Three-dimensional micro-coaxial structure coupled filter applying millimeter wave communication

Abstract

This invention discloses a three-dimensional micro-coaxial structure coupling filter for millimeter-wave communication, comprising a metal grounded shell, a signal transmission axis, a signal transmission line support structure, and a three-dimensional micro-coaxial line to coplanar waveguide adapter. The signal transmission axis is suspended within an air cavity inside the metal grounded shell via the signal transmission line support structure. The signal transmission axis includes multiple metal transmission lines arranged in two staggered columns, all with the same transmission direction and adjacent metal transmission lines coupled to each other. This invention employs a coupling line approach, where the radio frequency signal transmission lines are suspended and staggered within the metal shell. By controlling the length of the coupling lines and the coupling spacing, the electromagnetic characteristics of the filter can be adjusted, effectively achieving high-frequency, low-loss transmission characteristics. Furthermore, by using 3D printing technology combined with electroplating technology as processing methods, the processing cost is significantly reduced while ensuring high electromagnetic performance.

Description

Technical Field

[0001] This invention belongs to the field of wireless communication technology, specifically relating to a three-dimensional micro-coaxial structure coupling filter for millimeter-wave communication. Background Technology

[0002] Millimeter waves refer to radio frequencies with wavelengths between 1 and 10 millimeters, corresponding to a frequency range of 30-300 GHz. Compared to traditional communication frequency bands, millimeter waves have higher frequencies and larger bandwidths, thus enabling faster data transmission and more stable network connections. Millimeter wave communication is widely used in autonomous vehicles, vehicle-to-everything (V2X) communication, and other fields, enabling communication and information sharing between vehicles. It can also enable faster WiFi and 5G wireless network connections, improving user experience. Millimeter wave communication can be used to detect and identify human behavior and is widely used in security monitoring. Millimeter wave communication can also be used to detect and diagnose body surfaces and is widely used in the healthcare field.

[0003] Reducing losses in millimeter-wave communication has become a hot research topic. Loss not only affects the performance of millimeter-wave communication but also determines its cost. High loss in the passband requires high transmission power, which is unacceptable for cost savings. Currently, there are three main approaches to reducing loss. The first and most obvious is from a materials perspective: how to use new materials to improve the loss characteristics of filters in the passband. Microwave filters fabricated using high-resistivity silicon wafers not only have miniaturized dimensions but also reduce passband losses. However, high-resistivity silicon wafers are very expensive, resulting in high manufacturing costs. Another approach is to utilize new design theories, such as electromagnetic coupling theory, to improve the filter's in-band characteristics, such as loss and bandwidth, by changing the coupling strength of different resonant cavities. Finally, from a structural perspective, three-dimensional metal microcoaxial structures have become a focus. Because their exterior is encased in a three-dimensional metal shell, they exhibit very low electromagnetic radiation, and the metal transmission lines are suspended within the metal shell, providing an ideal air cavity environment that significantly reduces dielectric loss. These two factors contribute to the low-loss characteristics of this structure at high frequencies. This structure has a high frequency limit, reaching up to 500GHz, making it easy to achieve low-loss millimeter-wave communication. However, due to its three-dimensional structure, it is more difficult to manufacture and has higher costs compared to traditional planar transmission line structures. Summary of the Invention

[0004] Technical problem solved: This invention discloses a three-dimensional micro-coaxial structure coupling filter for millimeter-wave communication. It proposes a novel three-dimensional micro-coaxial structure that uses coupling lines, i.e., the radio frequency signal transmission lines are suspended and interleaved within a metal shell. By controlling the length of the coupling lines and the coupling spacing, the electromagnetic characteristics of the filter can be adjusted, effectively achieving high-frequency, low-loss transmission characteristics. This invention is particularly suitable for 60GHz coupling filters for millimeter-wave communication. At the same time, by using 3D printing technology combined with electroplating technology as processing methods, the processing cost is greatly reduced while ensuring high electromagnetic performance.

[0005] Technical solution:

[0006] In a first aspect, the present invention discloses a three-dimensional micro-coaxial structure coupling filter for millimeter-wave communication, the three-dimensional micro-coaxial structure coupling filter comprising a metal grounded shell, a signal transmission line, a signal transmission line support structure, and a three-dimensional micro-coaxial line to coplanar waveguide adapter interface;

[0007] The signal transmission axis is suspended in an air cavity inside a metal grounded shell via a signal transmission line support structure. An air resonant cavity for transmitting electromagnetic fields is formed between the metal grounded shell and the signal transmission axis. The signal transmission axis includes multiple metal transmission lines arranged in two columns and staggered. All metal transmission lines have the same transmission direction and are coupled to each other. The coupling strength is adjusted by adjusting the coupling length and coupling distance of the coupled parts, thereby adjusting the bandwidth, loss, and out-of-band suppression characteristics of the three-dimensional micro-coaxial structure coupling filter.

[0008] The three-dimensional micro-coaxial cable to coplanar waveguide adapter is installed at one end of the metal grounded housing and connected to the signal transmission axis, transforming the three-dimensional structure of the micro-coaxial cable into the planar structure of the coplanar waveguide.

[0009] Furthermore, the signal transmission line support structure includes multiple support components, each of which includes an L-shaped lower support member and a straight left and right support member; the end of the lower support member whose long side is away from the short side abuts against the inner wall of the metal grounding shell, and the end that intersects with the short side is located below the metal grounding shell, and is vertically supported by the short side between the bottom of the metal grounding shell and the bottom surface of the metal transmission line; one end of the left and right support members abuts against the inner wall of the metal grounding shell, and the other end abuts against one of the side walls of the metal transmission line; the left and right support members are symmetrically arranged on both sides of the lower support member and are located on two opposite sides of the metal transmission line.

[0010] Furthermore, the signal transmission line support structure is made of insulating material.

[0011] Furthermore, the metal transmission line is made of copper.

[0012] Furthermore, the sidewall of the metal grounding casing is periodically provided with holes; the size of the holes satisfies the following condition: W 孔洞 <W 微同轴 / 5; where W 孔洞 W represents the width of the square hole. 微同轴 It is the width of the metal grounding casing.

[0013] Furthermore, the metal grounding housing includes a micro-coaxial frame supported by an organic material and a metal layer electroplated on the surface of the micro-coaxial frame.

[0014] Furthermore, the micro-coaxial frame is manufactured using 3D printing.

[0015] Furthermore, the metal layer is a copper layer.

[0016] Furthermore, the length of the metal transmission line ranges from 1.96 mm to 2.04 mm; the coupling length of the coupling portion ranges from 0.375 mm to 0.425 mm; and the coupling distance of the coupling portion ranges from 0.03 mm to 0.11 mm.

[0017] Secondly, the present invention also discloses a method for fabricating a three-dimensional micro-coaxial structure coupled filter, the method comprising the following steps:

[0018] A micro-coaxial frame is fabricated using 3D printing technology. The micro-coaxial frame consists of an upper frame and a lower frame. The lower frame has a first groove at its center, and first steps are periodically arranged on both sides of the first groove. The upper frame has a second groove at its center, which is opposite to the first groove. Second steps are periodically arranged on both sides of the second groove. The second steps are connected by a connecting shaft to form a first periodic hole on the upper surface of the upper frame. The first and second steps are opposite to each other, and after the first and second steps are connected, the lower frame, combined with the connecting shaft, forms a second periodic hole on its lower surface.

[0019] Metal layers are plated on the inner and outer sides of the micro-coaxial frame using an electroplating process to obtain a metal grounding shell;

[0020] A transmission line support structure is used to suspend the metal transmission line in the air cavity of the metal grounded shell. The coupling length and coupling distance of the coupling part are adjusted to adjust the coupling strength, thereby adjusting the bandwidth, loss and out-of-band suppression characteristics of the three-dimensional micro-coaxial structure coupling filter.

[0021] A three-dimensional micro coaxial line to coplanar waveguide adapter is connected to one end of the metal grounded shell.

[0022] Beneficial effects:

[0023] First, the three-dimensional micro-coaxial structure coupling filter for millimeter-wave communication of the present invention has the high power capacity of traditional rectangular waveguides and can ensure extremely low disconnection loss at extremely high transmission frequencies.

[0024] Secondly, the three-dimensional micro-coaxial structure coupling filter of the present invention, which applies millimeter-wave communication, adopts an interface from micro-coaxial structure to CPW transmission line at the input and output, realizing the transition from three-dimensional structure to planar structure. Combined with the newly designed metal grounded shell structure, it facilitates testing and system assembly.

[0025] Third, the three-dimensional micro-coaxial structure coupling filter for millimeter-wave communication of the present invention adopts the principle of coupled transmission lines. The radio frequency signal transmission lines are suspended and interleaved within a metal shell. The coupling length and coupling spacing determine the zeros and poles of the filter's transmission characteristics. This three-dimensional micro-coaxial structure coupling filter breaks the constraints of high frequency and low loss, and realizes high-frequency and low-loss transmission. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the three-dimensional structure of a three-dimensional micro-coaxial structure coupling filter for millimeter-wave communication according to an embodiment of the present invention.

[0027] Figure 2 This is a perspective view of a three-dimensional micro-coaxial structure coupling filter for millimeter-wave communication according to an embodiment of the present invention;

[0028] Figure 3 This is an exploded view of a three-dimensional micro-coaxial structure coupling filter for millimeter-wave communication according to an embodiment of the present invention;

[0029] Figure 4 These are the key structural dimensions of the three-dimensional micro-coaxial structure coupling filter for millimeter-wave communication in this embodiment of the invention;

[0030] Figure 5 This is the S21 electromagnetic characteristic curve of a three-dimensional micro-coaxial structure coupling filter for millimeter-wave communication according to an embodiment of the present invention. Detailed Implementation

[0031] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0033] It should be understood that when a component or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other components or layers, it may be directly on, adjacent to, connected to, or coupled to other components or layers, or there may be intervening components or layers. Conversely, when a component is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other components or layers, there are no intervening components or layers. The term "connection" in this specification, if referring to the transmission of electrical signals or data between connected circuits, modules, units, etc., should be understood as "electrical connection," "communication connection," etc. It should be understood that although the terms first, second, third, etc., may be used to describe various components, parts, areas, layers, and / or portions, these components, parts, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one component, part, area, layer, or portion from another component, part, area, layer, or portion. Therefore, without departing from the teachings of this invention, the first element, component, region, layer or portion discussed below may be represented as a second element, component, region, layer or portion.

[0034] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein for convenience of description to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms are intended to also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, then the element or feature described as “below” or “under” the other element or feature will be oriented “above” the other element or feature. Therefore, the exemplary terms “below” and “under” can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or otherwise) and the spatial descriptive terms used herein will be interpreted accordingly.

[0035] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It will be understood that “at least one” means one or more, and “a plurality” means two or more. “At least a portion of an element” means part or all of an element. It should also be understood that the terms “compose” and / or “comprising,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0036] Embodiments of the invention are described herein with reference to cross-sectional views illustrating ideal embodiments (and intermediate structures). Thus, variations in the shape shown can be anticipated due to, for example, manufacturing techniques and / or tolerances. Therefore, embodiments of the invention should not be limited to the specific shapes of the areas shown herein, but include shape deviations due to, for example, manufacturing processes. For example, coupling holes shown as rectangular or circular often exhibit uneven edges due to instability in the etching process, resulting in a shape that is not ideally prototypical or square. Therefore, the areas shown in the figures are substantially schematic, and their shapes are not intended to show the actual shapes of areas of the device and are not intended to limit the scope of the invention.

[0037] The terminology used in this article in the fields of radio frequency communication and semiconductors are technical terms commonly used by those skilled in the art. For example, in radio frequency communication, IL represents insertion loss, and RL represents return loss due to impedance mismatch. Furthermore, standard processes involved in MEMS fabrication, such as positive / negative photoresist, deep silicon etching, metal stripping, and quasi-LIGA processes, are consistent with the general understanding of those skilled in the art.

[0038] See Figures 1 to 3 This invention discloses a three-dimensional micro-coaxial structure coupling filter for millimeter-wave communication. The three-dimensional micro-coaxial structure coupling filter includes a metal grounded shell, a signal transmission line, a signal transmission line support structure, and a three-dimensional micro-coaxial line to coplanar waveguide (CPW) adapter.

[0039] The signal transmission axis is suspended in an air cavity inside a metal grounded shell via a signal transmission line support structure. An air resonant cavity for transmitting electromagnetic fields is formed between the metal grounded shell and the signal transmission axis. The signal transmission axis includes multiple metal transmission lines arranged in two staggered columns. All metal transmission lines have the same transmission direction and are coupled to each other. The coupling strength is adjusted by adjusting the coupling length and coupling distance of the coupled parts, thereby adjusting the bandwidth, loss, and out-of-band suppression characteristics of the three-dimensional micro-coaxial structure coupling filter.

[0040] The three-dimensional micro-coaxial cable to coplanar waveguide adapter is installed at one end of the metal grounded housing and connected to the signal transmission axis, transforming the three-dimensional structure of the micro-coaxial cable into the planar structure of the coplanar waveguide.

[0041] This invention uses 3D printing technology to fabricate the outer shell, and then electroplating to create a thin film structure that confines and restricts the internal electromagnetic field, preventing electromagnetic waves from radiating outwards. Inside the metal shell are metal transmission lines and their supporting structures. Periodically distributed holes on the metal shell are for ease of processing and do not affect electromagnetic performance. Figure 2This diagram illustrates the three-dimensional stacked structure of the three-dimensional micro-coaxial filter of this invention. Structure 1 is the interface of the three-dimensional micro-coaxial filter, employing a micro-coaxial structure to CPW structure adapter. This interface facilitates testing while ensuring the electromagnetic performance of the micro-coaxial filter remains unchanged. Structure 2, the dark gray portion within the metal casing, is the supporting structure, serving to support the metal transmission lines. The material of this structure must possess sufficient rigidity and be an insulator; otherwise, the signal transmission lines will be short-circuited by the supporting structure, resulting in no signal output at the output end. Structure 3 consists of periodic small holes on the metal casing. Due to their small size, their impact on the electromagnetic field propagation model is negligible. The function of this structure is to facilitate electroplating of the inner surface during processing. Structure 4 is the metal casing, which also serves as the grounding metal for the entire structure. The main body of the casing is fabricated using 3D printing technology, and a thin-film structure is then created through electroplating. Therefore, this casing is not a truly all-metal casing, but rather possesses only a thin metal layer. However, this does not affect the electromagnetic performance, because under high-frequency electromagnetic wave conditions, the skin effect current exists only on the metal surface. Using an all-metal structure would not only increase costs but also be a waste of materials. The metal casing confines and restricts the internal electromagnetic field, preventing electromagnetic waves from radiating outward and reducing electromagnetic losses. Structure 5, the metal transmission line, is located inside the casing and suspended within the air cavity it encloses. This structure is supported by structure 2. Each transmission line segment has a coupling portion; the coupling length (the length of the overlapping portion of two transmission lines) and the coupling distance (the distance between two transmission lines) determine the coupling strength. By adjusting these parameters, the coupling strength is changed, thereby adjusting the bandwidth, loss, and out-of-band rejection characteristics of the micro-coaxial filter. Figure 3 This is an exploded view of a three-dimensional micro-coaxial low-loss filter. Sections 1-5 refer to the structure... Figure 2 Yes, they are consistent. The exploded view clearly shows the internal structure of the three-dimensional microcoaxial structure. The radio frequency signal is not transmitted through a single, continuous metal transmission line, but rather through multiple coupled metal transmission lines. Each transmission line has a coupling portion; the coupling length (the length of the overlapping portion between two transmission lines) and the coupling distance (the distance between two transmission lines) determine the coupling strength. By adjusting these parameters, the coupling strength is changed, thereby adjusting the bandwidth, loss, and out-of-band rejection characteristics of the microcoaxial structure filter. Each transmission line is supported by a supporting structure; otherwise, it would be impossible to suspend it within the metal casing.

[0042] I. Metal grounding casing

[0043] The function of the metal grounding shell is to shield the radio frequency (RF) signal transmission line from external electromagnetic interference. Simultaneously, the transmitted RF signal is tightly confined within the cavity by the metal shell, reducing signal loss. This metal shell is a key feature of the three-dimensional micro-coaxial structure, crucial for its high-frequency, low-loss performance. The metal shell also supports the signal transmission line within the cavity. Due to the encapsulating effect of the metal grounding shell, this structure exhibits lower loss than open-structure filters (microstrip lines, striplines, coplanar waveguide filters, etc.). It is unnecessary to use an all-metal structure for the metal grounding shell, as the skin effect at high frequencies limits current to the metal surface. Therefore, using an all-metal shell would not only be a waste of material but also increase manufacturing costs. In this invention, we employ 3D printing and electroplating copper thin films to process the metal grounding shell. Using organic materials such as ABS plastic, the basic framework of the micro-coaxial structure is fabricated using 3D printing. Then, an electroplating process is used to coat the inner and outer layers of the ABS plastic model, growing a thin copper layer. This significantly reduces manufacturing costs while maintaining high electromagnetic performance. Furthermore, during 3D printing, holes need to be etched into the enclosed metal shell. These holes facilitate the uniformity of the electroplated copper thin layer. Moreover, the size of these holes is very small, and their presence does not affect the propagation of the electromagnetic field, thus not altering the electromagnetic characteristics of the 3D micro-coaxial filter. The size of the holes must be small enough to ensure that they do not affect the transmission characteristics of electromagnetic waves in the micro-coaxial filter. The specific size range must satisfy the formula: W 孔洞 <W 微同轴 / 5. Where W 孔洞 W represents the width of the square hole. 微同轴 This refers to the width of the external grounding conductor shell of the micro-coaxial filter, which is the overall width of the filter.

[0044] II. Air cavity

[0045] The air cavity refers to the portion between the grounded metal casing and the radio frequency signal transmission line. This structure, surrounded by the grounded metal casing, forms an air resonant cavity, where the transmitted electromagnetic field exists. Therefore, the loss angle and dielectric constant of the medium in this region have a significant impact on the electromagnetic characteristics of the three-dimensional micro-coaxial filter. Because the medium surrounding this cavity is air, which is close to an ideal vacuum, this three-dimensional micro-coaxial filter has very low electromagnetic loss compared to filters using silicon substrates or radio frequency boards.

[0046] III. Radio Frequency Signal Transmission Axis

[0047] The function of the radio frequency (RF) signal transmission line is to transmit RF signals, and the signal current is transmitted to the output port through this transmission line. Due to the skin effect at high frequencies, the RF current exists only on the surface of the signal transmission line. Therefore, the material properties of this signal transmission line determine the loss and filtering characteristics of the three-dimensional micro-coaxial structure filter. Gold has the best conductivity, but its processing methods and material cost are very high. Therefore, considering processing feasibility, cost, and material performance, this invention chose copper as the material for the RF transmission line. This is not only due to its low price, but also its low electromagnetic properties, such as low resistive loss. Furthermore, unlike gold, which is processed using sputtering, copper can be processed using electroplating or even machining, significantly reducing its price.

[0048] IV. Signal Transmission Line Support Structure

[0049] The function of the signal transmission line support structure is to support the radio frequency (RF) transmission line. The RF transmission line is suspended within an air cavity enclosed by a metal casing. The support structure must secure the RF transmission line to the metal casing to ensure the stability of the micro-coaxial filter's performance. This support structure must be made of insulating material; otherwise, it will short-circuit the RF transmission signal, resulting in no RF signal at the output port. The support structure consists of three parts, located below and on the left and right sides of the RF transmission line, ensuring its stable suspension within the air cavity. Figure 2 and 3 As shown, the signal transmission line support structure includes multiple support components. Each support component includes an L-shaped lower support member and a straight left and right support member. The end of the lower support member with its long side away from its short side abuts against the inner wall of the metal grounding housing, and the end that intersects with the short side is located below the metal grounding housing, and is vertically supported by the short side between the bottom of the metal grounding housing and the bottom surface of the metal transmission line. One end of the left and right support members abuts against the inner wall of the metal grounding housing, and the other end abuts against one of the side walls of the metal transmission line. The left and right support members are symmetrically arranged on both sides of the lower support member and are located on two opposite sides of the metal transmission line.

[0050] V. Three-dimensional micro coaxial cable to CPW adapter

[0051] The 3D microcoaxial cable to CPW adapter provides a necessary interface for testing filter devices. Furthermore, the device's connection to other systems also relies on the CPW. This adapter transforms the 3D structure of the microcoaxial cable into the planar structure of the CPW, improving the integrability of the structure and making it easier to apply this 3D microcoaxial filter to systems.

[0052] Figure 4The key structural dimensions of the three-dimensional micro-coaxial structure filter of this invention include the length B1L of the outer metal conductor and the length l of each inner metal conductor (microstrip). i (i = 1…7, where l1 = l4, l2 = l3, l5 = l7), coupling distance d ij (d 15 =d 47 d 25 =d 37 d 26 =d 36 Coupling ratio p i These dimensional parameters are adjusted to achieve a better filtering effect. Specific dimensional ranges are shown in Table 1.

[0053] Table 1

[0054]

[0055] Figure 5 The curve shows the electromagnetic characteristics of the three-dimensional micro-coaxial structure filter S21 with the aforementioned parameters. As can be seen from the curve, the three-dimensional micro-coaxial structure achieves filtering effect in the millimeter wave band (60GHz).

[0056] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A three-dimensional micro-coaxial structure coupled filter applying millimeter wave communication, characterized by, The three-dimensional micro-coaxial structure coupling filter includes a metal grounded shell, a signal transmission axis, a signal transmission line support structure, and a three-dimensional micro-coaxial line to coplanar waveguide adapter interface. The signal transmission axis is suspended in an air cavity inside a metal grounded shell via a signal transmission line support structure. An air resonant cavity for transmitting electromagnetic fields is formed between the metal grounded shell and the signal transmission axis. The signal transmission axis includes multiple metal transmission lines arranged in two columns and staggered. All metal transmission lines have the same transmission direction and are coupled to each other. The coupling strength is adjusted by adjusting the coupling length and coupling distance of the coupled parts, thereby adjusting the bandwidth, loss, and out-of-band suppression characteristics of the three-dimensional micro-coaxial structure coupling filter. The three-dimensional micro-coaxial cable to coplanar waveguide adapter is installed at one end of the metal grounded housing and connected to the signal transmission axis, transforming the three-dimensional structure of the micro-coaxial cable into the planar structure of the coplanar waveguide. 2.The three-dimensional micro-coaxial structure coupled filter using millimeter wave communication according to claim 1, wherein, The signal transmission line support structure includes multiple support components. Each support component includes an L-shaped lower support member and a straight left and right support member. The end of the lower support member with its long side away from its short side abuts against the inner wall of the metal grounding housing, and the end that intersects with the short side is located below the metal grounding housing, and is vertically supported by the short side between the bottom of the metal grounding housing and the bottom surface of the metal transmission line. One end of the left and right support members abuts against the inner wall of the metal grounding housing, and the other end abuts against one of the side walls of the metal transmission line. The left and right support members are symmetrically arranged on both sides of the lower support member and are located on two opposite sides of the metal transmission line. 3.The three-dimensional micro-coaxial structure coupled filter for millimeter-wave communication of claim 1, wherein, The signal transmission line support structure is made of insulating material. 4.The three-dimensional micro-coaxial structure coupled filter for millimeter-wave communication of claim 1, wherein, The metal transmission line is made of copper. 5.The three-dimensional micro-coaxial structure coupled filter for millimeter-wave communication of claim 1, wherein, The side wall of the metal grounding shell is periodically provided with holes; the size of the holes satisfies the following condition: W 孔洞 <W 微同轴 / 5; wherein W 孔洞 represents the width of the square hole, W 微同轴 is the width of the metal grounding shell. 6.The three-dimensional micro-coaxial structure coupled filter for millimeter-wave communication of claim 1, wherein, The metal grounding housing includes a micro-coaxial frame supported by organic material and a metal layer electroplated on the surface of the micro-coaxial frame.

7. The three-dimensional micro-coaxial structure coupled filter for millimeter wave communication according to claim 6, wherein The micro-coaxial frame is manufactured using 3D printing.

8. The three-dimensional micro-coaxial structure coupled filter for millimeter wave communication according to claim 6, wherein, The metal layer is made of copper. 9.The three-dimensional micro-coaxial structure coupled filter for millimeter-wave communication of claim 1, wherein, The length of the metal transmission line ranges from 1.96 mm to 2.04 mm; the coupling length of the coupling part ranges from 0.375 mm to 0.425 mm; and the coupling distance of the coupling part ranges from 0.03 mm to 0.11 mm.

10. A method for manufacturing a three-dimensional micro coaxial structure coupled filter according to any one of claims 1 to 9, characterized by, The manufacturing method includes the following steps: A micro-coaxial frame is fabricated using 3D printing technology. The micro-coaxial frame consists of an upper frame and a lower frame. The lower frame has a first groove at its center, and first steps are periodically arranged on both sides of the first groove. The upper frame has a second groove at its center, which is opposite to the first groove. Second steps are periodically arranged on both sides of the second groove. The second steps are connected by a connecting shaft to form a first periodic hole on the upper surface of the upper frame. The first and second steps are opposite to each other, and after the first and second steps are connected, the lower frame, combined with the connecting shaft, forms a second periodic hole on its lower surface. Metal layers are plated on the inner and outer sides of the micro-coaxial frame using an electroplating process to obtain a metal grounding shell; The metal transmission line is suspended in the air cavity of the metal ground shell by a transmission line support structure, the coupling length and the coupling distance of the coupling part are adjusted to adjust the coupling strength, and then the bandwidth, the loss and the out-of-band suppression characteristics of the three-dimensional micro coaxial structure coupled filter are adjusted; A three-dimensional micro coaxial line to coplanar waveguide adapter is connected to one end of the metal ground shell.

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