CN116338674A - Circuit board assembly, radar and vehicle - Google Patents

Abstract

The embodiment of the application provides a circuit board assembly, a radar and a vehicle, wherein the circuit board assembly comprises a circuit board, at least one antenna and a radio frequency chip. The circuit board comprises a plurality of layers of core boards and a circuit layer arranged between two adjacent layers of core boards. The radio frequency chip is arranged on the circuit board. The circuit layer comprises a first transmission line and a second transmission line. The first transmission line includes a first transmission line body and a first bump array. The first protrusion array comprises a plurality of first protrusions which are periodically arranged along the length direction of the first transmission line body. The first bump array adjusts a transmission speed of the first radio frequency signal to a speed ratio of the transmission speed of the first radio frequency signal to the transmission speed of the second radio frequency signal, which is equal to a length ratio of the first transmission line to the second transmission line. The lengths of the first transmission line and the second transmission line can be unequal, so that the wiring is simple, the development period and difficulty of the radar are reduced, the line lengths of the first transmission line and the second transmission line are shortened, and lower transmission loss is brought.

Description

Circuit board assembly, radar and vehicle

Technical Field

The application relates to the technical field of semiconductors, in particular to a circuit board assembly, a radar and a vehicle.

Background

In recent years, radar applications are becoming more and more widespread, such as millimeter wave radar, which is increasingly playing an important role in the fields of automobile assisted driving, security, medical health, and the like. The normal operation of the radar needs to be interconnected between each radio frequency port of the radio frequency chip and each antenna through a low-loss and low-dispersion radio frequency transmission line. In order to meet the requirement that the transmission phases from each antenna to the transmission line are the same within a certain bandwidth, geometric equal length between the transmission lines corresponding to each antenna channel is also required. In order to achieve equal length, a structure of extending geometric paths such as an S-bend is required to be introduced into the transmission line, the equal length wiring process is extremely complicated, and the insertion loss and the inter-channel mutual coupling caused by equal length wiring also restrict the further improvement of the radar performance.

Disclosure of Invention

The embodiment of the application provides a circuit board assembly, a radar and a vehicle, which are used for improving the wiring efficiency of a transmission line, improving the radar performance, reducing the radar development difficulty and shortening the development period.

In order to achieve the above purpose, the present application adopts the following technical scheme:

in a first aspect of embodiments of the present application, a circuit board assembly is provided, including a circuit board, at least one antenna, and a radio frequency chip. The circuit board comprises a plurality of layers of core boards and a circuit layer arranged between two adjacent layers of core boards. The radio frequency chip is arranged on the circuit board. The circuit layer comprises a first transmission line and a second transmission line; the first transmission line and the second transmission line have different lengths; the two ends of the first transmission line are respectively and electrically connected with the antenna and the radio frequency chip. The first transmission line is used for transmitting a first radio frequency signal between the antenna and the radio frequency chip. The two ends of the second transmission line are respectively and electrically connected with the antenna and the chip, and the second transmission line is used for transmitting second radio frequency signals between the antenna and the radio frequency chip. The first transmission line comprises a first transmission line body and a first bulge array arranged on the first transmission line body, wherein the first bulge array comprises a plurality of first bulges which are periodically arranged along the length direction of the first transmission line body; the first bump array satisfies a first condition, where the first condition is that the first bump array adjusts a transmission speed of the first radio frequency signal to a speed ratio of the transmission speed of the first radio frequency signal to a transmission speed of the second radio frequency signal, which is equal to a length ratio of the first transmission line to the second transmission line. The lengths of the first transmission line and the second transmission line may not be required to be the same. Therefore, when the first transmission line and the second transmission line are wired, the limitation of the same wiring length is not needed to be considered, and when the requirements of wiring space and position are met, the first transmission line and the second transmission line can be arranged in a regular straight line shape as far as possible. Therefore, the first transmission line and the second transmission line are simple in wiring, the development period and development difficulty of the radar are reduced, the line lengths of the first transmission line and the second transmission line are shortened, and lower transmission loss is brought. In addition, the first transmission line and the second transmission line are mostly different, so that the occurrence probability of problems of insertion loss, inter-channel mutual coupling and chromatic dispersion caused by equal-length wiring is reduced, and the performance of the circuit board assembly is improved.

Optionally, the first protrusion has a width d. The width of the first bump is the same as the line width of the first transmission line. The width d satisfies a second condition that the width d is non-linearly related to the transmission speed of the first radio frequency signal, and the speed ratio of the transmission speed of the first radio frequency signal to the transmission speed of the second radio frequency signal is equal to the length ratio of the first transmission line to the second transmission line. According to the artificial surface plasmon theory, the transmission speed of the first radio frequency signal is affected by the width d of the periodically arranged first protrusions, and the width d is in nonlinear correlation with the transmission speed of the first radio frequency signal, which is also called curve correlation. By adjusting the width d, the dispersion characteristic of the first transmission line is changed accordingly so that the transmission speed of the first radio frequency signal is changed accordingly. Therefore, the speed ratio of the transmission speed of the first radio frequency signal to the transmission speed of the second radio frequency signal can be adjusted to be equal to the length ratio of the first transmission line to the second transmission line, so that the phase from the antenna to the first transmission line and the phase from the antenna to the second transmission line are equal.

Optionally, the first bump array has a first arrangement period p, where the first arrangement period p is a distance between two adjacent first bumps in a length direction of the first transmission line, and the first arrangement period p meets a third condition, where the third condition is that the first arrangement period p is non-linearly related to a transmission speed of the first radio frequency signal, and a speed ratio of the transmission speed of the first radio frequency signal to a transmission speed of the second radio frequency signal is equal to a length ratio of the first transmission line to the second transmission line. According to the artificial surface plasmon theory, the first arrangement period p of the periodically arranged first protrusions affects the transmission speed of the first radio frequency signal. By adjusting the first arrangement period p, the dispersion characteristic of the first transmission line is changed accordingly so that the transmission speed of the first radio frequency signal is changed accordingly. Therefore, the speed ratio of the transmission speed of the first radio frequency signal to the transmission speed of the second radio frequency signal can be adjusted to be equal to the length ratio of the first transmission line to the second transmission line, so that the phase from the antenna to the first transmission line and the phase from the antenna to the second transmission line are equal.

Optionally, the circuit board assembly according to claim 1, wherein the first transmission line has a line width w, the line width w satisfying a fourth condition that the line width w is non-linearly related to the transmission speed of the first radio frequency signal, such that a speed ratio of the transmission speed of the first radio frequency signal to the transmission speed of the second radio frequency signal is equal to a length ratio of the first transmission line to the second transmission line. According to the artificial surface plasmon theory, the line width w of the periodically arranged first protrusions influences the transmission speed of the first radio frequency signal. By adjusting the line width w, the dispersion characteristic of the first transmission line is changed so that the transmission speed of the first radio frequency signal is changed accordingly. Therefore, the speed ratio of the transmission speed of the first radio frequency signal to the transmission speed of the second radio frequency signal can be adjusted to be equal to the length ratio of the first transmission line to the second transmission line, so that the phase from the antenna to the first transmission line and the phase from the antenna to the second transmission line are equal.

Optionally, the second transmission line includes a second transmission line body and a second bump array disposed on the second transmission line body; the second protrusion array comprises a plurality of second protrusions which are periodically arranged along the length direction of the second transmission line body; the second bump array satisfies a second condition, where the second condition is that the second bump array adjusts a transmission speed of the second radio frequency signal to a speed ratio of the transmission speed of the first radio frequency signal to the transmission speed of the second radio frequency signal, which is equal to a length ratio of the first transmission line to the second transmission line. Therefore, the transmission speed of the first radio frequency signal can be adjusted through the first transmission structure and the transmission speed of the second radio frequency signal can be adjusted through the second transmission structure, so that the speed ratio of the transmission speed of the first radio frequency signal to the transmission speed of the second radio frequency signal can be adjusted, the adjustment mode is more flexible and finer, and the wiring requirement with more complexity can be met.

Optionally, the first transmission line further includes a third bump array disposed on the first transmission line body; the third bump array and the first bump array are symmetrically arranged with respect to the length direction of the first transmission line body; the third protrusion array comprises a plurality of third protrusions which are periodically arranged along the length direction of the first transmission line body. Therefore, the transmission speed of the first radio frequency signal can be adjusted through the structures of the first side surface a and the third side surface b on the first transmission, so that the speed ratio of the transmission speed of the first radio frequency signal to the transmission speed of the second radio frequency signal can be adjusted, the adjustment mode is more flexible, finer and adaptable to more complex wiring requirements.

Optionally, the second transmission line further includes a fourth bump array disposed on the first transmission line body; the fourth bump array and the second bump array are symmetrically arranged with respect to the length direction of the second transmission line body; the fourth bump array comprises a plurality of fourth bumps periodically arranged along the length direction of the second transmission line body. Therefore, the transmission speed of the second radio frequency signal can be adjusted through the structures of the second side surface a and the fourth side surface b on the second transmission line, so that the speed ratio of the transmission speed of the first radio frequency signal to the transmission speed of the second radio frequency signal is adjusted, the adjustment mode is more flexible, finer, and the wiring requirement with more complexity can be met.

Optionally, the at least one antenna comprises a transmitting antenna. The first transmission line includes a first transmitting transmission line. Two ends of the first transmitting transmission line are respectively and electrically connected with the transmitting antenna and the first radio frequency chip. The second transmission line comprises a second transmitting transmission line, and two ends of the second transmitting transmission line are respectively and electrically connected with the transmitting antenna and the second radio frequency chip. The length ratio of the first transmitting transmission line and the second transmitting transmission line is n, and the speed ratio of the transmission speed of the first radio frequency signal and the transmission speed of the second radio frequency signal is n, n >. Through carrying out targeted structural design to first transmission line for the transmission rate of first radio frequency signal and the transmission rate's of second radio frequency signal speed ratio equals the length ratio of first transmission line and second transmission line, with this transmission phase place that guarantees antenna to first transmission line, second transmission line is the same, makes millimeter wave signal not produce the phase difference in the transmission process.

Optionally, the at least one antenna comprises a receiving antenna. The first transmission line includes a first receiving transmission line. Two ends of the first receiving transmission line are respectively and electrically connected with the receiving antenna and the first radio frequency chip. The second transmission line includes a second receiving transmission line. And two ends of the second receiving transmission line are respectively and electrically connected with the receiving antenna and the second radio frequency chip. The length ratio of the first receiving transmission line and the second receiving transmission line is n, and the speed ratio of the transmission speed of the first radio frequency signal and the transmission speed of the second radio frequency signal is n, n >. Through carrying out targeted structural design to first receiving transmission line for the speed ratio of the transmission speed of first radio frequency signal and the transmission speed of second radio frequency signal equals the length ratio of first receiving transmission line and second receiving transmission line, with this transmission phase place that guarantees antenna to first receiving transmission line, second receiving transmission line is the same, makes millimeter wave signal not produce the phase difference in receiving process.

Optionally, at least one of the material, width and thickness of the first transmission line and the second transmission line are the same. Thus, the influence of the difference between the first transmission line and the second transmission line on the transmission speed of the radio frequency signal is reduced as much as possible, so that the transmission speed of the radio frequency signal can be adjusted through the structure of the first transmission line and the structure of the second transmission line.

Optionally, the first transmission line and the second transmission line comprise straight line segments. In this way, the wiring is more convenient.

In a second aspect of the embodiments of the present application, a radar is provided, the radar including a housing and the circuit board assembly described above, the circuit board assembly being disposed in the housing. The radar has higher resolution angle measurement capability.

A vehicle is provided with the radar on the outer periphery of the vehicle. The radar provides information of the distance, the speed and the azimuth angle of the target object, so that a driver or an unmanned system is assisted to judge, and the aim of safe driving is achieved.

Drawings

Fig. 1 is a schematic structural diagram of a vehicle according to an embodiment of the present application;

fig. 2 is a schematic structural diagram of a radar according to an embodiment of the present application;

fig. 3a is a schematic cross-sectional structure of a radar according to an embodiment of the present application;

fig. 3b is a schematic cross-sectional structure of a circuit board assembly according to an embodiment of the present disclosure;

Fig. 3c is a schematic length diagram of a transmission line according to an embodiment of the present application;

fig. 4 is a schematic top view of a circuit board assembly according to an embodiment of the present disclosure;

FIG. 5 is a schematic view of the partial enlarged structure at A of FIG. 4 in a situation;

fig. 6a is a flowchart of a method for determining a mapping relationship between a width d and a transmission speed of a first rf signal;

FIG. 6b is a graph of width d versus transmission line dispersion;

FIG. 7 is a graph of width d versus wave velocity;

fig. 8a is a schematic top view of a circuit board assembly according to another embodiment of the present disclosure;

FIG. 8b is a schematic view of the structure partially enlarged at A of FIG. 4 in another case;

FIG. 8c is a schematic view of the structure partially enlarged at A of FIG. 4 in another case;

fig. 9 is a partially enlarged schematic view of the structure at a in fig. 4 in another case.

Reference numerals:

01. a vehicle; 02. a radar; 021. a housing; 022. a circuit board assembly; 10. a circuit board; 11. a core plate; 12. a circuit layer; 13. a first transmission line; 14. a second transmission line; 100. a first array of bumps; 200. a second array of bumps; 300. a third array of bumps; 400. a fourth array of bumps;

131. a first transmission line; 132. a first receiving transmission line; 13a, a first side; 13b, a third side; 133. a first protrusion; 134. a third protrusion; 135. a first transmission line body;

141. A second transmission line; 142. a second receiving transmission line; 14a, a second side; 14b, fourth side; 143. a second protrusion; 144. a fourth protrusion; 145. a second transmission line body;

20. an antenna; 21. a transmitting antenna; 22. a receiving antenna; 30. a radio frequency chip; 1a, target; s1, transmitting millimeter waves; s2, reflecting millimeter waves.

Detailed Description

The following description of the technical solutions in the embodiments of the present application will be made with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are only some embodiments of the present application, but not all embodiments.

Hereinafter, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first", "a second", etc. may explicitly or implicitly include one or more such feature. In the description of the present application, unless otherwise indicated, the meaning of "a plurality" is two or more.

Furthermore, in this application, directional terms "upper", "lower", etc. may be defined as including, but not limited to, the orientation in which the components are schematically disposed with respect to one another, and it should be understood that these directional terms may be relative terms, which are used for descriptive and clarity with respect to one another, and which may be correspondingly altered with respect to the orientation in which the components are illustrated in the drawings.

In the present application, unless explicitly specified and limited otherwise, the term "coupled" is to be construed broadly, and for example, "coupled" may be either fixedly coupled, detachably coupled, or integrally formed; can be directly connected or indirectly connected through an intermediate medium. Furthermore, the term "coupled" may be a means of electrical connection for achieving signal transmission. "coupled" may be directly connected electrically, or indirectly connected electrically through an intermediary.

Referring to fig. 1, an embodiment of the present application provides a vehicle 01. The vehicle 01 may be a car, motorcycle, bus, truck, engineering vehicle, etc. The type of the vehicle 01 is not limited in this application, and a car is taken as an example for convenience of illustration.

Referring to fig. 1, the periphery of the car is provided with a radar 02. The radar 02 can be used for measuring distance, speed and azimuth angle of a target object 1a (such as an obstacle and a pedestrian) around the car, so that the driving safety of the car is improved, and auxiliary driving is realized. The radar 02 may be a laser radar, a millimeter wave radar, or an ultrasonic radar, and the type of the radar 02 is not limited in this application, and for convenience of illustration, the radar 02 is taken as a millimeter wave radar for illustration.

The following describes distance measurement, speed measurement and azimuth measurement principles of the millimeter wave radar on the target object 1a (such as an obstacle and a pedestrian). In some embodiments of the present application, the radar 02 shown in fig. 2 includes an antenna 20. The antenna 20 includes a transmitting antenna 21 and a receiving antenna 22. The number of the transmitting antennas 21 is plural, and the plurality of transmitting antennas 21 are generally juxtaposed. Similarly, the number of the receiving antennas 22 is plural, and the plurality of receiving antennas 22 are generally arranged in parallel, which means that the receiving antennas 22 are parallel to each other. The number of transmit antennas 21 and receive antennas 22 may be the same or different. The transmitting antenna 21 may transmit millimeter waves to the outside, and for convenience of description, the millimeter waves transmitted from the transmitting antenna 21 are referred to as transmitting millimeter waves S1. The receiving antenna 22 may receive the millimeter wave reflected from the outside, and for convenience of description, the millimeter wave received by the receiving antenna 22 is referred to as a reflected millimeter wave S2.

The radar 02 shown in fig. 1 may transmit millimeter waves S1 by continuously transmitting to the target 1a (e.g., obstacle, pedestrian). Then, the radar 02 receives the reflected millimeter wave S2 returned from the target object 1 a. In this case, the time difference between the emitted millimeter wave S1 and the reflected millimeter wave S2 is the time of flight of the millimeter wave. The distance of the target object 1a to the radar 02 is obtained by detecting the time of flight of the millimeter wave.

Alternatively, in other embodiments of the present application, the radar 02 may calculate the frequency change between the return millimeter wave S2 and the emitted millimeter wave S1 according to the doppler effect, so as to obtain the moving speed of the target 1a relative to the radar 02.

Alternatively, in other embodiments of the present application, the radar 02 may also calculate the azimuth angle of the target 1a relative to the radar 02 by using the phase difference of the reflected millimeter waves S2 returned from the same target 1a received by the parallel receiving antennas 22.

The radar 02 provides information of the distance, speed and azimuth angle of the target object 1a, so that a driver or an unmanned system is assisted to judge, and the aim of safe driving is achieved.

Specifically, referring to fig. 1, the radar 02 may be provided at the head, tail or body side position of the vehicle body. The radar 02 is not limited to a position provided on the vehicle body. Drivers are usually concerned about the targets 1a in front of and behind the vehicle, such as in front of or behind the vehicle, where the radar 02 may be located in the front and rear of the vehicle, which may be directed towards the targets 1a, so that the vehicle body itself is relatively less shielded from the radar 02. The transmitted millimeter wave S1 can be directly transmitted to the target object 1a, so that the returned reflected millimeter wave S2 has good signal quality, thereby improving the resolution of the radar 02.

The description above is given taking the radar 02 provided in the vehicle as an example. In other embodiments of the present application, the radar 02 may also be provided in a security inspection device for determining the distance to a security inspection object or in an imaging device for determining the distance to an imaging object.

The structure of the radar 02 is exemplified below. As illustrated in fig. 3a, the radar 02 may include a housing 021 and a circuit board assembly 022, the circuit board assembly 022 being disposed within the housing 021. The circuit board assembly 022 is an important element of the radar 02, and is mainly used for transmitting and receiving millimeter waves. The housing 021 provides a mounting space for the circuit board assembly 022. The housing 021 includes a cavity in which the circuit board assembly 022 is disposed. The whole radar 02 can be mounted on a target device, such as a security inspection device, a vehicle, through the housing 021.

Referring to fig. 4, the circuit board assembly 022 may include a circuit board 10, at least one antenna 20, and a radio frequency chip 30. Referring to fig. 3b, the circuit board 10 includes a plurality of core boards 11 and a circuit layer 12 disposed between two adjacent core boards 11. With continued reference to fig. 3b, the radio frequency chip 30 is disposed on the circuit board 10. Wherein the line layer 12 comprises a first transmission line 13 and a second transmission line 14. Referring to fig. 4, the first transmission line 13 and the second transmission line 14 are different in length; both ends of the first transmission line 13 are electrically connected to the antenna 20 and the radio frequency chip 30, respectively. The first transmission line 13 is used for transmitting a first radio frequency signal between the antenna 20 and the radio frequency chip 30. The two ends of the second transmission line 14 are respectively electrically connected with the antenna 20 and the chip, and the second transmission line 14 is used for transmitting a second radio frequency signal between the antenna 20 and the radio frequency chip 30. Referring to fig. 5, fig. 5 is a partially enlarged schematic view at a of fig. 4 for a situation.

The first transmission line 13 includes a first transmission line body 135 and a first bump array 133 array 100 disposed on the first transmission line body 135. The first bump array 133 array 100 includes a plurality of first bump arrays 133 periodically arranged along a length direction of the first transmission line body 135. The first bump array 133 array 100 satisfies a first condition that the first bump array 133 array 100 adjusts a transmission speed of the first radio frequency signal to a speed ratio of the transmission speed of the first radio frequency signal to the transmission speed of the second radio frequency signal, which is equal to a length ratio of the first transmission line 13 to the second transmission line. For example, the transmission speed of the first radio frequency signal may be V2, the transmission speed of the second radio frequency signal may be V3, the length of the first transmission line 13 may be L2, and the length of the second transmission line 14 may be L3, v2/v3=l2/L3.

In addition, referring to fig. 4, the above-described circuit board assembly 022 may include a circuit board 10, at least one antenna 20, and a radio frequency chip 30. The wiring layer 12 may include a plurality of transmission lines. The antenna 20 may be disposed between two adjacent core plates 11 as the wiring layer 12. The antenna 20 may be a transmitting antenna 21 or a receiving antenna 22. Wherein the transmitting antenna 21 is used for transmitting radio frequency signals, i.e. millimeter waves S1, to the outside. The receiving antenna 22 is used for receiving the radio frequency signal returned from the outside, i.e. receiving millimeter waves.

The antenna 20 is electrically connected to the radio frequency chip 30 via a transmission line. It should be noted that the number of transmission lines is plural, such as 2, 3, 4, 5, 6, etc., and is not limited to the specific number shown in fig. 4. The first transmission line 13 and the second transmission line 14 are two selected arbitrarily from the above transmission lines. The middle two transmission lines of the line layer 12 are selected for illustration in fig. 4, although other transmission lines may be selected in other embodiments.

Referring to the foregoing, the radar 02 calculates the azimuth angle of the target 1a relative to the radar 02 by receiving the phase difference of the reflected millimeter wave S2 returned from the same target 1a through the parallel receiving antennas 22. It is thus necessary to satisfy that the transmission phases of the respective antennas 20 to the transmission line are the same within a certain bandwidth so that the millimeter wave signals do not generate a phase difference on the transmission line. In the related art, the geometric equal length between the transmission lines corresponding to the channels of each antenna 20 is generally realized, and compared with the technology, the phase from the antenna 20 to the first transmission line 13 and the phase from the antenna 20 to the first transmission line 13 are realized by improving the structure of the first transmission line 13. In this way, the lengths of the first transmission line 13 and the second transmission line 14 may not be required to be the same, so that the scheme of realizing the same transmission phase from each antenna 20 to the transmission line within a certain bandwidth through geometric equal length is avoided, and the equal length wiring is performed by introducing structures of S-bend and other extended geometric paths into the transmission line, so that the wiring process is very complicated, and the insertion loss and the inter-channel mutual coupling caused by the equal length wiring also restrict the further improvement of the radar performance.

In summary, in the embodiment of the present application, the first transmission line 13 may include the first transmission line body 135. The first transmission line body 135 has a top surface, a bottom surface, and side surfaces. The top surface and the surface are surfaces of the first transmission line body 135 parallel to the plane of the circuit board 10. The side surface is a surface of the first transmission line body 135 perpendicular to the plane of the circuit board 10 and extending along the length direction of the first transmission line body 135. The first bump array 100 may be disposed on any one of the top surface, the bottom surface, and the side surfaces. For convenience of illustration, the first protrusions 133 are provided on the side surfaces.

As shown in fig. 5, the first transmission line body 135 has two opposite side surfaces, namely a first side surface 13a and a third side surface 13b, wherein the first side surface 13a and the third side surface 13b are symmetrically arranged along a center line of the first transmission line body 135 in a length direction X of the first transmission line body 135. The first bump array 100 may be disposed on any one side of the first transmission line body 135, such as the first side 13a described above. The first bump array 100 includes a plurality of first bumps 133. The first protrusions 133 are uniformly distributed along the length direction X of the first transmission line body 135 on the first side 13a, so that the first protrusions 133 are integrally arranged in a periodic manner. The first protrusion 133 may be rectangular, triangular, circular arc, etc. The embodiments of the present application are not limited. For convenience of illustration, the first protrusion 133 is taken as a rectangular shape.

The first protrusions 133 are spaced apart from each other on the first side 13a and are periodically arranged along the length direction of the first transmission line body 135. The first transmission line 13 has the first projections 133 periodically arranged. According to the artificial surface plasmon theory, the dispersion characteristic of the first transmission line 13 is changed by the influence of the first protrusion 133, so that the transmission speed of the first radio frequency signal transmitted through the first transmission line 13 is changed accordingly. Therefore, the speed ratio of the transmission speed of the first rf signal and the transmission speed of the second rf signal can be adjusted by the structural design of the first transmission line 13, so that the speed ratio is equal to the length ratio of the first transmission line 13 to the second transmission line 14, and the phases of the antenna 20 to the first transmission line 13 and the phase of the antenna 20 to the second transmission line 14 are equal.

It should be noted that, the length of the transmission line refers to the actual length of the transmission line, that is, the length of the transmission line along the actual wiring path, and not the length of the linear distance between the front end and the rear end of the transmission line after wiring. As shown in fig. 3c, the transmission line is routed in an "S" shaped routing path, the straight distance L1 between the head section and the tail section of the transmission line is 0.35 cm in length, and the length of the transmission line along the "S" shaped routing path is 0.5 cm. Thus, according to the definition of the embodiments of the present application, the length of the transmission line is 0.5 cm.

The lengths of the first transmission line 13 and the second transmission line 14 may not be required to be the same. Therefore, when the first transmission line 13 and the second transmission line 14 are wired, the first transmission line 13 and the second transmission line 14 can be wired in a regular straight line shape as much as possible when the wiring space and the position are satisfied without considering the limitation of the same wiring length. That is, in some embodiments, the first transmission line 13 and the second transmission line 14 comprise straight line segments. And in other embodiments, referring to fig. 4, portions of the first transmission line and/or the second transmission line are entirely linear segments, excluding curved segments. Therefore, the first transmission line 13 and the second transmission line 14 are simple in wiring, the development period and development difficulty of the radar 02 are reduced, the line length of the first transmission line 13 and the second transmission line 14 is shortened, and lower transmission loss is brought. In addition, the first transmission line 13 is mostly different from the second transmission line 14, so that the probability of occurrence of problems of insertion loss, inter-channel mutual coupling and chromatic dispersion caused by equal-length wiring is reduced, and the performance of the circuit board assembly 022 is improved. Of course, when the wiring space is limited or other elements need to be avoided, as shown in fig. 4, a bending portion may be disposed at a corresponding portion of the first transmission line 13 and the second transmission line 14.

Further, since the area of the circuit board 10 is limited. In order to provide more components, the first transmission line 13 and the second transmission line 14 are typically arranged more compactly with a narrower pitch. Therefore, the circuit board 10 is provided with a cover layer covering the first transmission line 13 to adjust the transmission speed of the first radio frequency signal, and the cover layer can easily cover the second transmission line 14 at the same time, so that the transmission speed of the second radio frequency signal is affected and uncontrollable, and a phase difference exists between the phase of the antenna 20 to the first transmission line 13 and the phase of the second transmission line 14. In the embodiment of the application, the method for realizing the phase equalization by carrying out the targeted structural design on the first transmission line 13 is flexible and can be suitable for the condition that the distance between the first transmission line 13 and the second transmission line 14 is narrower.

Moreover, the circuit board assembly 022 of the present embodiment is applicable not only to millimeter wave radars, but also to other radars 02 having equal phase requirements for each transmission line. The present embodiment will be described by taking a circuit board assembly 022 applicable to a millimeter wave radar as an example for convenience of description.

The following exemplifies a scheme of adjusting the transmission phase of each antenna 20 to the transmission line to be the same by adjusting the width d of the first protrusion 133. For example. In some embodiments of the present application, as shown in fig. 5, the first projection 133 has a width d. The width of the first bump 133 is the same as the line width of the first transmission line 13. The width d satisfies a second condition that the width d is non-linearly related to the transmission speed of the first radio frequency signal, and such that the speed ratio of the transmission speed of the first radio frequency signal to the transmission speed of the second radio frequency signal is equal to the length ratio of the first transmission line 13 to the second transmission line 14.

The width d of the first bump 133 is the same as the line width of the first transmission line 13 in the direction, i.e., the Y direction in fig. 5. According to the artificial surface plasmon theory, the width d of the periodically arranged first protrusions 133 affects the transmission speed of the first radio frequency signal, and the width d is non-linearly related to the transmission speed of the first radio frequency signal, which is also referred to as curve-related. By adjusting the width d, the dispersion characteristic of the first transmission line 13 is changed accordingly so that the transmission speed of the first radio frequency signal is changed accordingly. Therefore, the speed ratio of the transmission speed of the first radio frequency signal and the transmission speed of the second radio frequency signal can be adjusted so as to be equal to the length ratio of the first transmission line 13 to the second transmission line 14, so that the phases of the antenna 20 to the first transmission line 13 and the antenna 20 to the second transmission line 14 are equal.

The antenna 20 may be the transmitting antenna 21 or the receiving antenna 22. How to determine the mapping relationship between the width d and the transmission speed of the first rf signal will be described by taking the receiving antenna 22 as an example. For convenience of explanation, the first transmission line 13 to which the receiving antenna 22 is connected is named as a first receiving transmission line 132. The second transmission line 14 to which the receiving antenna 22 is connected is named a second receiving transmission line 142. That is, the first transmission line 13 includes a first receiving transmission line 132, and both ends of the first receiving transmission line 132 are electrically connected to the receiving antenna 22 and the first radio frequency chip 30, respectively. The second transmission line 14 includes a second receiving transmission line 142, and both ends of the second receiving transmission line 142 are electrically connected to the receiving antenna 22 and the second radio frequency chip 30, respectively. The ratio of the lengths of the first receiving transmission line 132 and the second receiving transmission line 142 is n2, and the ratio of the transmission speed of the first radio frequency signal to the transmission speed of the second radio frequency signal is n2, n2 > 0.

In this embodiment, by performing a targeted structural design on the first receiving transmission line 132, the speed ratio of the transmission speed of the first radio frequency signal to the transmission speed of the second radio frequency signal is equal to the length ratio of the first receiving transmission line 132 to the second receiving transmission line 142, so as to ensure that the transmission phases from the antenna 20 to the first receiving transmission line 132 and the second receiving transmission line 142 are the same, and no phase difference is generated in the receiving process of the millimeter wave signal. Specifically, the method for determining the mapping relationship between the width d and the transmission speed of the first radio frequency signal, referring to fig. 6a, includes steps S101 to S106.

S101, the radar 02 receiving antenna 22 and the layout are determined.

Referring to fig. 4, the receiving antenna 22 has interfaces Ra1, ra2, ra3, and Ra4. The rf chip 30 has Rx1, rx2, rx3 and Rx4. The first receiving transmission line 132 connects the interface Ra2 and the interface Rx2, and one of the second receiving transmission lines 142 connects the interface Ra3 and the interface Rx3. The operating frequency of the radio frequency chip 30 is 77GHz.

S102, calculating the dispersion characteristic of the transmission line.

The wave speed of the transmission line under the condition that the first bump 133 is different in width d can be simulated by full-wave electromagnetic simulation software. The structure of the first receiving transmission line 132 is shown in fig. 5. The simulation process is performed in this embodiment, where the specification (such as the material, the width, the first period P, the line width w, etc.) of the first receiving transmission line 132 and the length L2 are determined, and the dispersion characteristics of the first receiving transmission line 132 under the condition that the first protrusion 133 has different widths d are simulated by simulation software. A graph of the relationship between the width d and the transmission line dispersion is established according to the simulation result, wherein the working frequency is the vertical axis, and the phase difference is the horizontal axis. In this figure, the curves corresponding to different widths d are more similar, and in the range of phase differences between the three curves at the abscissa 80-128, the curves are relatively smooth approximate straight lines.

S103, calculating parameters of the electric equal-length transmission lines under different line length ratios.

The length of the first receiving transmission line 132 is denoted by L2, and the time required for the first rf signal from the interface Ra2 to the interface Rx2 is T2; l3 represents the length of the second receiving transmission line 142, and the time required for the second rf signal from the interface Ra3 to the interface Rx3 is T3. T2 and T3 satisfy respectively: t2=l2/V2, t3=l3/V3, where V2 and V3 represent the wave velocities of the L2 and L3 transmission lines, respectively. In order to equalize the transmission delays of each receiving antenna 22 to each Rx port of the chip, t2=t3 should be made. Namely:

L2/L3＝V2/V3 (1)

for the periodic structure transmission line in fig. 5, the wave speed can be controlled by controlling the width d. The simulation process is performed in this embodiment, where the specification (such as the material, the width, the first period P, the line width w, etc.) of the first receiving transmission line 132 and the length L2 are determined, and the wave velocity of the first receiving transmission line 132 under the condition that the first bump 133 has different widths d is simulated by the simulation software. From the scattered data obtained by the simulation, a graph of wave velocity-width d shown in fig. 7 was created with the ratio of wave velocity/light velocity as the vertical axis and the relative dielectric constant as the horizontal axis. The wave velocity is non-linearly related to the width d, and is curve-related.

S104, establishing a mapping relation between the line length ratio and the transmission line parameters.

Fitting is performed according to scattered data in a wave velocity-width d curve graph to obtain a mapping relation which is nonlinear, and in a specific embodiment, the specific mapping relation between d and V is as follows:

d＝-72.152V ³ +82.9021V ² +-0.32.8053V+4.7979 (2)

it should be noted that, the formula (2) is an exemplary mapping relationship, and under different conditions, such as any parameter adjustment of the specification (such as parameters of the material, the width, the first period P, the line width w, etc.) of the first receiving transmission line 132, the specific parameters in the formula (2) will be changed accordingly.

S105, a line length ratio of the first receiving transmission line 132 to the second receiving transmission line 142 is calculated.

The first receiving transmission line 132 and the second receiving transmission line 142 are wired in actual wiring requirements, such as shortest geometry routing, measuring the lengths of L2 and L3, and calculating the line length ratio. Taking the connection between L2 and L3 in fig. 4 as an example, the ratio of the line length between the two is about 0.8.

S106, according to the mapping relation between the line length ratio and the transmission line parameters, mapping the required line length ratio into the structural size of each transmission line.

For example, the transmission speed v2=0.48 of the first radio frequency signal may be determined by determining the requirement, and v3=0.37 is determined according to equation (1). And obtaining the transmission line parameters respectively with d2=0.15 mm according to the mapping relation between the line length ratio and the transmission line parameters in the fourth step, namely the formula (2).

The above description is given of a method of determining the mapping relationship between the width d and the transmission speed of the first radio frequency signal, taking the antenna 20 as the receiving antenna 22 as an example. In other embodiments of the present application, referring to fig. 8a, the mapping relationship between the width d and the transmission speed of the first radio frequency signal may also be determined by taking the antenna 20 as the transmitting antenna 21 as an example. For convenience of explanation, in a rectangular frame shown as B in fig. 8a, the first transmission line 13 to which the transmitting antenna 21 is connected is named as a first transmitting transmission line 131. The second transmission line 14 to which the transmitting antenna 21 is connected is named a second transmitting transmission line 141. That is, the first transmission line 13 includes a first transmitting transmission line 131, and both ends of the first transmitting transmission line 131 are electrically connected to the transmitting antenna 21 and the first radio frequency chip 30, respectively. The second transmission line 14 includes a second transmitting transmission line 141, and both ends of the second transmitting transmission line 141 are electrically connected to the transmitting antenna 21 and the second radio frequency chip 30, respectively. The length ratio of the first transmitting line 131 to the second transmitting line 141 is n1, and the speed ratio of the transmission speed of the first radio frequency signal to the transmission speed of the second radio frequency signal is n1, n1 > 0. In this embodiment, the determining of the width d and the transmission speed of the first rf signal may refer to an embodiment taking the antenna 20 as the receiving antenna 22, and only the parameters such as the transmission speed and the related parameters of the specific transmission line need to be replaced, which is not described herein.

In the above embodiment, the width d of the first protrusion 133 of the first transmission line 13 is adjusted to adjust the transmission phase from each antenna 20 to the transmission line to be the same. In another embodiment, the first arrangement period p of the first projections 133 may also be adjusted to adjust the transmission phase of each antenna 20 to the transmission line to be the same. The first bump array 100 has a first arrangement period p, where the first arrangement period p is a distance between two adjacent first bumps 133 in the length direction of the first transmission line 13, and the first arrangement period p satisfies a third condition, where the third condition is that the first arrangement period p is non-linearly related to the transmission speed of the first radio frequency signal, and a speed ratio of the transmission speed of the first radio frequency signal to the transmission speed of the second radio frequency signal is equal to a length ratio of the first transmission line 13 to the second transmission line 14.

As shown in fig. 5, the first arrangement period p refers to the length of one arrangement period in the length direction of the first transmission line body 135, that is, the distance between two adjacent first protrusions 133 in the X direction in fig. 5. Similarly, according to the artificial surface plasmon theory, the transmission speed of the first radio frequency signal is affected by the first arrangement period p of the periodically arranged first protrusions 133, and the first arrangement period p is non-linearly related to the transmission speed of the first radio frequency signal, which is also referred to as curve-related. The method for determining the mapping relationship between the first arrangement period p and the transmission speed of the first radio frequency signal may refer to the method for determining the mapping relationship between the width d and the transmission speed of the first radio frequency signal.

By adjusting the first arrangement period p, the dispersion characteristic of the first transmission line 13 is changed accordingly so that the transmission speed of the first radio frequency signal is changed accordingly. Therefore, the speed ratio of the transmission speed of the first radio frequency signal and the transmission speed of the second radio frequency signal can be adjusted so as to be equal to the length ratio of the first transmission line 13 to the second transmission line 14, so that the phases of the antenna 20 to the first transmission line 13 and the antenna 20 to the second transmission line 14 are equal.

In another embodiment, the line width w of the first bump 133 may also be adjusted to adjust the transmission phase of each antenna 20 to the transmission line to be the same. The first transmission line 13 has a line width w. The line width w satisfies a fourth condition that the line width w is non-linearly related to the transmission speed of the first radio frequency signal such that the speed ratio of the transmission speed of the first radio frequency signal to the transmission speed of the second radio frequency signal is equal to the length ratio of the first transmission line 13 to the second transmission line 14.

As shown in fig. 5, the line width w is the sum of the first line width w1 of the first transmission line body 135 and the width d of the first bump 133. Similarly, according to the artificial surface plasmon theory, the line width w of the periodically arranged first protrusions 133 affects the transmission speed of the first rf signal, and the line width w is non-linearly related to the transmission speed of the first rf signal, which is also referred to as curve-related. The method for determining the mapping relationship between the line width w and the transmission speed of the first radio frequency signal may refer to the method for determining the mapping relationship between the width d and the transmission speed of the first radio frequency signal.

By adjusting the line width w, the dispersion characteristic of the first transmission line 13 is changed accordingly so that the transmission speed of the first radio frequency signal is changed accordingly. Therefore, the speed ratio of the transmission speed of the first radio frequency signal and the transmission speed of the second radio frequency signal can be adjusted so as to be equal to the length ratio of the first transmission line 13 to the second transmission line 14, so that the phases of the antenna 20 to the first transmission line 13 and the antenna 20 to the second transmission line 14 are equal.

In the above-described embodiment, the transmission phases of the respective antennas 20 to the transmission line are adjusted to be the same by adjusting the width d, the line width w, and the first arrangement period p of the first bump 133 of the first transmission line 13. In another embodiment, reference may also be made to the first transmission line 13, while a corresponding design is made on the second transmission line 14. Referring to fig. 8b, the second transmission line 14 includes a second transmission line body 145 and a second bump array 200 provided to the second transmission line body 145; the second bump array 200 includes a plurality of second bumps 143 periodically arranged along the length direction of the second transmission line body 145; the second bump array 200 satisfies a second condition that the second bump array 200 adjusts a transmission speed of the second radio frequency signal to a speed ratio of the transmission speed of the first radio frequency signal to the transmission speed of the second radio frequency signal, which is equal to a length ratio of the first transmission line to the second transmission line.

As shown in fig. 8b, fig. 8b is a partially enlarged schematic view at a of fig. 4 for a situation. In this embodiment, the first transmission line 13 may include a first transmission line body 135, as shown in fig. 5, where the first transmission line body 135 has two opposite sides, namely a first side 13a and a third side 13b, and the first side 13a and the third side 13b are symmetrically disposed along a center line of the first transmission line body 135 along a length direction X of the first transmission line body 135. The first side 13a includes a plurality of first protrusions 133 thereon. The first protrusions 133 are spaced apart from each other on the first side 13a and are periodically arranged along the length direction of the first transmission line body 135. Similarly, the second transmission line body 145 has two opposite sides, namely a second side 14a and a fourth side 14b. The second bump array 200 is disposed on the third side 13b of the second transmission line body 145. The plurality of second protrusions 143 are uniformly distributed along the length direction X of the second transmission line body 145 at the second side 14a such that the plurality of second protrusions 143 are entirely arranged in a periodic arrangement.

The dispersion characteristics of the second transmission line 14 are changed accordingly so that the transmission speed of the second radio frequency signal transmitted through the second transmission line 14 is changed accordingly. Therefore, the speed ratio of the transmission speed of the first radio frequency signal and the transmission speed of the second radio frequency signal can be adjusted so as to be equal to the length ratio of the first transmission line 13 to the second transmission line 14, so that the phases of the antenna 20 to the first transmission line 13 and the antenna 20 to the second transmission line 14 are equal. The second protrusions 143 may be disposed in a manner referring to the first protrusions 133. It will be appreciated that p, w, d associated with the second projection 143 in the second side 14a may be the same as p, w, d associated with the first projection 133 in the first side 13a as shown in fig. 8b, or may be different as shown in fig. 8 c. The mapping relationship between the parameters p, w, d and the like in the second transmission line 14 and the transmission speed of the second radio frequency signal is determined, and the mapping relationship between the parameters p, w, d and the like in the first transmission line 13 and the transmission speed of the first radio frequency signal can be referred to.

In this embodiment, the transmission speed of the first radio frequency signal can be adjusted through the first transmission structure and the transmission speed of the second radio frequency signal can be adjusted through the second transmission structure at the same time, so that the speed ratio of the transmission speed of the first radio frequency signal to the transmission speed of the second radio frequency signal can be adjusted, the adjustment mode is more flexible, finer, and the wiring requirement can be met.

In the foregoing embodiments, it has been described that the first side 13a may be provided with the first protrusion 133. Similarly, the third side 13b may also be provided with a third protrusion 134. In one embodiment, referring to fig. 9, the first transmission line 13 further includes a third bump array 300 disposed on the first transmission line body 135; the third bump array 300 and the first bump array 100 are symmetrically arranged with respect to the length direction of the first transmission line body 135; the third bump array 300 includes a plurality of third bumps 134 periodically arranged along the length direction of the first transmission line body.

The third bump array 300 is disposed on the third side 13b of the first transmission line body 135. The third protrusions 134 are uniformly distributed along the length direction X of the first transmission line body 135 on the third side 13b, so that the third protrusions 134 are integrally arranged in a periodic manner. The third protrusions 134 may be provided in a manner referring to the first protrusions 133. It is understood that p, w, d associated with the third protrusion 134 in the third side 13b may be the same as or different from p, w, d associated with the first protrusion 133 in the first side 13 a. When p, w, d associated with the third protrusion 134 is the same as p, w, d associated with the first protrusion 133, the first protrusion 133 and the first protrusion 133 may be aligned or staggered in the length direction of the first transmission line 13. The mapping relationship between the p, w, d and other parameters related to the third side 13b and the transmission speed of the first radio frequency signal may be determined by referring to the mapping relationship between the p, w, d and other parameters corresponding to the first side 13a and the transmission speed of the first radio frequency signal.

Obviously, the third protrusions 134, which are periodically arranged, may also change the dispersion characteristics of the first transmission line 13, so that the transmission speed of the first radio frequency signal is changed accordingly. Therefore, the speed ratio of the transmission speed of the first radio frequency signal and the transmission speed of the second radio frequency signal can be adjusted so as to be equal to the length ratio of the first transmission line 13 to the second transmission line 14, so that the phases of the antenna 20 to the first transmission line 13 and the antenna 20 to the second transmission line 14 are equal.

In this embodiment, the transmission speed of the first rf signal can be adjusted by the structures of the first side 13a and the third side 13b on the first transmission line 13 at the same time, so as to adjust the speed ratio of the transmission speed of the first rf signal to the transmission speed of the second rf signal, thereby the adjustment mode is more flexible, finer, and adaptable to more complex wiring requirements.

In the foregoing embodiments, it has been described that the second side 14a may be provided with the second protrusions 143. Similarly, the fourth side 14b may also be provided with a fourth protrusion 144. Referring to fig. 9, the second transmission line 14 further includes a fourth bump array 400 disposed on the first transmission line body; the fourth bump array 400 and the second bump array 200 are symmetrically arranged with respect to the length direction of the second transmission line body 145; the fourth bump array 400 includes a plurality of fourth bumps 144 periodically arranged along the length direction of the second transmission line body 145.

The fourth bump array 400 is disposed on the fourth side 14b of the second transmission line body 145. The fourth protrusions 144 are uniformly distributed along the length direction X of the second transmission line body 145 on the fourth side 14b, so that the fourth protrusions 144 are integrally arranged in a periodic manner. In the foregoing embodiments, it has been described that the second side 14a may be provided with the second protrusions 143. Similarly, fourth side 14b may be provided with fourth protrusion 144. The fourth protrusion 144 may be provided in a manner referring to the second protrusion 143. It will be appreciated that p, w, d associated with the fourth protrusion 144 in the fourth side 14b may be the same as or different from p, w, d associated with the first protrusion 133 in the third side 13 b. When p, w, d associated with the fourth protrusion 144 is the same as p, w, d associated with the second protrusion 143, the fourth protrusion 144 and the second protrusion 143 may be aligned or staggered in the length direction of the first transmission line 13. The mapping relationship between the parameters p, w, d and the like related to the fourth side 14b and the transmission speed of the second radio frequency signal may be determined by referring to the mapping relationship between the parameters p, w, d and the like corresponding to the first side 13a and the transmission speed of the first radio frequency signal.

Obviously, the periodically arranged fourth protrusions 144 may also change the dispersion characteristic of the second transmission line 14, so that the transmission speed of the second radio frequency signal is correspondingly changed. Therefore, the speed ratio of the transmission speed of the first radio frequency signal and the transmission speed of the second radio frequency signal can be adjusted so as to be equal to the length ratio of the first transmission line 13 to the second transmission line 14, so that the phases of the antenna 20 to the first transmission line 13 and the antenna 20 to the second transmission line 14 are equal.

In this embodiment, the transmission speed of the second rf signal can be adjusted by the structures of the second side 14a and the fourth side 14b on the second transmission line 14 at the same time, so as to adjust the speed ratio of the transmission speed of the first rf signal to the transmission speed of the second rf signal, thereby the adjustment mode is more flexible, finer, and adaptable to more complex wiring requirements.

In one embodiment, at least one of the material, width and thickness of the first transmission line 13 and the second transmission line 14 is the same. The material, width and thickness may affect the transmission speed of the radio frequency signal to a certain extent, and at least one of the material, width and thickness is the same, so as to minimize the influence of the difference between the first transmission line 13 and the second transmission line 14 on the transmission speed of the radio frequency signal, so as to adjust the transmission speed of the radio frequency signal through the structure of the first transmission line 13 and the structure of the second transmission line 14.

The foregoing is merely a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any changes or substitutions within the technical scope of the present disclosure should be covered in the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims (13)

1. A circuit board assembly, comprising:

the circuit board comprises a plurality of layers of core boards and a circuit layer arranged between two adjacent layers of core boards;

at least one antenna;

the radio frequency chip is arranged on the circuit board,

the circuit layer comprises a first transmission line and a second transmission line; the lengths of the first transmission line and the second transmission line are different;

the two ends of the first transmission line are respectively and electrically connected with the antenna and the radio frequency chip, and the first transmission line is used for transmitting a first radio frequency signal between the antenna and the radio frequency chip; the two ends of the second transmission line are respectively and electrically connected with the antenna and the chip, and the second transmission line is used for transmitting a second radio frequency signal between the antenna and the radio frequency chip;

the first transmission line comprises a first transmission line body and a first bulge array arranged on the first transmission line body, wherein the first bulge array comprises a plurality of first bulges which are periodically arranged along the length direction of the first transmission line body; the first bump array satisfies a first condition, where the first condition is that the first bump array adjusts a transmission speed of the first radio frequency signal to a speed ratio of the transmission speed of the first radio frequency signal to a transmission speed of the second radio frequency signal, which is equal to a length ratio of the first transmission line to the second transmission line.

2. The circuit board assembly of claim 1, wherein the first bump has a width d, the width of the first bump being the same as the direction in which the line width of the first transmission line is located; the width d satisfies a second condition that the width d is non-linearly related to the transmission speed of the first radio frequency signal, and a speed ratio of the transmission speed of the first radio frequency signal to the transmission speed of the second radio frequency signal is equal to a length ratio of the first transmission line to the second transmission line.

3. The circuit board assembly according to claim 1, wherein the first bump array has a first arrangement period p, the first arrangement period p being a distance between two adjacent first bumps in a length direction of the first transmission line, the first arrangement period p satisfying a third condition that the first arrangement period p is non-linearly related to a transmission speed of the first radio frequency signal and that a speed ratio of the transmission speed of the first radio frequency signal to a transmission speed of the second radio frequency signal is equal to a length ratio of the first transmission line to the second transmission line.

4. The circuit board assembly of claim 1, wherein the first transmission line has a line width w that satisfies a fourth condition that the line width w is non-linearly related to a transmission speed of the first radio frequency signal such that a speed ratio of the transmission speed of the first radio frequency signal to the transmission speed of the second radio frequency signal is equal to a length ratio of the first transmission line to the second transmission line.

5. The circuit board assembly of claim 1, wherein the second transmission line comprises a second transmission line body and a second array of bumps disposed on the second transmission line body;

the second protrusion array comprises a plurality of second protrusions which are periodically arranged along the length direction of the second transmission line body; the second bump array satisfies a second condition, where the second condition is that the second bump array adjusts a transmission speed of the second radio frequency signal to a speed ratio of the transmission speed of the first radio frequency signal to the transmission speed of the second radio frequency signal, which is equal to a length ratio of the first transmission line to the second transmission line.

6. The circuit board assembly of claim 1, wherein the first transmission line further comprises a third array of bumps disposed on the first transmission line body; the third bump array and the first bump array are symmetrically arranged with respect to the length direction of the first transmission line body;

The third protrusion array comprises a plurality of third protrusions which are periodically arranged along the length direction of the first transmission line body.

7. The circuit board assembly of claim 5, wherein the second transmission line further comprises a fourth array of bumps disposed on the first transmission line body; the fourth bump array and the second bump array are symmetrically arranged with respect to the length direction of the second transmission line body;

the fourth bump array comprises a plurality of fourth bumps periodically arranged along the length direction of the second transmission line body.

8. The circuit board assembly of claim 1, wherein the at least one antenna comprises a transmitting antenna;

the first transmission line comprises a first transmission line, and two ends of the first transmission line are respectively and electrically connected with the transmission antenna and the first radio frequency chip;

the second transmission line comprises a second transmitting transmission line, and two ends of the second transmitting transmission line are respectively and electrically connected with the transmitting antenna and the second radio frequency chip;

the length ratio of the first transmitting transmission line to the second transmitting transmission line is n1, and the speed ratio of the transmission speed of the first radio frequency signal to the transmission speed of the second radio frequency signal is n1, n1 > 0.

9. The circuit board assembly of claim 1 or 8, wherein the at least one antenna comprises a receiving antenna;

the first transmission line comprises a first receiving transmission line, and two ends of the first receiving transmission line are respectively and electrically connected with the receiving antenna and the first radio frequency chip;

the second transmission line comprises a second receiving transmission line, and two ends of the second receiving transmission line are respectively and electrically connected with the receiving antenna and the second radio frequency chip;

the length ratio of the first receiving transmission line to the second receiving transmission line is n2, and the speed ratio of the transmission speed of the first radio frequency signal to the transmission speed of the second radio frequency signal is n2, wherein n2 is more than 0.

10. The circuit board assembly of any one of claims 1-9, wherein at least one of a material, a width, and a thickness of the first transmission line and the second transmission line are the same.

11. The circuit board assembly of any one of claims 1-9, wherein the first transmission line and the second transmission line comprise straight line segments.

12. A radar, the radar comprising:

a housing;

the circuit board assembly of any one of claims 1-11 disposed within the housing.

13. A vehicle comprising a vehicle body, and the radar of claim 12 disposed on the vehicle body.

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