4. The coplanar waveguide structure according to claim 3, characterized in that: The connection points between the microstrip line area differential line and the first coplanar waveguide area signal line and the second coplanar waveguide area signal line are all configured in an arc shape.

5. The coplanar waveguide structure according to claim 1, characterized in that: Two groups of microstrip line area stratum reference strata are provided, the first coplanar waveguide area line is a first coplanar waveguide area differential line, and the second coplanar waveguide area line is a second coplanar waveguide area differential line; The coplanar waveguide area edge reference ground line, the first coplanar waveguide area differential line, the coplanar waveguide area middle reference ground line, the second coplanar waveguide area differential line, the coplanar waveguide area edge reference ground line, the first coplanar waveguide area differential line, the coplanar waveguide area middle reference ground line, the second coplanar waveguide area differential line, and the coplanar waveguide area edge reference ground line are arranged at intervals.

6. The coplanar waveguide structure according to claim 5, characterized in that: The connection points between the microstrip line area differential line and the first coplanar waveguide area line are both configured in an arc shape.

7. The coplanar waveguide structure according to claim 1, characterized in that: The radius of the transition hole is less than W G1 / 2, where W G1 is the line width of the reference ground line in the middle of the coplanar waveguide area.

8. The coplanar waveguide structure according to claim 1, characterized in that: The line width of the reference ground line in the middle of the coplanar waveguide area is less than or equal to the line width of the first coplanar waveguide area line.

9. The coplanar waveguide structure according to claim 1, characterized in that: The two ends of the reference ground line in the middle of the coplanar waveguide area are set to be semicircular, and the radius of the semicircle is equal to (W G1 / 2+S1), wherein S1 is the distance between the first coplanar waveguide area line and the middle reference ground line of the coplanar waveguide area.

10. The coplanar waveguide structure according to claim 1, characterized in that: W S2 / (S2+W S2 )≤0.5, where W S2 is the line width of the first coplanar waveguide area line, and S2 is the distance between the first coplanar waveguide area line and the middle reference ground line of the coplanar waveguide area.

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