Waveguide device and related product

Abstract

A waveguide device and related products relate to the technical field of millimeter wave radars. The waveguide device comprises N radiation ports, a resonant cavity, a coupling cavity and a feed-in structure, wherein N is an integer greater than or equal to 1; the feed-in structure is used for feeding in a signal; the coupling cavity is used for coupling the signal to the resonant cavity; the resonant cavity is used for radiating the signal from the N radiation ports along a first direction; the coupling cavity is located between the resonant cavity and the feed-in structure; the coupling cavity and the resonant cavity are connected in a second direction, and the first direction is perpendicular to the second direction. According to the waveguide device, same-layer coupling of signals in the transmission process can be achieved through the coupling cavity, the profile height of the waveguide antenna can be reduced, and therefore the complexity of the three-dimensional structure of the waveguide antenna is reduced, the requirement for the machining precision is lowered, and the machining cost is reduced.

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] Compared to traditional printed circuit board (PCB) antennas, waveguide antennas offer significant advantages in radiation efficiency. Current radar implementations use vertical multi-stage power splitters to create the waveguide antenna feed network. However, this waveguide antenna feed network has a complex three-dimensional structure, requires high machining precision, and is expensive, making it less practical for engineering applications.

[0004] Summary of the Invention

[0005] The embodiments of the present application provide a waveguide device and related products, which can reduce the complexity of the three-dimensional structure of the waveguide antenna, reduce the requirements for processing accuracy, and reduce processing costs.

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

[0007] N radiation ports, resonant cavities, coupling cavities and feeding structures, where N is an integer greater than or equal to 1;

[0008] The feeding structure is used to feed a signal;

[0009] The coupling cavity is used to couple the signal to the resonant cavity;

[0010] The resonant cavity is used to radiate the signal from the N radiation ports along a first direction;

[0011] The coupling cavity is located between the resonant cavity and the feeding structure;

[0012] The coupling cavity and the resonant cavity are connected in a second direction, and the first direction and the second direction are perpendicular to each other.

[0013] In an embodiment of the present application, the coupling cavity and the resonant cavity in the waveguide device are connected in the second direction, and the resonant cavity radiates the signal from N radiation ports along the first direction, and the first direction and the second direction are perpendicular. In this way, the coupling cavity can be used to achieve same-layer coupling of the signal during the transmission process (that is, the signal is fed into the feeding structure, passes through the coupling cavity and the resonant cavity in sequence, and is radiated from the N radiation ports).

[0014] However, the current use of vertical multi-stage power dividers to implement the feeding network of the waveguide antenna results in multi-layer coupling of the signal during transmission, which leads to a large cross-sectional height of the waveguide antenna, a complex three-dimensional structure, high requirements for processing accuracy, and high processing costs.

[0015] Compared with the current use of vertical multi-stage power dividers to implement the feeding network of the waveguide antenna, the embodiment of the present application uses a coupling cavity to achieve same-layer coupling of signals during transmission, which can reduce the cross-sectional height of the waveguide antenna, thereby reducing the complexity of the three-dimensional structure of the waveguide antenna, reducing the requirements for processing accuracy, and reducing processing costs.

[0016] In a possible implementation, the coupling cavity and the feeding structure are connected in a third direction, and the third direction is perpendicular to the first direction and the second direction respectively.

[0017] In an embodiment of the present application, a possible specific implementation of the connection between a coupling cavity and a feed structure is provided. Specifically, the coupling cavity and the feed structure are connected in a third direction, and the third direction is perpendicular to the first direction and the second direction. It can be understood that the first direction, the second direction, and the third direction are mutually perpendicular to each other to form a three-dimensional space. Through this embodiment of the present application, same-layer coupling can be achieved during the transmission process of the signal being fed from the feed structure, passing through the coupling cavity and the resonant cavity, and then radiated from N radiating ports, thereby reducing the cross-sectional height of the waveguide antenna.

[0018] In a possible implementation, the coupling cavity includes a first cavity and a second cavity that are connected, the first cavity and the resonant cavity are connected in the second direction, and the second cavity and the feeding structure are connected in the third direction.

[0019] In an embodiment of the present application, a possible specific implementation of a coupling cavity is provided, specifically, the first cavity and the resonant cavity in the coupling cavity are connected in the second direction, the second cavity in the coupling cavity and the feeding structure are connected in the third direction, and the first cavity and the second cavity are interconnected, and the second direction and the third direction are perpendicular to each other. This can achieve same-layer coupling during the transmission process in which the signal is fed into the feeding structure, passes through the second cavity of the coupling cavity, the first cavity of the coupling cavity, the resonant cavity, and then radiates out from N radiation ports, thereby reducing the cross-sectional height of the waveguide antenna.

[0020] In a possible implementation manner, the value range of the side lengths a1 and b1 of the cross section of the first cavity in the second direction satisfies the following conditions: 0.3λ≤b1≤0.8λ, 0 <a1≤1 / 2×b1;

[0021] The λ represents the wavelength of the electromagnetic wave with a frequency less than the first threshold.

[0022] In the embodiment of the present application, the cross-sectional side lengths a1 and b1 of the first cavity in the second direction meet the above conditions, which can achieve impedance matching transformation and improve the transmission efficiency of the signal in the coupling cavity.

[0023] It is understood that the first threshold value in the embodiments of the present application is not a fixed value and can be adjusted according to different application scenarios. For example, the waveguide device in the embodiments of the present application can be applied to millimeter waves between 76 and 81 GHz. In this case, the first threshold value can be adjusted so that λ represents the wavelength of the millimeter waves in the frequency band between 76 and 81 GHz.

[0024] In a possible implementation manner, a1 and b1 are perpendicular to each other.

[0025] In the embodiment of the present application, the side lengths a1 and b1 of the cross section of the first cavity in the second direction are perpendicular to each other. It can be understood that the cross section of the first cavity in the second direction is a rectangle.

[0026] In a possible implementation manner, the length L1 of the first cavity in the second direction satisfies the following condition: 0.1λ≤L1≤0.4λ;

[0027] The λ represents the wavelength of the electromagnetic wave with a frequency less than the first threshold.

[0028] In the embodiment of the present application, the length L1 of the first cavity in the second direction meets the above conditions, which can achieve impedance matching transformation and improve the transmission efficiency of the signal in the coupling cavity.

[0029] In a possible implementation, the connection end between the first cavity and the resonant cavity is located at the center of the resonant cavity in the third direction.

[0030] In the embodiment of the present application, the connection end between the first cavity and the resonant cavity is located at the center of the resonant cavity in the third direction, which is conducive to the signal in the first cavity being radiated out from the N radiation ports through the resonant cavity, thereby improving the radiation efficiency of the signal.

[0031] In a possible implementation, the connecting end of the first cavity and the second cavity is located at any position between the bottom and the top of the second cavity in the first direction.

[0032] In an embodiment of the present application, the connecting end of the first cavity and the second cavity is located at any position between the bottom and the top of the second cavity in the first direction, which can realize the rotation of the electric field in the vertical plane, so that the signal fed into the feeding structure can be transmitted to the resonant cavity through the coupling cavity in the same layer, thereby reducing the cross-sectional height of the waveguide antenna.

[0033] In a possible implementation, the value ranges of the cross-sectional side lengths a2 and b2 of the resonant cavity in the third direction satisfy the following conditions: 0.6λ≤b2≤λ, 0.35×b2 <a2≤0.5×b2;

[0034] The λ represents the wavelength of the electromagnetic wave with a frequency less than the first threshold.

[0035] In the embodiment of the present application, the cross-sectional dimensions a2 and b2 of the resonant cavity in the third direction meet the above conditions, which can achieve a steady-state field distribution in the resonant cavity and improve the transmission efficiency of the signal in the resonant cavity.

[0036] In a possible implementation manner, a2 and b2 are perpendicular to each other.

[0037] In the embodiment of the present application, the side lengths a2 and b2 of the cross section of the resonant cavity in the third direction are perpendicular to each other. It can be understood that the cross section of the resonant cavity in the third direction is a rectangle.

[0038] In a possible implementation manner, the length L2 of the resonant cavity in the third direction satisfies the following condition: 0.85×(N×λ g / 2)≤L2≤1.15×(N×λ g / 2);

[0039] Among them, the λ g Characterizes the wavelength of the electromagnetic wave transmitted in the resonant cavity.

[0040] In the embodiment of the present application, the length L2 of the resonant cavity in the third direction meets the above conditions, which can achieve a steady-state field distribution in the resonant cavity and improve the transmission efficiency of the signal in the resonant cavity.

[0041] In a possible implementation manner, the spacing s between two adjacent radiation ports among the N radiation ports satisfies the following condition: 0.3λ≤S≤λ;

[0042] The λ represents the wavelength of the electromagnetic wave with a frequency less than the first threshold.

[0043] In the embodiment of the present application, the spacing s between two adjacent radiation ports among the N radiation ports meets the above conditions, which can achieve a lower sidelobe level and improve the anti-interference ability of the waveguide antenna, so that the cross-sectional height of the waveguide antenna can be reduced and the complexity of the three-dimensional structure of the waveguide antenna can be reduced, while at the same time, the advantages of the waveguide antenna in radiation transmission efficiency can be guaranteed.

[0044] In a possible implementation manner, a length L3 of any one of the N radiation ports in the third direction satisfies the following condition: 0.4λ≤L3≤0.7λ;

[0045] The λ represents the wavelength of the electromagnetic wave with a frequency less than the first threshold.

[0046] In the embodiment of the present application, the length L3 of any one of the N radiation ports in the third direction meets the above conditions, which can achieve a lower sidelobe level and improve the anti-interference ability of the waveguide antenna, so that the cross-sectional height of the waveguide antenna can be reduced and the complexity of the three-dimensional structure of the waveguide antenna can be reduced, while at the same time, the advantages of the waveguide antenna in radiation transmission efficiency can be guaranteed.

[0047] In a possible implementation, a cross-sectional height of the waveguide device in the first direction is less than a second threshold.

[0048] In the embodiment of the present application, by achieving same-layer coupling of signals during transmission through a coupling cavity, the cross-sectional height of the waveguide antenna can be reduced, so that the cross-sectional height of the waveguide device in the first direction is less than the second threshold, thereby reducing the complexity of the three-dimensional structure of the waveguide antenna, reducing the requirements for processing accuracy, and reducing processing costs.

[0049] It is understood that the second threshold value in the embodiments of the present application is not a fixed value and can be adjusted according to different application scenarios. For example, the waveguide device in the embodiments of the present application can reduce the cross-sectional height of the waveguide antenna compared to the current waveguide antenna feed network using a vertical multi-stage power splitter. In this case, the cross-sectional height of the waveguide device in the first direction can be adjusted to be smaller than the cross-sectional height of the waveguide antenna feed network currently using a vertical multi-stage power splitter.

[0050] In a possible implementation manner, a sidelobe level of the directivity pattern corresponding to the waveguide device is less than a third threshold.

[0051] In the embodiment of the present application, by setting the spacing and / or length of N radiation ports, a lower side lobe level can be achieved, so that the side lobe level of the radiation pattern corresponding to the waveguide device is less than the third threshold, thereby improving the anti-interference ability of the waveguide antenna, so that the cross-sectional height of the waveguide antenna can be reduced, the complexity of the three-dimensional structure of the waveguide antenna can be reduced, and the advantages of the waveguide antenna in radiation transmission efficiency can be guaranteed.

[0052] It is understood that the third threshold value in the embodiments of the present application is not a fixed value and can be adjusted according to different application scenarios. For example, the waveguide device in the embodiments of the present application has a significant advantage in radiation efficiency compared to traditional PCB printed antennas. In this case, the third threshold value can be adjusted to make the sidelobe level of the radiation pattern corresponding to the waveguide device lower than the sidelobe level of the radiation pattern corresponding to the traditional PCB printed antenna.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] In the embodiment of the present application, by achieving same-layer coupling of signals during transmission through a coupling cavity, the cross-sectional height of the waveguide antenna can be reduced, thereby reducing the complexity of the three-dimensional structure of the waveguide antenna, reducing the requirements for processing accuracy, and reducing processing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] 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.

[0058] FIG1 is a schematic diagram of a radar distribution according to an embodiment of the present application;

[0059] FIG2 is a schematic diagram of the architecture of a radar provided in an embodiment of the present application;

[0060] FIG3 is a schematic structural diagram of a waveguide antenna feeding network provided in an embodiment of the present application;

[0061] FIG4 is a schematic structural diagram of a waveguide device provided in an embodiment of the present application;

[0062] FIG5 is a plan view of a waveguide device provided in an embodiment of the present application;

[0063] FIG6 is a schematic structural diagram of a coupling cavity provided in an embodiment of the present application;

[0064] FIG7A is a schematic plan view of a coupling cavity provided in an embodiment of the present application;

[0065] FIG7B is a schematic plan view of a coupling cavity provided in an embodiment of the present application;

[0066] FIG8A is a schematic structural diagram of another waveguide device provided in an embodiment of the present application;

[0067] FIG8B is a schematic structural diagram of another waveguide device provided in an embodiment of the present application;

[0068] FIG9 is a schematic diagram of a cross-sectional height effect provided by an embodiment of the present application;

[0069] FIG10 is a schematic diagram showing the effects of impedance bandwidth and return loss provided by an embodiment of the present application;

[0070] FIG11 is a schematic diagram of a radiation pattern provided by an embodiment of the present application;

[0071] FIG12 is a schematic diagram showing the effect of a two-dimensional array of waveguide antennas provided in an embodiment of the present application;

[0072] FIG13A is a schematic diagram illustrating the electrical performance of a two-dimensional array of waveguide antennas provided in an embodiment of the present application;

[0073] FIG13B is a schematic diagram showing the effect of the electrical performance of a two-dimensional array of waveguide antennas 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, there is a need to study how to address the issues of large cross-sectional heights and complex three-dimensional structures of waveguide antennas. This application provides a waveguide device and related products related to millimeter-wave radar technology, which can reduce the cross-sectional height of waveguide antennas, thereby reducing the complexity of the three-dimensional structure of waveguide antennas.

[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 radar transmitting the electromagnetic wave signal to the receipt of the echo signal), 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 in 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 being developed to meet the evolving needs of system functionality, requiring them to achieve higher efficiency and wider bandwidth. Compared to traditional printed circuit board (PCB) antennas, waveguide antennas offer significant advantages in radiation transmission efficiency and broadband performance. However, the complex three-dimensional structure of waveguide antenna feed networks limits their application in millimeter-wave radar due to size and manufacturing costs. Therefore, significantly simplifying the waveguide antenna structure while maintaining performance could greatly enhance its application in millimeter-wave radar.

[0094] Please refer to FIG3 , which is a schematic structural diagram of a waveguide antenna feeding network provided in an embodiment of the present application.

[0095] As shown in FIG3 , FIG3 (a) is a feed network for a waveguide antenna implemented using a vertical multi-stage T-type power divider, and FIG3 (b) is a cross-sectional schematic diagram of the waveguide antenna feed network.

[0096] Specifically, (a) in FIG3 adopts a two-stage HT power divider in the vertical direction to realize one-to-four power splitting feeding, and adopts an offset feed design in the final power divider to realize amplitude and phase weighting of the radiation port, thereby reducing the sidelobe level of the V-plane radiation pattern.

[0097] The processing technology for preparing the waveguide antenna feed network is to achieve processing through a four-layer cutting method. After cutting, each layer of structural parts is formed by plastic mold processing, and then the surface is metallized through a surface electroplating process. Finally, the structure of the waveguide antenna feed network is obtained through an interlayer brazing process.

[0098] As can be seen from (a) and (b) in Figure 3, the cross-sectional height of the waveguide antenna feeding network is relatively large (having a four-layer structure: layer 1, layer 2, layer 3, layer 4), and the embodiment of the present application only uses four radiation ports as an exemplary illustration. As the number of radiation ports increases, the waveguide antenna feeding network requires more levels of T-type power dividers, which will cause the cross-sectional height of the waveguide antenna feeding network to be larger, thereby causing the three-dimensional structure of the waveguide antenna feeding network to be complex, the multi-layer processing has high requirements on processing accuracy, the performance tolerance is poor, the processing cost is high, and the value of application in engineering practice is low.

[0099] In response to the problem that the above-mentioned waveguide antenna feed network has a complex three-dimensional structure due to its large cross-sectional height and is not valuable for practical engineering applications, the embodiment of the present application designs a radar waveguide antenna feed network that can operate in the millimeter wave frequency band of 76 to 81 GHz based on the principle of electromagnetic coupling. The cross-sectional height of the waveguide antenna feed network can be reduced, thereby reducing the complexity of the three-dimensional structure of the waveguide antenna, reducing the requirements for processing accuracy, reducing processing costs, and ensuring the signal transmission performance of the antenna at a lower cross-sectional height.

[0100] It is understandable that coupling structures (gaps, holes, cavities, etc.) based on the electromagnetic coupling principle can enable the electromagnetic field in the waveguide to be transmitted, power distributed, and synthesized in a more agile and rapid manner.

[0101] 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.

[0102] Please refer to FIG4 , which is a schematic structural diagram of a waveguide device provided in an embodiment of the present application.

[0103] As shown in FIG4 , the waveguide device includes:

[0104] N radiation ports, resonant cavity, coupling cavity and feeding structure.

[0105] Wherein, N is an integer greater than or equal to 1. It is understood that the waveguide device shown in FIG4 includes four radiation ports (in this case, N=4), which is only a possible exemplary description and should not constitute a limitation to the embodiments of the present application.

[0106] The feeding structure is used for feeding in signals;

[0107] The coupling cavity is used to couple the signal fed into the feeding structure to the resonant cavity;

[0108] The resonant cavity is used to radiate the signal from N radiation ports along a first direction (z direction);

[0109] The coupling cavity is located between the resonant cavity and the feeding structure, which can also be expressed as follows: the coupling cavity is used to couple the energy in the feeding structure into the resonant cavity;

[0110] The coupling cavity and the resonant cavity are connected in the second direction (x direction), and the first direction (z direction) and the second direction (x direction) are perpendicular.

[0111] It can be understood that the coupling cavity and the resonant cavity in the waveguide device are connected in the second direction (x direction), and the resonant cavity radiates the signal from N radiation ports along the first direction (z direction), and the first direction (z direction, i.e., vertical direction) is perpendicular to the second direction (x direction). In this way, the coupling cavity can be used to achieve same-layer coupling of the signal in the transmission process (i.e., the signal is fed into the feeding structure, passes through the coupling cavity, the resonant cavity in turn, and then radiates out from the N radiation ports). Specifically, it means that the coupling cavity and the resonant cavity are located in the same layer structure in the first direction (z direction).

[0112] Specifically, in Figure 4, the coupling cavity is the dotted area in Figure 4, which has an L-shaped structure. The coupling cavity is connected to the wider surface of the resonant cavity in the second direction (x direction) and is connected to the feeding structure in the third direction (y direction), so that the signal fed into the feeding structure passes through the coupling cavity in the third direction (y direction) and the second direction (x direction) in sequence, and is coupled to the resonant cavity. The resonant cavity then radiates the signal from N radiation ports along the first direction (z direction).

[0113] Currently, a vertical multi-stage power divider is used to implement the feed network of the waveguide antenna (as shown in FIG3 ). This results in multi-layer coupling of the signal during transmission, which leads to a large cross-sectional height of the waveguide antenna, a complex three-dimensional structure, high requirements for processing accuracy, and high processing costs.

[0114] Compared with the current use of a vertical multi-stage power divider to implement the feeding network of a waveguide antenna (as shown in Figure 3 above), when having the same number of radiation ports, the current use of a vertical multi-stage power divider to implement the feeding network of a waveguide antenna is multi-layer coupled during signal transmission (having a four-layer structure: layer 1, layer 2, layer 3, layer 4), and the vertical cross-sectional height is relatively large. The embodiment of the present application uses a coupling cavity to achieve same-layer coupling of signals during transmission (having a two-layer structure: the coupling cavity and the resonant cavity are one layer in the first direction z direction, and the radiation port is one layer in the first direction z direction), which can reduce the cross-sectional height of the waveguide antenna, thereby reducing the complexity of the three-dimensional structure of the waveguide antenna, reducing the requirements for processing accuracy, and reducing processing costs.

[0115] In a possible embodiment, the coupling cavity and the feeding structure are connected in a third direction (y direction).

[0116] The third direction (y direction) is the direction in which the cavity of the resonant cavity extends, and the third direction (y direction) is perpendicular to the first direction (z direction) and the second direction (x direction).

[0117] It can be understood that the first direction (z-direction), the second direction (x-direction), and the third direction (y-direction) are mutually perpendicular to each other to form a three-dimensional space. Specifically, the first direction (z-direction) is the direction of the radiation port radiating the signal, the second direction (x-direction) is the direction perpendicular to the wide surface of the resonant cavity, and the third direction (y-direction) is the direction parallel to the wide surface of the resonant cavity.

[0118] In the embodiment of the present application, the cross-section of the feeding structure, the coupling cavity, and the resonant cavity in the first direction (z direction) is a three-dimensional structure of the same layer. The coupling cavity is used to realize same-layer coupling of the signal during the transmission process (the signal passes through the feeding structure, the coupling cavity, and the resonant cavity in sequence), thereby reducing the cross-sectional height of the waveguide antenna and thus reducing the complexity of the waveguide antenna.

[0119] For details, please refer to Figure 5, which is a plan view of a waveguide device provided in an embodiment of the present application. It is understood that the waveguide device shown in Figure 5 can be implemented as a separate embodiment; alternatively, the waveguide device shown in Figure 5 can be understood as a variation or supplement to the waveguide device shown in Figure 4 above. In this case, Figure 5 can be understood as a top view of the waveguide device shown in Figure 4 above in the first direction (z direction).

[0120] As shown in FIG5 , the waveguide device includes:

[0121] Four radiation ports, resonant cavity, coupling cavity and feeding structure.

[0122] Wherein, the feeding structure is used to feed the signal;

[0123] The coupling cavity is used to couple the signal fed into the feeding structure to the resonant cavity;

[0124] The resonant cavity is used to radiate the signal from four radiation ports along a first direction (z direction);

[0125] The coupling cavity is located between the resonant cavity and the feeding structure;

[0126] The coupling cavity and the resonant cavity are connected in a second direction (x direction), the coupling cavity and the feeding structure are connected in a third direction (y direction), and the second direction (x direction) and the third direction (y direction) are perpendicular.

[0127] It can be understood that the plane formed by the second direction (x-direction) and the third direction (y-direction) is perpendicular to the first direction (z-direction), and the first direction (z-direction), the second direction (x-direction), and the third direction (y-direction) are mutually perpendicular to each other to form a three-dimensional space. Specifically, the first direction (z-direction) is the direction of the signal radiated from the radiation port, the second direction (x-direction) is the direction perpendicular to the wide surface of the resonant cavity, and the third direction (y-direction) is the direction parallel to the wide surface of the resonant cavity.

[0128] In the embodiment of the present application, the signal is fed into the feeding structure, passes through the coupling cavity and the resonant cavity in sequence, and is radiated out from the four radiation ports. In the process of signal transmission, the signal is coupled on the same layer through the coupling cavity, which reduces the cross-sectional height of the waveguide antenna and thus reduces the complexity of the waveguide antenna.

[0129] In a possible embodiment, the coupling cavity in the waveguide device shown in FIG. 4 or FIG. 5 includes a first cavity and a second cavity that are connected.

[0130] For details, please refer to Figure 6, which is a schematic diagram of the structure of a coupling cavity provided in an embodiment of the present application. It is understood that the coupling cavity shown in Figure 6 can be implemented as a separate embodiment; alternatively, the coupling cavity shown in Figure 6 can be understood as a variation or supplement to the waveguide device shown in Figures 4 or 5 above. In this case, Figure 6 can be understood as a component (coupling cavity) of the waveguide device shown in Figures 4 or 5 above.

[0131] As shown in FIG6 , the coupling cavity includes a first cavity and a second cavity that are connected.

[0132] In combination with Figure 4 or Figure 5 above, it can be seen that the first cavity and the resonant cavity in the coupling cavity shown in Figure 6 are connected in the second direction (x direction), specifically, port 2 (port2) of the first cavity in the coupling cavity and the resonant cavity are connected in the second direction (x direction); the second cavity in the coupling cavity and the feeding structure are connected in the third direction (y direction), specifically, port 1 (port1) of the second cavity in the coupling cavity and the feeding structure are connected in the third direction (y direction).

[0133] Moreover, the first cavity and the second cavity are interconnected. The signal is fed into the feeding structure, enters the second cavity from port 1 (port 1), passes through the first cavity and is output from port 2 (port 2), coupled to the resonant cavity, and then radiated out from the radiation port.

[0134] It can be understood that the second direction (x direction) and the third direction (y direction) are perpendicular to each other, and the first cavity and the second cavity in the coupling cavity are also perpendicular to each other along the second direction (x direction) and the third direction (y direction).

[0135] Through the coupling cavity in the embodiment of the present application, the signal can be fed into the feeding structure, passed through the second cavity of the coupling cavity, the first cavity of the coupling cavity, the resonant cavity in sequence, and then radiated from N radiation ports. Same-layer coupling can be achieved during the transmission process, thereby reducing the cross-sectional height of the waveguide antenna and thus reducing the complexity of the waveguide antenna.

[0136] Please refer to Figures 7A and 7B, which are schematic plan views of the coupling cavity provided in an embodiment of the present application. It is understood that the coupling cavity shown in Figures 7A and 7B can be implemented as a separate embodiment; alternatively, the coupling cavity shown in Figures 7A and 7B can also be understood as a variation or supplement to the coupling cavity shown in Figures 4 to 6 above. In this case, Figure 7A can be understood as a side view of the coupling cavity shown in Figures 4 to 6 above in the third direction (y direction), and Figure 7B can be understood as a top view of the coupling cavity shown in Figures 4 to 6 above in the first direction (z direction).

[0137] As shown in FIG. 7A and FIG. 7B , the coupling cavity includes a first cavity and a second cavity that are connected.

[0138] The first cavity and the resonant cavity are connected in the second direction (x direction), specifically, port 2 (port2) of the first cavity and the resonant cavity are connected in the second direction (x direction); the second cavity and the feeding structure are connected in the third direction (y direction), specifically, port 1 (port1) of the second cavity and the feeding structure are connected in the third direction (y direction).

[0139] Moreover, the first cavity and the second cavity are interconnected. The signal is fed into the feeding structure, enters the second cavity from port 1 (port 1), passes through the first cavity and is output from port 2 (port 2), coupled to the resonant cavity, and then radiated out from the radiation port.

[0140] It is understood that in Figure 7A, the first direction (z-direction) and the second direction (x-direction) are perpendicular, and the plane formed by the first direction (z-direction) and the second direction (x-direction) is perpendicular to the third direction (y-direction). The first direction (z-direction), the second direction (x-direction), and the third direction (y-direction) are mutually perpendicular to each other to form a three-dimensional space. It is understood that the first cavity and the second cavity are also perpendicular to each other along the second direction (x-direction) and the first direction (z-direction), respectively.

[0141] It is understood that in Figure 7B, the third direction (y-direction) is perpendicular to the second direction (x-direction), and the plane formed by the third direction (y-direction) and the second direction (x-direction) is perpendicular to the first direction (z-direction). The first direction (z-direction), the second direction (x-direction), and the third direction (y-direction) are mutually perpendicular to each other to form a three-dimensional space. It is understood that the first cavity and the second cavity are also perpendicular to each other along the second direction (x-direction) and the third direction (y-direction), respectively.

[0142] Through the coupling cavity in the embodiment of the present application, the signal can be fed into the feeding structure, passed through the second cavity of the coupling cavity, the first cavity of the coupling cavity, the resonant cavity in sequence, and then radiated from N radiation ports. Same-layer coupling can be achieved during the transmission process, thereby reducing the cross-sectional height of the waveguide antenna and thus reducing the complexity of the waveguide antenna.

[0143] In a possible embodiment, the value range of the cross-sectional side lengths a1 and b1 of the first cavity in the second direction (x direction) satisfies the following conditions: 0.3λ≤b1≤0.8λ, 0 <a1≤1 / 2×b1;

[0144] Here, λ represents the wavelength of the electromagnetic wave having a frequency less than the first threshold.

[0145] 6 , 7A and 7B , a1 is the shorter side of the cross section of the first cavity in the second direction (x direction), and b1 is the longer side of the cross section of the first cavity in the second direction (x direction).

[0146] It is understood that the first threshold value in the embodiments of the present application is not a fixed value and can be adjusted according to different application scenarios. For example, the waveguide device in the embodiments of the present application can be applied to millimeter waves between 76 and 81 GHz. In this case, the first threshold value can be adjusted so that λ represents the wavelength of the millimeter waves in the frequency band between 76 and 81 GHz.

[0147] Optionally, a1 and b1 are perpendicular to each other.

[0148] It can be understood that, at this time, the cross section of the first cavity in the second direction (x direction) is rectangular.

[0149] In a possible embodiment, the length L1 of the first cavity in the second direction (x direction) satisfies the following conditions: 0.1λ≤L1≤0.4λ;

[0150] Here, λ represents the wavelength of the electromagnetic wave having a frequency less than the first threshold.

[0151] 6 , 7A and 7B , L1 is the length of the first cavity in the second direction (x direction), that is, the length of the first cavity in the direction of signal transmission within the cavity.

[0152] It is understood that the first threshold value in the embodiments of the present application is not a fixed value and can be adjusted according to different application scenarios. For example, the waveguide device in the embodiments of the present application can be applied to millimeter waves between 76 and 81 GHz. In this case, the first threshold value can be adjusted so that λ represents the wavelength of the millimeter waves in the frequency band between 76 and 81 GHz.

[0153] It should be understood that the dimensions a1, b1, and L1 of the first cavity given above are merely a possible exemplary illustration and should not be used to limit the embodiments of the present application. Embodiments obtained based on supplements or reasonable deformations of the above exemplary dimensions all fall within the scope of protection of the embodiments of the present application.

[0154] In the embodiment of the present application, by setting the dimensions a1, b1, and L1 of the first cavity, impedance matching transformation can be achieved, thereby improving the transmission efficiency of the signal in the coupling cavity.

[0155] In a possible embodiment, the value range of the cross-sectional side lengths a2 and b2 of the resonant cavity in the third direction (y direction) satisfies the following conditions: 0.6λ≤b2≤λ, 0.35×b2 <a2≤0.5×b2;

[0156] The λ represents the wavelength of the electromagnetic wave with a frequency less than the first threshold.

[0157] 4 and 5 , a2 is the shorter side of the cross section of the resonant cavity in the third direction (y direction), and b2 is the longer side of the cross section of the resonant cavity in the third direction (y direction).

[0158] It is understood that the first threshold value in the embodiments of the present application is not a fixed value and can be adjusted according to different application scenarios. For example, the waveguide device in the embodiments of the present application can be applied to millimeter waves between 76 and 81 GHz. In this case, the first threshold value can be adjusted so that λ represents the wavelength of the millimeter waves in the frequency band between 76 and 81 GHz.

[0159] Optionally, a2 and b2 are perpendicular to each other.

[0160] It can be understood that the cross section of the resonant cavity in the third direction (y direction) is rectangular.

[0161] In a possible embodiment, the length L2 of the resonant cavity in the third direction (y direction) satisfies the following condition: 0.85×(N×λ g / 2)≤L2≤1.15×(N×λ g / 2);

[0162] Among them, λ g Characterizes the wavelength of the electromagnetic wave transmitted in the resonant cavity.

[0163] For details, please refer to FIG. 5 , where L2 is the length of the resonant cavity in the third direction (y direction).

[0164] It should be understood that the dimensions a2, b2, and L2 of the resonant cavity given above are merely a possible exemplary illustration and should not be used to limit the embodiments of the present application. Embodiments obtained based on supplementation or reasonable deformation of the above exemplary dimensions are all within the scope of protection of the embodiments of the present application.

[0165] In the embodiment of the present application, by setting the dimensions a2, b2, and L2 of the resonant cavity, a steady-state field distribution in the resonant cavity can be achieved, thereby improving the transmission efficiency of the signal in the resonant cavity.

[0166] Optionally, the following describes the conditions satisfied by the dimensions a2, b2, and L2 of the resonant cavity in combination with the steady-state field distribution principle of the resonant cavity, as follows:

[0167] The right-angle components of the electromagnetic field of the electromagnetic wave in the resonant cavity all satisfy the Helmholtz equation: u(x,y,z)=X(x)Y(y)Z(z)

[0168] From the metal boundary conditions, we can get: E x =A1cos k x x sin k y y sin k z z E y =A2cos k y ysin y k x sin x k z E z =A3cos k z z sin k y y sin k x x

[0169] According to the boundary conditions of the resonant cavity dimensions a2, b2, and L2, K×(a2, b2, L2) must be an integer multiple of π, so:

[0170] Where m, n, p = 0, 1, 2, 3, ...; Substitute it into The resonant frequency can be obtained as:

[0171] Among them, ω mnp is the local oscillator frequency of the resonant cavity, f mnp is the resonant frequency of the resonant cavity.

[0172] When the lowest resonant frequency of the resonant cavity is m,n,p=1,1,0, we have:

[0173] The corresponding wavelength is:

[0174] In the embodiment of the present application, assuming that the resonant frequency is 76.5 GHz, m,n,p=1,2*N-1,0, where N is the number of radiation ports, the length L2 of the resonant cavity in the third direction (y direction) can be obtained by reverse calculation.

[0175] In a possible embodiment, the spacing s between two adjacent radiation ports among the N radiation ports satisfies the following condition: 0.3λ≤s≤λ;

[0176] Here, λ represents the wavelength of the electromagnetic wave having a frequency less than the first threshold.

[0177] For details, please refer to FIG5 , where s is the distance between any two adjacent radiation ports.

[0178] It is understood that the first threshold value in the embodiments of the present application is not a fixed value and can be adjusted according to different application scenarios. For example, the waveguide device in the embodiments of the present application can be applied to millimeter waves between 76 and 81 GHz. In this case, the first threshold value can be adjusted so that λ represents the wavelength of the millimeter waves in the frequency band between 76 and 81 GHz.

[0179] In a possible embodiment, the length L3 of any one of the N radiation ports in the third direction (y direction) satisfies the following conditions:

[0180] 0.4λ≤L3≤0.7λ;

[0181] Here, λ represents the wavelength of the electromagnetic wave having a frequency less than the first threshold.

[0182] For details, please refer to FIG. 5 , where L3 is the length of any radiation port in the third direction (y direction).

[0183] It is understood that the first threshold value in the embodiments of the present application is not a fixed value and can be adjusted according to different application scenarios. For example, the waveguide device in the embodiments of the present application can be applied to millimeter waves between 76 and 81 GHz. In this case, the first threshold value can be adjusted so that λ represents the wavelength of the millimeter waves in the frequency band between 76 and 81 GHz.

[0184] It should be understood that the dimensions s and L3 of the radiation port given above are only a possible exemplary illustration and should not be used to limit the embodiments of the present application. Embodiments obtained based on the supplementation or reasonable deformation of the above exemplary dimensions are all within the scope of protection of the embodiments of the present application.

[0185] In an embodiment of the present application, by setting the spacing s between two adjacent radiation ports among the N radiation ports and the length L3 of any radiation port among the N radiation ports in the third direction, a lower sidelobe level can be achieved and the anti-interference capability of the waveguide antenna can be improved, so that the cross-sectional height of the waveguide antenna can be reduced and the complexity of the three-dimensional structure of the waveguide antenna can be reduced, while at the same time, the advantages of the waveguide antenna in radiation transmission efficiency can be guaranteed.

[0186] In a possible embodiment, the connection end between the first cavity and the resonant cavity is located at the center of the resonant cavity in the third direction (y direction).

[0187] For details, please refer to Figure 5. The four radiation ports are evenly distributed on the narrow side walls of the resonant cavity. The connecting end of the first cavity in the coupling cavity and the resonant cavity is located at the center of the resonant cavity in the third direction (y direction), that is, at the center of the four radiation ports in the third direction (y direction).

[0188] It can be understood that the connection end between the first cavity and the resonant cavity is located at the center of the resonant cavity in the third direction (y direction), which is beneficial to improving the radiation efficiency of the signal, but this should not constitute a limitation on the embodiments of the present application. The connection end between the first cavity and the resonant cavity can also be located at other positions of the resonant cavity in the third direction (y direction), which all fall within the scope of protection of the embodiments of the present application.

[0189] In this embodiment of the present application, the connection between the first cavity and the resonant cavity is located at the center of the resonant cavity in the third direction (y-direction). This facilitates the radiation of the signal in the first cavity through the resonant cavity and out through the N radiation ports, thereby improving the radiation efficiency of the signal. Furthermore, the radiation ports are evenly distributed along the narrow sidewalls of the resonant cavity, further improving the radiation efficiency of the signal.

[0190] In a possible embodiment, the connection end of the first cavity and the second cavity is located at any position between the bottom and the top of the second cavity in the first direction (z direction).

[0191] For details, please refer to Figures 8A and 8B, which are schematic structural diagrams of the waveguide device provided in an embodiment of the present application.

[0192] As shown in FIG8A , the connecting end of the first cavity and the second cavity is located at the bottom of the second cavity in the first direction (z direction).

[0193] As shown in FIG8B , the connecting end of the first cavity and the second cavity is located at the top of the second cavity in the first direction (z direction).

[0194] As can be seen from FIG. 8A and FIG. 8B , the connection end between the first cavity and the second cavity is located at any position between the bottom and the top of the second cavity in the first direction (z direction).

[0195] In an embodiment of the present application, the connecting end of the first cavity and the second cavity is located at any position between the bottom and the top of the second cavity in the first direction (z direction), which can realize the rotation of the electric field in the vertical plane, so that the signal fed into the feeding structure passes through the first cavity and the second cavity in the coupling cavity, and can be coupled and transmitted to the resonant cavity in the same layer, thereby reducing the cross-sectional height of the waveguide antenna and thus reducing the complexity of the waveguide antenna.

[0196] It can be understood that, in the waveguide devices shown in FIG. 4 to FIG. 6 , FIG. 7A and FIG. 7B , and FIG. 8A and FIG. 8B , the cross-sectional height in the first direction (z direction) is less than the second threshold.

[0197] The second threshold value in the embodiment of the present application is not a fixed value and can be adjusted according to different application scenarios. For example, the waveguide device in the embodiment of the present application can reduce the cross-sectional height of the waveguide antenna compared to the current waveguide antenna feed network using a vertical multi-stage power splitter. In this case, the cross-sectional height of the waveguide device in the first direction (z direction) can be adjusted to be smaller than the cross-sectional height of the waveguide antenna feed network currently using a vertical multi-stage power splitter.

[0198] For details, please refer to Figures 9 and 10. Figure 9 is a schematic diagram of the effect of a cross-sectional height provided in an embodiment of the present application, and Figure 10 is a schematic diagram of the effect of an impedance bandwidth and return loss provided in an embodiment of the present application.

[0199] As shown in FIG9 , FIG9 (a) uses a vertical two-stage HT power divider to achieve a one-to-four power splitting feeding. Accordingly, the cross-sectional height of the waveguide antenna feeding network is relatively large (having a four-layer structure: layer 1, layer 2, layer 3, layer 4). FIG9 (b) (i.e., the embodiment of the present application) uses a coupling cavity to achieve same-layer coupling of signals during transmission. Accordingly, the cross-sectional height of the waveguide antenna feeding network is relatively small (having a two-layer structure: the coupling cavity and the resonant cavity are layer 1 in the first direction z, and the radiation port is layer 2 in the first direction z).

[0200] It can be seen that compared with the current use of a vertical multi-stage power divider to realize the feeding network of the waveguide antenna, when having the same number of radiation ports, the embodiment of the present application realizes the same-layer coupling of the signal during the transmission process through the coupling cavity, which can reduce the cross-sectional height of the waveguide antenna, so that the cross-sectional height of the waveguide device in the first direction (z direction) is less than the second threshold, thereby reducing the complexity of the three-dimensional structure of the waveguide antenna, reducing the requirements for processing accuracy, and reducing processing costs.

[0201] As shown in Figure 10, it can be seen that the port return loss S11 in the frequency range of 75.5 to 81.7 GHz is ≤ -15 dB, which meets the wide-band operation requirements for millimeter-wave radar.

[0202] Therefore, it can be seen from the above Figures 9 and 10 that the waveguide device in the embodiment of the present application can not only reduce the cross-sectional height of the waveguide antenna and reduce the complexity of the three-dimensional structure of the waveguide antenna, but also ensure the advantages of the waveguide antenna in radiation transmission efficiency.

[0203] It can be understood that, in the waveguide devices shown in FIG. 4 to FIG. 6 , FIG. 7A and FIG. 7B , and FIG. 8A and FIG. 8B , the corresponding side lobe levels of the directivity patterns are less than the third threshold.

[0204] Among them, the third threshold value in the embodiment of the present application is not a fixed value and can be adjusted according to different application scenarios. For example, the waveguide device in the embodiment of the present application has a great advantage in radiation efficiency compared with the traditional PCB printed antenna. At this time, the third threshold value can be adjusted to make the side lobe level of the directional pattern corresponding to the waveguide device smaller than the side lobe level of the directional pattern corresponding to the traditional PCB printed antenna. For another example, the waveguide device in the embodiment of the present application has a great advantage in radiation efficiency compared with the current use of a vertical multi-stage power divider to realize the feeding network of the waveguide antenna. At this time, the third threshold value can be adjusted to make the side lobe level of the directional pattern corresponding to the waveguide device smaller than the side lobe level of the directional pattern corresponding to the feeding network of the waveguide antenna that is currently used to realize the waveguide antenna.

[0205] For details, please refer to FIG11 , which is a schematic diagram of the effect of a radiation pattern provided in an embodiment of the present application.

[0206] As shown in Figure 11, it can be seen that within the frequency range of 76 to 81 GHz, the beam pointing is unbiased, and the beam gain is ≥11 dBi. The V-plane sidelobe level SLL corresponding to the lowest frequency of 76 GHz is ≥20 dB, which can achieve a lower sidelobe level. This allows the sidelobe level of the waveguide device's corresponding pattern to be less than the third threshold, improving the waveguide antenna's anti-interference capability. This allows the waveguide antenna's cross-sectional height to be reduced, reducing the complexity of its three-dimensional structure while maintaining its advantages in radiation transmission efficiency.

[0207] Optionally, the waveguide devices shown in FIG. 4 to FIG. 6 , FIG. 7A and FIG. 7B , and FIG. 8A and FIG. 8B may include a plurality of waveguide antennas.

[0208] By way of example, the following describes a small-pitch two-dimensional array formed by combining two waveguide antenna units and an ET power divider with reference to FIG. 12 , FIG. 13A , and FIG. 13B .

[0209] Please refer to FIG12 , which is a schematic diagram showing the effect of a two-dimensional array of waveguide antennas provided in an embodiment of the present application.

[0210] As shown in FIG12 , it can be seen that the waveguide device is a small-pitch two-dimensional array formed by combining two waveguide antenna units and an ET power divider, which can achieve two-dimensional array performance with equal amplitude and phase.

[0211] For details, please refer to Figures 13A and 13B, which are schematic diagrams of the electrical performance effects of the two-dimensional array of waveguide antennas provided in an embodiment of the present application.

[0212] As shown in FIG13A and FIG13B , it can be seen that the two-dimensional waveguide antenna array in FIG12 has S11 ≤ -12 dB in the range of 76 to 81 GHz, and the gain in the entire frequency band is increased to 15 dBi, which can achieve the performance of a two-dimensional array with equal amplitude and phase.

[0213] In addition, in a possible embodiment, a method for preparing a waveguide device is also provided. The specific process of the preparation method is as follows:

[0214] Method 1: Plastic layered molds can be opened to obtain N radiation ports, resonant cavities, coupling cavities and feeding structures, and then electroplating is performed on the surface of each mold. Finally, layer brazing is performed to obtain a waveguide device including N radiation ports, resonant cavities, coupling cavities and feeding structures.

[0215] Among them, the process of plastic layered mold opening is as follows: the plastic is first heated and melted in the bottom of the injection molding machine, and then, pushed by the screw of the injection molding machine, enters the mold cavity through the injection molding machine nozzle and the mold pouring system. The plastic cools and hardens into shape, and the product is demolded to obtain the product.

[0216] Plastic electroplating is to cover the plastic surface with a metal layer to give it metallic properties. The specific process is: surface cleaning, solvent treatment, conditioning treatment, and sensitization.

[0217] Brazing refers to a method of joining metals by simultaneously heating a filler metal (a material below the melting point of the workpiece) and the workpiece to the filler metal's melting point. Liquid filler metal then fills the gap between the solid workpieces, creating a metallic connection. During brazing, the oxide film and oil stains on the contact surface of the parent metal must be removed to facilitate capillary action after the filler metal melts, increasing the filler metal's wettability and capillary flow.

[0218] Method 2: N radiation ports, resonant cavities, coupling cavities and feeding structures can also be machined in layers, and then the N radiation ports, resonant cavities, coupling cavities and feeding structures can be formed by welding to obtain a waveguide device.

[0219] The waveguide device obtained by the above-mentioned preparation method can reduce the cross-sectional height of the waveguide antenna and reduce the complexity of the three-dimensional structure of the waveguide antenna, while ensuring the advantages of the waveguide antenna in radiation transmission efficiency.

[0220] Illustratively, through the above-mentioned method for preparing the waveguide device, a waveguide device as shown in any one of Figures 4 to 6, Figures 7A and 7B, and Figures 8A and 8B can be obtained. The structural characteristics and functional characteristics of the waveguide device can be found in the description of Figures 4 to 6, Figures 7A and 7B, and Figures 8A and 8B, and will not be repeated here.

[0221] 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.

[0222] 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.

[0223] 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: N radiation ports, resonant cavities, coupling cavities and feeding structures, wherein N is an integer greater than or equal to 1; The feeding structure is used to feed a signal; The coupling cavity is used to couple the signal to the resonant cavity; The resonant cavity is used to radiate the signal from the N radiation ports along a first direction; The coupling cavity is located between the resonant cavity and the feeding structure; The coupling cavity and the resonant cavity are connected in a second direction, and the first direction is perpendicular to the second direction.

2. The waveguide device according to claim 1, characterized in that The coupling cavity and the feeding structure are connected in a third direction, and the third direction is perpendicular to the first direction and the second direction respectively.

3. The waveguide device according to claim 1 or 2, characterized in that: The coupling cavity comprises a first cavity and a second cavity that are connected, the first cavity and the resonant cavity are connected in the second direction, and the second cavity and the feeding structure are connected in the third direction.

4. The waveguide device according to claim 3, characterized in that The value ranges of the side lengths a1 and b1 of the cross section of the first cavity in the second direction satisfy the following conditions: 0.3λ≤b1≤0.8λ,0 <a1≤1 / 2×b1; The λ represents the wavelength of the electromagnetic wave whose frequency is less than the first threshold.

5. The waveguide device according to claim 4, characterized in that The a1 and the b1 are perpendicular to each other.

6. The waveguide device according to claim 4 or 5, characterized in that The length L1 of the first cavity in the second direction satisfies the following condition: 0.1λ≤L1≤0.4λ; The λ represents the wavelength of the electromagnetic wave whose frequency is less than the first threshold.

7. The waveguide device according to any one of claims 3 to 6, characterized in that The connection end between the first cavity and the resonant cavity is located at the center of the resonant cavity in the third direction.

8. The waveguide device according to any one of claims 3 to 7, characterized in that The connecting end of the first cavity and the second cavity is located at any position between the bottom and the top of the second cavity in the first direction.

9. The waveguide device according to any one of claims 1 to 8, characterized in that The value ranges of the cross-sectional side lengths a2 and b2 of the resonant cavity in the third direction satisfy the following conditions: 0.6λ≤b2≤λ, 0.35×b2 <a2≤0.5×b2; The λ represents the wavelength of the electromagnetic wave whose frequency is less than the first threshold.

10. The waveguide device according to claim 9, characterized in that The a2 and the b2 are perpendicular to each other.

11. The waveguide device according to any one of claims 1 to 10, characterized in that The length L2 of the resonant cavity in the third direction satisfies the following condition: 0.85×(N×λ g / 2)≤L2≤1.15×(N×λ g / 2); Among them, the λ g Characterizes the wavelength of the electromagnetic wave transmitted in the resonant cavity.

12. The waveguide device according to any one of claims 1 to 11, characterized in that The spacing s between two adjacent radiation ports among the N radiation ports satisfies the following condition: 0.3λ≤s≤λ; The λ represents the wavelength of the electromagnetic wave whose frequency is less than the first threshold.

13. The waveguide device according to any one of claims 1 to 12, characterized in that The length L3 of any one of the N radiation ports in the third direction meets the following conditions: 0.4λ≤L3≤0.7λ; The λ represents the wavelength of the electromagnetic wave whose frequency is less than the first threshold.

14. The waveguide device according to any one of claims 1 to 13, characterized in that A cross-sectional height of the waveguide device in the first direction is smaller than a second threshold.

15. The waveguide device according to any one of claims 1 to 14, characterized in that The side lobe level of the directivity pattern corresponding to the waveguide device is less than a third threshold.

16. A radar, characterized in that: The radar comprises the waveguide device according to any one of claims 1 to 15.

17. A terminal device, characterized in that: The terminal device includes the waveguide device according to any one of claims 1 to 15, or the radar according to claim 16.

18. A vehicle end, characterized in that: The vehicle end includes the waveguide device according to any one of claims 1 to 15, or the radar according to claim 16, or the terminal equipment according to claim 17.

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