Conversion structure for RF testing of millimeter wave radar circuit boards

Abstract

The present application discloses a conversion structure for radio frequency testing of a millimeter-wave radar circuit board, including a structural body and an arc-bend waveguide. The structural body includes a dielectric layer, a copper-clad layer forming a short-circuit surface, a matching structure arranged on the dielectric layer, and a fixing seat fixed on the dielectric layer; the copper-clad layer and the matching structure are respectively arranged on both sides of the dielectric layer, and a plurality of grounded metal vias are arranged on the periphery of the matching structure; the fixing seat is provided with a conversion groove on the side connected to the dielectric layer; the arc-bend waveguide, one end of which is connected to one end of the conversion groove, and the other end is used to connect to the radio frequency test equipment to realize the radio frequency test of the millimeter-wave radar circuit board. The embodiment of the present application can reduce the complexity of the conversion structure of the radio frequency test of the circuit board, thereby facilitating the use of testers in radio frequency testing work.

Description

Technical Field

[0001] The present application relates to the field of radio frequency equipment, and in particular to a conversion structure for radio frequency testing of a millimeter wave radar circuit board. Background Art

[0002] With the development of automatic driving assistance systems and future driverless technology, millimeter-wave radar will become more and more common in the automotive market due to its advantages over cameras and lidar.

[0003] The RF test of the millimeter wave radar PCB (Printed Circuit Board), especially the test of the PCB RF performance in the 76GHz~81GHz frequency band, inevitably requires the use of a waveguide adapter for direct connection between the PCB board RF interface and the instrument interface, such as Figure 1 As shown. Because the principle of this conversion structure is almost the same as the conversion principle of waveguide and coaxial cable, this conversion structure is a conversion form in which a microstrip line probe 111 formed by a microstrip line 110 is inserted into a waveguide port 210 close to a waveguide short-circuit surface 211, but this structure is complex to process and difficult to install. In actual applications, additional accessories are required to make some cavities before the RF test on the circuit board end can be used.

[0004] Therefore, the existing conversion structure for radio frequency testing of circuit boards is relatively complex to use, which is not conducive to use by testers in radio frequency testing work. Summary of the invention

[0005] The present application provides a conversion structure for radio frequency testing of a millimeter wave radar circuit board, which can be convenient for testers to use during radio frequency testing work.

[0006] The embodiment of the present application provides a conversion structure for radio frequency testing of a millimeter wave radar circuit board, including:

[0007] The main structure includes a dielectric layer, a copper-clad layer forming a short-circuit path, a matching structure arranged on the dielectric layer, and a fixing seat fixed on the dielectric layer; the copper-clad layer and the matching structure are arranged on both sides of the dielectric layer, and a plurality of grounded metal vias are arranged on the periphery of the matching structure; the fixing seat is provided with a conversion slot on the side connected to the dielectric layer; and

[0008] One end of the arc curved waveguide is connected to one end of the conversion slot, and the other end is used to connect to the radio frequency testing equipment to realize the radio frequency test of the millimeter wave radar circuit board.

[0009] Optionally, the matching structure is a grounded coplanar waveguide matching structure or a microstrip line matching structure.

[0010] Optionally, a clearance area is extended outwardly around the matching structure, the shape of the clearance area at the matching structure matches the shape of the notch of the conversion part, and the metal vias are arranged around the periphery of the clearance area.

[0011] Optionally, a plurality of rows of metal vias with equal spacing are arranged in a direction perpendicular to the outside of each edge of the matching structure, and the direction of each row of the metal vias is parallel to the edge of the matching structure.

[0012] Optionally, the structural body is further provided with a circle of metal vias at the edge connected to the fixing seat.

[0013] Optionally, the conversion slot includes an introduction portion and a conversion portion connected to each other, and the matching structure includes a strip portion and a matching portion;

[0014] When the fixing seat is connected to the dielectric layer, the introduction part extends along the extension direction of the strip part of the matching structure, the conversion part is connected to the circular arc waveguide, and a connecting part is provided between the conversion part and the introduction part, and is opposite to the transition between the strip part and the matching part in the matching structure.

[0015] Optionally, the groove depth of the connecting portion is smaller than the groove depth at other positions of the introducing portion.

[0016] Optionally, a clearance area is extended outwardly around the matching structure, the shape of the clearance area at the matching structure matches the shape of the notch of the conversion part, and the metal via is arranged around the periphery of the clearance area;

[0017] The width of the clearance area of ​​the connecting portion gradually increases from the strip portion toward the matching structure.

[0018] Optionally, the specifications of the circular arc waveguide match the frequency band of the millimeter wave.

[0019] Optionally, the frequency band of the millimeter wave is 76 GHz~81 GHz.

[0020] From the above, it can be seen that in the embodiment of the present application, through the cooperation between the arc-bent waveguide and the structural body in the conversion structure, there is no need to insert a microstrip line probe into the waveguide port to achieve conversion, which changes the RF conversion form of the millimeter-wave antenna, thereby reducing the complexity of the conversion structure of the circuit board RF test, and making it easier for testers to use it in RF testing work. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of a conversion structure in the prior art provided in an embodiment of the present application.

[0022] Figure 2 A schematic diagram of the structure of a conversion structure for radio frequency testing of a millimeter wave radar circuit board provided in an embodiment of the present application.

[0023] Figure 3 A schematic top view of a conversion structure for radio frequency testing of a millimeter wave radar circuit board provided in an embodiment of the present application.

[0024] Figure 4 This is a schematic AA cross-sectional view of a conversion structure for radio frequency testing of a millimeter-wave radar circuit board provided in an embodiment of the present application.

[0025] Figure 5 A partial structural diagram of a conversion structure for radio frequency testing of a millimeter wave radar circuit board provided in an embodiment of the present application. DETAILED DESCRIPTION

[0026] The preferred embodiments of the present application are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present application can be more easily understood by those skilled in the art, thereby making a clearer definition of the protection scope of the present application.

[0027] See also Figure 2 , the figure shows a conversion structure for millimeter wave radar circuit board radio frequency testing provided by an embodiment of the present application.

[0028] like Figure 2 As shown, the conversion structure for millimeter wave radar circuit board radio frequency testing includes a structural body 1 and an arc curved waveguide 2 fixedly connected to the structural body 1.

[0029] The structural body 1 includes a dielectric layer 11, a copper-clad layer 12 forming a short-circuit, a matching structure 13 arranged on the dielectric layer 11, and a fixing seat fixed on the dielectric layer. The copper-clad layer 12 and the matching structure 13 are respectively arranged on both sides of the dielectric layer 11. The outer periphery of the matching structure 13 is provided with a plurality of metal vias 14, and the metal vias 14 are coupled with the copper-clad layer 12. The fixing seat 15 can be a columnar structure, a prism structure or other types of structures, which are not limited in the present application.

[0030] The copper clad layer 12 can be grounded to form a short-circuit, the metal via 14 is grounded by connecting to the ground, and the structural body 1 can be grounded through the metal via 14. The dielectric layer 11 can be a general PCB board, or other non-conductive materials, so that a certain distance is formed between the copper clad layer 12 and the antenna. The thickness of the dielectric layer 11 can be set according to the radio frequency requirements.

[0031] Specifically, the matching structure 13 of the structural body 1 can be a grounded coplanar waveguide matching structure 13 or a microstrip line matching structure 13. The frequency band of the millimeter wave matching structure is between 76 GHz and 81 GHz. In some embodiments, when the matching structure 13 of the structural body 1 is a grounded coplanar waveguide matching structure 13, the copper clad layer 12 is located on two surfaces of the dielectric layer 11, and the grounding performance is unified through metal vias.

[0032] In the microstrip line matching structure 13, the signal conductor line is processed on the top of the dielectric layer 11, and the ground conductor surface is at the bottom of the dielectric layer 11. In the grounded coplanar waveguide matching structure 13, in addition to the ground plane at the bottom of the dielectric layer 11, two additional ground planes are added on the top of the dielectric layer 11, and the signal conductor is placed in these two ground planes and spaced from each other. The top and bottom ground planes are connected through metal vias 14 to achieve consistent grounding performance.

[0033] It can be understood that the specific form and frequency band of the millimeter wave matching structure can be set according to actual conditions.

[0034] The arc-curved waveguide 2 is fixedly connected to the dielectric layer 11. In some embodiments, the specifications of the arc-curved waveguide 2 match the frequency band of the millimeter wave. For example, if the frequency band of the millimeter wave is 76 GHz to 81 GHz, the structure of the arc-curved waveguide 2 should be able to conduct the millimeter wave signal of the frequency band to reduce the loss during the conduction process. The fixing seat 15 can be fixedly connected to the structural body 1 by setting screws, buckles or other fixing parts in the fixing hole 152. Furthermore, the fixing seat 15 and the arc-curved waveguide 2 can be an integrated structure.

[0035] See also Figure 3 , the figure shows a top view of the conversion structure for millimeter wave radar circuit board RF testing provided by an embodiment of the present application; please refer to Figure 4 , the figure shows the AA cross-sectional structure of the conversion structure for millimeter wave radar circuit board radio frequency testing provided by an embodiment of the present application.

[0036] Combination Figure 3-4 A conversion slot 151 is provided on one side of the fixing seat 15 connected to the dielectric layer 1, which is opposite to the matching structure 13. One end of the conversion slot 151 is connected to one end of the circular arc waveguide 2. The other end of the circular arc waveguide 2 is used to connect to the RF test equipment to convert the RF matching emitted by the matching structure 13 to the RF test equipment.

[0037] Specifically, when the fixing base 15 is fixedly connected to the structural body 1 , the position of the conversion slot 151 of the fixing base 15 is opposite to the matching structure, so that the radio frequency generated by the matching structure 13 is converted to the radio frequency test equipment through the conversion slot 151 .

[0038] In some embodiments, the matching structure 13 may include a strip portion 131 and a matching portion 132. The conversion slot 151 extends along the extension direction of the strip portion 131 to one end close to the circular curved waveguide 2 and is connected to one end of the circular curved waveguide 2. The matching portion 132 of the matching structure 13 may be disposed opposite to one end of the circular curved waveguide 2.

[0039] Specifically, the conversion slot 151 may include an introduction portion 151a, a connection portion 151b and a conversion portion 151c that are interconnected. When the fixing seat 15 is connected to the dielectric layer 1, the introduction portion 151a extends along the extension direction of the strip portion 131 of the matching structure 13, the conversion portion 151c is connected to the circular arc waveguide 2, and the connection portion 151b is arranged between the introduction portion 151a and the conversion portion 151c, and is opposite to the conversion point 133 between the strip portion 131 and the matching portion 132 in the matching structure 13.

[0040] Further, the groove depth of the connecting portion 151b is less than the groove depth of the introduction portion 151a to achieve radio frequency conversion. In some embodiments, the groove depth of the introduction portion 151a is between 1.5 cm and 3.5 cm, and the groove depth of the connecting portion 151b is between 0.1 cm and 0.8 cm. The groove width of the introduction portion 151a can be slightly wider than that of the connecting portion 151b.

[0041] Through the above structure, the radio frequency signal generated by the structural body 1 can be smoothly converted and converted into the arc waveguide 2 through the conversion groove 151 to improve the radio frequency conversion effect of the matching structure 13.

[0042] In order to further ensure the radio frequency conversion effect, in some embodiments, a clearance area 17 is extended outwardly around the matching structure 13, and the clearance area forms a part of the matching structure. The shape of the clearance area 17 matches the notch shape of the conversion slot 151, and the metal via 14 is arranged around the clearance area 17. Preferably, the width of the clearance area 17 at the conversion part 133 can also gradually increase from the strip part 131 to the matching part 132.

[0043] See also Figure 5 , the figure shows a partial structure of a conversion structure for radio frequency testing of a millimeter wave radar circuit board provided in an embodiment of the present application.

[0044] In some embodiments, Figure 5As shown, the matching structure 13 is arranged with a plurality of rows of metal vias 14 with equal spacing in the vertical outward direction on each edge, and the direction of each row of metal vias 14 is parallel to the edge of the matching structure 13. The structural body 1 also includes a mounting hole 16 fixedly connected to the fixing hole 152 of the conversion structure 2.

[0045] Specifically, 3-5 columns of metal vias 14 may extend from each edge of the matching structure 13, and the metal vias 14 may further improve the grounding performance of the matching structure 13. Furthermore, the spacing between every two columns of metal vias 14 may be related to the frequency band of the millimeter wave to better match the radio frequency signal.

[0046] In other embodiments, Figure 5 As shown, the structural body 1 is provided with a circle of metal vias 14 at the edge connected to the fixing base 15. The circle of metal vias 14 can further improve the radio frequency conversion effect.

[0047] During use, the matching structure 13 can be first set on the PCB board, and a copper layer can be laid on the other side of the PCB board (if it is a grounded coplanar waveguide matching structure 13, a copper layer can be laid on both sides of the PCB board), the copper layer can be grounded, and grounded metal vias 14 can be opened around the matching structure 13 to complete the setting of the matching structure 13. Then, the fixing seat 15 with the arc-bend waveguide installed is installed on the PCB board so that the conversion slot 151 of the fixing seat 15 is opposite to the matching structure, and then the other end of the arc-bend waveguide 2 of the fixing seat 15 is connected to the radio frequency test equipment. The above method does not require the microstrip line probe to be inserted into the waveguide port to achieve conversion, which reduces the test structure and the complexity of use.

[0048] During testing, the RF signal emitted by the matching structure 13 will be converted into RF matching through the conversion slot 151 of the fixing seat 15, and will be converted from the circular arc waveguide 2 to the RF testing equipment to implement RF testing of the millimeter wave radar circuit board.

[0049] From the above, it can be seen that in the embodiment of the present application, through the cooperation between the arc-bent waveguide and the structural body in the conversion structure, there is no need to insert a microstrip line probe into the waveguide port to achieve conversion, which changes the RF conversion form of the millimeter-wave antenna, thereby reducing the complexity of the conversion structure of the circuit board RF test, and making it easier for testers to use it in RF testing work.

[0050] The implementation modes of the present application are described in detail above in conjunction with the accompanying drawings, but the present application is not limited to the above implementation modes, and various changes can be made within the knowledge scope of ordinary technicians in the field without departing from the purpose of the present application.

Claims

1. A conversion structure for radio frequency testing of a millimeter wave radar circuit board, characterized in that: include: The main structure includes a dielectric layer, a copper-clad layer forming a short-circuit path, a matching structure arranged on the dielectric layer, and a fixing seat fixed on the dielectric layer; the copper-clad layer and the matching structure are arranged on both sides of the dielectric layer, respectively, and a plurality of grounded metal vias are arranged on the periphery of the matching structure; a conversion slot opposite to the matching structure is arranged on one side of the fixing seat connected to the dielectric layer; as well as An arc curved waveguide, one end of which is connected to one end of the conversion slot, and the other end of which is used to connect to a radio frequency testing device to implement radio frequency testing of a millimeter wave radar circuit board; Wherein, the matching structure includes a strip-shaped portion and a matching portion, the conversion slot extends along the direction of the strip-shaped portion and is connected to one end of the circular arc waveguide, and the matching portion is arranged opposite to one end of the circular arc waveguide; The conversion slot includes an introduction portion, a connection portion and a conversion portion that are connected to each other, the introduction portion extends along the extension direction of the strip portion, and the conversion portion is connected to the circular arc waveguide; the connection portion is arranged between the introduction portion and the conversion portion, and is arranged opposite to the conversion portion between the strip portion and the matching portion; Among them, the specifications of the arc curved waveguide match the frequency band of the millimeter wave, the groove depth of the connecting part is smaller than the groove depth of the introducing part, the groove width of the introducing part is larger than the groove width of the connecting part, and the groove height of the introducing part is larger than the groove height of the connecting part.

2. The conversion structure for the radio frequency test of the millimeter wave radar circuit board according to claim 1, characterized in that: The matching structure is a grounded coplanar waveguide matching structure or a microstrip line matching structure.

3. The conversion structure for the radio frequency test of the millimeter wave radar circuit board as claimed in claim 2, characterized in that: The matching structure has a plurality of rows of metal vias arranged in a direction perpendicular to the outside of each edge with equal spacing, and the direction of each row of the metal vias is parallel to the edge of the matching structure.

4. The conversion structure for the radio frequency test of the millimeter wave radar circuit board as claimed in claim 3, characterized in that: The structural body is also provided with a circle of metal vias at the edge where it is connected to the fixing seat.

5. The conversion structure for the radio frequency test of the millimeter wave radar circuit board according to claim 1, characterized in that: A clearance area is extended outwardly around the matching structure, the shape of the clearance area at the matching part matches the shape of the notch of the conversion part, and the metal via is arranged around the periphery of the clearance area; The width of the clearance area at the transition gradually increases from the strip portion toward the matching structure.

6. The conversion structure for the radio frequency test of the millimeter wave radar circuit board as claimed in claim 5, characterized in that: The frequency band of the millimeter wave is 76GHz~81GHz.

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