Millimeter wave radar microstrip-to-gap waveguide structure

Abstract

The utility model discloses a millimeter wave radar microstrip-to-gap waveguide structure, which comprises a PCB (printed circuit board), a microstrip line is arranged on the PCB, one end of the microstrip line is connected with a radiation patch, and the radiation patch is connected with a waveguide structure; the waveguide structure comprises a copper sheet layer arranged on the PCB, a metal plate opposite to the PCB, a trapezoidal column and a plurality of metal columns, wherein the trapezoidal column and the metal columns are arranged on the metal plate. The end face, away from the metal plate, of the trapezoidal column makes contact with the radiation patch. The metal columns are arranged on the two sides of the trapezoidal column, located on the two sides of the microstrip line and symmetrically distributed on the two sides of the trapezoidal column. According to the millimeter wave radar microstrip-to-gap waveguide structure provided by the utility model, by arranging the trapezoidal column in contact with the radiation patch, quasi-TEM waves of radiation signals of the microstrip patch are converted into TE (10) waves of a waveguide, and then the TE (10) waves are transmitted through the waveguide formed by the microstrip-to-gap waveguide structure of the scheme. Therefore, the conversion from the on-board microstrip radio frequency signal to the one-layer waveguide signal is realized.

Description

Technical Field

[0001] The utility model relates to the technical field of millimeter-wave radar antennas, in particular to a millimeter-wave radar microstrip-to-slot waveguide structure. Background Technique

[0002] At present, vehicle-mounted millimeter-wave radar antennas are mainly in the form of planar printed antennas. Due to the size and layout limitations of the PCB board surface, it is difficult to arrange planar printed antennas closely. Moreover, the surface waves of planar antennas in the millimeter-wave band will greatly deteriorate the inter-element isolation of the antenna array, and at the same time will cause distortion of the radiation pattern, affecting the radiation performance. Using waveguide antennas or horn antennas can solve the problems of antenna layout and isolation. Therefore, the planar printed microstrip-to-waveguide technology is an indispensable technology for the implementation of millimeter-wave waveguide antennas or horn antennas in vehicle-mounted radars.

[0003] At present, there are three ways to use waveguide antennas or horn antennas in most vehicle-mounted radars, namely, stepped ridged waveguide transition structure, antipodal finline transition structure, and coupled probe transition structure. Among them, both the ridged waveguide structure and the antipodal finline transition structure are relatively complex, with high cost and precision requirements; although the coupled probe transition structure is simple, on the one hand, its integration level is low and the assembly consistency is poor, and on the other hand, it has certain requirements for installation positioning, with high process difficulty, and installation deviation will bring problems such as frequency offset, phase distortion, and large insertion loss, and the signal quality cannot be guaranteed.

[0004] In addition, the current microstrip-to-waveguide structure has certain losses when converting from patch radiation to waveguide, and has relatively high requirements for installation dimensions, with low reliability. Summary of the Utility Model

[0005] In order to overcome at least one of the above-mentioned defects of the prior art, the utility model provides a millimeter-wave radar microstrip-to-slot waveguide structure. By setting a trapezoidal column in contact with the radiation patch, the quasi-TEM wave of the microstrip patch radiation signal is converted into the TE_(10) wave of the waveguide, and then transmitted through the waveguide formed by the microstrip-to-slot waveguide structure of the present solution, so as to realize the conversion of the on-board microstrip radio frequency signal to the waveguide signal of one layer.

[0006] The technical solution adopted by the utility model to solve its problems is:

[0007] A millimeter-wave radar microstrip-to-slot waveguide structure, including a PCB board, on which a microstrip line is provided. One end of the microstrip line is connected to a radiation patch, and a waveguide structure is connected to the radiation patch. The waveguide structure includes a copper skin layer provided on the PCB board, a metal plate opposite to the PCB board, a trapezoidal column and several metal columns provided on the metal plate. The end face of the trapezoidal column far from the metal plate is in contact with the radiation patch. The metal columns are provided on both sides of the trapezoidal column and on both sides of the microstrip line.

[0008] Further, the metal columns are symmetrically distributed on both sides of the trapezoidal column.

[0009] Further: The trapezoidal column includes a first trapezoidal column, a second trapezoidal column and a third trapezoidal column that are sequentially connected and integrally formed. The first trapezoidal column is in contact with the radiation patch. The height of the second trapezoidal column is lower than that of the first trapezoidal column, and the height of the third trapezoidal column is lower than that of the second trapezoidal column.

[0010] Further: The second trapezoidal column and the third trapezoidal column are far from the microstrip line.

[0011] Further: A rear metal column is also provided on the metal plate. The rear metal column is provided close to the side of the first trapezoidal column far from the second trapezoidal column and is above the microstrip line.

[0012] Further: The height of the rear metal column is less than that of the first trapezoidal column and does not contact the microstrip line.

[0013] Further: The metal columns include a first metal column group and a second metal column group. The metal columns on both sides directly above the microstrip line form the first metal column group, and the metal columns on both sides of the trapezoidal column except the first metal column group form the second metal column group. The distance between the metal columns in the first metal column group is less than the distance between the metal columns in the second metal column group.

[0014] Further: A first via hole group and a second via hole group are provided on the copper skin layer of the PCB board. The first via hole group includes several first via holes, and the first via holes are evenly distributed outside the microstrip line. The second via hole group includes several second via holes, and the second via holes are evenly distributed outside the radiation patch. The first via holes and the second via holes penetrate the copper skin layer.

[0015] Further: An avoidance groove is provided on the copper skin layer. The microstrip line and the radiation patch are both placed in the avoidance groove and installed on the PCB board. The length of the copper skin layer is less than the length of the PCB board. One end of the copper skin layer is flush with the PCB board, and the other end is on the PCB board.

[0016] Furthermore, one end of the microstrip line away from the radiation patch extends out of the copper skin layer and extends from the PCB board.

[0017] Furthermore, the width of the avoidance groove located outside the microstrip line is 0.9 mm, the microstrip line is placed in the middle of the avoidance groove, the width of the avoidance groove located outside the radiation patch is 1.53 mm, and the radiation patch is placed in the middle of the avoidance groove.

[0018] In summary, a millimeter-wave radar microstrip-to-slot waveguide structure provided by the present invention has the following technical effects:

[0019] By providing a trapezoidal column in contact with the radiation patch, the quasi-TEM wave of the microstrip patch radiation signal is converted into the TE_(10) wave of the waveguide, and then transmitted through the waveguide formed by the microstrip-to-slot waveguide structure of this solution, so as to realize the conversion of the on-board microstrip radio frequency signal to the waveguide signal of one layer. Compared with the existing millimeter-wave conversion structure, it has the advantages of simple structure, easy implementation, small insertion loss, large redundancy in installation position and design size, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic structural diagram of an embodiment of a millimeter-wave radar microstrip-to-slot waveguide structure of the present invention.

[0021] Figure 2 It is Figure 1 front view.

[0022] Figure 3 It is Figure 2 A-A cross-sectional view in the middle.

[0023] Figure 4 It is a top view of the PCB board.

[0024] Figure 5 It is a three-dimensional view of the metal plate.

[0025] Figure 6 It is a bottom view of the metal plate.

[0026] Figure 7 It is Figure 6 B-B cross-sectional view of the metal plate in the middle.

[0027] Among them, the meanings of the reference numerals are as follows:

[0028] 1, PCB board; 2, microstrip line; 3, metal plate; 4, metal column; 5, copper skin layer; 6, trapezoidal column; 61, first trapezoidal column; 62, second trapezoidal column; 63, third trapezoidal column; 7, rear metal column; 8, radiation patch; 9, first via hole; 10, second via hole; 11, avoidance groove; 12, rear metal column. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] For better understanding and implementation, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0030] In the description of the present invention, it should be noted 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 accompanying drawings. It is only for the convenience of describing the present invention 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 invention.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the description of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0032] Refer to Figure 1 and Figure 2 , the present invention discloses a millimeter-wave radar microstrip-to-slot waveguide structure.

[0033] A millimeter-wave radar microstrip-to-slot waveguide structure includes a PCB board 1, a microstrip line 2 is arranged on the PCB board 1, one end of the microstrip line 2 is connected with a radiation patch 8, and a waveguide structure is connected to the radiation patch 8. The waveguide structure includes a copper skin layer 5 arranged on the PCB board 1, a metal plate 3 opposite to the PCB board 1, a trapezoidal column 6 arranged on the metal plate 3 and a plurality of metal columns 4. The end face of the trapezoidal column 6 far from the metal plate 3 is in contact with the radiation patch 8; the metal columns 4 are arranged on both sides of the trapezoidal column 6 and on both sides of the microstrip line 2.

[0034] Based on the above solution, the present invention realizes the conversion of the quasi-TEM wave of the microstrip patch radiation signal into the TE_(10) wave of the waveguide by arranging a trapezoidal column in contact with the radiation patch, and then transmits it through the waveguide formed by the microstrip-to-slot waveguide structure of the present solution, so as to realize the conversion of the on-board microstrip radio frequency signal into a layer of waveguide signal.

[0035] In the above solution, a waveguide structure is formed by a copper skin layer, a metal plate, trapezoidal columns, and metal columns. Compared with the existing millimeter-wave conversion structure, this waveguide structure has the advantages of simple structure, easy implementation, low insertion loss, and large redundancy in installation position and design size. The form of attaching the trapezoidal columns to the radiation patches has an in-band transmission insertion loss of about 0.4 dB. In the 76 - 81 GHz frequency band, the gap waveguide structure is simple and easy to process, and is not sensitive to installation deviation.

[0036] Based on the above solution, the signal conversion process is as follows: First, a signal is fed into the microstrip line, that is, the microstrip signal. Then the microstrip signal is transmitted to the radiation patch, and the microstrip signal is converted into a radiation signal. The energy of the radiation signal radiates and transmits outward. The trapezoidal columns in contact with the radiation patch receive the energy and convert it into the TE wave of the waveguide for signal transmission, completing the energy conversion of the signal from the on-board PCB to a single-layer metal gap waveguide. That is, the trapezoidal columns realize the conversion of the quasi-TEM wave of the radiation signal of the microstrip patch into the TE_(10) wave of the waveguide, and then transmit it through the waveguide formed by the ridge-free gap structure, thereby realizing the conversion of the on-board microstrip radio frequency signal to a single-layer waveguide signal.

[0037] The metal columns 4 are symmetrically distributed on both sides of the trapezoidal columns 6, so that the waveguide structures formed on both sides of the microstrip line 2 are symmetric.

[0038] As Figure 5 shown, the trapezoidal column 6 includes a first trapezoidal column 61, a second trapezoidal column 62, and a third trapezoidal column 63 that are sequentially connected and integrally formed. The first trapezoidal column 61 is in contact with the radiation patch 8. The height of the second trapezoidal column 62 is lower than the height of the first trapezoidal column 61, and the height of the third trapezoidal column 63 is lower than the height of the second trapezoidal column 62. In this solution, the structural design of the trapezoidal column 6 realizes the reception and transmission of radiation energy by the trapezoidal column 6, and at the same time transmits the radiation energy to the waveguide structure formed by the metal plate and the copper skin layer.

[0039] The second trapezoidal column 62 and the third trapezoidal column 63 are away from the microstrip line 2, so that the second trapezoidal column 62 and the third trapezoidal column 63 can form a waveguide structure with a larger space.

[0040] As Figure 5 shown, a rear metal column 7 is also provided on the metal plate 3. The rear metal column 7 is disposed close to the side of the first trapezoidal column 61 away from the second trapezoidal column 62 and is located above the microstrip line 2. The rear metal column is provided above the microstrip line, and the function of the rear metal column is to prevent the radiation of the microstrip line.

[0041] The height of the rear metal column 7 is less than that of the first trapezoidal column 61 and does not contact the microstrip line 2. The rear metal column 7 is used to prevent the radiation of the waveguide structure formed by the trapezoidal column 6 and the microstrip line.

[0042] As shown Figure 6 in the figure, the metal posts 4 include a first group of metal posts 4 and a second group of metal posts 4. The metal posts 4 located on both sides directly above the microstrip line 2 form the first group of metal posts 4, and the metal posts 4 on both sides of the trapezoidal post 6 except the first group of metal posts 4 form the second group of metal posts 4; the distance between the metal posts 4 in the first group of metal posts 4 is less than the distance between the metal posts 4 in the second group of metal posts 4. This design of the metal posts facilitates the formation of a waveguide structure.

[0043] As shown Figure 4 in the figure, a first via group and a second via group are provided on the copper skin layer 5 of the PCB board 1. The first via group includes a plurality of first vias 9, and the first vias 9 are evenly distributed outside the microstrip line 2. The second via group includes a plurality of second vias 10, and the second vias 10 are evenly distributed outside the radiation patch 8. The first vias 9 and the second vias 10 penetrate the copper skin layer 5. The setting of the first via group enables it to form a microstrip routing in the form of a ground coplanar waveguide with the microstrip line. The setting of the second via group restricts the signal energy to prevent leakage.

[0044] As shown Figure 4 in the figure, an avoidance groove 11 is provided on the copper skin layer 5. The microstrip line 2 and the radiation patch 8 are both placed in the avoidance groove 11 and installed on the PCB board 1. The length of the copper skin layer 5 is less than the length of the PCB board 1. One end of the copper skin layer 5 is flush with the PCB board 1, and the other end is located on the PCB board 1. The design of the avoidance groove facilitates the routing of the microstrip line.

[0045] In this solution, a specific embodiment of a millimeter-wave radar microstrip-to-gap waveguide structure is provided. In this embodiment, through software simulation, the optimal parameters of the millimeter-wave radar microstrip-to-gap waveguide structure within the radio frequency range of 77 GHz for the operation of this millimeter-wave radar are obtained.

[0046] The PCB board 1 uses a high-frequency RF board material with a dielectric constant of 3.0, a tangent loss of 0.0002, and a thickness of 5 mils.

[0047] The width of the PCB board 1 is 10 mm and the length is 15.22 mm.

[0048] The size of the copper skin layer 5 is a width of 10 mm and a length of 14.07 mm;

[0049] The width of the microstrip line is 0.30 to 0.50 mm and the length is 5.5 to 6.5 mm. Preferably, the width of the microstrip line is 0.30 mm and the length is 5.92 mm. When the frequency band is different, the microstrip line is slightly different.

[0050] The width of the radiation patch is 1.00 to 1.30 mm, and the length is 1.00 to 1.3 mm. Preferably, the width of the radiation patch is 1.07 mm and the length is 1.12 mm. When the frequency band is different, the width of the radiation patch is slightly different.

[0051] The width of the first trapezoidal pillar is 1.3 to 1.5 mm, the length is 1.0 to 1.2 mm, and the height is 1.3 to 1.5 mm. Preferably, the width of the first trapezoidal pillar 61 is 1.44 mm, the length is 1.02 mm, and the height is 1.47 mm. When the frequency band is different, the dimensions of the first trapezoidal pillar are slightly different.

[0052] The width of the second trapezoidal pillar is 1.1 to 1.3 mm, the length is 1.2 to 1.4 mm, and the height is 1.1 to 1.3 mm. Preferably, the width of the second trapezoidal pillar 62 is 1.31 mm, the length is 1.37 mm, and the height is 1.27 mm. When the frequency band is different, the dimensions of the second trapezoidal pillar are slightly different.

[0053] The width of the third trapezoidal pillar is 1.0 to 1.2 mm, the length is 0.7 to 0.9 mm, and the height is 0.7 to 0.9 mm. Preferably, the width of the third trapezoidal pillar 63 is 1.12 mm, the length is 0.82 mm, and the height is 0.86 mm. When the frequency band is different, the dimensions of the third trapezoidal pillar are slightly different.

[0054] The side inclination angles of the first trapezoidal pillar 61, the second trapezoidal pillar 62, and the third trapezoidal pillar 63 are the same, about 2.5 - 3°, preferably 2.86°. The first trapezoidal pillar 61, the second trapezoidal pillar 62, and the third trapezoidal pillar 63 are arranged at an inclined angle, which is convenient for processing.

[0055] The height of the rear metal pillar is 1.1 - 1.3 mm, preferably the height of the rear metal pillar 7 is 1.27 mm. The cross-section of the rear metal pillar 7 is rectangular. The maximum width of the rear metal pillar 7 is close to the metal plate 3 and is 0.5 to 0.7 mm, preferably 0.52 mm. The longitudinal section of the rear metal pillar 7 is trapezoidal, and the outer side inclination angle of the rear metal pillar 7 is 2.5 - 3°, preferably 2.86°. The rear metal pillar is arranged at an inclined angle, which is convenient for processing and forming.

[0056] The height of the metal pillar is 1.3 to 1.5 mm, preferably the height of the metal pillar 4 is 1.47 mm. The cross-section of the metal pillar 4 is rectangular. The maximum width of the metal pillar 4 is close to the metal plate 3 and is 0.5 to 0.7 mm, preferably 0.60 mm. The longitudinal section of the metal pillar 4 is trapezoidal, and the outer side inclination angle of the metal pillar 4 is 2.5 - 3°, preferably 2.86°. The metal pillar is arranged at an inclined angle, which is convenient for processing and forming.

[0057] The distance between the metal columns in the first metal column group is 2.5 to 2.7 mm, and the distance between the metal columns in the second metal column group is 3.3 to 3.5 mm. Preferably, the distance between the metal columns 4 in the first metal column 4 group is 2.60 mm, and the distance between the metal columns 4 in the second metal column 4 group is 3.40 mm.

[0058] The width of the outer part of the avoidance groove located outside the microstrip line is 0.8 to 1.0 mm. Preferably, the width of the outer part of the avoidance groove 11 located outside the microstrip line 2 is 0.9 mm. The microstrip line 2 is placed in the middle of the avoidance groove 11, and the width of the outer part of the avoidance groove 11 located outside the radiation patch 8 is 1.53 mm. The radiation patch 8 is placed in the middle of the avoidance groove 11.

[0059] In this embodiment, the metal column and the rear metal column are designed as trapezoids for easy processing. The solution of designing the metal column and the rear metal column as trapezoids can be applied to all embodiments of this solution.

[0060] The technical means disclosed in the solution of the present utility model are not limited to the technical means disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present utility model, several improvements and modifications can be made, and these improvements and modifications are also regarded as the protection scope of the present utility model.

Claims

1. A millimeter wave radar microstrip to gap waveguide structure, characterized in that: The invention comprises a PCB board, a microstrip line is arranged on the PCB board, one end of the microstrip line is connected to a radiation patch, and a waveguide structure is connected to the radiation patch; the waveguide structure comprises a copper layer arranged on the PCB board, a metal plate opposite to the PCB board, and a trapezoidal column and a plurality of metal columns arranged on the metal plate, the end surface of the trapezoidal column away from the metal plate is in contact with the radiation patch; the metal columns are arranged on both sides of the trapezoidal column and located on both sides of the microstrip line.

2. The millimeter wave radar microstrip to gap waveguide structure according to claim 1, characterized in that: The metal columns are symmetrically distributed on both sides of the trapezoidal column.

3. The millimeter wave radar microstrip to gap waveguide structure according to claim 1 or 2, characterized in that: The trapezoidal column includes a first trapezoidal column, a second trapezoidal column and a third trapezoidal column which are connected in sequence and formed integrally, the first trapezoidal column is in contact with the radiation patch, the second trapezoidal column is lower than the first trapezoidal column, and the third trapezoidal column is lower than the second trapezoidal column.

4. The millimeter wave radar microstrip to gap waveguide structure according to claim 3, characterized in that: The second trapezoidal column and the third trapezoidal column are far away from the microstrip line.

5. The millimeter wave radar microstrip to gap waveguide structure according to claim 3, characterized in that: A rear metal column is also arranged on the metal plate. The rear metal column is arranged close to the side of the first trapezoidal column away from the second trapezoidal column and is located above the microstrip line.

6. The millimeter wave radar microstrip to gap waveguide structure according to claim 5, characterized in that: The rear metal column is smaller in height than the first trapezoidal column and does not contact the microstrip line.

7. The millimeter wave radar microstrip to gap waveguide structure according to claim 5, characterized in that: The metal pillars include a first metal pillar group and a second metal pillar group; the metal pillars located on the two sides directly above the microstrip line form the first metal pillar group, and the metal pillars on both sides of the trapezoidal pillar except the first metal pillar group form the second metal pillar group; the distance between the metal pillars in the first metal pillar group is smaller than the distance between the metal pillars in the second metal pillar.

8. The millimeter wave radar microstrip to gap waveguide structure according to claim 1, characterized in that: A first via group and a second via group are provided on the copper layer on the PCB board, the first via group includes a plurality of first vias, the first vias are evenly distributed outside the microstrip line, the second via group includes a plurality of second vias, the second vias are evenly distributed outside the radiation patch, and the first vias and the second vias both penetrate the copper layer.

9. The millimeter wave radar microstrip to gap waveguide structure according to claim 1, characterized in that: The copper layer is provided with an avoidance groove, the microstrip line and the radiation patch are both placed in the avoidance groove and mounted on the PCB board, the length of the copper layer is less than the length of the PCB board, one end of the copper layer is flush with the PCB board, and the other end is located on the PCB board.

10. The millimeter wave radar microstrip to gap waveguide structure according to claim 1, characterized in that: One end of the microstrip line away from the radiation patch extends out of the copper layer and extends out from the PCB board.

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