Conversion assembly and power dividing device of cascade millimeter wave radar

Abstract

The utility model relates to the technical field of power dividers, in particular to a conversion assembly and a power dividing device of a cascade millimeter wave radar. The conversion assembly comprises a first coplanar waveguide structure and a first substrate integrated waveguide structure; the first substrate integrated waveguide structure is arranged on the outer side of the first coplanar waveguide structure, and the transmission path of the first substrate integrated waveguide structure is the same as the transmission path of the first coplanar waveguide structure. According to the conversion assembly and the power dividing device provided by the utility model, the coplanar waveguide technology and the substrate integrated waveguide technology are adopted at the same time, conversion and power dividing processing of a signal transmission mode are realized, and the metal wall surface of the substrate integrated waveguide structure can effectively inhibit generation of parasitic current in a coplanar waveguide circuit; therefore, the circuit transmission loss is reduced.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of power divider, especially relates to a conversion assembly and power divider of cascade millimeter wave radar. BACKGROUND

[0002] 4D millimeter wave radar, also known as 4D imaging millimeter wave radar, can obtain the distance, direction, height and speed (4D information) of the target at the same time, and realize the imaging of the target. Compared with the traditional 3D millimeter wave radar, the 4D millimeter wave radar has higher resolution and imaging capability, and can more accurately identify and track objects. Therefore, the 4D millimeter wave radar has also become a research hotspot in the field of vehicle-mounted radar.

[0003] At present, the main technical scheme to realize the 4D millimeter wave radar is to realize it by the cascade mode of multiple millimeter wave radar chips, and the local oscillator signal synchronization between the chips is one of the key technologies of the cascade of multiple millimeter wave radar chips. The current synchronization mode mainly has Wilkinson power divider or power divider chip to divide the local oscillator signal of the main chip, and then transmit it to all radar chips through a microstrip. This design has the disadvantages of large transmission loss, poor shielding performance and the like. UTILITY MODEL CONTENTS

[0004] In view of the above problems, the utility model provides a conversion assembly of cascade millimeter wave radar, the conversion assembly includes first coplanar waveguide structure and first substrate integrated waveguide structure;The first substrate integrated waveguide structure is arranged outside the first coplanar waveguide structure, and the transmission path of the first substrate integrated waveguide structure is the same as that of the first coplanar waveguide structure;

[0005] The conversion assembly includes an upper metal layer, a dielectric layer and a lower metal layer;The upper metal layer, the dielectric layer and the lower metal layer are sequentially stacked and arranged;

[0006] The first coplanar waveguide structure is arranged on the upper metal layer;The first substrate integrated waveguide structure is composed of a plurality of metal holes, and the metal holes sequentially penetrate the upper metal layer, the dielectric layer and the lower metal layer.

[0007] Further, the conversion assembly includes an input part and a first transition part;The input end of the first transition part is connected with the output end of the input part.

[0008] Further, the input part includes a first central strip and two parallel first metal hole strips;Two parallel first grooves are arranged on the two sides of the first central strip;Two first metal hole strips are arranged on the side away from the first central strip of the two first grooves respectively;The length direction of the first central strip, the first metal hole strip and the first groove is parallel;

[0009] The first center strip and the first channel are arranged on the upper metal layer; the first metal hole strip comprises a plurality of metal holes arranged at equal intervals, each metal hole in the first metal hole strip penetrates the upper metal layer, the dielectric layer and the lower metal layer in sequence; and one end of the first center strip, one end of the first metal hole strip and one end of the first channel are located at one side edge of the upper metal layer.

[0010] Further, the first transition part comprises two symmetrically arranged second channels and two symmetrically arranged second metal hole strips.

[0011] One end of each second channel is in communication with one end of a first channel, and the distance between the two ends of the two second channels away from the first channel is greater than the width of the first center strip; one end of each second metal hole strip is connected with one end of a first metal hole strip, and the distance between the two ends of the two second metal hole strips away from the first metal hole strip is greater than the parallel hole distance of the two first metal hole strips.

[0012] The included angle between the first channel and the second channel, and the included angle between the first metal hole strip and the second metal hole strip are obtuse angles; and the included angle between the first channel and the second channel is greater than the included angle between the first metal hole strip and the second metal hole strip.

[0013] The second channel is arranged on the upper metal layer; the second metal hole strip comprises a plurality of metal holes arranged at equal intervals, each metal hole in the second metal hole strip penetrates the upper metal layer, the dielectric layer and the lower metal layer in sequence.

[0014] Further, the conversion assembly comprises an output part and a second transition part; the output end of the second transition part is connected with the input end of the output part.

[0015] The utility model also provides a kind of power dividing device of cascaded millimeter wave radar, and the power dividing device includes above-mentioned conversion assembly and power dividing part;

[0016] The power dividing part comprises a second substrate integrated waveguide structure, and is divided into one power dividing input end and two power dividing output ends.

[0017] The first substrate integrated waveguide structure of one conversion assembly is connected with the power dividing input end of the power dividing part, and the first substrate integrated waveguide structure of the other two conversion assemblies is respectively connected with the two power dividing output ends of the power dividing part one by one.

[0018] The utility model has the advantages that:

[0019] 1, substrate integrated waveguide structure is arranged in conversion assembly part, which realizes the conversion of signal transmission mode, and the metal wall surface of substrate integrated waveguide structure can effectively suppress the generation of parasitic current in coplanar waveguide circuit, thereby reducing circuit transmission loss.

[0020] 2. The power dividing device has the coplanar waveguide technology and the substrate integrated waveguide technology simultaneously.

[0021] 3. The power dividing device has the advantages of small size, light weight, low processability and easy integration.

[0022] 4. The first channel, the second channel, the third channel, the fourth channel, the first metal hole belt, the second metal hole belt, the third metal hole belt and the fourth metal hole belt can be adjusted to meet different impedance matching requirements in the application of the power dividing device.

[0023] 5. The power dividing part adopts the substrate integrated waveguide technology, and the transmission paths of the two power dividing output ends are arranged in the same linear direction, and the transmission path of the power dividing input end is perpendicular to the transmission paths of the two power dividing output ends, so that the distribution signal power of the transmission paths of the power dividing output ends is equal and the phase is the same.

[0024] Other features and advantages of the present application will be described in the following description, and some will become apparent from the description, or will be understood from the practice of the present application. The purpose and other advantages of the present application can be achieved and obtained by the structure indicated in the description and the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0026] Figure 1 A front view of the power dividing device of the embodiment of the present application is shown;

[0027] Figure 2 A side view of the power dividing device of the embodiment of the present application is shown;

[0028] Figure 3 A structure schematic view of the input conversion assembly of the embodiment of the present application is shown;

[0029] Figure 4 A structure schematic view of the output conversion assembly of the embodiment of the present application is shown;

[0030] Figure 5 A structure schematic diagram of the power division part of the embodiment of the utility model is shown.

[0031] Figure 6 A simulation experiment data graph of the embodiment of the utility model is shown.

[0032] In the figure: 1 - conversion assembly; 2 - power division part; 3 - upper metal layer; 4 - dielectric layer; 5 - lower metal layer; 6 - first metal hole belt; 7 - first channel; 8 - first center belt; 9 - second channel; 10 - second metal hole belt; 11 - third metal hole belt; 12 - third channel; 13 - second center belt; 14 - fourth channel; 15 - fourth metal hole belt; 16 - fifth metal hole belt; 17 - sixth metal hole belt; 18 - seventh metal hole belt. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical scheme and advantages of the embodiment of the utility model more clear, the technical scheme in the embodiment of the utility model will be clearly and completely explained below in combination with the drawings in the embodiment of the utility model, obviously, the described embodiment is a part of the embodiment of the utility model, rather than all the embodiments. Based on the embodiment in the utility model, all other embodiments obtained by the person skilled in the art without making creative labor are within the protection scope of the utility model.

[0034] The utility model provides a kind of power division device of cascaded millimeter wave radar, as shown in Figure 1 The power division device includes three conversion assemblies 1 and a power division part 2;Among them, one conversion assembly 1 is input conversion assembly, and the other two conversion assemblies 1 are all output conversion assemblies.

[0035] The conversion assembly 1 includes first coplanar waveguide structure and first substrate integrated waveguide structure;The first substrate integrated waveguide structure is arranged outside the first coplanar waveguide structure, and the first substrate integrated waveguide structure transmission path in the same conversion assembly 1 is same with first coplanar waveguide structure transmission path.

[0036] Substrate integrated waveguide structure is arranged in conversion assembly part, which realizes the conversion of signal transmission mode, and the metal wall of substrate integrated waveguide structure can effectively suppress the generation of parasitic current in coplanar waveguide circuit, thereby reducing circuit transmission loss.

[0037] Further, the power division part 2 includes second substrate integrated waveguide structure, and is divided into a power division input end and two power division output ends.

[0038] The first substrate integrated waveguide structure of the input conversion assembly and the power division input end of the power division part 2 are connected;The first substrate integrated waveguide structure of each output conversion assembly and each power division output end of the power division part 2 are connected one by one respectively.

[0039] The design characteristics of the coplanar waveguide technology (CPW) can reduce the loss in the signal transmission process, while realizing a wide working frequency range and high frequency response, meeting the bandwidth requirements of various radio frequency systems; and the coplanar waveguide also has the advantages of low process difficulty, integration-based, strong anti-interference, etc. The substrate integrated waveguide technology (SIW) has the advantages of high inductance Q value, low cost, easy integration with planar circuits, etc. The power dividing device proposed in the utility model simultaneously uses the coplanar waveguide technology and the substrate integrated waveguide technology. The input and output of the signal are realized by using the coplanar waveguide structure, and the power dividing processing of the signal is realized by using the substrate integrated waveguide structure, so that the power dividing device has the advantages of low process difficulty, low cost, strong anti-interference, low transmission loss, etc.

[0040] Specifically, as shown in Figure 1 The input conversion assembly includes an input part and a first transition part; the input end of the first transition part is connected with the output end of the input part, and the output end of the first transition part is connected with the power dividing input end of the power dividing part 2.

[0041] The output conversion assembly includes an output part and a second transition part; the input end of the second transition part is connected with the power dividing output end of the power dividing part 2, and the output end of the second transition part is connected with the input end of the output part.

[0042] The input part and the output part have the same structure, and the transition parts are arranged between the input part and the power dividing part and between the output part and the power dividing part respectively, so as to switch the signal transmission mode. The device can realize the optimal performance state in terms of signal transmission and power dividing processing, reduce the signal transmission loss, and improve the electromagnetic shielding effect of the device.

[0043] Further, as shown in Figure 2 The power dividing device includes an upper metal layer 3, a dielectric layer 4 and a lower metal layer 5; the upper metal layer 3, the dielectric layer 4 and the lower metal layer 5 are sequentially stacked and arranged. The first coplanar waveguide structure is arranged on the upper metal layer 3; the first substrate integrated waveguide structure and the second substrate integrated waveguide structure are respectively composed of a plurality of metal holes, and the metal holes penetrate the upper metal layer 3, the dielectric layer 4 and the lower metal layer 5.

[0044] Exemplarily, the upper metal layer 3 and the lower metal layer 5 are both made of copper material, and the thicknesses of the upper metal layer 3 and the lower metal layer 7 are both 20 μm. The dielectric layer 4 is made of high-frequency circuit board material with a model of Rogers3003G2, and the thickness thereof is 0.127 mm.

[0045] The power dividing device has the advantages of small size, light weight, low processability and easy integration.

[0046] Specifically, as shown in the figure, Figure 3 The input part includes a first center strip 8 and two parallel first metal hole strips 6; two parallel first channels 7 are arranged on the two sides of the first center strip 8; the two first metal hole strips 6 are arranged on the sides of the two first channels 7 away from the first center strip 8; and the length directions of the first center strip 8, the first metal hole strips 6 and the first channels 7 are parallel.

[0047] The first center strip 8 and the first channel 7 are arranged on the upper metal layer 3; the first metal hole strip 6 includes a plurality of equidistantly arranged metal holes, and each metal hole in the first metal hole strip 6 penetrates the upper metal layer 3, the dielectric layer 4 and the lower metal layer 5 in sequence; and the input end of the first center strip 8, one end of the first metal hole strip 6 and one end of the first channel 7 are located at the side edge of the upper metal layer 3.

[0048] For example, the width of the first center strip 8 is 0.27mm, and the length is 3mm. The width of the first channel 7 is 0.1mm, and the length is 3mm. The diameter of each metal hole in the first metal hole strip 6 is 0.15mm, and the center distance between any two adjacent metal holes is 0.3mm; the parallel distance between the two first metal hole strips 6 is 0.77mm.

[0049] The first center strip is a signal input port of the power dividing device, and the local oscillator synchronous signal of the radar is input into the power dividing device through the first center strip.

[0050] Further, as shown in the figure, Figure 3 The first transition part includes two symmetrically arranged second channels 9 and two symmetrically arranged second metal hole strips 10; one end of each second channel 9 is in communication with one end of one first channel 7, and the distance between the ends of the two second channels 9 away from the first channels 7 is greater than the width of the first center strip 8; one end of each second metal hole strip 10 is connected with one end of one first metal hole strip 6, and the distance between the ends of the two second metal hole strips 10 away from the first metal hole strips 6 is greater than the parallel hole distance of the two first metal hole strips 6.

[0051] The included angle between the first channel 7 and the second channel 9, and the included angle between the first metal hole strip 6 and the second metal hole strip 10 are obtuse angles; and the included angle between the first channel 7 and the second channel 9 is greater than the included angle between the first metal hole strip 6 and the second metal hole strip 10.

[0052] The second channel 9 is arranged on the upper metal layer 3; the second metal hole strip 10 includes a plurality of equidistantly arranged metal holes, and each metal hole in the second metal hole strip 10 penetrates the upper metal layer 3, the dielectric layer 4 and the lower metal layer 5 in sequence.

[0053] The angle between the first channel 7 and the second channel 9 is 161°; the maximum distance between the two second channels 9 is 2mm, and the length along the signal transmission direction is 2.5mm.

[0054] The angle between the first metal hole strip 6 and the second metal hole strip 10 is 129°; the maximum distance between the two second metal hole strips 10 is 6.5mm, and the length along the signal transmission direction is 2.2mm. The diameter of each metal hole in the second metal hole strip 10 is 0.15mm, and the distance between the centers of any two adjacent metal holes is 0.3mm.

[0055] The first transition part is a converter for converting the transmission of the local synchronous signal through the waveguide coplanar structure into the transmission through the substrate integrated waveguide structure. Moreover, different impedance matching requirements in the power splitter application can be achieved by adjusting the angle between the first channel and the second channel, and the angle between the first metal hole strip and the second metal hole strip.

[0056] Further, as shown in Figure 4 Each output part includes a second central strip 13 and two parallel third metal hole strips 11; the two sides of the second central strip 13 are provided with two parallel third channels 12; the two third metal hole strips 11 are respectively arranged on the sides of the two third channels 12 away from the second central strip 13; the length directions of the second central strip 13, the third metal hole strips 11 and the third channels 12 in the same output part 2 are parallel.

[0057] The second central strip 13 and the third channel 12 are arranged on the upper metal layer 3; the third metal hole strip 11 includes a plurality of metal holes arranged at equal distances, and each metal hole in the third metal hole strip 11 penetrates the upper metal layer 3, the dielectric layer 4 and the lower metal layer 5 in sequence; and the output end of the second central strip 13, one end of the third metal hole strip 11 and one end of the third channel 12 are all located at the other side edge of the upper metal layer 3.

[0058] Specifically, the width of the second central strip 13 is 0.27mm, and the length is 3mm. The width of the third channel 12 is 0.1mm, and the length is 3mm. The diameter of each metal hole in the third metal hole strip 11 is 0.15mm, and the distance between the centers of any two adjacent metal holes is 0.3mm; the parallel distance between the two third metal hole strips 11 is 0.77mm.

[0059] The second central strip is the signal output port of the power splitter, and the synchronous signals with equal power and same phase output by the power splitting part are transmitted to the radar chips to be cascaded through the second central strips.

[0060] Further, as shown in Figure 4As shown, each of the second transition portions includes two symmetrically arranged fourth channels 14 and two symmetrically arranged fourth metal hole strips 15; one end of each fourth channel 14 is connected to one end of a third channel 12, and the distance between the ends of the two fourth channels 14 away from the third channel 12 is greater than the width of the second central strip 13; one end of each fourth metal hole strip 15 is connected to one end of a third metal hole strip 11, and the distance between the ends of the two fourth metal hole strips 15 away from the third metal hole strip 11 is greater than the parallel hole spacing of the two third metal hole strips 11.

[0061] The angle between the third channel 12 and the fourth channel 14, and the angle between the third metal hole strip 11 and the fourth metal hole strip 15 are both obtuse angles; and the angle between the third channel 12 and the fourth channel 14 is greater than the angle between the third metal hole strip 11 and the fourth metal hole strip 15.

[0062] The fourth channel 14 is disposed on the upper metal layer 3; the fourth metal hole strip 15 includes a plurality of metal holes arranged at equal intervals, and each metal hole in the fourth metal hole strip 15 passes through the upper metal layer 3, the dielectric layer 4 and the lower metal layer 5 in sequence.

[0063] For example, the angle between the third channel 12 and the fourth channel 14 is 161°; the maximum distance between the two fourth channels 14 is 2mm, and the length along the signal transmission direction is 2.5mm.

[0064] The angle between the third metal aperture strip 11 and the fourth metal aperture strip 15 is 129°; the maximum distance between the two fourth metal aperture strips 15 is 6.5 mm, and the length along the signal transmission direction is 2.2 mm. The diameter of each metal aperture in the fourth metal aperture strip 15 is 0.15 mm, and the center-to-center distance between any two adjacent metal apertures is 0.3 mm.

[0065] The second transition section is a converter that transforms the synchronization information processed by the power divider into transmission via a substrate-integrated waveguide structure and transmission via a waveguide coplanar structure. Furthermore, different impedance matching requirements in power divider applications can be achieved by adjusting the angles between the third and fourth channels, as well as the angles between the third and fourth metal aperture strips.

[0066] Furthermore, the power divider input terminals are respectively connected to each power divider output terminal; such as Figure 5 As shown, the power input terminal of the power distribution section 2 includes two parallel fifth metal aperture strips 16, one end of each fifth metal aperture strip 16 is connected to the ends of two second metal aperture strips 10 away from the input section 1; each power output terminal of the power distribution section 2 includes two parallel sixth metal aperture strips 17, one end of each sixth metal aperture strip 17 is connected to the ends of two fourth metal aperture strips 15 in a second transition section away from the output section.

[0067] Specifically, the fifth metal hole strip 16 and the sixth metal hole strip 17 respectively include a plurality of equidistantly arranged metal holes, each metal hole sequentially penetrates the upper metal layer 3, the dielectric layer 4 and the lower metal layer 5.

[0068] Illustratively, the diameter of each metal hole in the fifth metal hole strip 16 and the sixth metal hole strip 17 is 0.15mm; the center distance between any two adjacent metal holes in each metal hole strip is 0.3mm; the parallel distance between the two fifth metal hole strips 16 is 6.5mm, and the parallel distance between the two sixth metal hole strips 17 of the same power division output end is 6.5mm.

[0069] It should be noted that in actual application, the circuit has specific impedance requirements for the input part, the output part, the power division input end and each power division output end. For example, the circuit requires that the impedance of the connection ports such as the input part, the output part, the power division input end and each power division output end reaches 50 ohms. For the co-planar waveguide structure of the input part and the output part, part of the characteristic impedance is 50 ohms, which can meet the circuit requirements. However, the impedance of the substrate integrated waveguide structure of the power division input end and each power division output end cannot directly reach 50 ohms. Therefore, the angle size of the first metal hole strip and the second metal hole strip in the first transition part and the angle size of the third metal hole strip and the fourth metal hole strip in the second transition part need to be adjusted respectively to ensure that the impedance of the power division input end and each power division output end can reach 50 ohms. The angle size of the first metal hole strip and the second metal hole strip is related to the parallel distance between the two fifth metal hole strips, and the angle size of the third metal hole strip and the fourth metal hole strip is related to the parallel distance between the two sixth metal hole strips of the same power division output end.

[0070] Further, as shown in Figure 5 The power division part 2 further includes a seventh metal hole strip 18, and the seventh metal hole strip 18 is arranged at the symmetry axis of the power division part 2. The seventh metal hole strip 18 includes one metal hole or a plurality of equidistantly arranged metal holes, each metal hole sequentially penetrates the upper metal layer 3, the dielectric layer 4 and the lower metal layer 5. Each metal hole in the seventh metal hole strip 18 is a port tuning metal via hole.

[0071] Illustratively, as shown in Figure 5 The seventh metal hole strip 18 includes three equidistantly arranged metal holes, the diameter of each metal hole is 0.15mm, and the center distance between any two adjacent metal holes is 1.1mm.

[0072] It should be noted that the structure size data mentioned in the embodiments of the utility model is only illustrative, and the structure size can be adaptively adjusted according to the actual application requirements, which is not limited herein.

[0073] Preferably, as shown in Figure 5As shown, the connecting angle between the sixth metal hole strip 17 of the power division output end and the fifth metal hole strip 16 of the power division input end connected therewith is a right angle.

[0074] By arranging the transmission paths of the two power division output ends in the same linear direction, the transmission path of the power division input end is perpendicular to the transmission paths of the two power division output ends, so that the distribution signal power of the transmission paths of the power division output ends can be ensured to be equal and the phases are the same.

[0075] As Figure 6 As shown in the S parameter simulation results, in the frequency range of 17GHz-22GHz, the return loss of the power division device is low, which indicates that the port matching degree of the power division device is high, and the bandwidth can cover the actual use range of 19-20.25GHz. Moreover, the output loss of the two paths of the power division device is basically consistent, and the signal distribution is uniform.

[0076] The utility model discloses a coplanar waveguide structure is used as the interface end of power division device, makes the easy realization of power division device and passive, active device in microwave circuit connection, improves circuit density. Adopt the substrate integrated waveguide structure as the power division main part, and utilize substrate integrated waveguide structure to improve the transmission performance of interface end. The utility model discloses a power division device can effectively suppress parasitic current generation, reduce power division device transmission loss, and the shielding effect is excellent, can effectively reduce the interference of external electromagnetic wave. Power division device has the advantages of small size, light weight, low process.

[0077] Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it still can modify the technical scheme recorded in the foregoing each embodiment, or equivalent replacement to part technical feature to it, and these modifications or replacement, do not make the essence of corresponding technical scheme deviate from the spirit and scope of the utility model each embodiment technical scheme.

Claims

1. A conversion component for a cascaded millimeter-wave radar, characterized in that, The conversion assembly comprises a first coplanar waveguide structure and a first substrate integrated waveguide structure; the first substrate integrated waveguide structure is arranged outside the first coplanar waveguide structure, and the transmission path of the first substrate integrated waveguide structure is the same as that of the first coplanar waveguide structure; The conversion assembly comprises an upper metal layer (3), a dielectric layer (4) and a lower metal layer (5); the upper metal layer (3), the dielectric layer (4) and the lower metal layer (5) are arranged in sequence. The first coplanar waveguide structure is arranged on the upper metal layer (3); the first substrate integrated waveguide structure is composed of a plurality of metal holes, and the metal holes sequentially penetrate the upper metal layer (3), the dielectric layer (4) and the lower metal layer (5).

2. The conversion assembly of a cascaded millimeter wave radar according to claim 1, wherein, The conversion assembly comprises an input part and a first transition part; the input end of the first transition part is connected with the output end of the input part.

3. The conversion assembly of a cascaded millimeter wave radar according to claim 2, wherein, The input part comprises a first central strip (8) and two parallel first metal hole strips (6); the first central strip (8) is provided with two parallel first grooves (7) on both sides; the two first metal hole strips (6) are respectively arranged on one side of the two first grooves (7) away from the first central strip (8); the length direction of the first central strip (8), the first metal hole strip (6) and the first groove (7) is parallel; The first central strip (8) and the first groove (7) are arranged on the upper metal layer (3); the first metal hole strip (6) comprises a plurality of metal holes arranged at equal intervals, each metal hole in the first metal hole strip (6) sequentially penetrates the upper metal layer (3), the dielectric layer (4) and the lower metal layer (5); and one end of the first central strip (8), one end of the first metal hole strip (6) and one end of the first groove (7) are located at one side edge of the upper metal layer (3).

4. The conversion assembly of a cascaded millimeter wave radar according to claim 2, wherein, The first transition part comprises two symmetrically arranged second grooves (9) and two symmetrically arranged second metal hole strips (10); One end of each second groove (9) is in communication with one end of one first groove (7), and the distance between the ends of the two second grooves (9) away from the first grooves (7) is greater than the width of the first central strip (8); one end of each second metal hole strip (10) is connected with one end of one first metal hole strip (6), and the distance between the ends of the two second metal hole strips (10) away from the first metal hole strips (6) is greater than the parallel hole distance of the two first metal hole strips (6); The included angle between the first groove (7) and the second groove (9) and the included angle between the first metal hole strip (6) and the second metal hole strip (10) are obtuse angles; and the included angle between the first groove (7) and the second groove (9) is greater than the included angle between the first metal hole strip (6) and the second metal hole strip (10); The second groove (9) is arranged on the upper metal layer (3); the second metal hole strip (10) comprises a plurality of metal holes arranged at equal intervals, and each metal hole in the second metal hole strip (10) sequentially penetrates the upper metal layer (3), the dielectric layer (4) and the lower metal layer (5).

5. The conversion assembly of a cascaded millimeter wave radar according to claim 1, wherein, The conversion assembly comprises an output part and a second transition part; the output end of the second transition part is connected with the input end of the output part.

6. A power dividing device for a cascaded millimeter wave radar, the power dividing device comprising any of the conversion assemblies of claims 1-5, characterized in that, It also comprises a power division part (2); The power division part (2) comprises a second substrate integrated waveguide structure, which is divided into a power division input end and two power division output ends; The first substrate integrated waveguide structure of one conversion assembly is connected with the power division input end of the power division part (2), and the first substrate integrated waveguide structures of the other two conversion assemblies are respectively connected with the two power division output ends of the power division part (2) in one-to-one mode.

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