A multi-layer structured notch transmission line with back cavity

Abstract

The present invention relates to a multi-layer structured wave trap transmission line with a back cavity, comprising a first metal layer, a first dielectric layer, a second metal layer, a second dielectric layer, and a third metal layer stacked in sequence. The first dielectric layer, the first metal layer, and the second metal layer form a waveguide structure, and the second dielectric layer and the third metal layer form a metal back cavity. The second metal layer is provided with at least one annular gap, and each annular gap is provided within the area enclosed by a grounding post, which is connected to the second metal layer and the third metal layer, respectively. Compared with the prior art, the present invention integrates the wave trap structure with microwave and millimeter wave devices based on the influence of the parameters of the wave trap transmission line on its performance, thereby achieving the introduction of the wave trap function without increasing the size of the components.

Description

Technical Field

[0001] The present invention relates to the technical field of microwave and millimeter waves, in particular to a multi-layer structured trap-wave transmission line with a back cavity. Background Art

[0002] In recent years, wireless communication technology has been continuously advancing and innovating, driving the continuous development of society. However, it also faces the bottleneck of limited spectrum resources. Channel bands are becoming increasingly crowded, making crosstalk and signal blocking very likely to occur. A communication system's multiple operating frequency bands may be subject to interference from other communication systems. For example, the Ultra-Wideband (UWB) band is 3.1-10.6 GHz, while the Wireless Local Area Network (WLAN) frequency range is 5.15-5.825 GHz, and the Worldwide Interoperability for Microwave Access (WiMAX) frequency range is 3.1-3.6 GHz—all within the UWB band. To avoid interference with existing communication systems, it is often necessary to filter out unnecessary interfering signals.

[0003] Taking the antenna system as an example, there are two typical approaches to suppress interference signals: one is to add a dedicated filtering structure, such as a filter or duplexer, between the antenna and the RF front end, and the interference signal suppression is completely achieved by them; the other is to integrate part of the suppression function into other structures and design an interconnected transmission system or antenna feeder system with notch characteristics.

[0004] Chinese patent application number CN201620801286.8 discloses a common-mode transmission line structure comprising, from top to bottom, an upper metal ground plane, a dielectric layer, and a lower metal ground plane. The structure is characterized by an upper metal transmission line and a lower metal transmission line embedded within the dielectric layer, with the upper and lower metal transmission lines being symmetrical. This transmission line structure exhibits excellent impedance continuity at corners, surpassing differential transmission lines. However, this transmission line does not provide a notching function.

[0005] In summary, there is currently a lack of a transmission line that can introduce a notch function without increasing the size of components. Summary of the Invention

[0006] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide a multi-layer structured notch transmission line with a back cavity, so as to utilize this transmission structure to integrate the notch structure with the microwave and millimeter wave devices, thereby introducing the notch function without increasing the volume of the components.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] The present invention provides a multi-layer structured wave trap transmission line with a back cavity, comprising a first metal layer, a first dielectric layer, a second metal layer, a second dielectric layer, and a third metal layer stacked in sequence, wherein the first dielectric layer, the first metal layer, and the second metal layer constitute a waveguide structure, the second dielectric layer and the third metal layer constitute a metal back cavity, the second metal layer is provided with at least one annular gap, and a grounding hole column is provided in the area enclosed by each of the annular gaps, and the grounding hole column is connected to the second metal layer and the third metal layer respectively.

[0009] As a preferred technical solution, the sidewalls of the first dielectric layer are provided with a metal coating.

[0010] As a preferred technical solution, the material of the metal coating is copper.

[0011] As a preferred technical solution, the grounding hole column is arranged at the center of the area enclosed by the annular gap.

[0012] As a preferred technical solution, the area enclosed by the annular gap is rectangular.

[0013] As a preferred technical solution, it includes a plurality of annular gaps, and the annular gaps are arranged side by side to form a series structure.

[0014] As a preferred technical solution, the materials of the first metal layer, the second metal layer and the third metal layer are copper, and the materials of the first dielectric layer and the second dielectric layer are Rogers 3006.

[0015] As a preferred technical solution, the first metal layer, the first dielectric layer, the second metal layer, the second dielectric layer and the third metal layer have the same planar dimensions.

[0016] As a preferred technical solution, the transverse dimension of the annular gap is 1.5mm-3.5mm, the longitudinal dimension is 1mm-2mm, and the width is 0.1mm-0.4mm.

[0017] As a preferred technical solution, the distance between the center points of adjacent annular gaps is 3-6 mm.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] (1) The notch structure and microwave and millimeter wave devices are integrated into a design, and the notch function can be introduced without increasing the volume of the components. The first dielectric layer, the first metal layer, and the second metal layer form a waveguide structure to reduce transmission loss and prevent electromagnetic wave energy from escaping; the second dielectric layer and the third metal layer form a metal back cavity, thereby increasing the transmission bandwidth; the surface of the second metal layer is etched with an annular gap, and the annular gap and the grounding hole column form a notch structure, thereby forming a "band-stop" effect in the corresponding frequency band.

[0020] (2) The sidewalls of the first dielectric layer are covered with copper. Covering the sidewalls with copper helps to form a waveguide structure, reduce energy loss, and ensure energy transmission.

[0021] (3) Five groups of rectangular annular gaps are arranged at equal distances in the center of the second metal layer, and the notch structure composed of the five groups of gaps is arranged in parallel, thereby improving the notch performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of a multi-layer structured trap wave transmission line with a back cavity provided in Example 1;

[0023] Figure 2 A schematic diagram of the annular gap structure provided in Example 1;

[0024] Figure 3 When the width of the annular gap provided in Example 1 is g=0.1 mm, its transverse length L=2.5 mm, 3 mm and 3.5 mm S 21 Simulation results;

[0025] Figure 4 When the width of the annular gap provided in Example 1 is g=0.1 mm, its transverse length L=2.5 mm, 3 mm and 3.5 mm S 11 Simulation results;

[0026] Figure 5 When the width of the annular gap provided in Example 2 is g=0.2 mm, its transverse length L=2.5 mm, 3 mm and 3.5 mm S 21 Simulation results;

[0027] Figure 6 When the width of the annular gap provided in Example 2 is g=0.2 mm, its transverse length L=2.5 mm, 3 mm and 3.5 mm S 11 Simulation results,

[0028] Among them, 1. first metal layer, 2. first dielectric layer, 3. second metal layer, 4. second dielectric layer, 5. third metal layer, 6. annular gap, 7. grounding hole column. DETAILED DESCRIPTION

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0030] Example 1

[0031] This embodiment provides a multi-layered trap transmission line with a back cavity, comprising: a first dielectric layer 2, a second dielectric layer 4, a first metal layer 1, a second metal layer 3, a third metal layer 5, and a grounding via 7. This transmission structure enables the integration of a trap structure with microwave and millimeter wave devices, allowing the trap function to be introduced without increasing the size of the components and improving performance within the device's operating frequency band without degrading other performance indicators.

[0032] Figure 1 This is a schematic diagram of the structure of the trap transmission line provided in this embodiment. It includes two dielectric layers and three metal layers. Specifically, the side walls of the first dielectric layer 2 are covered with copper, forming a waveguide structure with the first metal layer 1 and the second metal layer 3. The second dielectric layer 4 is etched with five groups of rectangular annular gaps 6, and metal grounding holes 7 are distributed directly below the annular gaps 6 for support and grounding. The total length of the transmission line is 20 mm, the width is 2 mm, and the layer spacing is 0.33 mm. The side walls of the first dielectric layer are also metal, forming a rectangular waveguide. Five groups of rectangular annular gaps 6 are etched on the lower surface wall of the rectangular waveguide, evenly arranged along the center line of the wide side. The area enclosed by each gap is connected by a grounding hole column 7 and connected to the third metal layer 5 to form a good support. The second metal layer 3, the third metal layer 5, the grounding hole column 7 and the annular gap 6 constitute a resonant unit, and the distance between the unit centers is 4 mm.

[0033] Figure 2 1 is a schematic diagram of the structure of the annular gap 6 of the second metal layer 3 provided in an embodiment of the present invention. Specifically, its transverse dimension is l, its longitudinal dimension is w, and its gap width is g.

[0034] Optionally, the preset distance is 1.5 mm to 3.5 mm, preferably 2.5 mm.

[0035] Optionally, the preset distance w is 1mm-2mm, preferably 1.5mm.

[0036] Optionally, the preset distance g is 0.1mm-0.4mm, preferably 0.25mm.

[0037] Figure 3 In this embodiment, when the gap width g = 0.1 mm, the horizontal length L = 2.5 mm, 3 mm and 3.5 mm S21 Simulation results (S 21 ( is an insertion loss indicator; lower values ​​indicate greater loss). Specifically, this structure exhibits a very pronounced notch effect between approximately 20 GHz and 50 GHz, with a maximum insertion loss of approximately 40 dB. Furthermore, at approximately 0-20 GHz and 50-80 GHz, there is a very pronounced transmission effect, with relatively low insertion loss. This structure demonstrates a notch effect, with conduction at both ends and blocking in the middle. Furthermore, as the lateral length l increases, the notch frequency band shifts toward lower frequencies.

[0038] like Figure 4 In this embodiment, the gap width g = 0.1 mm, and the horizontal length L = 2.5 mm, 3 mm and 3.5 mm S 11 Simulation results (S 11 ( is the return loss indicator; lower values ​​indicate better matching). Specifically, this structure exhibits a notch effect, with good matching at both ends and poor matching in the middle. Furthermore, as the lateral length l increases, the notch frequency band shifts toward lower frequencies.

[0039] Example 2

[0040] This embodiment provides another multi-layer structured trap wave transmission line with a back cavity. Compared with the embodiment 1, the gap width of this embodiment is g=0.2 mm.

[0041] Figure 5 In this embodiment, when the gap width g = 0.2 mm, the horizontal length L = 2.5 mm, 3 mm and 3.5 mm S 21 Simulation results (S 21 (The insertion loss index is λ, and the lower the value, the greater the loss). Specifically, the structure has a very obvious notch effect at about 20GHz-50GHz, with the maximum insertion loss reaching about 40dB. Furthermore, there is a very obvious transmission effect at about 0-20GHz and 50-80GHz, with a small insertion loss. It can be seen that the structure exhibits a notch effect with the frequency bands at both ends being conductive and the middle band being cut off. Furthermore, when the lateral length l increases, the notch band moves to the low frequency band; further, with Figure 3 In contrast, when the gap g increases, the notch band moves toward the high frequency band; the smaller g is, the steeper the notch sideband is.

[0042] Figure 6 In this embodiment, when the gap width g = 0.2 mm, the horizontal length L = 2.5 mm, 3 mm and 3.5 mm S 11 Simulation results (S 11is the return loss index, the lower the better the matching). Specifically, the structure shows a notch effect with good matching at both ends and poor matching in the middle. Furthermore, when the horizontal length l increases, the notch frequency band moves to the low frequency band. Figure 4 In contrast, when the gap g increases, the notch band moves toward the high frequency band; the smaller g is, the steeper the notch sideband is.

[0043] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and such modifications or substitutions are intended to be within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A multi-layer structured notch transmission line with a back cavity, characterized in that: The invention comprises a first metal layer (1), a first dielectric layer (2), a second metal layer (3), a second dielectric layer (4), and a third metal layer (5) stacked in sequence, wherein the first dielectric layer (2), the first metal layer (1), and the second metal layer (3) constitute a waveguide structure, the second dielectric layer (4) and the third metal layer (5) constitute a metal back cavity, the second metal layer (3) is provided with a plurality of annular gaps (6), and a grounding hole column (7) is provided in an area surrounded by each of the annular gaps (6), and the grounding hole column (7) is connected to the second metal layer (3) and the third metal layer (5) respectively.

2. The multi-layer structured trap wave transmission line with back cavity according to claim 1, characterized in that: The side walls of the first dielectric layer (2) are provided with a metal coating.

3. The multi-layer structured trap wave transmission line with back cavity according to claim 2, characterized in that: The material of the metal coating is copper.

4. The multi-layer structured trap wave transmission line with back cavity according to claim 1, characterized in that: The grounding hole column (7) is arranged at the center of the area enclosed by the annular gap (6).

5. The multi-layer structured trap wave transmission line with back cavity according to claim 1, characterized in that: The area enclosed by the annular gap (6) is rectangular.

6. The multi-layer structured trap wave transmission line with back cavity according to claim 1, characterized in that: It comprises a plurality of annular gaps (6), and the annular gaps (6) are arranged side by side to form a series structure.

7. The multi-layer structured trap wave transmission line with back cavity according to claim 1, characterized in that: The first metal layer (1), the second metal layer (3) and the third metal layer (5) are made of copper, and the first dielectric layer (2) and the second dielectric layer (4) are both made of Rogers 3006.

8. The multi-layer structured trap wave transmission line with back cavity according to claim 1, characterized in that: The first metal layer (1), the first dielectric layer (2), the second metal layer (3), the second dielectric layer (4) and the third metal layer (5) have the same planar dimensions.

9. The multi-layer structured trap wave transmission line with back cavity according to claim 1, characterized in that: The annular gap (6) has a transverse dimension of 1.5 mm to 3.5 mm, a longitudinal dimension of 1 mm to 2 mm, and a width of 0.1 mm to 0.4 mm.

10. The multi-layer structured trap wave transmission line with back cavity according to claim 1, characterized in that: The distance between the center points of adjacent annular gaps (6) is 3-6 mm.

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