A miniaturized waveguide load based on metasurface lens

Abstract

The application discloses a kind of miniaturization waveguide load based on super surface lens, belongs to the waveguide component of communication technical field, including waveguide cavity (1), in the waveguide cavity (1) is sequentially provided with lens unit (2), first transition layer (3), absorption unit (4) and second transition layer (5) along the direction of incident wave, wherein the second transition layer (5) back is made with metallization layer (51), the metallization layer (51) is welded or bonded with waveguide cavity (1);The size in the microwave absorption direction is at least reduced to half of original by using the structure of the application.

Description

Technical Field

[0001] This invention relates to waveguide components in the field of communication technology, and more particularly to a miniaturized waveguide load based on a metasurface lens. Background Technology

[0002] Waveguide loads absorb microwaves through continuous reflection and absorption. There are two main structural forms of waveguide loads: one is a rectangular cavity loaded with a graded absorber, and the other is a graded cavity loaded with a rectangular absorber. Both absorb microwaves by reflecting them through a graded path between the cavity and the absorber, achieving short-distance absorption. The absorber is typically made of high-loss, high-permeability materials such as silicon carbide, carbonyl iron, ferrite, or absorbing rubber, while the cavity is a metallic cavity. A typical rectangular waveguide loaded with a graded absorber structure is shown below. Figure 1 As shown.

[0003] There are many existing reports on waveguide loads, such as patents for terahertz waveguide loads based on ceramic sheet signal absorption. This structure uses sputtering to deposit a 50Ω sheet resistance on a ceramic sheet to absorb microwaves. The main drawback of this method is the extremely small size of the absorber in the terahertz band, leading to high processing difficulty, low yield, and high manufacturing costs. Another example is a patent for a small-size insert-type waveguide-terminated ceramic load and its design method. This patent achieves miniaturization through ceramic composite blocks and printed resistive films on the ceramic surface. It also uses ceramic gradients to achieve microwave reflection and absorption, resulting in good standing wave matching. Its main drawback is that it is achieved through a multi-stage stacking process, with the front-end ceramic stack suspended. Furthermore, the thickness of each composite ceramic block is only 1 / 4 or 1 / 8 of the electrical length at the corresponding frequency, requiring a relatively long installation space and not truly achieving miniaturization.

[0004] In addition, the millimeter-wave embedded waveguide matching load patent, an X-band embedded waveguide matching load patent, and a waveguide terminal matching load patent each have their own advantages. However, the overall structure is still within the scope of loading a rectangular waveguide with a gradient absorbing material. The cavity part is only implemented by borrowing the cavity structure of the interlocking part. The main disadvantages of these three structures are that the absorber part is long, and the rest is suspended except for the tail bonding. They have low vibration resistance, poor reliability, and require a long installation space. They are not truly miniaturized.

[0005] That is, existing reports on waveguide loads have at least the following problems: (1) The overall structural reliability is relatively low; most of the miniaturized structures have the absorption structure suspended in front, which has poor resistance to vibration, impact and acceleration and other environmental conditions, resulting in low reliability. (2) Traditional absorption requires a long transmission direction dimension and a large waveguide load size; for example, when using materials such as silicon carbide, the cavity structure is still relatively large, and to achieve better performance, it is generally above 1 / 2 wavelength.

[0006] (3) Existing miniaturization simply moves the cavity of the product to the front end, but the design still does not meet the miniaturization requirements when the matching size is insufficient. That is, the transmission direction size of each structure to achieve absorption still needs to be very long. Most of the absorption size is just given to the docking device, and miniaturization is not truly achieved. Summary of the Invention

[0007] The purpose of this invention is to provide a miniaturized waveguide load based on a metasurface lens to solve the above-mentioned problems.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A miniaturized waveguide load based on a metasurface lens includes a waveguide cavity, in which a lens unit, a first transition layer, an absorption unit, and a second transition layer are sequentially disposed along the incident wave direction. A metallization layer is fabricated on the back side of the second transition layer, and the metallization layer is welded or bonded to the waveguide cavity.

[0009] The aforementioned reports, excluding flanges, indicate that the size of the absorbing material is generally between 1 / 4 and 1 wavelength in length. Taking BJ100 as an example, one wavelength is approximately 48.6 mm, 1 / 4 wavelength is 12.15 mm, and 1 / 8 wavelength is 6.075 mm. Several existing patent designs, compared to conventional load dimensions, do not show a significant reduction in overall length, only reducing the amount of metal encased in the cavity. This application, however, drastically reduces the size by using a lens, resulting in a significant reduction in the size of the absorbing material, allowing it to be directly embedded into the flange.

[0010] As a preferred technical solution: the front of the lens unit is a microwave incident surface, a part of the back is a microwave transmission area, and the rest of the back is a metallized reflective surface.

[0011] As a further preferred technical solution: the front side of the lens unit is a metamaterial lens layer.

[0012] As a preferred technical solution, the metallization layer on the back of the absorption unit is welded or bonded to the waveguide cavity.

[0013] As a preferred technical solution, the absorbing material in the absorption unit is mainly a resistive film layer.

[0014] As a further preferred technical solution: the absorption resistance film layer is made of tantalum nitride. It should be noted that, in addition to tantalum nitride, the absorption resistance film layer can be a film-type resistive material made by vacuum evaporation, DC or AC sputtering, chemical deposition, etc., including Ni-Co based, Ta based, Si based, cermet based resistive films, and Au-Cr, Ni-P and other resistive thin films.

[0015] Waveguide loads typically absorb microwaves through continuous reflection and absorption. Therefore, transition matching or reflection matching designs are always included in the structural design. The purpose is to allow microwaves to be continuously reflected or resonated after entering from the port, and thus be absorbed by the absorbing material.

[0016] According to microwave absorption theory, wall currents parallel to an electric field can influence the parallel electric field, thus achieving absorption. Wall currents perpendicular to the electric field act as ideal electric walls, resulting in total reflection of incident electromagnetic waves. However, conventional resistive films placed directly in the cavity reflect the electric field when the absorbing material is perpendicular to it, failing to achieve effective absorption. Figure 2 As shown, Figure 2 In the diagram, a represents the air medium, b represents the interface, c represents the resistive film layer, and d represents the reflected wave.

[0017] Therefore, the incident wave and the absorbing resistive layer need to have a certain angle to achieve a parallel incident effect. A conventional setup achieves absorption by making the absorbing material or cavity wedge-shaped, but this differs from... Figure 1 One approach is to load a rectangular cavity with a gradient absorbing material, but this method results in a long absorption distance, making it difficult to miniaturize.

[0018] The principle of this invention is to deflect an electric field incident perpendicular to the port using a metasurface lens, so that when it reaches the end, it forms a certain angle with the absorbing material and is thus absorbed. Based on the above theory, this invention innovatively introduces a lens to achieve wave deflection. Ordinary lenses require a very thick layer to achieve this deflection, while metasurface-based lenses can deflect the incident wave over a very narrow transmission distance. This creates an angled incident wave on the resistive film, resulting in a perpendicular wall current. By rationally adjusting the lens structure and the resistance of the resistive film, effective absorption can be achieved, reaching absorption over a shorter transmission distance. This enables the design of waveguide loads. The principle is as follows: Figure 3 As shown, Figure 3 In the middle, h1 refers to the thickness of the metasurface lens; the incident wave passes through a microwave-transparent region set at the center of the lens unit, so that the incident wave passes through and forms a certain angle with the absorption resistance film layer. Due to the setting of the metallized reflective surface, most of the incident wave is reflected inside the internal resistance film layer, and is thus quickly absorbed by loss.

[0019] The metamaterial of this invention, also known as an artificial electric field material, is an artificial composite material or composite material formed by arranging macroscopic basic units with specific geometric shapes periodically or aperiodically, giving them extraordinary electromagnetic properties not found in natural materials. A crucial application of metamaterials is providing an effective means of controlling electromagnetic waves to travel along predetermined paths. Based on this application, metasurface lenses can be realized, effectively controlling the transmission of electromagnetic waves along predetermined paths. The principle is as follows: Figure 9 As shown; the schematic diagram of metamaterial lenses can also be found in "The Control and Application of Electromagnetic Waves by Metamaterial Lenses and Metasurfaces", Qi Meiqing, Chapter 2.2. Figure 2 1.

[0020] The key point of this invention is that by combining metasurface lens technology, microwaves are deflected over short distances, enabling short-distance control of microwaves. Through effective matching design, microwave reflection and absorption can be achieved within a short transmission distance, and the absorption does not occupy the internal space of the cavity, truly realizing miniaturized design.

[0021] The stacking process for the integrated fabrication of metamaterial lenses and absorption layers in this invention specifically includes: On the back of the metamaterial lens, in the area where microwaves do not pass through, a metallized reflective layer is fabricated using existing thin-film technology. This layer is used to reflect the microwaves that first enter the absorption area but are not completely absorbed, causing them to be absorbed after multiple reflections within the absorption area. The fabrication process of the absorption layer is similar to that of existing chip thin-film resistors. The topmost protective layer corresponds to the first transition layer. The upper surface of the protective layer is metallized to correspond to the non-transparent area of ​​the metamaterial lens for welding with the metamaterial lens layer. The middle resistive layer achieves absorption. The back of the second transition layer is metallized again for mounting and fixing. For details on the absorption layer process and stacked structure, please refer to "Development and Optimization of Thin Film Layer Fabrication Process for Chip Resistors", Fang Liang, Chapter 1.2. Figure 1-1 .

[0022] The first layer is a metamaterial lens layer, followed by a metal reflective layer on the back and a microwave-transparent region in the middle, then a transition layer, followed by an absorption layer, and finally, a metallization of the back surface is achieved through the transition layer. The metal reflective layer on the back of the metamaterial lens of this invention has the effect of superimposing microwave reflections, thereby improving the absorption effect. This invention reduces the density of incident waves in a small array by using a lens absorption unit, thereby reducing the difficulty of the lens deflecting the incident waves and achieving effective control of incident waves in a small range.

[0023] The lens absorption unit of the present invention can be combined to form a large array, thereby effectively absorbing large areas.

[0024] Compared with the prior art, the advantages of the present invention are as follows: Using the structure of the present invention, the size of the load in the microwave absorption direction is very small, at least half that of the prior art; simultaneously, the load formed by this structure does not use bonding processes, the entire lens unit is integrally manufactured, formed as a whole according to the waveguide port size, and combined with the cavity by welding or bonding, with no protruding suspended parts, resulting in higher reliability than existing miniaturized suspended designs; furthermore, the entire absorption structure is inside the cavity, with no suspended positions, making the overall structure more reliable. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of a typical rectangular waveguide loaded with a graded absorber in existing technology; Figure 2 This is a schematic diagram of vertical reflection of air medium in existing technology; Figure 3 This is a schematic diagram of the lens offset absorption principle of the present invention; Figure 4 This is a structural diagram of an embodiment of the present invention; Figure 5 for Figure 4 Structural diagram of the middle lens unit; Figure 6 for Figure 4 Assembly diagram of the middle lens unit and absorption unit, etc.; Figure 7 This is a schematic diagram of the combination of a lens absorption array and a waveguide cavity; Figure 8 for Figure 7 Exploded view; Figure 9 This is a schematic diagram of the metamaterial lens of the present invention.

[0026] In the figure: 1. Waveguide cavity; 2. Lens unit; 21. Microwave incident surface; 22. Microwave transmission area; 23. Metallized reflective surface; 3. First transition layer; 4. Absorption unit; 5. Second transition layer; 51. Metallization layer. Implementation

[0027] The invention will now be further described with reference to the accompanying drawings.

[0028] Example 1:

[0029] This embodiment uses a BJ100 waveguide load as an example to illustrate the present invention. Figure 4 The waveguide load structure of this embodiment is shown below: A miniaturized waveguide load based on a metasurface lens includes a waveguide cavity 1. A lens unit 2, a first transition layer 3, an absorption unit 4, and a second transition layer 5 are sequentially arranged in the waveguide cavity 1 along the incident wave direction. A metallization layer 51 is fabricated on the back side of the second transition layer 5, and the metallization layer is welded to the waveguide cavity 1. In this embodiment, the front of the lens unit 2 is a microwave incident surface 21, a portion of the back is a microwave transmission region 22, and the remaining portion of the back is a metallized reflective surface 23; the front of the lens unit 2 is a metamaterial lens layer; the absorption unit 4 is an absorption resistance film layer, which is made of tantalum nitride material; the structural diagram of the lens unit 2 is shown below. Figure 5 As shown; the assembly diagram of the lens unit and absorption unit, etc., is as follows. Figure 6 As shown; the front of the lens unit 2 is the microwave incident surface 21, and a part of the back is the microwave transmission area 22 after aggregation. The aggregated microwaves are transmitted backward through this area. The remaining area is metallized, that is, the metallized reflective surface 23, which is used to reflect the microwaves in the absorption area behind, thereby increasing the absorption efficiency. After the metallized reflective surface 23, there is first the first transition layer 3, followed by the absorption unit 4, which adopts a tantalum nitride absorption resistor film layer, followed by the second transition layer 5, and finally the back metallization is performed. The back metallization layer 51 is directly welded and fixed to the waveguide cavity 1.

[0030] Figure 4 In the diagram, H represents the overall transmission direction dimension of the load, a represents the wide side dimension of the waveguide, b represents the narrow side dimension of the waveguide, h1 represents the thickness of the metamaterial lens, and h2 represents the overall thickness of the absorbing material. As an example, for the BJ100 waveguide load, H is the overall transmission direction dimension of the load, 5mm; a is the wide side dimension of the waveguide, 22.86mm; b is the narrow side dimension of the waveguide, 10.16mm; h1 is the thickness of the metamaterial lens, 1mm; and h2 is the thickness of the absorbing material, 1.2-1.5mm.

[0031] A schematic diagram of the lens absorption array combined with waveguide cavity 1 in this embodiment is shown below. Figure 7 As shown, the exploded view is as follows Figure 8 As shown.

[0032] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A miniaturized waveguide load based on a metasurface lens, comprising a waveguide cavity (1), characterized in that: A lens unit (2), a first transition layer (3), an absorption unit (4), and a second transition layer (5) are sequentially arranged in the waveguide cavity (1) along the incident wave direction. The second transition layer (5) has a metallization layer (51) on its back side, and the metallization layer (51) is welded or bonded to the waveguide cavity (1). The lens unit (2) has a metamaterial lens layer on its front side. The front of the lens unit (2) is a microwave incident surface (21), and the center of the back is set as a microwave transmission area (22). The converged microwaves are transmitted backward through the microwave transmission area (22). The remaining area is metallized to form a metallized reflective surface (23). After the metallized reflective surface (23), there is first a first transition layer (3), then an absorption unit (4), then a second transition layer (5), and finally back metallization. The back metallization layer (51) is directly fixed to the waveguide cavity (1). By using a metasurface lens, the electric field incident perpendicular to the port is deflected so that when it reaches the end, it forms an angle with the absorbing material and is thus absorbed. The incident wave passes through a microwave-transparent region set at the center of the lens unit (2), so that the incident wave passes through and forms an angle with the absorption unit (4), and due to the setting of the metallized reflective surface (23), the incident wave is reflected inside the absorption unit (4).

2. The metasurface-lens-based miniaturized waveguide load of claim 1, wherein: The metallization layer (51) is welded to the waveguide cavity (1).

3. The miniaturized waveguide load based on a metasurface lens according to claim 1, characterized in that: The absorption unit (4) is an absorption resistance film layer.

4. The miniaturized waveguide load based on a metasurface lens according to claim 3, characterized in that: The absorption resistance film layer is made of tantalum nitride.

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