A waveguide slot array antenna based on rectangular micro-coaxial technology

Abstract

The present invention discloses a waveguide slot array antenna based on rectangular micro-coaxial technology, which belongs to the field of microwave antenna technology. It includes a metal waveguide slot array antenna, a micro-coaxial transmission line, a coaxial-waveguide conversion transition structure and a Butler matrix. The metal waveguide slot array antenna has four evenly arranged slots distributed on the upper surface of the micro-coaxial structure, and radiates electromagnetic waves to the outer space through the slots. The coaxial-waveguide conversion transition structure is arranged between the metal waveguide slot array antenna and the micro-coaxial transmission line, and is matched to a ridge waveguide through a micro-coaxial gradient structure transition, and then the ridge waveguide is gradually matched to the waveguide to realize the coaxial-waveguide structure conversion. The present invention has the advantages of compact structure, high radiation efficiency, high isolation, small feeding loss, low mutual coupling effect and easy integration.

Description

Technical Field

[0001] The invention relates to the technical field of microwave antennas, and in particular to a waveguide slot array antenna based on rectangular micro-coaxial technology. Background Art

[0002] Driven by the demand for information development, modern radar communications, high-precision positioning, and satellite navigation and communication systems have put forward higher requirements for high-performance RF microsystems. The performance of antennas directly affects the communication quality of the entire system. In the millimeter wave band, the size and weight of metal waveguide slot array antennas are too large, making it difficult to integrate them at a high density; the planar waveguide slot array antenna structure has the disadvantages of high dielectric loss, severe coupling between adjacent units, and high decoupling cost. Summary of the invention

[0003] In view of this, the present invention provides a waveguide slot array antenna based on rectangular micro-coaxial technology. The antenna has the advantages of high gain, small size, light weight, small feed loss, high radiation efficiency, low mutual coupling effect, and easy integration.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] A waveguide slot array antenna based on rectangular micro-coaxial technology comprises a metal waveguide slot array antenna and a micro-coaxial transmission line, and also comprises a coaxial-waveguide conversion transition structure and a Butler matrix; the metal waveguide slot array antenna is connected to the Butler matrix through the coaxial-waveguide conversion transition structure and the micro-coaxial transmission line in sequence.

[0006] Furthermore, the metal waveguide slot array antenna and the micro-coaxial transmission line are both micro-coaxial structures.

[0007] Furthermore, it is divided into three layers: the upper layer is the metal waveguide slot array antenna, the coaxial-waveguide conversion transition structure and the front half of the micro-coaxial transmission line connected in sequence, the lower layer is the Butler matrix; the middle layer is the rear half of the micro-coaxial transmission line.

[0008] Furthermore, the metal waveguide slot array antenna includes four antenna arrays; the Butler matrix is ​​a four-input and four-output port network; the end of each antenna array is connected to the corresponding Butler matrix output port through a corresponding coaxial-waveguide conversion transition structure and a micro-coaxial transmission line; the lengths of the micro-coaxial transmission lines are all the same.

[0009] Furthermore, the Butler matrix is ​​a micro-coaxial structure.

[0010] The beneficial effects of the above technical solution of the present invention are:

[0011] 1. The micro-coaxial transmission line of the present invention has a strong shielding capability and can avoid signal crosstalk; it is filled with air medium and has a small transmission line loss.

[0012] 2. The Butler matrix of the present invention is a four-input and four-output port network. By selecting different input ports, equal-amplitude signals with a phase difference of 45° or 135° can be realized, thereby realizing one-dimensional scanning of the antenna.

[0013] 3. The metal waveguide slot array antenna and micro-coaxial transmission line of the present invention both adopt micro-coaxial technology, which periodically etches the outer conductor area of ​​the coaxial line to retain more shielding structures, has a stronger shielding effect than the printed circuit board, and effectively reduces radiation loss. Therefore, when expanded into a two-dimensional array, the coupling effect between antennas is smaller, the signal crosstalk between channels is small, and the array is easy to expand.

[0014] 4. The Butler matrix of the present invention does not contain a 0dB bridge and a cross-junction structure, and has the characteristics of small size and low process difficulty. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 4 is a top view of the inner conductor in the embodiment of the present invention.

[0016] Figure 2 yes Figure 1 A top view of the Butler matrix.

[0017] Figure 3 1 is a top view of the Butler matrix of the micro-coaxial structure in an embodiment of the present invention.

[0018] Figure 4 Schematic diagram of the micro-coaxial structure in an embodiment of the present invention.

[0019] Figure 5 Schematic diagram of the cross section of the micro-coaxial structure in an embodiment of the present invention.

[0020] Figure 6 Schematic diagram of a metal waveguide slot array antenna with a micro-coaxial structure in an embodiment of the present invention.

[0021] In the figure: 101, antenna array, 102, coaxial-waveguide conversion transition structure, 103, micro-coaxial transmission line, 104, Butler matrix, 201, release hole, 202, support structure, 203, inner conductor, 204, outer conductor. DETAILED DESCRIPTION

[0022] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0024] A waveguide slot array antenna based on rectangular micro-coaxial technology includes a metal waveguide slot array antenna and a micro-coaxial transmission line 103, and also includes a coaxial-waveguide conversion transition structure 102 and a Butler matrix; the metal waveguide slot array antenna is connected to the Butler matrix 104 in sequence through the coaxial-waveguide conversion transition structure and the micro-coaxial transmission line.

[0025] Furthermore, the metal waveguide slot array antenna and the micro-coaxial transmission line are both micro-coaxial structures.

[0026] Furthermore, it is divided into three layers: the upper layer is the metal waveguide slot array antenna, the coaxial-waveguide conversion transition structure and the front half of the micro-coaxial transmission line connected in sequence, the lower layer is the Butler matrix; the middle layer is the rear half of the micro-coaxial transmission line.

[0027] Furthermore, the metal waveguide slot array antenna includes four antenna arrays 101; the Butler matrix is ​​a four-input and four-output port network; the end of each antenna array is connected to the corresponding Butler matrix output port through a corresponding coaxial-waveguide conversion transition structure and a micro-coaxial transmission line; the lengths of the micro-coaxial transmission lines are all the same.

[0028] Furthermore, the Butler matrix is ​​a micro-coaxial structure.

[0029] This embodiment includes a metal waveguide slot array antenna, a micro-coaxial transmission line, a coaxial-waveguide conversion transition structure and a Butler matrix. The metal waveguide slot array antenna includes a metal radiation slot, a rectangular hollow metal and an air medium. The metal slot adopts a longitudinal slot on the wide side of the waveguide, and its length, width and center offset distance are all related to the radiation frequency. Considering the mutual coupling effect between adjacent slots, the distance between the slots is adjusted to reduce the coupling effect between the slots; the rectangular hollow metal is perpendicular to the metal slot, which does not affect the radiation performance of the waveguide slot array antenna while reducing the difficulty of process processing and the overall weight of the structure.

[0030] The micro-coaxial transmission line includes a rectangular hollow metal, an air dielectric and a dielectric support material. The rectangular coaxial transmission provides single TEM mode transmission. The structure has a strong shielding capability and can avoid signal crosstalk. The air dielectric is used for filling, and the transmission line loss is small. The coaxial-waveguide conversion transition structure includes a rectangular hollow metal and a metal waveguide. The signal in the waveguide can be transmitted to the rectangular micro-coaxial through the metal waveguide. The Butler matrix is ​​a four-input and four-output port network. By selecting different input ports, equal-amplitude signals with a phase difference of 45° or 135° can be achieved, thereby realizing one-dimensional scanning of the antenna.

[0031] Both the metal waveguide slot array antenna and the micro-coaxial transmission line use micro-coaxial technology, which can realize a coaxial structure with air as the transmission medium, which has a smaller size than the coaxial structure. This technology uses air as the transmission medium, which can effectively reduce dielectric loss;

[0032] Both the metal waveguide slot array antenna and the micro-coaxial transmission line adopt micro-coaxial technology, which periodically etches the outer conductor area of ​​the coaxial line to retain more shielding structures, which has a stronger shielding effect than the printed circuit board and effectively reduces radiation loss. Therefore, when expanded into a two-dimensional array, the coupling effect between antennas is smaller, the signal crosstalk between channels is small, and the array is easy to expand.

[0033] Both the metal waveguide slot array antenna and the micro-coaxial transmission line use micro-coaxial technology, which is compatible with traditional silicon-based CMOS processes. This technology can be used to achieve three-dimensional integrated design of RF components.

[0034] There is periodically arranged dielectric support material inside the micro-coaxial transmission line to support and fix the transmission metal.

[0035] The coaxial-waveguide conversion transition structure is composed of a rectangular micro-coaxial line-waveguide transition structure, realizing the design of the waveguide slot array antenna feeding structure.

[0036] The Butler matrix does not contain a 0dB bridge and a cross-junction structure, and has the characteristics of small size and low process difficulty.

[0037] Reference Figures 1 to 6 The waveguide slot array antenna based on copper-based rectangular micro-coaxial technology includes: a metal waveguide slot array antenna, a micro-coaxial transmission line, a coaxial-waveguide conversion transition structure and a Butler matrix.

[0038] The waveguide slot array antenna part of the waveguide slot array antenna based on copper-based rectangular micro-coaxial technology utilizes 5-layer rectangular micro-coaxial line technology. The inner conductor of the rectangular micro-coaxial line is located on the third layer, and its cross-sectional size is 700 um×100 um. The outer conductor 204 has a size of 1450 um×500 um, and the metal wall thickness is 100 um.

[0039] The waveguide slot array antenna consists of a three-layer structure, the first layer is a metal waveguide slot array antenna, a coaxial-waveguide conversion transition structure and a micro-coaxial transmission line.

[0040] The second layer is a micro-coaxial transmission line structure.

[0041] The third layer is the Butler matrix structure.

[0042] The micro-coaxial transmission line part of the waveguide slot array antenna based on copper-based rectangular micro-coaxial technology utilizes a 5-layer rectangular micro-coaxial line technology. The inner conductor of the rectangular micro-coaxial line is located on the third layer, and its cross-sectional size is 1000 um×100 um, its outer conductor size is 1450 um×300 um, and the metal wall thickness is 100 um.

[0043] The waveguide slot array antenna structure based on the copper-based rectangular micro-coaxial technology is designed with periodically arranged release holes 201, which are used to wash out the photoresist in the coaxial cavity in the final stage of the processing process. The size of the release hole 201 is 250um×400um×200um. The release holes 5 are symmetrically distributed on the upper and lower sides of the micro-coaxial.

[0044] The part 2 of the waveguide slot array antenna based on the copper-based rectangular micro-coaxial line technology is designed with a periodically arranged Su8 dielectric support structure 202 (dielectric constant is 2.85, loss tangent is 0.045, thickness is 20 um, cross-sectional size is 100 um×20 um) at the bottom of the third layer, which is used to support the inner conductor 203 of the rectangular coaxial line.

[0045] The metal waveguide slot array antenna is a micro-coaxial structure, specifically composed of an input port and slots evenly arranged on both sides of the center line of the waveguide section. Since the high characteristic impedance of the waveguide is easily matched with the high impedance of the half-wave slot antenna, the metal waveguide slot array antenna adopts a waveguide feeding method. Different forms of slots are formed depending on the position of the slot on the waveguide. Commonly used slots include inclined slots opened on the narrow side of the waveguide, longitudinal slots on the wide side of the waveguide deviating from the center line, and inclined slots opened on the center line of the wide side of the waveguide.

[0046] The coaxial-waveguide conversion transition structure is a structure from the output port of the micro-coaxial transmission line to the input end of the waveguide slot array antenna, and the coaxial-waveguide transition structure is a coaxial-waveguide horizontal transition structure, which is realized by the gradual transition matching of the micro-coaxial to the ridge waveguide, and then the gradual matching of the ridge waveguide to the waveguide. This structure can realize the feeding port and the same micro-coaxial layer to feed the slot antenna.

[0047] The Butler matrix structure is a four-input and four-output network, and the four output ports can output the same amplitude signal with a phase difference of 45° or 135°. The Butler matrix structure is a feeding network for a 4×4 array antenna, which can realize the array antenna scanning function.

[0048] Figure 6 This is a waveguide slot array antenna model. The array antenna has 4 input ports. Figure 2 It is a 4×4 Butler matrix, that is, four input ports and four output ports.

[0049] The connection relationship is as follows:

[0050] A and 5, B and 6, C and 7, D and 8. The slot antenna port and the Butler matrix port are connected using equal-length micro-coaxial transmission lines.

[0051] When the signal enters port 1, the output signals of ports 5 to 8 of the Butler matrix have a phase difference of 45 degrees, and ports 2, 3, and 4 are isolated ports;

[0052] When the signal enters port 2, the output signals of ports 5 to 8 of the Butler matrix have a phase difference of 135 degrees, and ports 1, 3, and 4 are isolated ports.

[0053] The above is a description of a waveguide slot array antenna design and a manufacturing method thereof provided by the present invention. For those skilled in the art, according to the concept of the embodiments of the present invention, there may be changes in the specific implementation and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A waveguide slot array antenna based on rectangular micro-coaxial technology, comprising a metal waveguide slot array antenna and a micro-coaxial transmission line, characterized in that: It also includes a coaxial-waveguide conversion transition structure and a Butler matrix; the metal waveguide slot array antenna is connected to the Butler matrix through the coaxial-waveguide conversion transition structure and the micro-coaxial transmission line in sequence; the metal waveguide slot array antenna and the micro-coaxial transmission line are both micro-coaxial structures; It is divided into three layers: upper, middle and lower. The upper layer is the metal waveguide slot array antenna, coaxial-waveguide conversion transition structure and the first half of the micro-coaxial transmission line connected in sequence, and the lower layer is the Butler matrix; the middle layer is the second half of the micro-coaxial transmission line; there is a periodically arranged dielectric support material inside the micro-coaxial transmission line.

2. The waveguide slot array antenna based on rectangular micro-coaxial technology according to claim 1, characterized in that: The metal waveguide slot array antenna includes four antenna arrays; the Butler matrix is ​​a four-input and four-output port network; the end of each antenna array is connected to the corresponding Butler matrix output port through a corresponding coaxial-waveguide conversion transition structure and a micro-coaxial transmission line; the lengths of the micro-coaxial transmission lines are all the same.

3. The waveguide slot array antenna based on rectangular micro-coaxial technology according to claim 2, characterized in that: The Butler matrix is ​​a micro-coaxial structure.

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