Single-layer waveguide signal constraint structure suitable for waveguide signal feed-in

Abstract

The utility model provides a single-layer waveguide signal constraint structure suitable for waveguide signal feed-in, and the structure comprises a PCB mainboard which is provided with a signal transmission bottom surface and a substrate integrated waveguide. The signal transmission bottom surface is used for being combined with the single-layer waveguide to form a signal transmission cavity, and the signal transmission bottom surface forms an H-surface bottom surface of the signal transmission cavity; the substrate integrated waveguide comprises grounding holes, and the grounding holes are distributed in the edge, located on the substrate integrated waveguide, of the PCB mainboard. The substrate integrated waveguide provides a first area, and the grounding holes are distributed at the tail end of the first area; wherein the first area comprises the arrangement position of the coupling slot. According to the utility model, the upper metallization surface of the PCB mainboard is used as the bottom surface of the H surface of the signal transmission cavity, so that a single-layer structure of the waveguide antenna is realized, the structure is more compact, the process is simpler, and the material cost is lower.

Description

Technical Field

[0001] The utility model relates to the technical field of waveguide structures, and particularly to a single-layer waveguide signal constraint structure suitable for waveguide signal feeding and a waveguide transmission line. Background Technique

[0002] With the rapid development of wireless communication technology, microwaves and millimeter waves have gradually come into people's vision and play an important role in the communication field.

[0003] Currently, in the application of vehicle-mounted millimeter-wave radars, waveguide antennas have received more and more attention due to their advantages such as low loss and high isolation; in the application of the 76-81 GHz frequency band of vehicle-mounted radars, since the new radio frequency chip technology with waveguide ports is not yet mature, using the existing radio frequency chips for waveguide connection has become an effective way to apply waveguide antennas in vehicle-mounted radars.

[0004] Currently, the signal conversion method from the PCB main board to the waveguide requires an additional signal conversion structure, and the waveguide layer structure is numerous and complex, resulting in difficult processing and assembly; how to make the structure of the waveguide antenna compact and guide the signal for conversion has become a key problem. Content of the Utility Model

[0005] Aiming at the defects in the prior art, the purpose of the utility model is to provide a single-layer waveguide signal constraint structure suitable for waveguide signal feeding.

[0006] According to a single-layer waveguide signal constraint structure suitable for waveguide signal feeding provided by the utility model, it includes: a PCB main board, on which a signal transmission bottom surface and a substrate integrated waveguide are respectively formed;

[0007] The signal transmission bottom surface is used to form a signal transmission cavity in combination with the single-layer waveguide, and the signal transmission bottom surface constitutes the H-plane bottom surface of the signal transmission cavity;

[0008] The substrate integrated waveguide includes grounding holes, and the grounding holes are distributed on the PCB main board at the edge of the substrate integrated waveguide;

[0009] The substrate integrated waveguide provides a first region, and the grounding holes are also distributed at the end of the first region;

[0010] Wherein, the first region includes the setting position of the coupling gap.

[0011] Preferably, a coupling gap is arranged in the first region, and the coupling gap generates or receives a radio frequency signal fed perpendicular to the H-plane bottom surface of the signal transmission cavity;

[0012] Preferably, the PCB main board includes a PCB top surface, a dielectric layer, and a PCB bottom surface that are stacked in sequence, and the PCB top surface and the PCB bottom surface are metallization layers;

[0013] The grounding holes electrically connect the PCB top surface and the PCB bottom surface and ground them; the PCB top surface, the grounding holes, and the PCB bottom surface form a substrate integrated waveguide.

[0014] Preferably, the coupling slot is a coupling slot;

[0015] The shape of the coupling slot is H-shaped, oblique slot-shaped, circular, annular, cross-shaped, or V-shaped.

[0016] Preferably, the grounding holes are located at the edge of the substrate integrated waveguide, and one or more columns of grounding holes are used to close the end of the substrate integrated waveguide.

[0017] Preferably, the slot antenna is made by removing metallization on the metal top surface of the substrate integrated waveguide.

[0018] Preferably, the single-layer waveguide includes shielding walls on both sides of the bottom;

[0019] The grounding holes are covered by the bottom end face of the shielding wall, and the grounding holes are located outside the signal transmission cavity.

[0020] A waveguide transmission line according to the present invention includes the single-layer waveguide signal constraint structure for feeding waveguide signals.

[0021] A waveguide antenna radar according to the present invention includes the waveguide transmission line.

[0022] An automobile according to the present invention includes the waveguide antenna radar.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The upper metallization surface of the PCB main board of the present invention serves as the bottom surface of the H-plane of the signal transmission cavity, and the signal transmission is guided through the grounding holes, realizing the single-layer structure of the waveguide antenna, with a more compact structure, simpler process, and lower material cost.

[0025] 2. The present invention generates or receives radio frequency signals perpendicular to the bottom surface of the H-plane of the waveguide end through slot coupling, without the need to provide a feeding component protruding from the PCB surface on the PCB main board, making the structure of the waveguide simple and compact.

[0026] 3. The single-layer waveguide structure disclosed by the present utility model is conducive to the plastic molding of the waveguide antenna and the subsequent surface metallization process, and does not require additional connection processes such as welding or cementing, which is more conducive to the processing and assembly of the radar waveguide antenna, reduces the dimensional accuracy requirements, and saves the manufacturing cost. Description of the Drawings

[0027] By reading the detailed description of the non-limiting embodiments with reference to the following drawings, other features, objectives, and advantages of the present utility model will become more obvious:

[0028] Figure 1 Schematic diagram of a waveguide transmission line in the prior art;

[0029] Figure 2 Schematic diagram of a waveguide transmission line with EH conversion in the prior art;

[0030] Figure 3 Stereogram of a millimeter-wave radar waveguide antenna with a single-layer waveguide structure disclosed by the present utility model;

[0031] Figure 4 Top view of a millimeter-wave radar waveguide antenna with a single-layer waveguide structure disclosed by the present utility model;

[0032] Figure 5 Schematic diagram of the matching between the waveguide antenna and the PCB main board disclosed by the present utility model;

[0033] Figure 6 Top view of the signal feeding structure disclosed by the present utility model;

[0034] Figure 7 Cross-sectional view of the grounded coplanar waveguide disclosed by the present utility model;

[0035] Figure 8 Cross-sectional view of the waveguide transition section disclosed by the present utility model;

[0036] Figure 9 Cross-sectional view of the substrate integrated waveguide disclosed by the present utility model;

[0037] Figure 10 Example diagram of different shapes of the coupling slot disclosed by the present utility model;

[0038] Figure 11 Example diagram of the shielding wall solution disclosed by the present utility model;

[0039] Figure 12 Schematic diagram of the S-parameters of the embodiment of the present utility model; S-parameters (Scatter parameters), that is, scattering parameters. In the figure, S(1,1) represents the reflection coefficient of port 1 when port 2 is matched, that is, the input return loss; S(2,1) represents the forward transmission coefficient from port 1 to port 2 when port 2 is matched, that is, the gain;

[0040] Figure 13 This is a three-dimensional exploded view of a practical case of the antenna with a 4T4R single-layer waveguide structure of the present utility model.

[0041] Explanation of reference numerals:

[0042] Specific implementation manners

[0043] The present utility model will be described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present utility model, but do not limit the present utility model in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present utility model, several changes and improvements can still be made. These all belong to the protection scope of the present utility model.

[0044] The respective functional surfaces of a typical waveguide are as Figure 1 shown. The conventional feeding method from a PCB main board to a waveguide is usually to set a patch probe parallel to the end face of the waveguide, or to use a feeding probe protruding into the waveguide cavity perpendicular to the bottom surface of the H-plane of the waveguide; since the PCB main board is usually parallel to the waveguide transmission direction, these feeding methods all require setting feeding components protruding from the surface of the PCB, resulting in problems of complex structure and difficult processing and assembly.

[0045] Another relatively mainstream feeding method is as Figure 2 shown. This feeding method adds an EH conversion structure at the end of the transverse waveguide, making the waveguide extend an end face with a downward direction, which is parallel and aligned with a patch probe set on the PCB main board to form a feeding structure. This feeding method has problems such as complex waveguide structure, requiring multiple-layer structures during plastic molding, high assembly process requirements, and high costs.

[0046] The present utility model provides a waveguide antenna with a single-layer structure. Referring to Figures 3 - 11 shown, it includes a PCB main board 1 and a waveguide antenna 2.

[0047] The PCB main board 1 includes a PCB top surface 11, a dielectric layer 12, and a PCB bottom surface 13. Among them, the PCB top surface 11 and the PCB bottom surface 13 are metallized layers, and the dielectric layer 12 uses a high-frequency PCB material suitable for the 76 - 81 GHz frequency band, with a thickness of 5 - 10 mil.

[0048] A feeder line 111 is provided on the top surface 11 of the PCB. One end of the feeder line 111 is connected to the signal pin of the RF chip to receive or feedback electromagnetic signals. Slots 115 are provided on both sides of the feeder line 111 on the top surface 11 of the PCB. Ground vias 116 with appropriate size and spacing are provided outside the slots 115. The ground vias 116 are respectively in good electrical connection with the top surface 11 and the bottom surface 13 of the PCB. A grounded coplanar waveguide is mainly formed by the combination of the feeder line 111, the slots 115 and the ground vias 116.

[0049] The ground vias 116 extend in the direction away from the RF chip, and the lateral spacing gradually increases. It mainly combines with the top surface 11 and the bottom surface 13 of the PCB to form a substrate integrated waveguide 113. One or more columns of ground vias 116 are closed at the end of the substrate integrated waveguide 113 to form a substrate integrated waveguide 113 with a closed end. The ground vias 116 can be single-column or multi-column to meet the performance requirements of good grounding and signal shielding.

[0050] Between the grounded coplanar waveguide and the substrate integrated waveguide 113, the width of the feeder line 111 gradually increases, the width of the slots 115 on both sides remains unchanged but the lateral spacing gradually increases, forming a waveguide transition section 112 between the grounded coplanar waveguide and the substrate integrated waveguide 113.

[0051] There are differences in the lateral widths of the grounded coplanar waveguide and the substrate integrated waveguide 113, that is: the grounded coplanar waveguide is smaller and the substrate integrated waveguide 113 is larger; by setting the waveguide transition section 112 with gradually increasing spacing, the grounded coplanar waveguide and the substrate integrated waveguide 113 can be effectively connected; the gradually increasing spacing is beneficial to the gradual transition of the signal transmission mode from the grounded coplanar waveguide to the substrate integrated waveguide 113, reducing adverse effects such as reflection and loss, and ensuring the transmission efficiency.

[0052] The substrate integrated waveguide 113 provides a first region, and the ground vias 116 are also distributed at the end of the first region; wherein, the first region includes the setting position of the coupling slot 114, and the end of the first region is the end of the substrate integrated waveguide 113.

[0053] A coupling slot 114 is provided in the first region, and the coupling slot 114 generates or receives RF signals fed into the bottom end of the H-plane of the signal transmission cavity perpendicular to it.

[0054] On the top surface 11 of the PCB within the area of the substrate integrated waveguide 113, a non-metallized or de-metallized coupling slot 114 is provided; the coupling slot 114 is provided at the end of the substrate integrated waveguide 113 and is aligned with the substrate integrated waveguide 113 along the center line; an electric field perpendicular to the H-plane of the waveguide is excited through the coupling slot 114, thereby coupling the energy of the baseband integrated waveguide into the waveguide. The shape of the coupling slot 114 can be in the form of an H-shape, a slanted slot shape, a circular shape, an annular shape, a cross shape, a V-shape, etc., without limitation here, as long as it can excite the mode conversion from the substrate integrated waveguide 113 to the waveguide. By adjusting the local dimensions of the shape, the reflection and impedance matching of the conversion can be improved, thereby enhancing the transmission efficiency.

[0055] Referring to Figure 10 as shown, the coupling slot 114 can be set to various different shapes. In the Figure 10 coupling slot 114 (the shaded part in the figure) shown, a is an H-shape, b is a slanted slot shape, c is a cross shape, d is a V-shape, e is a circular shape, and f is an annular shape.

[0056] The waveguide antenna 2 includes: a waveguide top layer 21, a shielding wall 22, a magnetic conductor 24, and a slot antenna 23.

[0057] The waveguide top layer 21 is the main component of the waveguide antenna 2, and a shielding wall 22 and a magnetic conductor 24 are provided below it; the shielding wall 22 and the magnetic conductor 24 are combined with the waveguide top layer 21 to form two E-plane sides, an H-plane top surface, and two end end faces of the waveguide cavity. A signal transmission bottom surface 117 is also formed on the top surface of the PCB main board 1, and the signal transmission bottom surface 117 covers the waveguide cavity and constitutes the H-plane bottom surface of the waveguide cavity, combining to form a complete waveguide cavity.

[0058] The end feed port 26 on the H-plane bottom surface of the waveguide cavity covers the coupling slot 114. As Figure 5 shown, a feed port 26 for the signal to go from the coupling slot 114 to the waveguide antenna is formed on the H-plane bottom surface of the waveguide cavity. The coupling slot 114 and the feed port 26 are centered and aligned along the signal transmission direction. The coupling slot 114 maintains an appropriate distance from the end feed port 26 on the H-plane bottom surface of the waveguide to ensure excellent coupling efficiency. The extending direction of the waveguide cavity is parallel to the PCB main board 1. Among them, both the H-plane top surface and the H-plane bottom surface of the waveguide cavity are parallel to the PCB main board 1.

[0059] The bottom end face of the shielding wall 22 covers the grounding hole 116, and the grounding hole 116 is located outside the signal transmission cavity; the inner side face of the shielding wall 22 is located between the side of the coupling slot 114 and the grounding hole 116.

[0060] In the design of the waveguide antenna 2, the fewer the number of waveguide layers, the simpler the manufacturing process, the smaller the volume, and the lower the cost. Therefore, the optimal structure of the waveguide antenna 2 is a single layer. And the single-layer waveguide antenna 2 needs to use the metal top surface of the PCB main board 1 as the bottom surface of the H-plane of the waveguide. The single-layer structure is beneficial to the plastic molding of the waveguide antenna and the subsequent surface metallization process, and does not require additional connection processes such as welding or gluing, which is more conducive to the processing and assembly of the radar waveguide antenna, reduces the dimensional accuracy requirements, and saves manufacturing costs.

[0061] The main characteristic requirement of waveguide feeding is that the electric field direction of the fed signal must be perpendicular to the H-plane of the waveguide (i.e., the long-side plane). Since in the design of the single-layer waveguide body, the top surface of the PCB main board 1 is parallel to and closely adheres to the bottom surface H-plane of the waveguide cavity, the electric field direction of the electromagnetic signal excited by the patch probe provided by the traditional microstrip design is necessarily parallel to the H-plane of the waveguide, so the waveguide transmission mode cannot be excited.

[0062] The utility model adopts signal conversion through the coupling slot 114 on the substrate integrated waveguide 113, which solves the signal transmission problem from the PCB main board 1 to the single-layer waveguide antenna 2. The slot coupling principle is a kind of waveguide coupler in principle. The basic structure of the waveguide coupler includes an input waveguide, an output waveguide, and a coupling component. When the microwave signal enters the coupling component from the input waveguide, the signal can be coupled to the output waveguide to achieve signal transmission and distribution.

[0063] At the other end of the waveguide cavity, multiple slot structures are provided to penetrate the top layer 21 of the waveguide to form the waveguide slot antenna 23 for signal transmission and reception of the waveguide antenna 2. The number of slots of the slot antenna 23 is determined according to different antenna radiation performances. In vehicle-mounted radar applications, considering the size scale of the waveguide structure itself, generally 4 - 12 slots are set.

[0064] Refer to Figure 11 As shown, the internal dimensions of the waveguide cavity formed by the shielding wall 22 and the magnetic conductor 24 are set such that the ratio of the width of the H-plane to the height of the E-plane is 2:1 or a similar ratio, and it meets the transmission requirements of the 76 - 81 GHz frequency band; the magnetic conductor 24 can be one circle, two circles, or multiple circles, and the shielding wall 22 is arranged outside the magnetic conductor 24; the magnetic conductor 24 is one of geometric shapes such as a periodically arranged cylinder, rectangular body, trapezoidal body, etc., and can be selected according to different material, process, isolation performance and other technical requirements; a ridge 25 can be added as needed to form a ridged waveguide form. A ridge 25 is provided at the midline of the waveguide cavity below the top layer of the waveguide to form a ridged waveguide transmission line. The orthographic projection of the ridge 25 on the PCB main board 1 is staggered from the coupling slot 114, and the waveguide cavity is a cavity at the feeding port 26.

[0065] The material of the waveguide antenna 2 is a metal material or a plastic material with surface metallization.

[0066] The connection between the waveguide antenna 2 and the PCB main board 11 generally includes fastening connection with metal parts and fastening connection with plastic parts. Among them, the shielding wall 22 and the magnetic conductor 24 can be closely connected or arranged with a gap to the PCB main board 1; the feeding port 26 at the end of the bottom surface of the H-plane of the waveguide cavity maintains an appropriate distance from the coupling slot 114 to excite signal coupling.

[0067] Refer to Figure 12 As shown, the structure of the waveguide antenna 2 disclosed by the present utility model realizes an efficient conversion with a working frequency of 76 - 81 GHz, a -10 dB relative bandwidth of 12.16%, and a loss of -0.6 dB, and is applicable to the application of vehicle-mounted radars. From Figure 12 it can be seen that the present utility model realizes the feeding from the substrate integrated waveguide to the feeding port 26 at the end of the bottom surface of the H-plane of the waveguide, with high transmission efficiency.

[0068] Refer to Figure 13 As shown, in a specific embodiment provided by the present utility model, a practical case of a 4T4R single-layer waveguide structure transmission line is introduced, which includes a radio frequency chip and 8 single-layer waveguide antennas 2 connected to the radio frequency chip.

[0069] The present utility model provides a waveguide antenna radar, which adopts the above-mentioned waveguide transmission line of the present utility model. The present utility model also provides a vehicle, on which the above-mentioned waveguide antenna radar is installed.

[0070] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0071] The specific embodiments of the present utility model have been described above. It should be understood that the present utility model is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present utility model. Without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A single-layer waveguide signal constraint structure applicable to waveguide signal feeding, characterized in that Comprising: A PCB main board (1) on which a signal transmission bottom surface (117) and a substrate integrated waveguide (113) are respectively formed; The signal transmission bottom surface (117) is used to combine with a single-layer waveguide to form a signal transmission cavity, and the signal transmission bottom surface (117) constitutes the H-plane bottom surface of the signal transmission cavity; The substrate integrated waveguide (113) includes via holes (116), and the via holes (116) are distributed on the PCB main board (1) at the edge of the substrate integrated waveguide (113); The substrate integrated waveguide (113) provides a first region, and the via holes (116) are also distributed at the end of the first region; Wherein, the first region includes the setting position of the coupling slot (114).

2. The single-layer waveguide signal constraint structure applicable to waveguide signal feeding according to claim 1, wherein A coupling slot (114) is arranged in the first region, and the coupling slot (114) generates or receives a radio frequency signal fed perpendicular to the H-plane bottom surface of the signal transmission cavity; 3. The single-layer waveguide signal constraint structure applicable to waveguide signal feeding according to claim 1, wherein The PCB main board (1) includes a PCB top surface (11), a dielectric layer (12), and a PCB bottom surface (13) stacked in sequence, and the PCB top surface (11) and the PCB bottom surface (13) are metallized layers; The via holes (116) electrically connect the PCB top surface (11) and the PCB bottom surface (13) and ground them; the PCB top surface (11), the via holes (116), and the PCB bottom surface (13) constitute the substrate integrated waveguide (113).

4. The single-layer waveguide signal constraint structure applicable to waveguide signal feeding according to claim 1, characterized in that, The coupling slot is the coupling slot (114); The shape of the coupling slot (114) is H-shaped, oblique slot-shaped, circular, annular, cross-shaped or V-shaped.

5. The single-layer waveguide signal constraint structure applicable to waveguide signal feeding according to claim 3, wherein The via holes (116) are located at the edge of the substrate integrated waveguide (113), and one or more rows of via holes (116) are used for closing at the end of the substrate integrated waveguide (113) 113.

6. The single-layer waveguide signal constraint structure applicable to waveguide signal feeding according to claim 4, wherein The slot antenna (23) is made by removing metallization on the metal top surface of the substrate integrated waveguide (113).

7. The single-layer waveguide signal constraint structure applicable to waveguide signal feeding according to claim 1, wherein The single-layer waveguide includes shielding walls (22) located on both sides of the bottom; The via holes (116) are covered by the bottom end faces of the shielding walls (22), and the via holes (116) are located outside the signal transmission cavity.

8. A waveguide transmission line, characterized in that, Comprising the single-layer waveguide signal constraint structure for waveguide signal feeding according to any one of claims 1 to 7.

9. A waveguide antenna radar, characterized in that, Comprising the waveguide transmission line according to claim 8.

10. A vehicle, characterized in that, Comprising the waveguide antenna radar according to claim 9.

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