CN218215635U - Air coaxial transmission line based on gap waveguide packaging - Google Patents

Abstract

The utility model provides a coaxial transmission line of air based on clearance waveguide encapsulation, including metal sheet and last metal sheet down, the top surface of metal sheet has a plurality of metal band gap posts down, transmission line inner conductor and a plurality of metal support columns, and the transmission line inner conductor is supported by the metal support column, makes the unsettled setting in metal sheet down of transmission line inner conductor, has the air gap between the bottom surface of going up the metal sheet and the top surface of metal band gap post, goes up the bottom surface of metal sheet, electromagnetism band gap structure and the top surface of metal sheet constitutes the transmission line outer conductor down. The utility model provides an air coaxial transmission line based on clearance waveguide encapsulation utilizes the electromagnetic band gap structure of clearance waveguide, under the broadband of not sacrificing air coaxial transmission line, low-loss transmission performance's prerequisite, the equivalent has replaced the outer conductor of air coaxial transmission line, has realized that electromagnetic shielding performance is good, processing and simple packaging structure of assembly have reached the purpose that the metal sheet subtracts heavy and manufacturing process flexibility promotes.

Description

Air coaxial transmission line based on gap waveguide packaging

Technical Field

The utility model belongs to the technical field of the microwave, more specifically say, relate to a coaxial transmission line of air based on clearance waveguide encapsulation.

Background

The air coaxial transmission line adopts air as a coaxial line medium, has the advantages of small dielectric loss, small dispersion loss, small crosstalk with an adjacent channel and strong structural flexibility, and can support TEM mode broadband single-mode transmission. The air coaxial transmission line architecture has been applied to various microwave and millimeter wave passive devices, such as resonator filters, antenna feed networks, transition couplers, power dividers, and the like. An air coaxial transmission line includes an inner conductor, an air medium and an outer conductor, wherein the inner conductor is usually connected with the outer conductor by a plurality of terminal short-circuit branches or supported by a layer of low-loss dielectric film so as to be suspended in the air medium, and the outer conductor is usually a closed metal shell. Two main challenges exist in manufacturing the air coaxial transmission line structure, and firstly, the inner conductor and the outer conductor of the air coaxial transmission line are required to have good conductive performance and electromagnetic shielding performance, so that radio frequency loss caused by processing and assembling errors of the air coaxial transmission line is minimized; second, the structural material of the air coaxial transmission line is required to have high compatibility with the processing process, so as to simplify the manufacturing process of the inner conductor suspension structure to the maximum extent.

In the traditional technology, an air coaxial transmission line structure working in a millimeter wave to submillimeter wave frequency band is often manufactured by adopting a high-precision photoresist thick film or silicon-based micromachining process, the processing procedure is complex, the cost is high, the multilayer structure stacking is required to be realized, and the requirement on the assembly precision is high; the air coaxial transmission line structure working in the microwave low frequency band can be realized by adopting a multilayer Printed Circuit Board (PCB) process, or the mixed integration of the PCB and a metal cavity, and can also be manufactured and molded integrally by adopting a 3-D printing process. The following problems mainly exist in the processing of air coaxial transmission line structures by these manufacturing techniques: (1) Release holes (fabrication holes) are needed to be designed on the coaxial outer conductor for etching the sacrificial layer material of the coaxial medium region or assisting the metallization treatment of the inner surface of the coaxial line, and the existence of the release holes makes modeling and processing more complicated; (2) The closed structure of the coaxial line makes the process quality of the inner surface difficult to control, and easily generates structural defects, which causes the deterioration of the radio frequency performance of the coaxial line, and the internal structural defects are difficult to detect in the processing process; (3) The air coaxial transmission line manufactured by stacking and laminating a multilayer structure has alignment errors and gaps among layers, and ray performance is easy to deteriorate.

SUMMERY OF THE UTILITY MODEL

An object of the embodiment of the utility model is to provide an air coaxial transmission line based on clearance waveguide encapsulation, under the broadband of not sacrificing air coaxial transmission line, low-loss transmission performance's prerequisite, as an alternative scheme of traditional air coaxial transmission line structure, realize good electromagnetic shielding performance and convenient, accurate processing and assembly.

In order to achieve the above object, the utility model adopts the following technical scheme: the utility model provides a coaxial transmission line of air based on clearance waveguide encapsulation, includes the metal sheet down and is fixed in the last metal sheet of metal sheet down, down the metal sheet towards go up metal sheet one side does the top surface of metal sheet down, the face of going up the metal sheet is down metal sheet one side does the bottom surface of going up the metal sheet, the top surface of metal sheet has the metal band gap post, transmission line inner conductor and a plurality of metal support post that a plurality of arrays set up down, the transmission line inner conductor by the metal support post supports, makes the transmission line inner conductor unsettled set up in the metal sheet down, go up the bottom surface of metal sheet with have the air gap between the top surface of metal band gap post, the metal band gap post down the metal sheet with the partial top surface of metal band gap post junction, go up the metal sheet with the part bottom surface that the metal band gap post just right forms the electromagnetic band gap structure of clearance waveguide jointly, go up the bottom surface of metal sheet, electromagnetic band gap structure with the top surface of metal sheet constitutes the transmission line outer conductor down.

Optionally, one side of the lower metal plate, which faces the upper metal plate, is further provided with a plurality of branch inner conductors, one ends of the branch inner conductors are connected to the transmission line inner conductors, the other ends of the branch inner conductors are connected to the metal supporting columns, the lengths of the branch inner conductors are quarter waveguide wavelengths, and the waveguide wavelengths are waveguide wavelengths corresponding to the central frequency of the working frequency band of the air coaxial transmission line.

Optionally, one side of the branch inner conductor close to the upper metal plate and one side of the transmission line inner conductor close to the upper metal plate are arranged in a coplanar manner.

Optionally, the cross-sectional dimensions of the branch inner conductor and the transmission line inner conductor are the same.

Optionally, a midpoint of the transmission line inner conductor is a symmetry center, and the branch segment inner conductors are arranged in central symmetry or axial symmetry with respect to the symmetry center.

Optionally, the metal band gap pillars are disposed on both sides of the transmission line inner conductor, and the heights of the metal band gap pillars are equal.

Optionally, the metal band gap pillars on the same side of the transmission line inner conductor have at least two rows, and each row of the metal band gap pillars is arranged along the length direction of the transmission line inner conductor.

Optionally, a sunken groove is formed in the lower metal plate, and the plurality of metal supporting columns are arranged in the sunken groove.

Optionally, the air coaxial transmission line based on gap waveguide packaging further includes a coaxial connector, a first through hole axially disposed at an end of the transmission line inner conductor, the lower metal plate is opposite to a second through hole penetrating through the first through hole, the inner conductor of the coaxial connector passes through the second through hole and is inserted into the first through hole, and a medium is disposed between a hole wall of the second through hole and the inner conductor of the coaxial connector.

Optionally, the second through hole includes a first hole section and a second hole section that are coaxially disposed, a connection portion of the first hole section and the second hole section is formed with a shoulder, the second hole section is disposed close to the first through hole, an inner wall of the first hole section forms an outer conductor of the coaxial connector, a medium of the coaxial connector is disposed between the inner wall of the first hole section and the inner conductor of the coaxial connector, and an air medium is disposed between the inner wall of the second hole section and the inner conductor of the coaxial connector.

The utility model provides a coaxial transmission line of air based on clearance waveguide encapsulation's beneficial effect lies in: (1) The electromagnetic band gap structure of the gap waveguide is utilized to equivalently replace the outer conductor of the traditional air coaxial transmission line (the outer conductor of the transmission line in the prior art is usually a solid metal wall), so that a good electromagnetic shielding effect is achieved, and the radio frequency loss caused by the existence of gaps in the laminating process of the traditional outer conductor structure is avoided; (2) The packaging structure is simple to process and assemble, the broadband and low-loss transmission performance of the air coaxial transmission line is not sacrificed by 'equivalent substitution', particularly, the packaging structure is compatible with a metal computer numerical control milling (CNC) process, and the conductive performance of the packaging structure material is good; (3) The electromagnetic band gap structure of the gap waveguide is introduced, so that the outer conductor part is hollowed out, and the hollowed-out structure essentially belongs to the functional structure of the gap waveguide, so that additional process holes do not need to be designed; (4) The outer conductor with the partially hollowed-out part enables execution of a machining procedure and quality inspection to be more convenient and faster.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive labor.

Fig. 1 is a three-dimensional disassembled structure diagram of an air coaxial transmission line based on gap waveguide package according to an embodiment of the present invention;

FIG. 2 is a perspective half-sectional view of the lower metal plate, the transmission line inner conductor, and the electromagnetic bandgap structure of FIG. 1;

FIG. 3 is a perspective view of the transmission line inner conductor, branch section inner conductor and metal support column of FIG. 1;

fig. 4 is an air cavity simulation model of an air coaxial transmission line based on gap waveguide package according to an embodiment of the present invention;

FIG. 5 is an enlarged view of the left end of FIG. 4;

FIG. 6 is a graph of a scattering parameter for the model of FIG. 4 without the structure of FIG. 5;

FIG. 7 is a graph of scattering parameters for the model of FIG. 5;

FIG. 8 is a simulated dispersion map of the periodic cell structure of the gap waveguide of FIG. 1;

fig. 9 is a scattering parameter graph of a simulation of an air coaxial transmission line based on gap waveguide package according to an embodiment of the present invention;

fig. 10 is a scattering parameter graph of simulation and measurement of an air coaxial transmission line based on gap waveguide package according to an embodiment of the present invention;

FIG. 11 is a graph of the transmission coefficients (S) of FIG. 10 ₂₁ ) A zoomed-in view of the curve;

fig. 12 is a graph illustrating the radio frequency loss according to simulation and measurement of an air coaxial transmission line based on gap waveguide package according to an embodiment of the present invention;

fig. 13 is a simulation and measurement S of an air coaxial transmission line based on gap waveguide package provided by an embodiment of the present invention ₂₁ Graph of group delay of the parameters.

Wherein, in the figures, the respective reference numerals:

1-lower metal plate; 11-a second via; 111-a first bore section; 112-a second bore section; 12-a threaded hole; 2-upper metal plate; 21-connecting hole; 3-a transmission line inner conductor; 30-a first via; 4-branch inner conductor; 5-a metal support post; 6-electromagnetic bandgap structure; 60-metal band gap pillars; 71-inner conductor of coaxial connector; 72-medium of coaxial connector; 73-air medium.

Detailed Description

In order to make the technical problem, technical solution and advantageous effects to be solved by the present invention more clearly understood, the following description is given in conjunction with the accompanying drawings and embodiments to illustrate the present invention in further detail. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element.

It will be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "top," "bottom," "inner," "outer," and the like are used in the orientation or positional relationship indicated in the drawings for convenience in describing the invention and to simplify the description, and do not indicate or imply that the device or element so referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or to implicitly indicate the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically limited otherwise.

The embodiment of the present invention provides an air coaxial transmission line based on gap waveguide package.

Referring to fig. 1 to 3, fig. 1 is a three-dimensional disassembled structure diagram of an air coaxial transmission line based on gap waveguide package according to an embodiment of the present invention, fig. 2 is a three-dimensional half-sectional view of a lower metal plate 1, a transmission line inner conductor 3, and an electromagnetic band gap structure 6 in fig. 1, and fig. 3 is a three-dimensional structure diagram of a transmission line inner conductor 3, a branch section inner conductor 4, and a metal supporting pillar 5 in fig. 1. The air coaxial transmission line comprises a lower metal plate 1 and an upper metal plate 2, wherein the lower metal plate 1 is fixedly connected with the upper metal plate 2. One side of the lower metal plate 1 facing the upper metal plate 2 is the top surface of the lower metal plate 1, and one side of the upper metal plate 2 facing the lower metal plate 1 is the bottom surface of the upper metal plate 2. The top surface of lower metal sheet 1 has metal band gap post 60, transmission line inner conductor 3 and a plurality of metal support post 5 that a plurality of arrays set up, and a plurality of metal support posts 5 are used for supporting transmission line inner conductor 3, make transmission line inner conductor 3 unsettled set up in lower metal sheet 1, have the air gap between the bottom surface of last metal sheet 2 and the top surface of metal band gap post 60, are air medium around the transmission line inner conductor 3. The metal band gap column 60, the partial top surface of the lower metal plate 1 connected with the metal band gap column 60, and the partial bottom surface of the upper metal plate 2 opposite to the metal band gap column 60 jointly form the electromagnetic band gap structure 6 of the gap waveguide. The bottom surface of the upper metal plate 2, the electromagnetic bandgap structure 6 and the top surface of the lower metal plate 1 constitute the transmission line outer conductor. The transmission line outer conductor, the air medium and the transmission line inner conductor 3 together constitute an air coaxial transmission line.

The air coaxial transmission line in the above embodiment, (1) the electromagnetic band gap structure 6 of the gap waveguide is used to equivalently replace the outer conductor of the conventional air coaxial transmission line (the outer conductor of the transmission line in the prior art is usually a solid metal wall), so as to achieve a good electromagnetic shielding effect, and avoid the radio frequency loss caused by the existence of the gap in the lamination process of the conventional outer conductor structure; (2) The processing and the assembly are simple, the broadband and low-loss transmission performance of the air coaxial transmission line is not sacrificed by 'equivalent substitution', particularly, the packaging structure is compatible with a computer numerical control milling (CNC) process of metal, and the conductivity of the packaging structure material is good; (3) The electromagnetic band gap structure 6 of the gap waveguide is introduced, so that the outer conductor part is hollowed out, and the hollowed-out structure essentially belongs to a functional structure of the gap waveguide, so that an additional process hole is not required to be designed; (4) The outer conductor with the partially hollowed-out part enables execution of a machining procedure and quality inspection to be more convenient and faster.

Wherein the transmission line inner conductor 3 and the transmission line outer conductor are coaxially arranged, i.e. both have a common central axis.

Alternatively, the air coaxial transmission line is a rectangular coaxial structure, i.e., the cross section of the transmission line inner conductor 3 is rectangular, and the boundary profile of the transmission line outer conductor is rectangular. Alternatively, the air coaxial transmission line has a circular coaxial structure, i.e., the cross section of the transmission line inner conductor 3 is circular, and the boundary profile of the transmission line outer conductor is circular.

In one embodiment of the present invention, referring to fig. 1 and 3, the top side of the lower metal plate 1 has a plurality of branch inner conductors 4, and the plurality of branch inner conductors 4 are used for supporting the transmission line inner conductor 3, so that the transmission line inner conductor 3 is suspended. One end of the branch inner conductor 4 is connected with the transmission line inner conductor 3, and the other end of the branch inner conductor 4 is connected with the transmission line outer conductor in a short circuit mode. The length of each branch section inner conductor 4 is a quarter of the waveguide wavelength, and the waveguide wavelength here refers to the waveguide wavelength corresponding to the central frequency of the working frequency band of the air coaxial transmission line.

The transmission line inner conductor 3 may be linear or curved, and the specific shape is not limited herein.

Optionally, one end of each branch inner conductor 4, which is far away from the transmission line inner conductor 3, is connected to the metal support columns 5 in a short circuit manner, the number of the branch inner conductors 4 is the same as that of the metal support columns 5, and each branch inner conductor 4 is supported by one corresponding metal support column 5, that is, both the branch inner conductor 4 and the transmission line inner conductor 3 are supported by the metal support columns 5.

Optionally, one side of the branch inner conductor 4 close to the upper metal plate 2 and one side of the transmission line inner conductor 3 close to the upper metal plate 2 are arranged in a coplanar manner, so that the branch inner conductor 4 and the transmission line inner conductor 3 can be conveniently machined and molded. In other embodiments, the side of the branch inner conductor 4 close to the upper metal plate 2 and the side of the transmission line inner conductor 3 close to the upper metal plate 2 may not be coplanar.

Optionally, the cross-sectional dimensions of the stub inner conductor 4 and the transmission line inner conductor 3 are the same, so that the design and modeling of the stub inner conductor 4 and the transmission line inner conductor 3 are simplified.

In one embodiment of the present invention, referring to fig. 3, the midpoint of the transmission line inner conductor 3 is a symmetric center, and the plurality of branch inner conductors 4 are distributed in a central symmetry manner about the symmetric center. The number of the branch inner conductors 4 is even, and the same number of branch inner conductors 4 are respectively arranged on two sides of the transmission line inner conductor 3. For example, the number of the branch inner conductors 4 is four, two branch inner conductors 4 are disposed on opposite sides of the transmission line inner conductor 3, and the four branch inner conductors 4 are distributed in central symmetry with respect to the above-mentioned symmetry center.

In another embodiment of the present invention, the center plane of the transmission line inner conductor 3 in the length direction is used as a symmetry plane, and the plurality of branch inner conductors 4 are distributed in axial symmetry with respect to the symmetry plane.

In one embodiment of the present invention, referring to fig. 1 and 2, the transmission line outer conductor is replaced by the electromagnetic bandgap structure 6 of the gap waveguide, the electromagnetic bandgap structure 6 includes a plurality of metal bandgap columns 60 distributed in an array, the adjacent metal bandgap columns 60 are spaced apart from each other, the heights of the metal bandgap columns 60 are the same, and when the upper metal plate 2 is fixed to the lower metal plate 1, an air gap is formed between the bottom surface of the upper metal plate 2 and the top surface of the metal bandgap column 60. The opposite sides of the transmission line inner conductor 3 are provided with metal band gap pillars 60, so that the electromagnetic band gap structure 6 is arranged coaxially with the transmission line inner conductor 3. The cross section of metal band gap pillar 60 may be square or circular in shape.

Alternatively, in order to achieve good electromagnetic shielding performance, the metal band-gap pillars 60 located on the same side of the transmission line inner conductor 3 have at least two columns, and the metal band-gap pillars 60 may have two, three or more columns, wherein each column of metal band-gap pillars 60 is arranged along the length direction of the transmission line inner conductor 3.

In one embodiment of the present invention, referring to fig. 1, the lower metal plate 1 is provided with a sinking groove, and the plurality of metal supporting pillars 5 are all disposed in the sinking groove. The sinking grooves are arranged on two opposite sides of the lower metal plate 1, and the number and the positions of the sinking grooves are determined by the number and the positions of the branch inner conductors 4 and the metal supporting columns 5.

The upper metal plate 2 is covered on the lower metal plate 1, the upper metal plate 2 can be flat, and the upper metal plate 2 and the lower metal plate 1 can be fixedly connected through fixing parts such as threaded parts. For example, the upper metal plate 2 is formed with a connection hole 21, the connection hole 21 is a through hole, the lower metal plate 1 is formed with a screw hole 12, and a screw passes through the connection hole 21 and is connected to the screw hole 12, so that the upper metal plate 2 and the lower metal plate 1 are fixed to each other.

In one embodiment of the present invention, the air coaxial transmission line based on the gap waveguide package further includes a coaxial connector, the end of the transmission line inner conductor 3 has a first through hole 30, the lower metal plate 1 has a second through hole 11 opposite to the first through hole 30, the second through hole 11 is disposed through the lower metal plate 1, and the second through hole 11 is used for installing the coaxial connector. Specifically, the inner conductor 71 of the coaxial connector passes through the second through hole 11 and is inserted into the interior of the first through hole 30, at least a part of the hole wall of the second through hole 11 forms the outer conductor of the coaxial connector, and a medium is provided between the outer conductor of the coaxial connector and the inner conductor 71 of the coaxial connector. First through holes 30 are formed at two ends of the transmission line inner conductor 3, and second through holes 11 are formed at two opposite sides of the lower metal plate 1, so that the coaxial connectors can be connected to two opposite sides of the lower metal plate 1.

Optionally, the second through hole 11 includes a first hole section 111 and a second hole section 112 connected to each other, the first hole section 111 and the second hole section 112 are coaxially disposed, and inner diameters of the first hole section 111 and the second hole section 112 are different, so that a joint of the first hole section 111 and the second hole section 112 forms a shoulder. The second bore section 112 is arranged close to the first through hole 30 such that the inner wall of the second through hole 11, the inner conductor 71 of the coaxial connector and the medium between them form a transitional coaxial line. The inner wall of the first bore section 111 forms the outer conductor of the coaxial connector, the medium 72 of the coaxial connector is arranged between the inner wall of the first bore section 111 and the inner conductor 71 of the coaxial connector, and the medium 72 of the coaxial connector can be solid or air. An air medium 73 is provided between the inner wall of the second bore section 112 and the inner conductor 71 of the coaxial connector.

In other embodiments, the electromagnetic bandgap structure 6, the transmission line inner conductor 3 and the plurality of metal supporting pillars 5 may be disposed to protrude from the top side of the lower metal plate 1, two sides of the upper metal plate 2 extend toward the lower metal plate 1 to form a supporting structure, and the second through hole 11 is opened on the supporting structure.

The characteristic impedance of the air coaxial transmission line is 50 ohms, and can be 30 ohms, 70 ohms and the like.

Referring to fig. 4 and 5, fig. 4 is an air cavity simulation model of an air coaxial transmission line based on gap waveguide package according to an embodiment of the present invention, and fig. 5 is an enlarged structure diagram of the left end in fig. 4. In order to measure the radio frequency performance of the air coaxial transmission line, a pair of coaxial connectors is installed on the metal shell of the air coaxial transmission line as shown in fig. 4, the inner conductor 71 of the coaxial connector is inserted into the first through hole 30 of the inner conductor 3 of the transmission line, the medium 72 of the coaxial connector is inserted into the second through hole 11, and the transition from the air coaxial transmission line to the coaxial connector is realized through a stepped transition coaxial line. The inner conductor of the transition coaxial line is the inner conductor 71 of the coaxial connector, the outer conductor of the transition coaxial line is the second through hole 11, and the medium of the transition coaxial line is air.

Referring to fig. 6 and 7, fig. 6 is a graph of scattering parameters of the model of fig. 4 without the structure of fig. 5, and fig. 7 is a graph of scattering parameters of the model of fig. 5. Simulation results show that the air coaxial transmission line has broadband and low-loss transmission performance, and the reflection coefficient of the air coaxial transmission line in a K full frequency band is less than-25 dB; the transition coaxial line also has broadband and low-loss transmission performance, and the reflection coefficient of most frequency points at 16-28GHz is less than-20 dB; the air coaxial transmission line after the transition coaxial line is cascaded has a reflection coefficient of less than-17 dB and an insertion loss of 0.2-0.4dB in a K full frequency band.

The utility model discloses utilize clearance waveguide's periodic electromagnetic band gap structure 6, the outer conductor (being solid metal wall usually) that traditional air coaxial transmission line has been replaced to the equivalence, has played good electromagnetic shield effect, can avoid traditional outer conductor structure because of there being the radio frequency loss that the gap produced at range upon range of in-process, and this forbidden band that just requires clearance waveguide covers the bandwidth of air coaxial transmission line completely. Therefore, in order to obtain a forbidden band characteristic covering the K full band, electromagnetic simulation is performed on the periodic unit structure of the gap waveguide. The side length, height, spacing and air gap height of the periodic cell structure of the gap waveguide affect the forbidden bandwidth, which is characterized by the dispersion map. Referring to fig. 8, fig. 8 is a simulated dispersion map of the periodic cell structure of the gapped waveguide of fig. 1. Under a set of preferred dimensions, the gap waveguide has a forbidden band coverage of 10-60GHz, a corresponding air gap height of 0.05 mm, a metal band gap pillar 60 with a side length of 1.5 mm, a height of 2.35 mm, and a spacing of 1.5 mm.

Referring to fig. 9, fig. 9 is a scattering parameter curve diagram of a simulation of an air coaxial transmission line based on gap waveguide package according to an embodiment of the present invention. In the figure, the transmission performances of the air coaxial transmission line before and after being packaged by the gap waveguide are compared, and the simulated transmission performances are consistent and identical, which shows that the broadband and low-loss transmission performance of the air coaxial transmission line is not sacrificed in the equivalent substitution. Particularly, the packaging structure is compatible with a metal CNC (computerized numerical control) process, the conductivity of the packaging structure material is good, and the good electromagnetic shielding performance of the air coaxial transmission line is further guaranteed.

Referring to fig. 10 to 13, fig. 10 is a scattering parameter graph of simulation and measurement of an air coaxial transmission line based on gap waveguide package according to an embodiment of the present invention, and fig. 11 is a transmission coefficient (S) in fig. 10 ₂₁ ) The drawing of curve, fig. 12 is the embodiment of the utility model provides a simulation and measured radio frequency loss curve graph of coaxial transmission line of air based on clearance waveguide encapsulation, fig. 13 is the embodiment of the utility model provides a simulation and measured S of coaxial transmission line of air based on clearance waveguide encapsulation ₂₁ Graph of group delay of the parameters. The insertion loss measured by the packaged air coaxial transmission line is 0.36-1.09dB at 16-28 GHz; the measured return loss is about 10dB at the worst, and is deteriorated to a certain extent compared with a simulation result, which is mainly caused by poor contact between the inner conductor 71 of the coaxial connector and the inner conductor 3 of the transmission line, and the processing error also causes the deterioration of the return loss; the radio frequency loss calculated by the test data is less than 0.92dB, and after the radio frequency loss introduced by the coaxial connector is removed, the attenuation factor of the air coaxial transmission line is calculated to be 0.09-0.39dB/cm; s ₂₁ The group delay response of the parameters is flat, the group delay is 0.12-0.16ns, the fluctuation is less than 20ps, and the low dispersion characteristic of the air coaxial transmission line is verified.

Key structural dimensions of a preferred set of gap waveguide package based air coaxial transmission lines corresponding to the simulation results in fig. 10-13 are as follows.

The cross section of the transmission line inner conductor 3 is square, the side length is 0.96 mm, and the side length of the cross section of the gap waveguide equivalent outer conductor is 2.4 mm; the height of the metal support column 5 is 4 mm, the distance between two branch inner conductors 4 positioned on the same side of the transmission line inner conductor 3 is 4.2 mm, and the distance between the end surface of the transmission line inner conductor 3 and the adjacent branch inner conductor 4 is 5.8 mm; the end face of the transmission line inner conductor 3 is 0.45 mm away from the inner side wall of the lower metal plate 1, and the diameter of the second hole section 112 is 0.84 mm; the side length of the metal band gap column 60 is 1.5 mm, the height is 2.35 mm, the distance is 1.5 mm, and the air gap is 0.05 mm; the upper metal plate 2 and the lower metal plate 1 have a total length of 20 mm, a total width of 15 mm and a total height of 16.4 mm after being mounted.

In the embodiments provided in the present invention, it should be understood that the disclosed gap waveguide packaging scheme of the air coaxial transmission line can be generally applied to devices with other air coaxial transmission line architectures, the structure of the air coaxial transmission line is only schematic, and in practical application, the path of the air coaxial transmission line packaged by the gap waveguide can be flexibly designed according to the radio frequency index requirement and the circuit layout. In addition, the packaging scheme provides convenience for the air coaxial transmission line framework to adopt metal CNC machining, and further proves the flexibility of the manufacturing process of the air coaxial transmission line.

The above description is only exemplary of the present invention and should not be taken as limiting the scope of the present invention, as any modifications, equivalents, improvements and the like made within the spirit and principles of the present invention are intended to be included within the scope of the present invention.

Claims (10)

1. An air coaxial transmission line based on gap waveguide package, its characterized in that: include the metal sheet down and be fixed in the last metal sheet of metal sheet down, down the metal sheet towards go up metal sheet one side do down the top surface of metal sheet, the orientation of going up the metal sheet do down metal sheet one side does the bottom surface of going up the metal sheet, the top surface of metal sheet has the metal band gap post, transmission line inner conductor and a plurality of metal support post that a plurality of arrays set up down, the transmission line inner conductor by the metal support post supports, makes the unsettled setting in of transmission line inner conductor is in down the metal sheet, go up the bottom surface of metal sheet with have the air gap between the top surface of metal band gap post, the metal band gap post down the metal sheet with the partial top surface of metal band gap post junction, go up the metal sheet with the partial bottom surface that the metal band gap post just right forms the electromagnetic band gap structure of gap waveguide jointly, the bottom surface of going up the metal sheet, the electromagnetic band gap structure with the top surface of metal sheet constitutes the transmission line outer conductor down.

2. The gap waveguide package based air coaxial transmission line of claim 1, wherein: the lower metal plate faces the upper metal plate, a plurality of branch inner conductors are further arranged on one side of the lower metal plate, one ends of the branch inner conductors are connected with the transmission line inner conductors, the other ends of the branch inner conductors are connected with the metal supporting columns, the length of each branch inner conductor is a quarter of waveguide wavelength, and the waveguide wavelength is the waveguide wavelength corresponding to the central frequency of the working frequency band of the air coaxial transmission line.

3. The gap waveguide package based air coaxial transmission line of claim 2, wherein: one side of the branch inner conductor, which is close to the upper metal plate, and one side of the transmission line inner conductor, which is close to the upper metal plate, are arranged in a coplanar manner.

4. The gap waveguide package based air coaxial transmission line of claim 2, wherein: the cross section sizes of the branch inner conductor and the transmission line inner conductor are the same.

5. The gap waveguide package based air coaxial transmission line of claim 2, wherein: the middle point of the transmission line inner conductor is a symmetrical center, and the branch section inner conductors are arranged in central symmetry or axial symmetry relative to the symmetrical center.

6. The gap waveguide package based air coaxial transmission line of claim 1, wherein: the two sides of the transmission line inner conductor are provided with the metal band gap columns, and the heights of the metal band gap columns are equal.

7. The gap waveguide package based air coaxial transmission line of claim 6, wherein: the metal band gap columns positioned on the same side of the transmission line inner conductor are at least provided with two columns, and each column of the metal band gap columns are arranged along the length direction of the transmission line inner conductor.

8. The gap waveguide package based air coaxial transmission line of claim 1, wherein: the lower metal plate is provided with a sinking groove, and the metal supporting columns are arranged in the sinking groove.

9. The gap waveguide package based air coaxial transmission line of claim 8, wherein: the coaxial connector comprises a transmission line inner conductor and is characterized by further comprising a coaxial connector, a first through hole is formed in the end portion of the transmission line inner conductor and is axially arranged along the transmission line inner conductor, the lower metal plate is right opposite to the first through hole, a second through hole penetrating through the lower metal plate is formed in the first through hole, the inner conductor of the coaxial connector penetrates through the second through hole and is inserted into the first through hole, and a medium is arranged between the hole wall of the second through hole and the inner conductor of the coaxial connector.

10. The gap waveguide package based air coaxial transmission line of claim 9, wherein: the second through hole comprises a first hole section and a second hole section which are coaxially arranged, a shaft shoulder is formed at the joint of the first hole section and the second hole section, the second hole section is close to the first through hole, the inner wall of the first hole section forms the outer conductor of the coaxial connector, the inner wall of the first hole section and the inner conductor of the coaxial connector are provided with the medium of the coaxial connector, and the inner wall of the second hole section and the inner conductor of the coaxial connector are provided with the air medium.

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