Low-loss dielectric integrated suspended coplanar waveguide slow wave structure

Abstract

The application provides a low-loss dielectric integrated suspended coplanar waveguide slow wave structure, which comprises nine dielectric substrates arranged in sequence, a first substrate to a ninth substrate, wherein each dielectric substrate is a double-sided copper-clad plate; the first substrate and the ninth substrate are cover plates and are double-sided copper-clad plates; the fifth substrate is plated with copper on the side walls of the internal grooves and the side walls of the outer frame around the substrate to form a complete metal edge covering structure; the first substrate and the ninth substrate are plated with copper on the side edges to form a complete edge covering substrate; the second substrate, the fourth substrate, the sixth substrate and the eighth substrate are all metal edge covered, that is, the side edges are covered with copper; the third substrate and the seventh substrate are both metal edge covered, so that the internal dielectric is completely wrapped, thereby forming a complete metal edge covering structure. The metal edge covering structure can minimize or eliminate the dielectric loss of the internal dielectric to the greatest extent, thereby reducing the loss of the overall circuit.

Description

Technical Field

[0001] This invention relates to the field of radio frequency microwave circuit technology, and in particular to a low-loss dielectric integrated suspended coplanar waveguide slow wave structure. Background Technology

[0002] Coplanar waveguides are a common type of transmission line in radio frequency and microwave circuits, typically consisting of a signal line in the middle and metal grounds on both sides. However, traditional coplanar waveguide transmission lines are semi-open, with part of the structure exposed to the air, resulting in some radiation loss.

[0003] Furthermore, the size of uniform coplanar waveguide transmission lines is still relatively large, resulting in a large circuit size for the constructed RF / microwave passive circuits. Slow-wave structures are typically periodically loaded transmission line structures, offering the advantage of circuit miniaturization. Common slow-wave coplanar waveguide structures usually involve periodically arranging strip-shaped grounding structures under the signal line, but the following problems still exist. First, such slow-wave coplanar waveguides are still partially exposed in open space, resulting in some radiation loss. Additionally, due to the large amount of lossy dielectric between the signal line and the strip grounding wire or trench ground, these slow-wave coplanar waveguides exhibit significant dielectric loss. Summary of the Invention

[0004] The purpose of this invention is to address the problem of high loss in existing slow-wave coplanar waveguides by providing a low-loss dielectric integrated suspended coplanar waveguide slow-wave structure that combines the advantages of circuit miniaturization and low loss.

[0005] To achieve the objectives of this invention, the technical solution provided by this invention is as follows:

[0006] A low-loss dielectric integrated suspended coplanar waveguide slow wave structure includes nine dielectric substrates arranged sequentially, namely the first substrate to the ninth substrate, wherein each dielectric substrate is a double-sided copper-clad laminate.

[0007] The first substrate and the ninth substrate serve as cover plates, both of which are double-sided copper-clad laminates;

[0008] The second substrate, the fourth substrate, the sixth substrate, and the eighth substrate are all support plates, and all are double-sided copper-clad.

[0009] The third and seventh substrates are slow-wave loading ground structures, both employing periodic trenching to achieve the slow-wave loading effect, and both are double-sided copper-clad laminates.

[0010] The fifth substrate is the substrate layer where the signal line, i.e. the coplanar waveguide structure, is located, and it uses double-sided copper plating;

[0011] The fifth substrate has its sidewalls, including the internal grooves, and the sidewalls of the outer frame around the substrate plated with copper to form a complete metal edging structure.

[0012] The first substrate and the ninth substrate are copper-plated on their sides to form a complete edge-sealing substrate;

[0013] The second substrate, the fourth substrate, the sixth substrate, and the eighth substrate are all metal-clad, that is, copper-clad on the sides;

[0014] Both the third and seventh substrates are edged with metal to completely enclose the internal medium, thus forming a complete metal-edged structure.

[0015] Furthermore, the coplanar waveguide signal lines on the fifth substrate are stubbed, thereby further increasing the slow wave effect.

[0016] Furthermore, the loaded branches are edged with metal to reduce losses.

[0017] Compared with the prior art, the metal edging structure adopted in this invention can minimize or eliminate the dielectric loss of the internal medium to the greatest extent, thereby reducing the overall circuit loss. Attached Figure Description

[0018] Figure 1 This is a three-dimensional multilayer decomposition diagram of the low-loss slow-wave coplanar waveguide of the present invention;

[0019] Figure 2 yes Figure 1 A planar view of substrate 1 for a medium-slow wave coplanar waveguide;

[0020] Figure 3 yes Figure 1 Diagram of the lower metal layer of substrate 1 for the medium-slow wave coplanar waveguide;

[0021] Figure 4 yes Figure 1 Diagram of the upper metal layer of substrate 1 of the medium-slow wave coplanar waveguide;

[0022] Figure 5 yes Figure 1 A planar view of substrate 2 for a medium-slow wave coplanar waveguide;

[0023] Figure 6 yes Figure 1 Schematic diagram of the upper metal layer of substrate 2 of the medium-slow wave coplanar waveguide;

[0024] Figure 7 yes Figure 1 Diagram of the lower metal layer of substrate 2 for the medium-slow wave coplanar waveguide;

[0025] Figure 8 yes Figure 1 A planar view of substrate 3 for the medium-slow wave coplanar waveguide;

[0026] Figure 9 yes Figure 1 Diagram of the upper metal layer of substrate 3 for the medium-slow wave coplanar waveguide;

[0027] Figure 10 yes Figure 1 Diagram of the lower metal layer of substrate 3 for the medium-slow wave coplanar waveguide;

[0028] Figure 11 yes Figure 1 A plan view of substrate 4 for the medium-slow wave coplanar waveguide;

[0029] Figure 12 yes Figure 1 Diagram of the upper metal layer of substrate 4 for the medium-slow wave coplanar waveguide;

[0030] Figure 13 yes Figure 1 Diagram of the lower metal layer of substrate 4 for the medium-slow wave coplanar waveguide;

[0031] Figure 14 yes Figure 1 A plan view of the substrate 5 of the medium-slow wave coplanar waveguide;

[0032] Figure 15 yes Figure 1 Diagram of the upper metal layer of substrate 5 for the medium-slow wave coplanar waveguide;

[0033] Figure 16 yes Figure 1 Diagram of the lower metal layer of substrate 5 for the medium-slow wave coplanar waveguide;

[0034] Figure 17 This is a plan view of substrate 5 of a slow-wave coplanar waveguide with loaded stubs;

[0035] Figure 18 This is a diagram of the upper metal layer of substrate 5, which is a slow-wave coplanar waveguide with loaded stubs.

[0036] Figure 19 This is a diagram of the lower metal layer of substrate 5, which is a slow-wave coplanar waveguide with loaded stubs.

[0037] Figure 20 This is a schematic cross-sectional view of a substrate with nine layers of metal edging stacked together. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0039] Coplanar waveguides are a common transmission line type in RF and microwave circuits, typically consisting of a signal line in the middle and metal grounds on both sides. However, uniform coplanar waveguide transmission lines are still relatively large. Slow-wave structures are usually a periodically loaded transmission line structure, offering the advantage of circuit miniaturization. Common slow-wave coplanar waveguide structures often involve periodically arranging strip-shaped grounding structures under the signal line, but they still have the following problems. First, these slow-wave coplanar waveguides are still partially exposed in open space, resulting in some radiation loss. Secondly, due to the large amount of lossy dielectric between the signal line and the strip grounding wire or trench ground, these slow-wave coplanar waveguides suffer from significant dielectric loss.

[0040] like Figure 1 and Figure 20 As shown in the figure, this embodiment provides a low-loss dielectric integrated suspended coplanar waveguide slow wave structure, which includes nine dielectric substrates arranged in sequence, namely the first substrate to the ninth substrate, wherein each dielectric substrate is a double-sided copper-clad laminate.

[0041] The first substrate 1 and the ninth substrate 9 serve as cover plates, which are double-sided copper-clad boards. Alternatively, they can be copper-plated on the sides to form a complete edge-clad substrate. The second substrate 2, the fourth substrate 4, the sixth substrate 6, and the eighth substrate 8 are all support plates, all of which are double-sided copper-clad boards. They can also all be metal-clad, that is, copper-plated on the sides.

[0042] The third substrate 3 and the seventh substrate 7 are slow-wave loading ground structures, which can realize the slow-wave loading effect. Both the third substrate 3 and the seventh substrate 7 are double-sided copper-clad boards, and can also be metal-clad, so as to completely wrap the internal dielectric, thereby reducing dielectric loss. That is to say, copper can be clad on the sides of the third substrate 3 and the seventh substrate 7 (including the sidewalls of the internal grooves and the sidewalls of the outer frame around the substrate), thus forming a complete metal-clad structure.

[0043] The fifth substrate 5 is the substrate layer where the signal lines, i.e., the coplanar waveguide structure, are located. It also uses double-sided copper plating, and copper plating can be applied to both the sidewalls of the internal grooves and the sidewalls of the outer frame around the substrate to form a complete metal cladding structure. In addition, the coplanar waveguide signal lines on the fifth substrate 5 can also be stubbed, which can further increase the slow wave effect. It should be noted that the stubbed parts are also metal-clad in this case, thereby reducing losses.

[0044] The sixth substrate 6 is similar to the fourth substrate 4, the seventh substrate 7 is similar to the third substrate 3, and the seventh substrate 7 may differ from the third substrate 3 in the periodic trenching process, such as in size or number of cycles. The eighth substrate 8 is similar to the second substrate 2, and the ninth substrate 9 is similar to the first substrate 1.

[0045] The metal edging structure used in the aforementioned substrates can minimize or eliminate dielectric loss of the internal dielectric to the greatest extent, thereby reducing the overall circuit loss. Furthermore, due to the support provided by the second substrate 2, fourth substrate 4, sixth substrate 6, and eighth substrate 8, the third substrate 3, fifth substrate 5, and sixth substrate 7 are all suspended structures. The slow-wave loaded signal ground structures on the third substrate 3 and the seventh substrate 7 employ periodic trenching, with copper plating and metal edging applied to the trenches. This reduces losses, and the periodically loaded trenching structure can generate a certain slow-wave loading effect on the coplanar waveguide signal lines on the fifth substrate 5, thus giving the coplanar waveguide structure a slow-wave effect. Furthermore, the passive circuit designed using this slow-wave coplanar waveguide structure will have a smaller circuit area.

[0046] Meanwhile, since the first substrate 1 and the ninth substrate 9 are metal-edged, they are equivalent to a metal cover. Furthermore, since the other substrates also adopt a metal-edged structure, the overall structure is equivalent to a metal cavity shielding effect encapsulated by an external metal shell, thereby further reducing the radiation loss of the internal circuitry.

[0047] It should be noted that the slow-wave coplanar waveguide structure proposed in this invention can be made of substrates of any thickness, with any number of periodic slotted grounds, with any number of multilayer loaded slotted grounds, and with any number and shape of signal line loaded stubs, depending on the needs of the actual circuit, and is not limited to the embodiments shown in the figure.

[0048] Finally, it should be noted that the above embodiments are merely illustrative and explanatory of the present invention, and are not intended to limit the present invention to the scope of the described embodiments. Furthermore, those skilled in the art will understand that the present invention is not limited to the above embodiments, and many more variations and modifications can be made based on the teachings of the present invention, all of which fall within the scope of protection claimed by the present invention.

Claims

1. A low-loss dielectric integrated suspended coplanar waveguide slow-wave structure, characterized in that, It includes nine dielectric substrates arranged in sequence, namely, the first substrate (1) to the ninth substrate (9), wherein each dielectric substrate is a double-sided copper-clad laminate; The first substrate (1) and the ninth substrate (9) serve as cover plates, both of which are double-sided copper-clad laminates; The second substrate (2), the fourth substrate (4), the sixth substrate (6), and the eighth substrate (8) are all support plates, and all have double-sided copper plating; The third substrate (3) and the seventh substrate (7) are slow-wave loading ground structures. Both adopt periodic trenching to achieve slow-wave loading effect. Both are double-sided copper-clad laminates. The fifth substrate (5) is the substrate layer where the signal line, i.e. the coplanar waveguide structure, is located, and it is coated with copper on both sides. The fifth substrate (5) is copper plated on the sidewalls including the internal groove and the sidewalls of the outer frame around the substrate to form a complete metal edging structure. The first substrate (1) and the ninth substrate (9) are plated with copper on their sides to form a complete edge-sealing substrate; The second substrate (2), the fourth substrate (4), the sixth substrate (6), and the eighth substrate (8) are all metal-clad, that is, copper-clad on the sides; Both the third substrate (3) and the seventh substrate (7) are edged with metal to completely enclose the internal medium, thus forming a complete metal edged structure.

2. The low-loss dielectric integrated suspended coplanar waveguide slow-wave structure according to claim 1, characterized in that, The coplanar waveguide signal lines on the fifth substrate (5) are stubbed, thereby further increasing the slow wave effect.

3. The low-loss dielectric integrated suspended coplanar waveguide slow-wave structure according to claim 2, characterized in that, The loaded branches are edged with metal to reduce losses.

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