A substrate integrated waveguide slot antenna

Abstract

The present invention relates to the field of antenna technology, and specifically to a substrate-integrated waveguide slot antenna, comprising: a first metal plate, a first plate body, a second metal plate, a second plate body, and a third metal plate sequentially stacked and connected along a first direction, wherein a coaxial probe is provided on the first metal plate; a first power divider is provided on the first plate body, and a central through hole for the coaxial probe to pass through is also provided; a first coupling slot is provided on the second metal plate; an impedance matching slot is provided on the second plate body; and a plurality of groups of slot units distributed in an array are provided on the third metal plate. Based on the substrate-integrated waveguide slot antenna, the present application adopts a series-feeding form to design it into a traveling wave antenna array, so that it has wide-band characteristics, and at the same time solves the OSB problem of the series-fed antenna by arranging slot units arranged in an array.

Description

Technical Field

[0001] The present invention relates to the technical field of antennas, and in particular to a substrate integrated waveguide slot antenna. Background Art

[0002] With the rapid development of modern communications technology, especially the continued advancement of applications such as millimeter-wave radar, military radar, satellite communications, 5G, and even future 6G communications, communication systems are placing higher demands on antenna performance. Substrate-integrated waveguide slot antennas (SIWSAs) are widely used in these scenarios due to their advantages such as ease of integration, high efficiency, compact structure, ease of processing, diverse structural forms, and low cost. Furthermore, their arrays can achieve high gain and low sidelobe performance. However, compared to some broadband antennas, SISSAs have a narrower operating bandwidth, limiting their application in broadband communication systems.

[0003] A traveling wave antenna array is an antenna system composed of multiple antenna elements arranged in a certain pattern. The current in each antenna element is distributed in a traveling wave pattern, meaning that the electromagnetic wave fed into it exhibits a traveling wave state. Traveling wave antenna arrays offer the advantages of a wide operating frequency band, high directivity, low loss, high efficiency, and flexible design. Traveling wave antenna arrays come in two forms: parallel-fed and series-fed. Parallel-fed arrays have a complex feeding network structure, resulting in larger antennas or a higher profile. Series-fed arrays, on the other hand, have a simpler structure and smaller antennas. Therefore, designing a substrate-integrated waveguide slot antenna into a traveling wave antenna array using series feeding can achieve a compact structure and broadband characteristics, better suited to the requirements of communication systems. Summary of the Invention

[0004] The purpose of this application is to provide a substrate integrated waveguide slot antenna. Based on the substrate integrated waveguide slot antenna, it is designed into a traveling wave antenna array in the form of series feeding, so that it has wide-band characteristics. At the same time, a special matching structure is set to solve the OSB problem of the series-fed antenna.

[0005] To achieve the above-mentioned object, the present application adopts a substrate integrated waveguide slot antenna, comprising: a first dielectric plate and a second dielectric plate sequentially stacked and connected along a first direction;

[0006] The first dielectric plate includes a first metal plate, a first plate body, and a second metal plate, wherein the first metal plate and the second metal plate are respectively attached to the lower surface and the upper surface of the first plate body. A coaxial probe is provided on a side surface of the first metal plate close to the first plate body, and a central through hole is provided on the first plate body for the coaxial probe to pass through. A first power divider is also provided on the first plate body, wherein the first power divider has a plurality of output ports symmetrically arranged along a second direction, and the signals of the plurality of output ports have the same phase. A first coupling slot is provided on the second metal plate, and the first coupling slot is provided corresponding to the output port.

[0007] The second dielectric plate includes a second plate body and a third metal plate, the third metal plate is attached to the upper surface of the second plate body, and a surface of the second metal plate away from the first plate body is attached to the second plate body, the second plate body is provided with a plurality of impedance matching slots distributed in an array, and the third metal plate is provided with a plurality of groups of slot units distributed in an array, each group of slot units includes a radiation slot and two impedance matching slots, the two impedance matching slots are symmetrically arranged on both sides of the radiation slot, and the impedance matching slots are arranged in a one-to-one correspondence with the impedance matching slots;

[0008] The first direction and the second direction are perpendicular.

[0009] As a preferred solution, the coaxial probe is arranged on the center line of the first metal plate.

[0010] As a preferred solution, the widths of the plurality of output ports gradually decrease from the middle to both sides along the third direction, wherein the first direction, the second direction and the third direction are perpendicular to each other.

[0011] As a preferred embodiment, a plurality of first through holes and second through holes are provided on the first plate body, and metal is affixed to the inner walls of the first through holes and the second through holes. The first through holes and the second through holes are both provided on the same side of the first plate body, and the second through holes are provided along the side edge of the first plate body. The first metal plate, the second metal plate, the first through holes and the second through holes jointly define the first power divider.

[0012] As a preferred solution, a second power divider is further provided on the first plate, the first power divider and the second power divider are symmetrically distributed along the third direction, and the first and second power dividers have the same structure, and a second coupling slot is further provided on the second metal plate, and the second coupling slot is arranged corresponding to the output port of the second power divider.

[0013] As a preferred solution, a third through hole and a fourth through hole are provided on the second plate body, and metal is affixed to the inner walls of the third through hole and the fourth through hole. The third through hole is distributed in an array in the second plate body, and the fourth through hole is arranged along the peripheral side of the second plate body.

[0014] As a preferred solution, the signal phase difference between the first power divider and the second power divider is 180°.

[0015] As a preferred solution, the widths of the plurality of radiation slots and the plurality of impedance matching slots gradually decrease from the middle position to both sides and are symmetrical about the third direction.

[0016] As a preferred solution, the first metal plate, the first plate body, the second metal plate, the second plate body and the third metal plate are connected by screws.

[0017] As a preferred solution, the substrate integrated waveguide slot antenna is manufactured using a printed circuit board process.

[0018] The substrate integrated waveguide slot antenna provided by the above technical solution has the following advantages compared with the prior art:

[0019] On the one hand, the present application stacks and connects the first metal plate, the first dielectric plate, the second metal plate, the second dielectric plate, and the third metal plate in sequence from bottom to top, and sets a coaxial probe on the first metal plate. The coaxial probe transmits the signal to the first dielectric plate through the central through hole on the first plate body, and further transmits it to the output port of the first power divider, and then transmits it to the second dielectric plate via the first coupling slot. The signal is transmitted to the impedance matching slot on the third metal plate through the impedance matching slot, and then transmitted to the radiation slot through the impedance matching slot. The energy wave is transmitted from one side of the slot unit to the other side, forming a traveling wave, so that the antenna has a wider operating frequency band, that is, it has a broadband characteristic.

[0020] On the other hand, the slot unit consists of a radiation slot and two impedance matching slots symmetrically arranged on both sides thereof. Multiple slot units are distributed in an array, and multiple impedance matching slots correspond one-to-one to multiple impedance matching slots. The one-to-one corresponding impedance matching slots and impedance matching slots can broaden the impedance bandwidth of the antenna to a certain extent, so that the antenna maintains good impedance matching performance within a wider frequency range, and reduces the impact of the OSB problem on the antenna performance; at the same time, this matching structure will affect the electromagnetic field distribution around the antenna, making it more uniform and stable, reducing energy reflection and scattering caused by electromagnetic field distortion, improving the radiation characteristics of the antenna, and suppressing the OSB problem. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present application is further described in detail below with reference to the accompanying drawings and preferred embodiments. However, those skilled in the art will appreciate that these drawings are drawn only for the purpose of explaining the preferred embodiments and therefore should not be construed as limiting the scope of the present application. In addition, unless otherwise specified, the drawings are intended only to conceptually represent the composition or structure of the described objects and may contain exaggerated representations, and the drawings are not necessarily drawn to scale.

[0022] Figure 1 Schematic diagram of the structure of the antenna of the present invention;

[0023] Figure 2 is a schematic diagram of a first dielectric plate of the present invention;

[0024] Figure 3is a schematic diagram of the second dielectric plate of the present invention;

[0025] Figure 4 is a schematic diagram of a third metal plate of the present invention;

[0026] Figure 5 A line graph showing the reflection coefficient of the antenna array of the present invention;

[0027] Figure 6 is the radiation pattern of the antenna of the present invention;

[0028] Among them: 1. first dielectric plate; 11. first metal plate; 110. coaxial probe; 12. second metal plate; 120. first coupling slot; 121. second coupling slot; 13. first plate body; 130. center through hole; 131. first through hole; 132. second through hole; 133. output port; 134. first power divider; 135. second power divider; 2. second dielectric plate; 21. second plate body; 210. third through hole; 211. fourth through hole; 212. impedance matching slot; 22. third metal plate; 220. slot unit; 221. radiation slot; 222. impedance matching slot. DETAILED DESCRIPTION

[0029] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0030] In the description of this application, it should be understood that the terms "front," "back," "top," "bottom," "inside," "outside," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, in the description of the present invention, "plurality" means two or more, unless otherwise expressly and specifically defined.

[0031] See Figure 1-5 , a substrate integrated waveguide slot antenna provided in an embodiment of the present application, comprising: a first dielectric plate 1 and a second dielectric plate 2 sequentially stacked and connected along a first direction;

[0032] The first dielectric plate 1 includes a first metal plate 11, a first plate body 13, and a second metal plate 12. The first metal plate 11 and the second metal plate 12 are respectively attached to the lower surface and the upper surface of the first plate body 13. A coaxial probe 110 is provided on a side surface of the first metal plate 11 close to the first plate body 13. The first plate body 13 is provided with a central through hole 130 for the coaxial probe 110 to pass through. The first plate body 13 is also provided with a first power divider 134. The first power divider 134 has a plurality of output ports 133 symmetrically arranged along a second direction, and the signals of the plurality of output ports 133 have the same phase. The second metal plate 12 is provided with a first coupling slot 120, and the first coupling slot 120 is provided corresponding to the output port 133.

[0033] The second dielectric plate 2 includes a second plate body 21 and a third metal plate 22. The third metal plate 22 is attached to the upper surface of the second plate body 21. The second metal plate 12 is attached to the second plate body 21 on a surface away from the first plate body 13. The second plate body 21 is provided with a plurality of impedance matching slots 212 distributed in an array. The third metal plate 22 is provided with a plurality of groups of slot units 220 distributed in an array. Each group of slot units 220 includes a radiation slot 221 and two impedance matching slots 222. The two impedance matching slots 222 are symmetrically arranged on both sides of the radiation slot 221, and the impedance matching slots 222 are arranged in a one-to-one correspondence with the impedance matching slots 212.

[0034] The first direction and the second direction are perpendicular.

[0035] In this embodiment, screws are preferably used to sequentially stack and connect the first metal plate 11, the first plate body 13, the second metal plate 12, the second plate body 21, and the third metal plate 22, so that the overall structural connection is more stable. On the one hand, in this application, the signal is emitted from the coaxial probe 110, and the coaxial probe 110 transmits the signal to the first plate body 13 through the central through hole 130. Then, the signal flows from the middle of the first plate body 13 to the first power divider 134, and flows to the first coupling slot 120 through the output port 133 of the first power divider 134, so that the signal is transmitted from the first dielectric plate 1 to the second dielectric plate 2. The signal flows to the radiation slot 221 through the impedance matching slot 212 and the impedance matching slot 222, forming a traveling wave in the second dielectric plate 2, so that the antenna has a wider operating frequency band to meet the requirements of broadband communication systems. On the other hand, please refer to Figure 5Based on the special structure of the slot units 220, that is, each group of slot units 220 consists of a radiation slot 221 and two impedance matching slots 222 symmetrically arranged on both sides thereof, the impedance matching slots 222 are arranged in a one-to-one correspondence with the impedance matching slots 212, and multiple slot units 220 are distributed in an array. This arrangement broadens the impedance bandwidth of the antenna to a certain extent. As shown in the reflection coefficient line graph, the reflection coefficient of the antenna is less than -10dB within the frequency range shown in the figure, which means that it can maintain good impedance matching performance within a wider frequency range, solve the OSB (open stopband) problem of the series-fed antenna, and improve the radiation performance of the antenna.

[0036] It is worth noting that the minimum array composed of multiple slot units 220 is a 2×2 matrix. This array size is the minimum array that can ensure the above-mentioned antenna performance. The matrix size can be appropriately adjusted according to the actual performance requirements of the antenna to enable the antenna to have better performance.

[0037] Furthermore, the coaxial probe 110 is arranged on the center line of the first metal plate 11. On the one hand, it can make the electric and magnetic field distributions more uniform and symmetrical during signal transmission, reduce signal distortion and attenuation caused by position offset, and ensure the quality and stability of the transmitted signal; on the other hand, it helps to better achieve impedance matching between the coaxial probe 110 and the system in which the first metal plate 11 is located, reduce the reflection coefficient, improve energy transmission efficiency, reduce signal reflection, enable more energy to be effectively received, and enhance system performance; in addition, during installation, the center line position is clear and fixed, which facilitates the accurate installation and positioning of the coaxial probe 110, reduces installation difficulty and errors, improves the consistency and repeatability of the system, and is also conducive to alignment and connection with other plates to ensure the normal operation of the system.

[0038] Further, see Figure 6 The widths of the multiple output ports 133 gradually decrease from the center toward the sides along the third direction, which can reduce the sidelobe level of the antenna's H-plane radiation pattern. As shown in the radiation pattern, the sidelobe level of the H-plane (dashed line) is less than -15 dB, indicating a low sidelobe level. It is worth noting that the first, second, and third directions are perpendicular to each other.

[0039] Furthermore, the widths of the multiple radiating slots 221 and the multiple impedance matching slots 222 gradually decrease from the center toward the sides and are symmetrical about the third direction. This arrangement can reduce the sidelobe level of the antenna's E-plane radiation pattern. As shown in the radiation pattern, the sidelobe level of the E-plane (solid line) in the figure is less than -15dB, meaning that the sidelobe level is low, reducing interference with the mainlobe signal and interference with other frequency bands. In a multi-antenna system, this helps improve the system's anti-interference capability and spectrum utilization.

[0040] It is worth noting that the above settings are based on different requirements for sidelobe levels, and are based on methods such as Taylor distribution and Chebyshev distribution commonly used in array synthesis theory to determine the energy ratio of each output port 133 of the power divider and the energy radiation ratio of different radiation slots 221, so as to set the width of the output port 133 and the radiation slot 221 accordingly.

[0041] Furthermore, a plurality of first through holes 131 and second through holes 132 are provided on the first plate body 13, and metal is affixed to the inner walls of the first through holes 131 and the second through holes 132. The first through holes 131 and the second through holes 132 are both arranged on the same side of the first plate body 13, and the second through holes 132 are arranged along the side edge of the first plate body 13. The first metal plate 11, the second metal plate 12, the first through holes 131 and the second through holes 132 jointly define the first power divider 134. The first through holes 131 and the second through holes 132 define the output port 133 of the first power divider 134. In this embodiment, there are eight output ports 133.

[0042] Furthermore, the second plate 21 is provided with a third through hole 210 and a fourth through hole 211. The inner circumferential walls of the third through hole 210 and the fourth through hole 211 are affixed with metal. The third through holes 210 are distributed in an array within the second plate 21, and the fourth through holes 211 are provided along the circumference of the second plate 21. The array of third through holes 210 can generate an electromagnetic field with a specific polarization direction, meeting the polarization requirements of different communication scenarios and improving communication quality and anti-interference capabilities.

[0043] It's worth noting that the metallized vias, as part of the antenna structure, adjust the antenna's input impedance to better match the characteristic impedance of the feeder line. They also form a specific waveguide structure, reducing signal reflections, improving signal transmission efficiency and antenna radiation efficiency, and ensuring the overall performance of the antenna system. Furthermore, the second via 132 and the fourth via 211 are designed to prevent signal leakage outside the board, which could cause energy dissipation.

[0044] Furthermore, a second power divider 135 is provided on the first plate 13. The first power divider 134 and the second power divider 135 are symmetrically distributed along the third direction, and the first and second power dividers 135 have the same structure. A second coupling slot 121 is also provided on the second metal plate 12, and the second coupling slot 121 is corresponding to the output port 133 of the second power divider 135. The symmetrical distribution of the first and second power dividers 135 makes the overall structure compact and saves space. The symmetrical distribution also ensures better signal balance during transmission, reduces signal differences caused by different transmission paths, and improves signal quality and transmission efficiency. Furthermore, the symmetrical arrangement of the two power dividers allows signals to be transmitted from either side of the slot unit 220 to the opposite side, forming standing waves within the second dielectric plate 2, ensuring that the beam pointing of the antenna array does not change with frequency.

[0045] Furthermore, the signal phase difference between the first power divider 134 and the second power divider 135 is 180°, realizing differential feeding. On the one hand, it can effectively improve the anti-interference ability of the signal, making the transmitted signal quality higher and more stable; on the other hand, the use of differential feeding can make the radiation field distribution of the antenna more uniform, reduce the radiation zero point and sidelobe level, thereby improving the gain and directivity of the antenna, improving the radiation efficiency and coverage range of the antenna, and enhancing the performance of the communication system; secondly, the OSB problem of the series-fed antenna has been solved by the above-mentioned matching structure, and by using the differential feeding method to excite the two symmetrically distributed power dividers, the antenna can obtain a fixed beam.

[0046] Furthermore, the substrate-integrated waveguide slot antenna is manufactured using a printed circuit board (PCB) process. This facilitates compact antenna design, making it easier to integrate into various miniaturized electronic devices, meeting the requirements for miniaturization and lightweight communications equipment. Furthermore, this process achieves high processing precision, ensuring consistent and stable antenna performance, and offers high production efficiency and low costs. Furthermore, the PCB manufacturing process facilitates adjustment and optimization of the structure, size, shape, and other parameters of the substrate-integrated waveguide slot antenna, resulting in a robust antenna structure that is less susceptible to external influences and has a longer service life.

[0047] To sum up, the substrate integrated waveguide slot antenna provided in this embodiment adopts the form of serial feeding to design the multi-layer substrate integrated waveguide slot antenna into a traveling wave antenna array, so that it has a wide-band characteristic. At the same time, by arranging a plurality of slot units 220 structures arranged in an array on the third metal plate 22, the OSB problem of the serial-fed antenna is better solved.

[0048] This specification discloses the present application with reference to the accompanying drawings and also enables those skilled in the art to practice the present application, including making and using any device or system, employing suitable materials, and using any combined methods. The scope of the present application is defined by the claimed technical solution and includes other examples that occur to those skilled in the art. As long as such other examples include structural elements that are not different from the literal language of the claimed technical solution, or such other examples include equivalent structural elements that are not substantially different from the literal language of the claimed technical solution, such other examples should be deemed to be within the scope of protection determined by the claimed technical solution.

Claims

1. A substrate integrated waveguide slot antenna, characterized in that: include: A first dielectric plate and a second dielectric plate sequentially stacked and connected along a first direction; The first dielectric plate includes a first metal plate, a first plate body, and a second metal plate, wherein the first metal plate and the second metal plate are respectively attached to the lower surface and the upper surface of the first plate body. A coaxial probe is provided on a side surface of the first metal plate close to the first plate body, and a central through hole is provided on the first plate body for the coaxial probe to pass through. A first power divider is also provided on the first plate body, wherein the first power divider has a plurality of output ports symmetrically arranged along a second direction, and the signals of the plurality of output ports have the same phase. A first coupling slot is provided on the second metal plate, and the first coupling slot is provided corresponding to the output port. The second dielectric plate includes a second plate body and a third metal plate, the third metal plate is attached to the upper surface of the second plate body, and a surface of the second metal plate away from the first plate body is attached to the second plate body, the second plate body is provided with a plurality of impedance matching slots distributed in an array, and the third metal plate is provided with a plurality of groups of slot units distributed in an array, each group of slot units includes a radiation slot and two impedance matching slots, the two impedance matching slots are symmetrically arranged on both sides of the radiation slot, and the impedance matching slots are arranged in a one-to-one correspondence with the impedance matching slots; The first direction and the second direction are perpendicular.

2. The substrate integrated waveguide slot antenna according to claim 1, wherein: The coaxial probe is arranged on the center line of the first metal plate.

3. The substrate integrated waveguide slot antenna according to claim 1, wherein: The widths of the plurality of output ports gradually decrease from the middle to both sides along the third direction, wherein the first direction, the second direction and the third direction are perpendicular to each other.

4. The substrate integrated waveguide slot antenna according to claim 3, wherein: A plurality of first through holes and second through holes are provided on the first plate body, and metal is affixed to the inner peripheral walls of the first through holes and the second through holes. The first through holes and the second through holes are both provided on the same side of the first plate body, and the second through holes are provided along the side edge of the first plate body. The first metal plate, the second metal plate, the first through holes, and the second through holes jointly define the first power divider.

5. The substrate integrated waveguide slot antenna according to claim 4, wherein: A second power divider is also provided on the first plate, and the first power divider and the second power divider are symmetrically distributed along the third direction, and the first and second power dividers have the same structure. A second coupling slot is also provided on the second metal plate, and the second coupling slot is arranged corresponding to the output port of the second power divider.

6. The substrate integrated waveguide slot antenna according to claim 5, wherein: The second plate body is provided with a third through hole and a fourth through hole, the inner peripheral walls of the third through hole and the fourth through hole are affixed with metal, the third through holes are distributed in an array in the second plate body, and the fourth through holes are arranged along the peripheral side of the second plate body.

7. The substrate integrated waveguide slot antenna according to claim 5, wherein: The signal phase difference between the first power divider and the second power divider is 180°.

8. The substrate integrated waveguide slot antenna according to claim 1, wherein: The widths of the plurality of radiation slots and the plurality of impedance matching slots gradually decrease from the middle position to both sides and are symmetrical about the third direction.

9. The substrate integrated waveguide slot antenna according to claim 1, wherein: The first metal plate, the first plate body, the second metal plate, the second plate body and the third metal plate are connected by screws.

10. The substrate integrated waveguide slot antenna according to any one of claims 1 to 9, wherein: The substrate integrated waveguide slot antenna is manufactured using a printed circuit board process.

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