Waveguide device and related product

Abstract

The invention discloses a waveguide device and a related product, and relates to the technical field of millimeter wave radars. The waveguide device comprises a cross structure waveguide; the cross structure waveguide comprises a first cavity and a second cavity which are intersected, and the first cavity and the second cavity are intersected at the central point of the cross structure waveguide; a filling medium of the cross-structure waveguide is a first material with a dielectric constant greater than a first preset threshold value, and the outer surface of the cross-structure waveguide is a conductive material. According to the waveguide device, the miniaturization characteristic of the waveguide can be realized, and the multi-channel cross transmission requirement of the millimeter wave radar is met.

Description

Waveguide devices and related products Technical Field

[0001] The present application relates to the field of millimeter wave radar technology, and in particular to a waveguide device and related products. Background Art

[0002] A waveguide is a structure used to guide electromagnetic waves in a certain direction. It is primarily used as a transmission line at microwave frequencies, connecting microwave transmitters and receivers to their antennas in microwave radio link equipment such as radar.

[0003] Currently, in multi-channel transmission scenarios for visible light integrated optoelectronic devices, waveguides manufactured using a silicon-on-insulator (SiO2) process with high and low refractive indexes are often used for power transmission. However, in the multi-channel cross-transmission scenario of millimeter-wave radar, these waveguides are too large to be practically applied in engineering applications. Therefore, there is an urgent need to design a miniaturized waveguide device that can meet the multi-channel cross-transmission requirements of millimeter-wave radar.

[0004] Summary of the Invention

[0005] The embodiments of the present application provide a waveguide device and related products, which can realize the miniaturization characteristics of the waveguide and meet the multi-channel cross-transmission requirements of millimeter-wave radar.

[0006] In a first aspect, an embodiment of the present application provides a waveguide device, the waveguide device comprising:

[0007] Cross-structure waveguide;

[0008] The cross-structure waveguide includes a first cavity and a second cavity intersecting each other, wherein the first cavity and the second cavity intersect at a center point of the cross-structure waveguide;

[0009] The filling medium of the cross-structure waveguide is a first material having a dielectric constant greater than a first preset threshold, and the outer surface of the cross-structure waveguide is a conductive material.

[0010] In the embodiment of the present application, the cross-structure waveguide included in the waveguide device can be centrosymmetrical, the first cavity and the second cavity included in the cross-structure waveguide are centrosymmetrical about the center point of the cross-structure waveguide, and the filling medium of the cross-structure waveguide is a first material with a dielectric constant greater than a first preset threshold, and the outer surface of the cross-structure waveguide is a conductive material. According to the electromagnetic wave medium wavelength calculation formula (where DK is the dielectric constant of the material) It can be seen that the full wavelength size λ at the same frequency point 介质 will become the vacuum wavelength λ times, which can significantly reduce the size of the waveguide structure while ensuring the same number of field mode distributions within the waveguide device. Through the embodiments of the present application, the cross-structure waveguide is filled with a high-dielectric material, which ensures that the waveguide device can be miniaturized while maintaining the electromagnetic wave transmission performance, and can meet the multi-channel cross-transmission requirements of millimeter-wave radar.

[0011] The high-dielectric material in the embodiments of the present application includes a material with a relatively high dielectric constant. A relatively high dielectric constant may refer to a dielectric constant greater than a first preset threshold value. The first preset threshold value is not a fixed value and can be adjusted according to different application scenarios. For example, the dielectric constant of the high-dielectric material in the embodiments of the present application is greater than the dielectric constant of the dielectric material used in the dielectric waveguide implemented based on the silicon on insulator (SOI) process with high and low refractive index inside and outside.

[0012] In a possible implementation, the waveguide device further includes a metal plate, the cross-structure waveguide is located on an upper layer of the metal plate, and an outer surface of the cross-structure waveguide is a metal plating layer.

[0013] In an embodiment of the present application, a possible specific embodiment of a waveguide device is provided, specifically, the waveguide device also includes a metal plate, the cross-structure waveguide is coupled to the metal plate, the cross-structure waveguide is located on the upper layer of the metal plate, and the outer surface of the cross-structure waveguide is a metal coating. Through the embodiment of the present application, high-dielectric material deposition on the metal surface and etching of the high-dielectric material layer are used to form a high-dielectric material filling inside the cross-structure waveguide, and an outer electroplating process is used to form a metal coating on the outer surface of the cross-structure waveguide. In engineering, the dielectric filling of the high-dielectric material of the cross-structure waveguide can be realized, which can ensure that the waveguide device can be miniaturized while maintaining the electromagnetic wave transmission performance, and can meet the multi-channel cross transmission requirements of millimeter-wave radar.

[0014] In a possible implementation, the first material includes at least one of the following: silicon, ceramic, and glass.

[0015] In the embodiment of the present application, a possible specific embodiment of the first material is provided, specifically, the first material includes but is not limited to high dielectric materials such as silicon, ceramics, and glass. According to the electromagnetic wave medium wavelength calculation formula (where DK is the dielectric constant of the material) It can be seen that in high dielectric materials such as silicon, ceramics, and glass, the full wavelength size λ at the same frequency point 介质 will become the vacuum wavelength λ times, which can greatly compress the size of the waveguide structure while ensuring the same number of field mode distributions in the waveguide device.

[0016] In a possible implementation, the main body of the waveguide device is a printed circuit board (PCB), and the PCB includes a plurality of metallized through holes penetrating the upper and lower surfaces;

[0017] The area where the multiple metallized through holes are formed is the cross-structure waveguide.

[0018] In an embodiment of the present application, a possible specific embodiment of a waveguide device is provided. Specifically, the main body of the waveguide device is a printed circuit board (PCB), and the PCB is covered with multiple metallized through-holes running through the upper and lower surfaces. The area surrounded by these metallized through-holes constitutes a cross-structure waveguide in the waveguide device. Through the embodiment of the present application, a cross-structure waveguide in the form of a substrate integration waveguide (SIW) is realized using a PCB processing technology. The upper and lower metal layers of the PCB board serve as the upper and lower electrical walls of the cross-structure waveguide, and the metallized through-holes on the sides of the PCB board form the side electrical walls of the cross-structure waveguide. The size of the dielectric compression device (cross-structure waveguide) inside the PCB board can ensure the miniaturization design of the waveguide device while maintaining the electromagnetic wave transmission performance in engineering terms, and can meet the multi-channel cross transmission requirements of millimeter wave radar.

[0019] Optionally, the multiple metallized through holes are spaced equally apart.

[0020] In a possible implementation manner, the first material is a plate material of the PCB.

[0021] In the embodiment of the present application, a possible specific implementation of the first material is provided. Specifically, when the main body of the waveguide device is a PCB board, the upper and lower metal layers of the PCB board serve as the upper and lower electrical walls of the cross-structure waveguide, and the metallized through-holes on the side of the PCB board form the side electrical walls of the cross-structure waveguide. The filling medium (i.e., the first material) of the cross-structure waveguide is the plate material of the PCB board. The internal medium of the PCB board can compress the size of the device (cross-structure waveguide). In engineering, it can ensure that the waveguide device can achieve a miniaturized design while maintaining the electromagnetic wave transmission performance unchanged, and can meet the multi-channel cross-transmission requirements of the millimeter-wave radar.

[0022] In a possible implementation, the first cavity includes a first fundamental mode input waveguide, a first fundamental mode and multimode matching waveguide, and a first multimode interference waveguide;

[0023] Wherein, the first fundamental mode input waveguide and the first multimode interference waveguide are connected via the first fundamental mode and multimode matching waveguide, and the width of the first multimode interference waveguide is greater than the width of the first fundamental mode input waveguide;

[0024] The first fundamental mode input waveguide is used to input electromagnetic waves. The electromagnetic waves enter the first multimode interference waveguide through the first fundamental mode and multimode matching waveguide. The first multimode interference waveguide is used to interfere with the electromagnetic waves, and the fundamental mode field shape of the electromagnetic waves entering the first multimode interference waveguide is presented at the center point.

[0025] In an embodiment of the present application, a possible specific implementation of a first cavity is provided. Specifically, the first fundamental mode input waveguide and the first multimode interference waveguide in the first cavity are connected via a first fundamental mode and multimode matching waveguide. Since the cross-structure waveguide is centrosymmetrical, and the first and second cavities of the cross-structure waveguide intersect at the center of the cross-structure waveguide, the first cavity includes two sections of the first fundamental mode input waveguide, two sections of the first fundamental mode and multimode matching waveguide, and one section of the first multimode interference waveguide. The center point of the cross-structure waveguide is the center point of the first multimode interference waveguide in the first cavity. That is, the connection order of the waveguide sections in the first cavity is "first fundamental mode input waveguide, first fundamental mode and multimode matching waveguide, first multimode interference waveguide, first fundamental mode and multimode matching waveguide, and first fundamental mode input waveguide." The width of the first multimode interference waveguide is greater than that of the first fundamental mode input waveguide. The waveguide width design enables the expansion of the fifth-order higher-order modes of each waveguide section in the first cavity. Through the embodiments of the present application, the first fundamental mode input waveguide inputs an electromagnetic wave, and the electromagnetic wave enters the first multimode interference waveguide through the first fundamental mode and multimode matching waveguide. After interference, the fundamental mode field shape where the electromagnetic wave enters the first multimode interference waveguide is presented at the center point, which can better suppress crosstalk and reduce electromagnetic wave transmission loss.

[0026] It can be understood that the composition structure of the second cavity is the same as that of the first cavity.

[0027] In a possible implementation, a connection between the first fundamental mode and multimode matching waveguide and the first fundamental mode input waveguide is a tapered structure, and a connection between the first fundamental mode and multimode matching waveguide and the first multimode interference waveguide is a tapered structure.

[0028] In an embodiment of the present application, a possible specific implementation of a waveguide connection is provided. Specifically, the connection between the first fundamental mode and multimode matching waveguide and the first fundamental mode input waveguide is a tapered structure, and the connection between the first fundamental mode and multimode matching waveguide and the first multimode interference waveguide is a tapered structure. By designing a tapered, gradually changing structure at the connection between different waveguides in this embodiment, it is possible to improve mode matching at the connection between the first multimode interference waveguide and the first fundamental mode input waveguide, thereby optimizing the echo.

[0029] In a possible implementation manner, the cross-sectional dimensions of the first multimode interference waveguide satisfy the following conditions: 0.53λ≤a≤0.72λ;

[0030] Wherein, a is the first side of the cross section of the first multimode interference waveguide, and λ is the vacuum wavelength of the transmitted electromagnetic wave.

[0031] In an embodiment of the present application, a possible specific implementation of the cross-sectional size of a first multimode interference waveguide is provided. Specifically, the waveguide device includes a cross-structure waveguide and a metal plate, the cross-structure waveguide is coupled to the metal plate, and the cross-structure waveguide is located on the upper layer of the metal plate. The outer surface of the cross-structure waveguide is a metal plating layer. When the above-mentioned waveguide device is implemented, the size of the first side of the cross-section of the first multimode interference waveguide in the waveguide device (which can be understood as the width of the cross-section of the first multimode interference waveguide) is greatly reduced, thereby realizing a miniaturized design of the waveguide device.

[0032] In a possible implementation manner, the cross-sectional dimensions of the first multimode interference waveguide satisfy the following conditions: 1.2λ≤a≤1.5λ;

[0033] Wherein, a is the first side of the cross section of the first multimode interference waveguide, and λ is the vacuum wavelength of the transmitted electromagnetic wave.

[0034] In an embodiment of the present application, a possible specific implementation of the cross-sectional dimensions of a first multimode interference waveguide is provided. Specifically, the main body of the waveguide device is a PCB board, the upper and lower metal layers of the PCB board serve as the upper and lower electrical walls of the cross-structure waveguide, the metallized through-holes on the side of the PCB board form the side electrical walls of the cross-structure waveguide, and the size of the dielectric compression device (cross-structure waveguide) inside the PCB board. When the above-mentioned waveguide device is implemented, the size of the first side of the cross-sectional dimension of the first multimode interference waveguide in the waveguide device (which can be understood as the width of the cross-sectional dimension of the first multimode interference waveguide) is greatly reduced, thereby realizing a miniaturized design of the waveguide device.

[0035] In a possible implementation manner, the length of the first multimode interference waveguide satisfies the following condition: 1.9λ≤L3≤2.1λ;

[0036] Wherein, L3 is the length of the first multimode interference waveguide, and λ is the vacuum wavelength of the transmitted electromagnetic wave.

[0037] In an embodiment of the present application, a possible specific implementation of the length of a first multimode interference waveguide is provided. Specifically, the waveguide device includes a cross-structure waveguide and a metal plate, the cross-structure waveguide is coupled to the metal plate, and the cross-structure waveguide is located on the upper layer of the metal plate. The outer surface of the cross-structure waveguide is a metal plating layer. When the above-mentioned waveguide device is implemented, the length of the first multimode interference waveguide in the waveguide device is greatly reduced, thereby realizing a miniaturized design of the waveguide device.

[0038] In a possible implementation manner, the length of the first multimode interference waveguide satisfies the following condition: 4.8λ≤L3≤5.3λ;

[0039] Wherein, L3 is the length of the first multimode interference waveguide, and λ is the vacuum wavelength of the transmitted electromagnetic wave.

[0040] In an embodiment of the present application, a possible specific implementation of the length of the first multimode interference waveguide is provided. Specifically, the main body of the waveguide device is a PCB board, the upper and lower metal layers of the PCB board serve as the upper and lower electrical walls of the cross-structure waveguide, the metallized through holes on the side of the PCB board form the side electrical walls of the cross-structure waveguide, and the size of the dielectric compression device (cross-structure waveguide) inside the PCB board is reduced. When the above-mentioned waveguide device is implemented, the length of the first multimode interference waveguide in the waveguide device is greatly reduced, thereby realizing a miniaturized design of the waveguide device.

[0041] In a possible implementation manner, the lengths of the first fundamental mode and multimode matching waveguides satisfy the following condition: 0.13λ≤L2≤0.18λ;

[0042] Wherein, L2 is the length of the first fundamental mode and multimode matching waveguide, and λ is the vacuum wavelength of the transmitted electromagnetic wave.

[0043] In an embodiment of the present application, a possible specific implementation of the length of the first fundamental mode and the multi-mode matching waveguide is provided. Specifically, the waveguide device includes a cross-structure waveguide and a metal plate, the cross-structure waveguide is coupled to the metal plate, and the cross-structure waveguide is located on the upper layer of the metal plate. The outer surface of the cross-structure waveguide is a metal plating layer. When the above-mentioned waveguide device is implemented, the length of the first fundamental mode and the multi-mode matching waveguide in the waveguide device is greatly reduced, thereby realizing a miniaturized design of the waveguide device.

[0044] In a possible implementation manner, the lengths of the first fundamental mode and multimode matching waveguides satisfy the following condition: 0.3λ≤L2≤0.45λ;

[0045] Wherein, L2 is the length of the first fundamental mode and multimode matching waveguide, and λ is the vacuum wavelength of the transmitted electromagnetic wave.

[0046] In an embodiment of the present application, a possible specific implementation method for the length of the first fundamental mode and multi-mode matching waveguide is provided. Specifically, the main body of the waveguide device is a PCB board, the upper and lower metal layers of the PCB board serve as the upper and lower electrical walls of the cross-structure waveguide, the metallized through holes on the side of the PCB board form the side electrical walls of the cross-structure waveguide, and the size of the dielectric compression device (cross-structure waveguide) inside the PCB board is reduced. When the above-mentioned waveguide device is implemented, the length of the first fundamental mode and multi-mode matching waveguide in the waveguide device is greatly reduced, thereby realizing a miniaturized design of the waveguide device.

[0047] In a possible implementation manner, the thickness of the cross-structure waveguide satisfies the following condition: 0.35W1≤h≤0.6W1;

[0048] Wherein, h is the thickness of the cross-structure waveguide, and W1 is the width of the first fundamental mode input waveguide.

[0049] In an embodiment of the present application, a possible specific implementation of matching the length of a first fundamental mode and a multimode waveguide is provided. Specifically, a waveguide device includes a cross-structured waveguide and a metal plate, wherein the cross-structured waveguide is coupled to the metal plate, the cross-structured waveguide is located on the upper layer of the metal plate, and the outer surface of the cross-structured waveguide is metal-plated. Alternatively, the waveguide device comprises a PCB board, wherein the upper and lower metal layers of the PCB board serve as the upper and lower electrical walls of the cross-structured waveguide, and the metalized through-holes on the side of the PCB board form the side electrical walls of the cross-structured waveguide. The size of the dielectric compression device (cross-structured waveguide) inside the PCB board is reduced. In any of the above implementations of the waveguide device, the thickness of the cross-structured waveguide in the waveguide device is greatly reduced, thereby achieving a miniaturized design of the waveguide device.

[0050] In a possible implementation, when the first cavity is fed with electricity to form an electromagnetic current, the magnetic current density in the second cavity is less than a second preset threshold.

[0051] In an embodiment of the present application, a possible specific implementation method of electromagnetic wave transmission is provided. Specifically, when the first cavity is fed to form an electromagnetic current, the magnetic current density in the second cavity is less than a second preset threshold value, that is, the electromagnetic current is ensured to be transmitted in the first cavity, which can better suppress crosstalk and reduce electromagnetic wave transmission loss. In engineering, it can be ensured that the waveguide device can meet the multi-channel cross-transmission requirements of the millimeter wave radar under the premise that the electromagnetic wave transmission performance remains unchanged.

[0052] Optionally, when the second cavity is fed with electricity to form an electromagnetic current, the magnetic current density in the first cavity is less than a third preset threshold.

[0053] In a possible implementation manner, a plurality of the cross-structured waveguides in the waveguide device are arranged in cascade.

[0054] In an embodiment of the present application, a possible specific implementation of a waveguide device is provided. Specifically, the waveguide device may include multiple cross-structured waveguides, and the multiple cross-structured waveguides are arranged in cascade. Through the embodiment of the present application, it is possible to ensure that the waveguide device can be miniaturized while maintaining the electromagnetic wave transmission performance, and can meet the multi-channel cross-transmission requirements of the millimeter-wave radar.

[0055] In a second aspect, embodiments of the present application provide a radar or radar system, comprising the waveguide device described in the first aspect or any possible implementation of the first aspect. It should be noted that there may be smart sensors integrating multiple sensors. If the smart sensor includes millimeter-wave detection capabilities, the smart sensor may also be referred to as a millimeter-wave radar or millimeter-wave radar system.

[0056] In a third aspect, an embodiment of the present application provides a terminal device, which includes the waveguide device described in the first aspect or any possible embodiment of the first aspect, or includes the radar or radar system described in the second aspect.

[0057] In a fourth aspect, an embodiment of the present application provides a vehicle end, which includes the waveguide device described in the first aspect or any possible embodiment of the first aspect, or includes the radar or radar system described in the second aspect, or includes the terminal equipment described in the third aspect.

[0058] In the embodiment of the present application, the cross-structured waveguide is filled with a high-dielectric material, which can ensure the miniaturization of the waveguide device while maintaining the electromagnetic wave transmission performance, and can meet the multi-channel cross-transmission requirements of the millimeter-wave radar. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0060] FIG1 is a schematic diagram of a radar distribution according to an embodiment of the present application;

[0061] FIG2 is a schematic diagram of the architecture of a radar provided in an embodiment of the present application;

[0062] FIG3 is a schematic structural diagram of a waveguide device provided in an embodiment of the present application;

[0063] FIG4 is a schematic structural diagram of a waveguide device provided in an embodiment of the present application;

[0064] FIG5 is a three-dimensional structural diagram of a waveguide device provided in an embodiment of the present application;

[0065] FIG6 is a schematic structural diagram of a waveguide device provided in an embodiment of the present application;

[0066] FIG7 is a schematic structural diagram of a waveguide device provided in an embodiment of the present application;

[0067] FIG8 is a three-dimensional structural diagram of a waveguide device provided in an embodiment of the present application;

[0068] FIG9A is a schematic diagram of a waveguide transmission effect provided by an embodiment of the present application;

[0069] FIG9B is a schematic diagram of a waveguide transmission effect provided by an embodiment of the present application;

[0070] FIG10 is a schematic structural diagram of a waveguide device provided in an embodiment of the present application;

[0071] FIG11 is a schematic diagram of a return loss provided in an embodiment of the present application;

[0072] FIG12 is a schematic diagram of a transmission insertion loss provided in an embodiment of the present application;

[0073] FIG13 is a schematic diagram of transmission isolation provided in an embodiment of the present application. DETAILED DESCRIPTION

[0074] In order to make the purpose, technical solutions and advantages of this application clearer, the embodiments of this application will be described below in conjunction with the drawings in the embodiments of this application.

[0075] The terms "first" and "second" in the specification, claims, and drawings of this application are used to distinguish different objects, not to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or units that are inherent to the process, method, product, or device.

[0076] References to "embodiments" herein mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it refer to independent or alternative embodiments that are mutually exclusive of other embodiments. It will be understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0077] It should be understood that in the present application, "at least one (item)" refers to one or more, "more than one" refers to two or more, "at least two (items)" refers to two or three and more than three, and "and / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following items" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0078] As described in the background technology section, it is necessary to study how to design a miniaturized waveguide device to meet the multi-channel cross-transmission requirements of millimeter-wave radar. This application provides a waveguide device and related products related to the field of millimeter-wave radar technology, which can realize the miniaturization characteristics of the waveguide and meet the multi-channel cross-transmission requirements of millimeter-wave radar.

[0079] In order to more clearly describe the solution of this application, some knowledge related to radar is first introduced below.

[0080] Radar is the transliteration of the English word Radar, which comes from the abbreviation of "radio detection and ranging", meaning "radio detection and ranging". It uses radio methods to detect targets and determine the spatial position of targets.

[0081] Radar uses electromagnetic waves as its detection medium, and it uses the transmission and reception of electromagnetic waves to detect targets, for example, to measure distance, speed, or azimuth. Radar can measure distance to a target based on the time of flight of electromagnetic waves, which is the time difference between the transmission and reception of electromagnetic waves. Radar transmits an electromagnetic wave signal and receives an echo signal. The distance to the target is determined based on the time difference between the received echo signal and the transmitted electromagnetic wave signal and the propagation speed of the electromagnetic wave. The distance between the radar and the target can be determined using the following formula: s = c * t / 2, where s is the distance to the target, t is the time of flight (the time from the electromagnetic wave signal being transmitted by the radar to the echo signal being received), and c is the speed of light.

[0082] Radar uses the Doppler effect to measure target velocity. The Doppler effect works as follows: when a vibration source, such as sound, light, or radio waves, moves relative to an observer at a relative speed, the frequency of the vibration received by the observer differs from the frequency emitted by the source. When the electromagnetic waves emitted by the radar and the target are in relative motion, the frequency of the echo signal will differ from the frequency of the transmitted electromagnetic wave. When the target approaches the radar antenna, the frequency of the echo signal will be higher than the frequency of the transmitted electromagnetic wave; conversely, when the target moves away from the radar antenna, the frequency of the echo signal will be lower than the frequency of the transmitted electromagnetic wave. The frequency change caused by the Doppler effect is called the Doppler shift, which is proportional to the relative velocity and inversely proportional to the vibration frequency. Therefore, by detecting the frequency difference between the transmitted electromagnetic wave signal and the echo signal, the target's speed relative to the radar—that is, the relative speed between the target and the radar—can be measured.

[0083] Radar can use amplitude method, phase method and other methods to measure azimuth angle. The amplitude method uses the amplitude value of the echo signal received by the antenna to measure the angle. The change pattern of the amplitude value depends on the antenna radiation pattern and the antenna scanning method; the phase method uses the phase difference between the echo signals received by multiple antenna units to measure the angle. For example, the radar receives the echo signal reflected by the same target through the antenna array, and calculates the azimuth angle of the target based on the phase difference of the echo signal.

[0084] Millimeter-wave radar uses electromagnetic waves within a certain wavelength range, such as microwaves. Currently, millimeter waves and adjacent centimeter waves (e.g., centimeter waves in the 24 GHz band) are more commonly used. Millimeter waves have wavelengths of 1 to 10 millimeters (mm), with those in the 24 GHz band having wavelengths slightly larger than 10 mm. Because the wavelength of millimeter-wave radar's detection medium lies within the overlapping wavelength range of microwaves and far-infrared waves, it combines the characteristics of both spectrums. According to wave propagation theory, higher frequencies and shorter wavelengths yield higher resolution and greater penetration, but also greater propagation losses and shorter transmission distances. Conversely, lower frequencies and longer wavelengths yield greater diffraction resistance and longer transmission distances. Therefore, compared to microwaves, millimeter-wave radar's detection medium offers higher resolution, better directivity, stronger anti-interference capabilities, and superior detection performance. Compared to infrared, millimeter-wave radar experiences less atmospheric attenuation, has better penetration of smoke and dust, and is less affected by weather. Therefore, millimeter-wave radar has been increasingly widely used in many fields such as smart vehicles, drones, smart transportation, and industrial automation.

[0085] Radar can be categorized by detection range into long-range radar (LRR), mid-range radar (MRR), and short-range radar (SRR). LRR has higher detection range requirements but lower angular detection width requirements. SRR has lower detection range requirements but higher angular detection width requirements. MRR's detection range and angular detection width requirements can be understood as falling between those of LRR and SRR. For example, LRR's detection range can exceed 200 meters and its angular detection width can be ±15°; MRR's detection range is within 100 meters and its angular detection width can be ±45°; and SRR's detection range is within 60 meters and its angular detection width can be ±80°. Different types of radar can be installed in different locations on the vehicle body, depending on the autonomous driving functional requirements and the use of other sensors. The number and type of radars can be selected as needed.

[0086] Please refer to FIG1 , which is a schematic diagram of a radar distribution provided in an embodiment of the present application.

[0087] FIG1 shows possible installation locations of several types of radars. This is only an example. In actual use, a greater or lesser number of radars may be selected, and the types may also be adjusted.

[0088] As shown in Figure 1, the LRR can be installed in front of the vehicle as a forward-facing radar; the MRR can be installed in front of or behind the vehicle as a forward-facing radar or a rear-facing radar; and the SRR can be installed on the side or at the four corners of the vehicle as a side-facing radar or a corner radar. Furthermore, the MRR can also be installed on the side or at the four corners of the vehicle, and the SRR can also be installed in the front or rear of the vehicle.

[0089] Radars can be classified based on the modulation method (or radiation method) of their electromagnetic waves. Radar electromagnetic wave modulation methods include pulse and continuous wave, so radars can be divided into pulse radars and continuous wave radars. Continuous wave methods can be further divided into frequency shift keying (FSK), phase shift keying (PSK), constant frequency / single frequency continuous wave (CW), frequency modulated continuous wave (FMCW), multiple frequency shift keying (MFSK), and phase modulated continuous wave (PMCW). FMCW has become the mainstream radar modulation method due to its ability to detect multiple targets, high resolution, and low cost.

[0090] Please refer to FIG2 , which is a schematic diagram of the architecture of a radar provided in an embodiment of the present application.

[0091] As shown in Figure 2, the radar includes an MMIC, a microcontroller unit (MCU), and a power management integrated circuit (PMIC). The MMIC can integrate the functions of the radio frequency part, and the MCU can integrate the functions of the baseband part, such as the function of the integrated signal processor. In addition, it can also provide a communication interface with other on-board devices. The PMIC is the chip that powers the radar hardware system.

[0092] A waveguide is a structure used to guide electromagnetic waves in a certain direction. In electromagnetics and communications engineering, a waveguide refers to any linear structure that transmits electromagnetic waves between its endpoints. Waveguides are primarily used as transmission lines at microwave frequencies, connecting microwave transmitters and receivers to their antennas in radar, communications satellites, and microwave radio link equipment.

[0093] Currently, millimeter-wave automotive radar antennas are evolving towards lower-loss, multi-channel, and large-format designs as system functionality improves. Compared to traditional PCB printed antennas, waveguide antennas offer significant advantages in low loss and broadband performance. However, the introduction of multi-channel transmission requirements increases the difficulty of routing multiple waveguide feed lines within limited system space. Therefore, designing a single-layer, cross-structured waveguide with low insertion loss and a compact size is key to achieving multi-channel waveguide antennas. However, during electromagnetic wave transmission in traditional cross-structured waveguides, a significant portion of the energy is severely lost at the waveguide intersections due to mode coupling, resulting in poor transmission performance.

[0094] To address the problem that the aforementioned waveguides are not practical for engineering applications due to their large electrical dimensions, the present invention, based on the principle of cross multimode interference (MMI), designs a cross-structured waveguide for use in radar waveguide antenna feed networks operating in the 76-77 GHz millimeter wave band through a combination of theoretical calculation and simulation optimization. This design achieves excellent transmission performance with lower single-pass transmission loss (as low as 0.2 dB) and higher isolation (as high as 37 dB). Furthermore, a cross-structured waveguide in the form of a SIW, implemented using PCB board material and PCB processing technology, is also designed to meet the design requirements of radar waveguide antenna feed networks operating in the 76-77 GHz millimeter wave band.

[0095] The waveguide device provided in the embodiment of the present application is described below in conjunction with the drawings in the embodiment of the present application.

[0096] Example 1:

[0097] Please refer to FIG3 , which is a schematic structural diagram of a waveguide device provided in an embodiment of the present application.

[0098] As shown in FIG3 , the waveguide device includes a cross-structure waveguide;

[0099] The cross-structure waveguide may be centrosymmetric;

[0100] The cross-structure waveguide includes a first cavity A and a second cavity B intersecting in the same layer, wherein the first cavity A and the second cavity B intersect at the center point of the cross-structure waveguide;

[0101] The filling medium of the cross-structure waveguide is a first material having a dielectric constant greater than a first preset threshold, and the outer surface of the cross-structure waveguide is a conductive material.

[0102] It can be understood that the cross-structure waveguide included in the waveguide device in the embodiment of the present application can be centrally symmetrical, and the first cavity A and the second cavity B included in the cross-structure waveguide are centrally symmetrical about the center point of the cross-structure waveguide, and the filling medium of the cross-structure waveguide is a first material with a dielectric constant greater than a first preset threshold, that is, the filling medium of the first cavity A and the second cavity B is a first material with a dielectric constant greater than the first preset threshold, and the outer surface of the cross-structure waveguide is a conductive material, that is, the outer surface of the first cavity A and the second cavity B is a conductive material.

[0103] It is understandable that the first preset threshold in the embodiment of the present application is not a fixed value and can be adjusted according to different application scenarios so that the first material is a high-dielectric filling medium that meets the requirements of the cross-structure waveguide.

[0104] According to the calculation formula of electromagnetic wave medium wavelength (where DK is the dielectric constant of the material) It can be seen that the full wavelength size λ at the same frequency point 介质 will become the vacuum wavelength λ times, which can greatly compress the size of the waveguide structure while ensuring the same number of field mode distributions in the waveguide device.

[0105] Through the embodiments of the present application, the cross-structured waveguide is filled with a high-dielectric material and the outer surface is electroplated, which can ensure that the waveguide device can be miniaturized while maintaining the electromagnetic wave transmission performance and meet the multi-channel cross-transmission requirements of the millimeter-wave radar.

[0106] In a possible embodiment, the waveguide device further includes a metal plate, the cross-structure waveguide is located on an upper layer of the metal plate, and an outer surface of the cross-structure waveguide is a metal plating layer.

[0107] For details, please refer to Figure 4, which is a schematic diagram of the structure of a waveguide device provided in an embodiment of the present application. It is understood that the waveguide device shown in Figure 4 can be implemented as a separate embodiment; alternatively, the waveguide device shown in Figure 4 can be understood as a variation or supplement to the waveguide device shown in Figure 3 above. In this case, Figure 4 is a front view of the waveguide device, and Figure 3 above is a top view of the waveguide device.

[0108] As shown in FIG. 4 , the waveguide device further includes a metal plate 102 . The cross-structure waveguide 101 is located on the upper layer of the metal plate 102 . The outer surface of the cross-structure waveguide 101 is a metal coating 103 .

[0109] It can be understood that the waveguide device in the embodiment of the present application includes a cross-structure waveguide 101 and a metal plate 102, the cross-structure waveguide 101 is coupled with the metal plate 102, and the cross-structure waveguide 101 is located on the upper layer of the metal plate 102, and the outer surface of the cross-structure waveguide 101 is a metal coating 103.

[0110] Through the embodiments of the present application, high-dielectric material deposition on the metal surface and etching of the high-dielectric material layer are utilized to form a high-dielectric material filling inside the cross-structure waveguide, and an outer electroplating process is utilized to form a metal plating layer on the outer surface of the cross-structure waveguide. This allows engineering implementation of dielectric filling of the high-dielectric material of the cross-structure waveguide, ensuring that the electromagnetic wave transmission performance of the waveguide device remains unchanged while achieving a miniaturized design of the waveguide device and meeting the multi-channel cross-transmission requirements of the millimeter-wave radar.

[0111] Based on the structural diagrams of the waveguide device shown in FIG3 and FIG4 , a possible three-dimensional structural diagram of the waveguide device can be obtained.

[0112] For example, please refer to FIG5 , which is a three-dimensional structural diagram of a waveguide device provided in an embodiment of the present application.

[0113] As shown in FIG5 , the waveguide device in the embodiment of the present application includes a metal plate 102, a cross-structure waveguide 101, and a metal coating 103. The structural relationship and functional characteristics of the metal plate 102, the cross-structure waveguide 101, and the metal coating 103 are consistent with those described in FIG3 and FIG4 above and are not further described here.

[0114] It can be understood that the structural diagram of the waveguide device shown in Figure 3 above is a top view of the waveguide device in the embodiment of the present application, and the structural diagram of the waveguide device shown in Figure 4 above is a front view of the waveguide device in the embodiment of the present application.

[0115] Optionally, the filling medium (ie, the first material) of the cross-structure waveguide shown in FIG. 3 and / or FIG. 4 and / or FIG. 5 includes but is not limited to high dielectric materials such as silicon, ceramics, and glass.

[0116] It should be understood that according to the electromagnetic wave medium wavelength calculation formula (where DK is the dielectric constant of the material) It can be seen that in high dielectric materials such as silicon, ceramics, and glass, the full wavelength size λ at the same frequency point 介质 will become the vacuum wavelength λ times, which can greatly compress the size of the waveguide structure while ensuring the same number of field mode distributions in the waveguide device.

[0117] In a possible embodiment, the first cavity A includes a first fundamental mode input waveguide a1, a first fundamental mode and multimode matching waveguide a2, and a first multimode interference waveguide a3;

[0118] The first fundamental mode input waveguide a1 and the first multimode interference waveguide a3 are connected through the first fundamental mode and multimode matching waveguide a2, and the width (a) of the first multimode interference waveguide a3 is greater than the width (W1) of the first fundamental mode input waveguide a1;

[0119] The first fundamental mode input waveguide a1 is used to input electromagnetic waves. The electromagnetic waves pass through the first fundamental mode and multimode matching waveguide a2 and enter the first multimode interference waveguide a3. The first multimode interference waveguide a3 is used to interfere with the electromagnetic waves, and the fundamental mode field shape where the electromagnetic waves enter the first multimode interference waveguide a3 is presented at the above-mentioned center point.

[0120] It can be understood that the first fundamental mode input waveguide a1 and the first multimode interference waveguide a3 in the first cavity A are connected through the first fundamental mode and multimode matching waveguide a2. Since the cross-structure waveguide is centrally symmetrical, and the first cavity A and the second cavity B included in the cross-structure waveguide intersect at the center point of the cross-structure waveguide, the first cavity A includes two sections of first fundamental mode input waveguides, two sections of first fundamental mode and multimode matching waveguides, and one section of first multimode interference waveguide, and the center point of the cross-structure waveguide is the center point of the first multimode interference waveguide in the first cavity A, that is, the connection order of the waveguide sections included in the first cavity is "first fundamental mode input waveguide a1, first fundamental mode and multimode matching waveguide a2, first multimode interference waveguide a3, first fundamental mode and multimode matching waveguide a4, first fundamental mode input waveguide a5". Optionally, the first cavity A may also include two sections of first fundamental mode input waveguides, two sections of first fundamental mode and multimode matching waveguides, and two sections of first multimode interference waveguides, and the center point of the cross-structure waveguide is the connection point of the two sections of first multimode interference waveguides in the first cavity A, that is, the connection order of the waveguide sections included in the first cavity is "first fundamental mode input waveguide a1, first fundamental mode and multimode matching waveguide a2, first multimode interference waveguide a3, first multimode interference waveguide a3, first fundamental mode and multimode matching waveguide a4, first fundamental mode input waveguide a5", and the two sections of first multimode interference waveguide a3 may also be an integrally formed section of multimode interference waveguide, and the embodiment of the present application does not impose any restrictions on this.

[0121] It should be understood that if either of the first fundamental mode input waveguide a1 and the first fundamental mode input waveguide a5 serves as the input waveguide, the other serves as the output waveguide. The width of the first multimode interference waveguide is greater than the width of the first fundamental mode input waveguide. The waveguide width is designed to expand the fifth-order higher-order modes of each waveguide segment within the first cavity.

[0122] Through the embodiments of the present application, the first fundamental mode input waveguide inputs an electromagnetic wave, and the electromagnetic wave enters the first multimode interference waveguide through the first fundamental mode and multimode matching waveguide. After interference, the fundamental mode field shape where the electromagnetic wave enters the first multimode interference waveguide is presented at the center point, which can better suppress crosstalk and reduce electromagnetic wave transmission loss.

[0123] It is understandable that the composition structure of the second cavity B is the same as that of the first cavity A, and will not be described in detail here.

[0124] In a possible embodiment, the connection between the first fundamental mode and multimode matching waveguide a2 and the first fundamental mode input waveguide a1 is a tapered structure, and the connection between the first fundamental mode and multimode matching waveguide a2 and the first multimode interference waveguide a3 is a tapered structure.

[0125] Through the embodiments of the present application, by designing a tapered gradual structure at the connection between different waveguides, the mode matching at the connection between the first multimode interference waveguide and the first fundamental mode input waveguide can be improved, thereby optimizing the echo.

[0126] In a possible embodiment, the cross-sectional dimensions of the first multimode interference waveguide a3 meet the following conditions:

[0127] 0.53λ≤a≤0.72λ;

[0128] Wherein, a is the first side of the cross section of the first multimode interference waveguide a3, and λ is the vacuum wavelength of the transmitted electromagnetic wave.

[0129] Through the embodiment of the present application, the size of the first side of the cross section of the first multimode interference waveguide a3 in the waveguide device (which can be understood as the width a of the cross section of the first multimode interference waveguide) is greatly reduced, realizing the miniaturized design of the waveguide device.

[0130] In a possible embodiment, the length L3 of the first multimode interference waveguide a3 satisfies the following conditions:

[0131] 1.9λ≤L3≤2.1λ;

[0132] Wherein, L3 is the length of the first multimode interference waveguide a3, and λ is the vacuum wavelength of the transmitted electromagnetic wave.

[0133] Through the embodiments of the present application, the length L3 of the first multimode interference waveguide a3 in the waveguide device is greatly reduced, thereby achieving a miniaturized design of the waveguide device.

[0134] In a possible embodiment, the lengths of the first fundamental mode and the multimode matching waveguide a2 satisfy the following conditions:

[0135] 0.13λ≤L2≤0.18λ;

[0136] Wherein, L2 is the length of the first fundamental mode and the multimode matching waveguide, and λ is the vacuum wavelength of the transmitted electromagnetic wave.

[0137] Through the embodiments of the present application, the length L2 of the first fundamental mode and the multi-mode matching waveguide a2 in the waveguide device is greatly reduced, thereby realizing a miniaturized design of the waveguide device.

[0138] In a possible embodiment, the thickness h of the cross-structure waveguide satisfies the following conditions:

[0139] 0.35W1≤h≤0.6W1;

[0140] Wherein, h is the thickness of the cross-structure waveguide, and W1 is the width of the first fundamental mode input waveguide a1.

[0141] Through the embodiments of the present application, the thickness h of the cross-structure waveguide in the waveguide device is greatly reduced, thereby achieving a miniaturized design of the waveguide device.

[0142] In one possible embodiment, when the first cavity A is fed to form an electromagnetic current, the magnetic current density in the second cavity B is less than a second preset threshold value, that is, the electromagnetic current is ensured to be transmitted within the first cavity, which can better suppress crosstalk and reduce electromagnetic wave transmission loss. In engineering, it can be ensured that the waveguide device can meet the multi-channel cross-transmission requirements of the millimeter wave radar under the premise that the electromagnetic wave transmission performance remains unchanged.

[0143] Optionally, when the second cavity B is fed with power to form an electromagnetic current, the magnetic current density in the first cavity A is less than a third preset threshold.

[0144] For details, please refer to Figures 9A and 9B, which are schematic diagrams of the effect of waveguide transmission provided in an embodiment of the present application.

[0145] As shown in Figures 9A and 9B, when any one of the first cavity A and the second cavity B is fed to form an electromagnetic flow (the electromagnetic flow is transmitted in the direction of the arrows in Figures 9A and 9B), the magnetic flow density in the other cavity will be much smaller than the magnetic flow density in the cavity where the electromagnetic flow is being transmitted, and specifically may be smaller than a preset threshold.

[0146] Through the embodiments of the present application, since the pattern expansion and interference of the electromagnetic current are realized during the transmission of the electromagnetic current, it is possible to ensure that the electromagnetic current is transmitted in a certain cavity in the cross-structure waveguide, better suppress crosstalk, and reduce the electromagnetic wave transmission loss. In engineering, it can be ensured that the waveguide device can meet the multi-channel cross-transmission requirements of the millimeter wave radar under the premise that the electromagnetic wave transmission performance remains unchanged.

[0147] In a possible embodiment, the waveguide device may include a plurality of cross-structure waveguides, and the plurality of cross-structure waveguides are arranged in cascade.

[0148] Please refer to FIG10 for details, which is a schematic structural diagram of a waveguide device provided in an embodiment of the present application.

[0149] As shown in FIG10 , the waveguide device includes four cross-structure waveguides, and the four cross-structure waveguides are arranged in cascade.

[0150] It is understandable that there is no limit on the number of cascade-arranged cross-structure waveguides, and there is no limit on the fundamental mode length of the cascade-arranged cross-structure waveguides.

[0151] It is understandable that, in addition to being arranged as shown in FIG10 , the four cross-structure waveguides may also be arranged as a series of cross-structure waveguides, which is not limited in this embodiment of the present application.

[0152] Through the cascade arrangement shown in the embodiment of the present application, it is possible to ensure that the waveguide device can be miniaturized while maintaining the electromagnetic wave transmission performance, and can meet the multi-channel cross-transmission requirements of the millimeter wave radar.

[0153] Example 2:

[0154] Please refer to Figure 6, which is a schematic diagram of the structure of a waveguide device provided in an embodiment of the present application. It is understood that the waveguide device shown in Figure 6 can be implemented as a separate embodiment; alternatively, the waveguide device shown in Figure 6 can also be understood as a variation or supplement to the waveguide device in Figure 3 above.

[0155] As shown in FIG6 , the waveguide device includes a cross-structure waveguide;

[0156] The cross-structure waveguide may be centrosymmetric;

[0157] The cross-structure waveguide includes a first cavity A and a second cavity B intersecting in the same layer, wherein the first cavity A and the second cavity B intersect at the center point of the cross-structure waveguide;

[0158] The filling medium of the cross-structure waveguide is a first material having a dielectric constant greater than a first preset threshold, and the outer surface of the cross-structure waveguide is a conductive material.

[0159] It can be understood that the cross-structure waveguide included in the waveguide device in the embodiment of the present application can be centrally symmetrical, and the first cavity A and the second cavity B included in the cross-structure waveguide are centrally symmetrical about the center point of the cross-structure waveguide, and the filling medium of the cross-structure waveguide is a first material with a dielectric constant greater than a first preset threshold, that is, the filling medium of the first cavity A and the second cavity B is a first material with a dielectric constant greater than the first preset threshold, and the outer surface of the cross-structure waveguide is a conductive material, that is, the outer surface of the first cavity A and the second cavity B is a conductive material.

[0160] It is understandable that the first preset threshold in the embodiment of the present application is not a fixed value and can be adjusted according to different application scenarios so that the first material is a high-dielectric filling medium that meets the requirements of the cross-structure waveguide.

[0161] According to the calculation formula of electromagnetic wave medium wavelength (where DK is the dielectric constant of the material) It can be seen that the full wavelength size λ at the same frequency point 介质 will become the vacuum wavelength λ times, which can greatly compress the size of the waveguide structure while ensuring the same number of field mode distributions in the waveguide device.

[0162] Through the embodiments of the present application, the cross-structured waveguide is filled with a high-dielectric material and the outer surface is electroplated, which can ensure that the waveguide device can be miniaturized while maintaining the electromagnetic wave transmission performance and meet the multi-channel cross-transmission requirements of the millimeter-wave radar.

[0163] In a possible embodiment, the main body of the waveguide device is a printed circuit board (PCB), and the PCB includes a plurality of metallized through holes penetrating the upper and lower surfaces;

[0164] The area formed by the multiple metallized through holes is a cross-structure waveguide.

[0165] Furthermore, the envelope of the metallized through hole forms a cross region, and a cavity for transmitting electromagnetic waves is formed inside the cross region. It can be understood that the cavity formed for transmitting electromagnetic waves also has a cross structure.

[0166] For details, please refer to Figure 7, which is a schematic diagram of the structure of a waveguide device provided in an embodiment of the present application. It is understood that the waveguide device shown in Figure 7 can be implemented as a separate embodiment; alternatively, the waveguide device shown in Figure 7 can be understood as a variation or supplement to the waveguide device shown in Figure 6 above. In this case, Figure 7 is a front view of the waveguide device, and Figure 6 above is a top view of the waveguide device.

[0167] As shown in FIG7 , the main body of the waveguide device is a printed circuit board PCB, which includes a plurality of metallized through holes 201 penetrating the upper and lower surfaces, a PCB lower metal layer 202 and a PCB upper metal layer 203;

[0168] The region formed by the plurality of metallized through holes 201 is a cross-structure waveguide.

[0169] It can be understood that the main body of the waveguide device in the embodiment of the present application is a printed circuit board PCB, which is covered with multiple metallized through holes 201 running through the upper and lower surfaces. The area surrounded by these metallized through holes 201 is the cross-structure waveguide in the waveguide device.

[0170] Through the embodiment of the present application, a cross-structure waveguide in the form of an SIW is realized by using a PCB processing technology. The upper and lower metal layers (202 and 203) of the PCB board serve as the upper and lower electrical walls of the cross-structure waveguide. The metallized through-hole 201 on the side of the PCB board forms the side electrical wall of the cross-structure waveguide. The size of the dielectric compression device (cross-structure waveguide) inside the PCB board can ensure the miniaturization of the waveguide device under the premise of unchanged electromagnetic wave transmission performance in engineering, and can meet the multi-channel cross transmission requirements of the millimeter wave radar.

[0171] Optionally, the spacing between the plurality of metallized through holes 201 is equal.

[0172] Based on the structural diagrams of the waveguide device shown in FIG6 and FIG7 , a possible three-dimensional structural diagram of the waveguide device can be obtained.

[0173] For example, please refer to FIG8 , which is a three-dimensional structural diagram of a waveguide device provided in an embodiment of the present application.

[0174] As shown in FIG8 , the main body of the waveguide device in the embodiment of the present application is a printed circuit board (PCB), which includes a plurality of metallized through-holes 201 extending through the upper and lower surfaces of the PCB, a lower metal layer 202 of the PCB, and an upper metal layer 203 of the PCB. The structural relationship and functional characteristics of the plurality of metallized through-holes 201, the lower metal layer 202 of the PCB, and the upper metal layer 203 of the PCB are consistent with those described above in FIG6 and FIG7 and are not further described here.

[0175] It can be understood that the structural diagram of the waveguide device shown in Figure 6 above is a top view of the waveguide device in the embodiment of the present application, and the structural diagram of the waveguide device shown in Figure 7 above is a front view of the waveguide device in the embodiment of the present application.

[0176] Optionally, the filling medium (ie, the first material) of the cross-structure waveguide shown in FIG. 6 and / or FIG. 7 and / or FIG. 8 is a PCB board.

[0177] It should be understood that according to the electromagnetic wave medium wavelength calculation formula (where DK is the dielectric constant of the material) It can be seen that in high dielectric materials such as PCB boards, the full wavelength size λ at the same frequency point 介质 will become the vacuum wavelength λ times, which can greatly compress the size of the waveguide structure while ensuring the same number of field mode distributions in the waveguide device.

[0178] In a possible embodiment, the first cavity A includes a first fundamental mode input waveguide a1, a first fundamental mode and multimode matching waveguide a2, and a first multimode interference waveguide a3;

[0179] The first fundamental mode input waveguide a1 and the first multimode interference waveguide a3 are connected through the first fundamental mode and multimode matching waveguide a2, and the width (a) of the first multimode interference waveguide a3 is greater than the width (W1) of the first fundamental mode input waveguide a1;

[0180] The first fundamental mode input waveguide a1 is used to input electromagnetic waves. The electromagnetic waves pass through the first fundamental mode and multimode matching waveguide a2 and enter the first multimode interference waveguide a3. The first multimode interference waveguide a3 is used to interfere with the electromagnetic waves, and the fundamental mode field shape where the electromagnetic waves enter the first multimode interference waveguide a3 is presented at the above-mentioned center point.

[0181] It can be understood that the first fundamental mode input waveguide a1 and the first multimode interference waveguide a3 in the first cavity A are connected through the first fundamental mode and multimode matching waveguide a2. Since the cross-structure waveguide is centrally symmetrical, and the first cavity A and the second cavity B included in the cross-structure waveguide intersect at the center point of the cross-structure waveguide, the first cavity A includes two sections of first fundamental mode input waveguides, two sections of first fundamental mode and multimode matching waveguides, and one section of first multimode interference waveguide, and the center point of the cross-structure waveguide is the center point of the first multimode interference waveguide in the first cavity A, that is, the connection order of the waveguide sections included in the first cavity is "first fundamental mode input waveguide a1, first fundamental mode and multimode matching waveguide a2, first multimode interference waveguide a3, first fundamental mode and multimode matching waveguide a4, first fundamental mode input waveguide a5". Optionally, the first cavity A may also include two sections of first fundamental mode input waveguides, two sections of first fundamental mode and multimode matching waveguides, and two sections of first multimode interference waveguides, and the center point of the cross-structure waveguide is the connection point of the two sections of first multimode interference waveguides in the first cavity A, that is, the connection order of the waveguide sections included in the first cavity is "first fundamental mode input waveguide a1, first fundamental mode and multimode matching waveguide a2, first multimode interference waveguide a3, first multimode interference waveguide a3, first fundamental mode and multimode matching waveguide a4, first fundamental mode input waveguide a5", and the two sections of first multimode interference waveguide a3 may also be an integrally formed section of multimode interference waveguide, and the embodiment of the present application does not impose any restrictions on this.

[0182] It should be understood that if either of the first fundamental mode input waveguide a1 and the first fundamental mode input waveguide a5 serves as the input waveguide, the other serves as the output waveguide. The width of the first multimode interference waveguide is greater than the width of the first fundamental mode input waveguide. The waveguide width is designed to expand the fifth-order higher-order modes of each waveguide segment within the first cavity.

[0183] Through the embodiments of the present application, the first fundamental mode input waveguide inputs an electromagnetic wave, and the electromagnetic wave enters the first multimode interference waveguide through the first fundamental mode and multimode matching waveguide. After interference, the fundamental mode field shape where the electromagnetic wave enters the first multimode interference waveguide is presented at the center point, which can better suppress crosstalk and reduce electromagnetic wave transmission loss.

[0184] It is understandable that the composition structure of the second cavity B is the same as that of the first cavity A, and will not be described in detail here.

[0185] In a possible embodiment, the connection between the first fundamental mode and multimode matching waveguide a2 and the first fundamental mode input waveguide a1 is a tapered structure, and the connection between the first fundamental mode and multimode matching waveguide a2 and the first multimode interference waveguide a3 is a tapered structure.

[0186] Through the embodiments of the present application, by designing a tapered gradual structure at the connection between different waveguides, the mode matching at the connection between the first multimode interference waveguide and the first fundamental mode input waveguide can be improved, thereby optimizing the echo.

[0187] In a possible embodiment, the cross-sectional dimensions of the first multimode interference waveguide a3 meet the following conditions:

[0188] 1.2λ≤a≤1.5λ;

[0189] Wherein, a is the first side of the cross section of the first multimode interference waveguide a3, and λ is the vacuum wavelength of the transmitted electromagnetic wave.

[0190] Through the embodiment of the present application, the size of the first side of the cross section of the first multimode interference waveguide a3 in the waveguide device (which can be understood as the width a of the cross section of the first multimode interference waveguide) is greatly reduced, realizing the miniaturized design of the waveguide device.

[0191] In a possible embodiment, the length L3 of the first multimode interference waveguide a3 satisfies the following conditions:

[0192] 4.8λ≤L3≤5.3λ;

[0193] Wherein, L3 is the length of the first multimode interference waveguide a3, and λ is the vacuum wavelength of the transmitted electromagnetic wave.

[0194] Through the embodiments of the present application, the length L3 of the first multimode interference waveguide a3 in the waveguide device is greatly reduced, thereby achieving a miniaturized design of the waveguide device.

[0195] In a possible embodiment, the lengths of the first fundamental mode and the multimode matching waveguide a2 satisfy the following conditions:

[0196] 0.3λ≤L2≤0.45λ;

[0197] Wherein, L2 is the length of the first fundamental mode and the multimode matching waveguide, and λ is the vacuum wavelength of the transmitted electromagnetic wave.

[0198] Through the embodiments of the present application, the length L2 of the first fundamental mode and the multi-mode matching waveguide a2 in the waveguide device is greatly reduced, thereby realizing a miniaturized design of the waveguide device.

[0199] In a possible embodiment, the thickness h of the cross-structure waveguide satisfies the following conditions:

[0200] 0.35W1≤h≤0.6W1;

[0201] Wherein, h is the thickness of the cross-structure waveguide, and W1 is the width of the first fundamental mode input waveguide a1.

[0202] Through the embodiments of the present application, the thickness h of the cross-structure waveguide in the waveguide device is greatly reduced, thereby achieving a miniaturized design of the waveguide device.

[0203] In one possible embodiment, when the first cavity A is fed to form an electromagnetic current, the magnetic current density in the second cavity B is less than a second preset threshold value, that is, the electromagnetic current is ensured to be transmitted within the first cavity, which can better suppress crosstalk and reduce electromagnetic wave transmission loss. In engineering, it can be ensured that the waveguide device can meet the multi-channel cross-transmission requirements of the millimeter wave radar under the premise that the electromagnetic wave transmission performance remains unchanged.

[0204] Optionally, when the second cavity B is fed with power to form an electromagnetic current, the magnetic current density in the first cavity A is less than a third preset threshold.

[0205] For details, please refer to Figures 9A and 9B, which are schematic diagrams of the effect of waveguide transmission provided in an embodiment of the present application.

[0206] As shown in Figures 9A and 9B, when any one of the first cavity A and the second cavity B is fed to form an electromagnetic flow (the electromagnetic flow is transmitted in the direction of the arrows in Figures 9A and 9B), the magnetic flow density in the other cavity will be much smaller than the magnetic flow density in the cavity where the electromagnetic flow is being transmitted, and specifically may be smaller than a preset threshold.

[0207] Through the embodiments of the present application, since the pattern expansion and interference of the electromagnetic current are realized during the transmission of the electromagnetic current, it is possible to ensure that the electromagnetic current is transmitted in a certain cavity in the cross-structure waveguide, better suppress crosstalk, and reduce the electromagnetic wave transmission loss. In engineering, it can be ensured that the waveguide device can meet the multi-channel cross-transmission requirements of the millimeter wave radar under the premise that the electromagnetic wave transmission performance remains unchanged.

[0208] In a possible embodiment, the waveguide device may include a plurality of cross-structure waveguides, and the plurality of cross-structure waveguides are arranged in cascade.

[0209] Please refer to FIG10 for details, which is a schematic structural diagram of a waveguide device provided in an embodiment of the present application.

[0210] As shown in FIG10 , the waveguide device includes four cross-structure waveguides, and the four cross-structure waveguides are arranged in cascade.

[0211] It is understandable that there is no limit on the number of cascade-arranged cross-structure waveguides, and there is no limit on the fundamental mode length of the cascade-arranged cross-structure waveguides.

[0212] It is understandable that, in addition to being arranged as shown in FIG10 , the four cross-structure waveguides may also be arranged as a series of cross-structure waveguides, which is not limited in this embodiment of the present application.

[0213] Through the cascade arrangement shown in the embodiment of the present application, it is possible to ensure that the waveguide device can be miniaturized while maintaining the electromagnetic wave transmission performance, and can meet the multi-channel cross-transmission requirements of the millimeter wave radar.

[0214] It can be understood that in the above-mentioned embodiments 1 and 2, the dielectric filling of the cross-structure waveguide with high dielectric material can ensure the miniaturization design of the waveguide device while maintaining the electromagnetic wave transmission performance, and can meet the multi-channel cross-transmission requirements of the millimeter wave radar.

[0215] Specifically, the performance indicators of the above-mentioned embodiment 1 and embodiment 2 can be shown in the following table:

[0216]

[0217] As can be seen from the above table, both the miniaturization performance of the waveguide device and the waveguide transmission performance have been improved.

[0218] Furthermore, the miniaturization process of the waveguide device based on the MMI principle can be as follows:

[0219] Step 1: Determine the width a of the multimode interferometer.

[0220] 1. Under vacuum conditions, the conditions that must be met for electromagnetic waves to propagate in a rectangular waveguide are:

[0221]

[0222] Where λ represents the vacuum wavelength of the lowest frequency (76 GHz) to be transmitted, c represents the longest wavelength (cutoff wavelength) that can be transmitted by the waveguide structure, m and n represent the mode number of the TE mode, and a and b represent the long and narrow dimensions of the rectangular waveguide cross section. Once λ is determined, for the TE50 mode, m = 5 and n = 0, the above formula can be used to calculate that the waveguide cross section a must satisfy: a ≥ 2.5λ.

[0223] Step 2: Determine the length x of the multimode interferometer.

[0224] 1. The electromagnetic waves in the waveguide satisfy the constraints of the dispersion equation, which is as follows:

[0225]

[0226]

[0227]

[0228] In the above formula, β m is the propagation constant of the m-th order mode, k ym is the vacuum wave number of the m-order mode, a is the MMI width, k0 is the vacuum wave number of the fundamental mode, n r is the refractive index of the medium in the waveguide.

[0229] From the above three equations, we can get β m Taylor expansion of :

[0230]

[0231] 2. Define the beat length L π : Calculated from the propagation constants of the fundamental mode and the first-order higher-order mode:

[0232]

[0233] 3. Make the racket length L π Then substitute the propagation constant β m Expression, simplified to establish β m , β0 order m and L π The relational expression is:

[0234]

[0235] 4. The mode expansion in the waveguide, after calculation, only the mode number m and beat length L are retained in the expression π and transmission length x;

[0236] Field function at the MMI entrance:

[0237] Transmission x distance backfield function within MMI:

[0238]

[0239] When the transmission length x in the above formula satisfies the following formula:

[0240]

[0241] When Interferometric self-imaging.

[0242] Step 3: Silicon medium realizes the principle of miniaturization.

[0243] According to the calculation formula of electromagnetic wave medium wavelength (DK is the dielectric constant of the material) It can be seen that the full wavelength size λ at the same frequency point 介质 will become the vacuum wavelength λ This significantly reduces the size of the structure while maintaining the same number of field modes within the device. The dielectric constant of pure silicon is 11.9. Through a process involving silicon deposition on a metal surface, etching the silicon layer to form the waveguide interior filler, and then electroplating the exterior, it is feasible to fill a rectangular cross-shaped waveguide with silicon dielectric. This allows for miniaturization while maintaining transmission performance.

[0244] Furthermore, the waveguide transmission performance of the waveguide device based on the MMI principle (such as the waveguide device shown in Figures 3 to 5 above) can be seen in Figures 11, 12 and 13.

[0245] Please refer to FIG. 11 , which is a schematic diagram of return loss provided in an embodiment of the present application.

[0246] As shown in FIG. 11 , it can be seen that the port return loss S11 ≤ -30 dB when the operating frequency band is millimeter wave 76 to 77 GHz (λ = 3.9 mm).

[0247] Please refer to FIG. 12 , which is a schematic diagram of a transmission insertion loss provided in an embodiment of the present application.

[0248] As shown in FIG12 , it can be seen that the transmission insertion loss is <0.2 dB in the operating frequency band of millimeter wave 76 to 77 GHz (λ = 3.9 mm).

[0249] Please refer to FIG. 13 , which is a schematic diagram of transmission isolation provided in an embodiment of the present application.

[0250] As shown in FIG13 , it can be seen that the isolation in the operating frequency band of millimeter wave 76 to 77 GHz (λ=3.9 mm) is ≥37 dB.

[0251] It can be seen from the schematic diagrams of various performance indicators of the waveguide transmission performance of the waveguide device shown in Figures 11, 12 and 13 above that the waveguide device provided in the embodiment of the present application can achieve high transmission performance of 76-77GHz radio frequency signals.

[0252] In a possible embodiment, a method for preparing a waveguide device is further provided. The specific process of the preparation method is as follows:

[0253] A cross-structure waveguide is formed by depositing / etching a metal surface high-dielectric material (first material) on a first metal layer; wherein the cross-structure waveguide includes a first cavity and a second cavity intersecting in the same layer, and the first cavity and the second cavity intersect at the center point of the cross-structure waveguide.

[0254] Then, a metal plating layer is formed on the outer surface of the cross-structure waveguide by utilizing an outer electroplating process.

[0255] The above-described preparation method demonstrates that the resulting waveguide device's filling medium is a first material having a dielectric constant greater than a first predetermined threshold, and the outer surface of the cross-structure waveguide is a conductive material. It is understood that this first predetermined threshold is not a fixed value and can be adjusted based on different application scenarios to ensure that the first material is a high-dielectric filling medium that satisfies the requirements of the cross-structure waveguide.

[0256] Illustratively, through the above-mentioned method for preparing the waveguide device, a waveguide device as shown in any one of Figures 3 to 5 can be obtained. The structural characteristics and functional characteristics of the waveguide device can be found in the description of Figures 3 to 5 above, and will not be repeated here.

[0257] In a possible embodiment, another method for preparing a waveguide device is provided. The specific process of the preparation method is as follows:

[0258] A PCB processing technology is used to cover the PCB board with multiple metallized through-holes that penetrate the upper and lower surfaces. The area surrounded by these metallized through-holes forms the side electrical wall of the cross-structure waveguide; wherein, the cross-structure waveguide includes a first cavity and a second cavity intersecting on the same layer, and the first and second cavities intersect at the center point of the cross-structure waveguide.

[0259] The upper and lower metal layers of the PCB board serve as the upper and lower electrical walls of the cross-structure waveguide.

[0260] The above-described preparation method demonstrates that the resulting waveguide device's filling medium is a first material having a dielectric constant greater than a first predetermined threshold, and the outer surface of the cross-structure waveguide is a conductive material. It is understood that this first predetermined threshold is not a fixed value and can be adjusted based on different application scenarios to ensure that the first material is a high-dielectric filling medium that satisfies the requirements of the cross-structure waveguide.

[0261] Illustratively, through the above-mentioned method for preparing the waveguide device, a waveguide device as shown in any one of Figures 6 to 8 can be obtained. The structural characteristics and functional characteristics of the waveguide device can be found in the description of Figures 6 to 8 above, and will not be repeated here.

[0262] The present application provides a radar or radar system including the waveguide device provided in the present application. It should be noted that there may be smart sensors that integrate multiple sensors. If the smart sensor includes millimeter wave detection capabilities, the smart sensor may also be referred to as a millimeter wave radar or millimeter wave radar system.

[0263] This application provides a terminal device that includes the waveguide device provided herein. For example, the terminal device can be a transportation vehicle, such as a car, truck, aircraft, drone, slow-moving transport vehicle, spacecraft, or ship, or any other vehicle used in any possible scenario. It can also be any device capable of carrying a millimeter wave detection device, such as surveying and mapping equipment. One or more waveguide devices provided herein are deployed on the terminal device.

[0264] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A waveguide device, characterized in that: include: Cross-structure waveguide; The cross-structure waveguide includes a first cavity and a second cavity intersecting each other, wherein the first cavity and the second cavity intersect at a center point of the cross-structure waveguide; The filling medium of the cross-structure waveguide is a first material having a dielectric constant greater than a first preset threshold, and the outer surface of the cross-structure waveguide is a conductive material.

2. The waveguide device according to claim 1, wherein The waveguide device further includes a metal plate, the cross-structure waveguide is located on an upper layer of the metal plate, and an outer surface of the cross-structure waveguide is a metal plating layer.

3. The waveguide device according to claim 1 or 2, characterized in that The first material includes at least one of the following: silicon, ceramic, and glass.

4. The waveguide device according to claim 1, wherein The main body of the waveguide device is a printed circuit board PCB, and the PCB includes a plurality of metallized through holes penetrating the upper and lower surfaces; The area where the multiple metallized through holes are formed is the cross-structure waveguide.

5. The waveguide device according to claim 4, characterized in that The first material is the plate material of the PCB.

6. The waveguide device according to any one of claims 1 to 5, characterized in that The first cavity includes a first fundamental mode input waveguide, a first fundamental mode and multimode matching waveguide, and a first multimode interference waveguide; Wherein, the first fundamental mode input waveguide and the first multimode interference waveguide are connected via the first fundamental mode and multimode matching waveguide, and the width of the first multimode interference waveguide is greater than the width of the first fundamental mode input waveguide; The first fundamental mode input waveguide is used to input electromagnetic waves. The electromagnetic waves enter the first multimode interference waveguide through the first fundamental mode and multimode matching waveguide. The first multimode interference waveguide is used to interfere with the electromagnetic waves, and the fundamental mode field shape of the electromagnetic waves entering the first multimode interference waveguide is presented at the center point.

7. The waveguide device according to claim 6, characterized in that The connection between the first fundamental mode and multimode matching waveguide and the first fundamental mode input waveguide is a tapered structure, and the connection between the first fundamental mode and multimode matching waveguide and the first multimode interference waveguide is a tapered structure.

8. The waveguide device according to claim 2 or 3, characterized in that The cross-sectional dimensions of the first multimode interference waveguide satisfy the following conditions: 0.53λ≤a≤0.72λ; Wherein, a is the first side of the cross section of the first multimode interference waveguide, and λ is the vacuum wavelength of the transmitted electromagnetic wave.

9. The waveguide device according to claim 4 or 5, characterized in that The cross-sectional dimensions of the first multimode interference waveguide satisfy the following conditions: 1.2λ≤a≤1.5λ; Wherein, a is the first side of the cross section of the first multimode interference waveguide, and λ is the vacuum wavelength of the transmitted electromagnetic wave.

10. The waveguide device according to claim 2 or 3, characterized in that The length of the first multimode interference waveguide satisfies the following condition: 1.9λ≤L3≤2.1λ; Wherein, L3 is the length of the first multimode interference waveguide, and λ is the vacuum wavelength of the transmitted electromagnetic wave.

11. The waveguide device according to claim 4 or 5, characterized in that The length of the first multimode interference waveguide satisfies the following condition: 4.8λ≤L3≤5.3λ; Wherein, L3 is the length of the first multimode interference waveguide, and λ is the vacuum wavelength of the transmitted electromagnetic wave.

12. The waveguide device according to claim 2 or 3, characterized in that The lengths of the first fundamental mode and multimode matching waveguides satisfy the following conditions: 0.13λ≤L2≤0.18λ; Wherein, L2 is the length of the first fundamental mode and multimode matching waveguide, and λ is the vacuum wavelength of the transmitted electromagnetic wave.

13. The waveguide device according to claim 4 or 5, characterized in that The lengths of the first fundamental mode and multimode matching waveguides satisfy the following conditions: 0.3λ≤L2≤0.45λ; Wherein, L2 is the length of the first fundamental mode and multimode matching waveguide, and λ is the vacuum wavelength of the transmitted electromagnetic wave.

14. The waveguide device according to any one of claims 1 to 13, characterized in that The thickness of the cross-structure waveguide satisfies the following conditions: 0.35W1≤h≤0.6W1; Wherein, h is the thickness of the cross-structure waveguide, and W1 is the width of the first fundamental mode input waveguide.

15. The waveguide device according to any one of claims 1 to 14, characterized in that When the first cavity is fed with electricity to form an electromagnetic current, the magnetic current density in the second cavity is less than a second preset threshold.

16. The waveguide device according to any one of claims 1 to 12, characterized in that A plurality of the cross-structured waveguides in the waveguide device are arranged in cascade.

17. A radar, characterized in that: The radar includes the waveguide device according to any one of claims 1 to 16.

18. A terminal device, characterized in that: The terminal device includes the waveguide device according to any one of claims 1 to 16, or the radar according to claim 17.

19. A vehicle end, characterized in that: The vehicle end includes the waveguide device according to any one of claims 1 to 16, or the radar according to claim 17, or the terminal equipment according to claim 18.

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