CN111106416B

CN111106416B - Substrate integrated coaxial line feed broadband circular waveguide rotary joint

Info

Publication number: CN111106416B
Application number: CN201911402808.1A
Authority: CN
Inventors: 施金; 赵亮; 徐凯
Original assignee: Nantong University; Nantong Research Institute for Advanced Communication Technologies Co Ltd
Current assignee: Nantong University; Nantong Research Institute for Advanced Communication Technologies Co Ltd
Priority date: 2019-12-31
Filing date: 2019-12-31
Publication date: 2021-12-10
Anticipated expiration: 2039-12-31
Also published as: CN111106416A

Abstract

The invention discloses a substrate integrated coaxial line feed broadband circular waveguide rotary joint, which comprises: the device comprises two same substrate integrated coaxial line feeds and a circular waveguide which is vertically connected with the two substrate integrated coaxial line feeds. The substrate integrated coaxial line feed comprises a top metal layer, an upper medium substrate, a middle metal layer, a lower medium substrate, a bottom metal layer and metal through holes communicated with all the layers which are sequentially stacked from top to bottom to form a substrate integrated coaxial line and a substrate integrated circular cavity. The middle metal layer is of a linear structure, and the terminal is positioned in the substrate integrated circular cavity and is circular. And a metal connecting hole is formed in the center of the terminal and is vertically connected to the top metal layer. And the top metal layer is also provided with an annular coupling groove which is positioned in the substrate integrated circular cavity. The invention solves the problems that the existing circular waveguide rotary joint can not simultaneously meet the requirements of broadband, has simple structure and is easy to be connected with a substrate integrated system, and particularly has obvious improvement on the bandwidth.

Description

Substrate integrated coaxial line feed broadband circular waveguide rotary joint

Technical Field

The invention relates to the field of microwave communication, in particular to a microwave broadband circular waveguide rotary joint.

Background

The rotary joint has a rotation function and can stably transmit signals, and is widely applied to communication systems such as radars, satellite communication, communication in motion, microwave darkroom turntables and the like, and provides the system with an azimuth angle of 360 degrees or +/-90 degrees rotation in pitching. Since the rotary joint requires a rotationally symmetric field distribution, generally, a rotating body of the rotary joint is mainly classified into a coaxial type or a circular waveguide type. In which a coaxial rotating body transmits a wide-band TEM mode, but the structure is complicated. Circular waveguide type rotating body mainly uses rotationally symmetric TM₀₁And the structure is simple. The feeding form of the rotary joint is determined by the application environment of the rotary joint. At present, the substrate integrated coaxial line has the characteristics of high integration, wide bandwidth, small loss, small size, simple manufacturing process, low cost, light weight, good shielding property, non-dispersive property and the like, so that the substrate integrated coaxial line is widely applied to a microwave system with high integration level and wide band. In summary, the circular waveguide rotary joint for substrate integrated coaxial line feeding is suitable for the substrate integrated coaxial line system, and the rotary part has a simple structure, so that the rotary joint can be used for solving the problem of obtaining enough bandwidthThe problem of the rotary transmission of the substrate integrated coaxial line system is solved.

Various rotary joint design techniques based on a circular waveguide rotary body have been reported. Most of the circular waveguide rotary joints adopt the traditional transmission lines such as rectangular waveguide to feed, and use TE in the rectangular waveguide₁₀TM in mode-excited circular waveguide₀₁Or TE₀₁The mode, however, the feed volume of the circular waveguide rotary joint is large, the circular waveguide rotary joint is not easy to integrate, and the bandwidth is narrow. Few designs use substrate integrated waveguide to feed the circular waveguide rotating body, such as using single-layer substrate integrated waveguide fed plug-in substrate integrated probe to feed the circular waveguide rotating body to excite TM in the circular waveguide₀₁Mode(s). The method reduces the whole volume, is easy to access the substrate integrated system and has the defect of narrow bandwidth. The other method utilizes the etched magnetic current ring on the surface of the double-layer substrate integrated waveguide to feed the circular waveguide and excite the TM in the circular waveguide₀₁Mode(s). The method improves the bandwidth to 11% to a certain extent on the basis of easy access to a substrate integrated system, but the bandwidth is far from TM₀₁The ultimate bandwidth of the mode. However, at present, there is no circular waveguide rotary joint based on substrate integrated coaxial line feed, and if the rotary joint can meet the requirements of broadband, simple structure and easy connection with a substrate integrated system, it will be beneficial to an integrated microwave system in a rotary transmission application environment.

Disclosure of Invention

The purpose of the invention is as follows: aiming at the prior art, the broadband circular waveguide rotary joint for substrate integrated coaxial line feeding is provided, and the problems that the existing circular waveguide rotary joint cannot meet the requirement of broadband and is simple in structure and easy to connect with a substrate integrated system at the same time are solved.

The technical scheme is as follows: a substrate integrated coaxial line feed broadband circular waveguide rotary joint is characterized by comprising: the device comprises two identical substrate integrated coaxial line feeds and a circular waveguide, wherein the circular waveguide is vertically connected with the two substrate integrated coaxial line feeds, and is provided with a choke groove which divides the circular waveguide into an upper half part and a lower half part;

the substrate integrated coaxial line feed comprises a top metal layer, an upper medium substrate, a middle metal layer, a lower medium substrate, a bottom metal layer and metal through holes communicated with all the layers, wherein the top metal layer, the upper medium substrate, the middle metal layer, the lower medium substrate, the bottom metal layer and the metal through holes are sequentially stacked from top to bottom;

the middle metal layer is a linear structure, the linear structure is positioned between the metal through holes, and the terminal of the middle metal layer is positioned in the substrate integrated circular cavity and is circular; a metal connecting hole is formed in the center of the terminal and is vertically connected to the top metal layer; and the top metal layer is also provided with an annular coupling groove, and the annular coupling groove is positioned in the substrate integrated circular cavity.

Further, the annular groove is concentrically arranged with the substrate integrated circular cavity.

Further, the terminal of the middle metal layer is offset from the center of the substrate integrated circular cavity.

Furthermore, the metal through holes which are arranged in a circular shape are adjacent to the annular coupling groove.

Furthermore, the substrate integrated circular cavity is excited by the substrate integrated coaxial line and is coupled with the circular waveguide rotating body through the annular coupling groove, so that the TM in the substrate integrated circular cavity is formed₂₁₀And TM₀₂₀Mode and TM in a rotating body of circular waveguide₀₁₀And TM₀₁₁The modes operate simultaneously.

Has the advantages that: TM in substrate integrated circular cavity₂₁₀And TM₀₂₀The mode is excited coaxially by the substrate integration and passes through the annular groove and TM in the circular waveguide rotating body₀₁₀And TM₀₁₁The mode is coupled, and the obtained substrate integrated coaxial line feed circular waveguide rotary joint has the characteristics of wide band, simple structure and easy connection with a substrate integrated system. The method has the following specific beneficial effects:

1. the substrate integrated circular cavity is excited by the substrate integrated coaxial line and coupled with the circular waveguide rotating body through the annular groove, so that the substrate setTM in a rounded lumen₂₁₀And TM₀₂₀Mode and TM in a rotating body of circular waveguide₀₁₀And TM₀₁₁The modes can operate simultaneously to achieve broadband performance.

2. The circular coupling groove is overlapped with the circle center of the substrate integrated circular cavity, and the circular groove is close to the circular arrangement via holes, so that the circular groove is positioned in the substrate integrated circular cavity TM₂₁₀And TM₀₂₀Where the mode electric field is strong, it is ensured that a strong coupling is obtained, so that a broadband behavior is formed.

3. The circular terminal of the middle metal layer is positioned in the substrate integrated circular cavity and is deviated from the center of the substrate integrated circular cavity by a distance, so that the TM of the substrate integrated circular cavity can be excited simultaneously₂₁₀And TM₀₂₀Mode, and enables broadband matching throughout the rotary joint.

Drawings

FIG. 1 is a schematic cross-sectional view of the present invention;

FIG. 2 is a schematic diagram of a substrate integrated coaxial line feed structure;

fig. 3 is a simulation diagram of a rotary joint.

Detailed Description

The invention is further explained below with reference to the drawings.

As shown in fig. 1, a substrate integrated coaxial line fed broadband circular waveguide rotary joint includes: two identical substrate integrated

coaxial line feeds

1, 2 and a circular waveguide, wherein the circular waveguide is vertically connected with the substrate integrated coaxial line feed 1 and the substrate integrated coaxial line feed 2. The circular waveguide is provided with a choke groove 4, and the choke groove 4 divides the circular waveguide into an upper half 31 and a lower half 32.

As shown in fig. 2, the substrate-integrated

coaxial line feed

1, 2 includes a top metal layer 11, an upper dielectric substrate 12, a middle metal layer 13, a lower dielectric substrate 14, a bottom metal layer 15, and a metal via 16 connecting the layers, which are stacked in this order from top to bottom. The metal through holes 16 are arranged in two rows from the side edge and form substrate integrated coaxial lines with the top metal layer 11, the upper medium substrate 12, the middle metal layer 13, the lower medium substrate 14 and the bottom metal layer 15; then two rows of metal through holes 16 are circularly arranged and integrated with the top metal layer 11, the upper dielectric substrate 12, the lower dielectric substrate 14 and the bottom metal layer 15 to form a circular cavity.

The middle metal layer 13 is a linear structure, and the linear structure is located between the metal through holes 16. The terminal end of the middle metal layer 13 is located in the substrate-integrated circular cavity and has a circular shape, and the circular terminal end is offset from the center of the substrate-integrated circular cavity. A metal connection hole 18 is formed at the center of the terminal and is vertically connected to the top metal layer 11. And an annular coupling groove 17 is further formed in the top metal layer 11, the annular coupling groove 17 is located in the substrate integrated circular cavity, the annular coupling groove and the substrate integrated circular cavity are concentrically arranged, and the metal through holes 16 which are arranged in a circular shape are close to the annular coupling groove 17.

Signals are fed in through a port of the substrate integrated coaxial line feed structure 1 to excite a TEM mode of the substrate integrated coaxial line, and the signals extend into the substrate integrated circular cavity through the middle metal layer 13 to be converted into two resonance modes TM with symmetrical field distribution₂₁₀And TM₀₂₀。TM₂₁₀And TM₀₂₀The signal is coupled to the

circular waveguides

31 and 32 through the metal connecting hole 18, the top metal layer 11 and the annular coupling groove 17 to excite the rotationally symmetric TM in the

circular waveguides

31 and 32₀₁₀And TM₀₁₁Mode(s). Finally, the signals are transmitted from the

circular waveguides

31 and 32 to the substrate integrated coaxial line 2 through an inverse process, and broadband performance is obtained. The choke groove 4 maintains electrical continuity during the relative rotation of the upper and

lower halves

32 and 31 of the circular waveguide to prevent leakage of signals. Compared with the existing circular waveguide rotary joint, the invention simultaneously satisfies the requirements of broadband, simple structure and easy connection with a substrate integrated system, and especially has obvious improvement on bandwidth.

The simulation result is shown in FIG. 3, and it can be seen that the 10-dB matching bandwidth covers 8.2GHz-10.42GHz, i.e. the relative bandwidth is 23.9%, and covers TM₀₁The ultimate bandwidth of the mode. The insertion loss is 0.5-1.2dB, and the performance change is small when the feed is rotated at different angles, so that the feed has better stability. The physical dimensions of the rotary joint are 32.2mm by 27.6mm, corresponding to electrical dimensions of 1 λ_g×0.8λ_g，λ_gThe guided wave wavelength corresponding to the center frequency. This example employs an RO4003C substrate having a dielectric constantThe number was 3.38, the loss angle was 0.0027, and the thickness was 0.813 x 2 mm.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. A substrate integrated coaxial line feed broadband circular waveguide rotary joint is characterized by comprising: the integrated coaxial line feed (1, 2) of two the same substrates and circular waveguide, the said circular waveguide connects two said integrated coaxial line feeds of substrates (1, 2) vertically, there are choke grooves (4) on the said circular waveguide, the said choke groove (4) splits the circular waveguide into the upper half (31) and lower half (32);

the substrate integrated coaxial line feed (1, 2) comprises a top metal layer (11), an upper medium substrate (12), a middle metal layer (13), a lower medium substrate (14), a bottom metal layer (15) and metal through holes (16) communicated with each layer, wherein the top metal layer, the upper medium substrate, the middle metal layer, the lower medium substrate, the bottom metal layer and the metal through holes are sequentially stacked from top to bottom, the metal through holes (16) are arranged in two rows in parallel from the side edge to form a substrate integrated coaxial line, and then the two rows of the metal through holes (16) are arranged in a circular shape to form a substrate integrated circular cavity;

the middle metal layer (13) is a linear structure, the linear structure is positioned between the metal through holes (16), and the terminal of the middle metal layer (13) is positioned in the substrate integrated circular cavity and is circular; a metal connecting hole (18) is formed in the center of the terminal and is vertically connected to the top metal layer (11); an annular coupling groove (17) is further formed in the top metal layer (11), and the annular coupling groove (17) is located in the substrate integration circular cavity;

the annular coupling groove and the substrate integrated circular cavity are concentrically arranged; the terminal of the middle metal layer (13) is deviated from the center of the substrate integrated circular cavity; the metal through holes (16) arranged in a circle are adjacent to the annular coupling grooves (17); the substrate integrated round cavityExcited by the substrate integrated coaxial line, and coupled with the circular waveguide rotating body through the annular coupling groove (17), so that TM in the substrate integrated circular cavity₂₁₀And TM₀₂₀Mode and TM in a rotating body of circular waveguide₀₁₀And TM₀₁₁The modes operate simultaneously.