A waveguide antenna array and millimeter wave radar

Abstract

The embodiment of the application discloses a waveguide antenna array and a millimeter wave radar, and relates to the technical field of communication. The waveguide antenna array comprises a radio frequency interface layer, a waveguide power division network layer and a radiation layer which are sequentially stacked. The radio frequency interface layer is provided with at least one radio frequency chip interface, the radio frequency chip interface is a transition structure of waveguide to microstrip, the waveguide power division network layer comprises a waveguide power divider in communication with the radio frequency chip interface, and the radiation layer comprises a plurality of radiation antenna units, each of which is provided with a plurality of radiation slots, and the plurality of radiation antenna units are in one-to-one correspondence with the plurality of waveguide branches in communication. In the above manner, the embodiment of the application can realize direct docking between the waveguide antenna array and the radio frequency chip, eliminate the additional loss introduced by the external connector, improve the interface matching and signal transmission efficiency, realize the integration of the waveguide antenna array and the radio frequency chip at the same time, and meet the application requirements of miniaturization and high integration of the millimeter wave radar.

Description

Technical Field

[0001] This application relates to the field of communication technology, and in particular to a waveguide antenna array and a millimeter-wave radar. Background Technology

[0002] Millimeter-wave radar is a wireless sensing device that uses electromagnetic waves in the millimeter-wave band for target detection. It boasts advantages such as large bandwidth, high resolution, strong anti-interference capabilities, and low susceptibility to environmental influences. It can operate stably in complex environments such as rain, fog, and nighttime, and has been widely applied in fields such as advanced driver assistance systems (ADAS), autonomous driving, industrial sensing, and intelligent transportation. As a key component of millimeter-wave radar, the antenna array's performance directly determines the radar system's detection range, angular resolution, and target recognition accuracy. With the continuous improvement of automotive intelligence and autonomous driving levels, the market is placing increasingly higher demands on the detection range, resolution, miniaturization, and lightweight design of millimeter-wave radar. Consequently, millimeter-wave radar antenna arrays are rapidly developing towards higher frequencies, higher integration, and large-scale arrays, gradually becoming a core component in high-frequency wireless detection equipment.

[0003] In implementing the embodiments of this application, the inventors discovered that currently, millimeter-wave radar antenna arrays and radio frequency chips typically require cascading via external connectors or additional transition structures, resulting in poor interface matching between the antenna array and the radio frequency chip. This not only introduces additional losses during signal transmission, affecting the overall radiation efficiency of the antenna array, but also hinders the integrated integration of the antenna array and the radio frequency chip, making it difficult to further reduce the size of the entire radar system and meet the application requirements of miniaturization and high integration of millimeter-wave radar. Summary of the Invention

[0004] The main technical problem solved by the embodiments of this application is to provide a waveguide antenna array that can be directly connected to the output of an RF chip without the need for external connectors or additional transition structures for cascading.

[0005] To address the aforementioned technical problems, one technical solution adopted in this application embodiment is as follows: a waveguide antenna array is provided, comprising an RF interface layer, a waveguide power divider network layer, and a radiating layer. The RF interface layer is provided with at least one RF chip interface, which is used to interface with the output terminal of an RF chip. The waveguide power divider network layer is stacked on top of the RF interface layer and includes a waveguide power divider connected to the RF chip interface. The waveguide power divider includes multiple waveguide branches, which are used to distribute the power of the RF signal fed into the RF chip interface. The radiating layer is stacked on top of the waveguide power divider network layer and includes multiple radiating antenna elements. Each radiating antenna element is provided with several radiating slots. The multiple radiating antenna elements are respectively connected to the multiple waveguide branches one-to-one to receive the RF signal distributed by the waveguide power divider and radiate it outward through the radiating slots.

[0006] Optionally, the waveguide antenna array further includes a resonant cavity layer, which is stacked between the waveguide power divider network layer and the radiation layer. The resonant cavity layer includes multiple resonant cavity units, the input terminals of which are respectively connected to the multiple waveguide branches, and the output terminals of which are respectively connected to the multiple radiating antenna units.

[0007] Optionally, the resonant cavity unit is provided with an electromagnetic bandgap structure, which includes a plurality of metal pillars arranged periodically along the inner edge of the resonant cavity unit. The plurality of metal pillars are used to confine the radio frequency signal to propagate inside the resonant cavity unit in order to suppress higher-order modes within the resonant cavity unit.

[0008] Optionally, the electromagnetic bandgap structure further includes multiple rectangular slots located in the central region of the resonant cavity unit and arranged sequentially along the signal propagation direction of the resonant cavity unit. The multiple rectangular slots are used to resonantly couple the passing radio frequency signals.

[0009] Optionally, the electromagnetic bandgap structure further includes multiple trapezoidal structures and multiple first protrusions. The multiple trapezoidal structures are arranged sequentially along the signal propagation direction of the resonant cavity unit, and each trapezoidal structure is located between two adjacent rectangular slots or at both ends of the multiple rectangular slots. The multiple first protrusions are respectively disposed in the vicinity of the multiple rectangular slots. The multiple trapezoidal structures are used to form multi-level impedance matching in the resonant cavity unit and to distribute and adjust the radio frequency signal energy between the multiple rectangular slots. The multiple first protrusions are used to adjust the resonant characteristics and radiation characteristics of the multiple rectangular slots.

[0010] Optionally, the surface of the radiating layer is further provided with a first rectangular strip assembly and a second rectangular strip assembly. The first rectangular strip assembly includes a plurality of first rectangular strips arranged in parallel along the longitudinal direction of the radiating layer. The first rectangular strips extend continuously along the longitudinal direction of the radiating layer, and their projection range in the length direction covers the corresponding positions of the plurality of radiating antenna elements on the radiating layer. The second rectangular strip assembly includes a plurality of second rectangular strips respectively disposed in the vicinity of the plurality of radiating antenna elements, and the length of each second rectangular strip is less than the length of the first rectangular strip. The first rectangular strip assembly is used to suppress surface waves propagating on the surface of the radiating layer along the longitudinal direction, and the second rectangular strip assembly is used to suppress surface waves in the area surrounding the radiating antenna elements.

[0011] Optionally, the radiating antenna element is provided with a groove and a third rectangular strip. The groove is disposed in the radiating layer and surrounds the plurality of radiating slots. The third rectangular strip is disposed in the groove and extends along the arrangement direction of the plurality of radiating slots. The groove is used to define the radiating aperture of the radiating antenna element, and the third rectangular strip is used to adjust the electromagnetic field distribution around the plurality of radiating slots.

[0012] Optionally, a plurality of radiating slots in each of the radiating antenna elements are arranged sequentially at intervals along the waveguide axis, and two adjacent radiating slots are alternately offset relative to the waveguide axis. The offset of the plurality of radiating slots relative to the waveguide axis is non-uniformly distributed according to a preset weighting law. The plurality of radiating slots are used to radiate the radio frequency signals received by the radiating antenna elements outward in a manner that is in-phase superimposed and aperture-weighted.

[0013] Optionally, the waveguide power divider includes multiple T-junctions, and the multiple waveguide branches are cascaded through the multiple T-junctions to form a symmetrically distributed branch structure. The multiple T-junctions are used to perform multi-stage one-to-two power distribution on the RF signal fed into the RF chip interface, and the multiple waveguide branches are used to output the RF signal distributed by the multiple T-junctions to the radiating layer in an equal amplitude and in phase manner.

[0014] To solve the above-mentioned technical problems, another technical solution adopted in this application embodiment is: to provide a millimeter-wave radar, the millimeter-wave radar including a waveguide antenna array of any of the above-mentioned radio frequency chips, the radio frequency chip interface of the waveguide antenna array being connected to the output terminal of the radio frequency chip, and the waveguide antenna array being used to radiate the radio frequency signal output by the radio frequency chip outward through the radiation gap.

[0015] This application provides a waveguide antenna array, which is formed by stacking an RF interface layer, a waveguide power divider network layer, and a radiation layer in sequence to form an integrated structure. A waveguide-to-microstrip transition structure is set in the RF interface layer as an RF chip interface, enabling the waveguide antenna array to directly interface with the output of the RF chip without the need for external connectors or additional transition structures for cascading. On the one hand, by eliminating the additional losses introduced by external connectors or transition structures, the interface compatibility between the waveguide antenna array and the RF chip is improved, and the transmission efficiency of RF signals between the two is effectively improved, thereby improving the overall radiation efficiency of the waveguide antenna array. On the other hand, the three-layer integrated stacked structure design enables the waveguide antenna array and the RF chip to achieve compact integration without reserving additional installation space for external connectors, thereby reducing the size of the entire radar system and meeting the application requirements of miniaturization and high integration of millimeter-wave radar. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0017] Figure 1 This is a schematic diagram of the overall structure of the waveguide antenna array provided in the embodiments of this application; Figure 2 This is an exploded structural diagram of the waveguide antenna array provided in the embodiments of this application; Figure 3 This is a schematic diagram of the resonant cavity layer and the radio frequency interface layer in the waveguide antenna array provided in the embodiments of this application; Figure 4 yes Figure 3 Enlarged view of part A in the middle; Figure 5 This is a schematic diagram of the structure of the radiating layer and the waveguide power divider network layer in the waveguide antenna array provided in the embodiments of this application; Figure 6 yes Figure 5 Enlarged view of part B in the middle; Figure 7 This is a simulation result of the radiation pattern of the waveguide antenna array provided in the embodiments of this application at the center frequency of the operating frequency band; Figure 8 This is a simulation result diagram of the S11 parameters of the waveguide antenna array provided in the embodiment of this application within the operating frequency band.

[0018] The reference numerals in the detailed embodiments are as follows: 100, waveguide antenna array; 10, radio frequency interface layer; 11, radio frequency chip interface; 20, waveguide power divider network layer; 21, waveguide power divider; 211, T-junction; 201, multi-path waveguide branch; 30, radiating layer; 301, radiating slot; 31, radiating antenna element; 311, groove; 312, third rectangular strip; 32, first rectangular strip assembly; 321, first rectangular strip; 33, second rectangular strip assembly; 331, second rectangular strip; 40, resonant cavity layer; 41, resonant cavity element; 42, electromagnetic bandgap structure; 421, metal pillar; 422, rectangular slot; 423, trapezoidal structure; 424, first protrusion. Detailed Implementation

[0019] To facilitate understanding of this application, a more detailed description is provided below with reference to the accompanying drawings and specific embodiments. It should be noted that when an element is described as "fixed to" another element, it can be directly on the other element, or one or more intermediate elements may exist between them. When an element is described as "connected" to another element, it can be directly connected to the other element, or one or more intermediate elements may exist between them. The terms "upper," "lower," "inner," "outer," "vertical," "horizontal," etc., used in this specification indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0020] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the application. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.

[0021] Furthermore, the technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0022] Please see Figure 1This application provides a waveguide antenna array 100, which can be applied to wireless detection devices in the millimeter-wave band, such as vehicle-mounted millimeter-wave radar, industrial sensors, intelligent traffic monitoring devices, and other electronic devices that require high-frequency electromagnetic wave radiation and reception. In this embodiment, the waveguide antenna array 100 includes a radio frequency interface layer 10, a waveguide power divider network layer 20, and a radiation layer 30. The three components—the radio frequency interface layer 10, the waveguide power divider network layer 20, and the radiation layer 30—are stacked sequentially from bottom to top, together forming an integrated waveguide antenna array.

[0023] The radio frequency (RF) interface layer 10 is located at the bottom of the waveguide antenna array 100, serving as the interface layer for signal interaction between the entire waveguide antenna array and the external RF chip. In this embodiment, the RF interface layer 10 is provided with at least one RF chip interface 11, which is used to directly interface with the output terminal of the external RF chip.

[0024] Specifically, such as Figure 3 As shown, the RF chip interface 11 can adopt a waveguide-to-microstrip transition structure. This transition structure smoothly transitions the electromagnetic field distribution of the waveguide to the electromagnetic field distribution of the microstrip line in terms of physical form, enabling the RF signal to achieve efficient conversion between the two transmission media, waveguide and microstrip. Through this waveguide-to-microstrip transition structure design, the RF chip interface 11 can directly achieve physical docking and electrical connection with the microstrip output terminal of the external RF chip without the need to insert additional connectors or transition structures between them. This eliminates the signal loss introduced by external connectors or transition structures in traditional solutions, and greatly improves the transmission efficiency of RF signals from the RF chip to the waveguide antenna array.

[0025] It should be noted that the number of RF chip interfaces 11 can be flexibly configured according to actual application requirements. It can be a single RF chip interface or multiple RF chip interfaces. In the preferred embodiment shown in this example, the RF interface layer 10 is provided with 8 RF chip interfaces 11 to adapt to the multi-channel signal output requirements of multi-channel RF chips. In other embodiments, the number of RF chip interfaces 11 can be adjusted to 2, 4, 16 or other numbers according to the number of channels of the RF chip. This application embodiment does not limit the specific number of RF chip interfaces.

[0026] A waveguide power divider network layer 20 is stacked above the radio frequency interface layer 10, serving as a signal distribution layer between the radio frequency interface layer 10 and the radiation layer 30. The waveguide power divider network layer 20 includes a waveguide power divider 21 connected to the radio frequency chip interface 11. This waveguide power divider 21 is physically constructed as a waveguide cavity, using a waveguide as the transmission medium instead of the microstrip transmission line used in conventional antenna solutions. As a low-loss transmission medium, the waveguide exhibits superior transmission performance compared to microstrip lines in the millimeter-wave band, effectively reducing the loss of radio frequency signals during transmission within the waveguide power divider network layer 20.

[0027] The waveguide power divider 21 includes multiple waveguide branches 201. Starting from the input of the waveguide power divider 21, the multiple waveguide branches 201 branch sequentially to form multiple symmetrically distributed output branches. Each waveguide branch 201 corresponds to an independent RF signal transmission path. The core function of the multiple waveguide branches 201 is to distribute the power of the RF signal fed into the RF chip interface 11, enabling a single input RF signal to be divided into multiple output signals, which are then fed to multiple radiating antenna elements 31 of the radiating layer 30. In the preferred embodiment shown, the internal branch layout of the waveguide power divider 21 adopts a symmetrical structure, ensuring that the transmission path lengths of each waveguide branch 201 are approximately equal, thereby guaranteeing the consistency of amplitude and phase of each output signal and laying the foundation for uniform excitation of the radiating layer.

[0028] The radiating layer 30 is stacked above the waveguide power divider network layer 20, serving as the outermost structure of the waveguide antenna array 100, and directly converts radio frequency signals into spatially radiated electromagnetic waves. The radiating layer 30 includes multiple radiating antenna elements 31, each with several radiating slots 301. In the preferred embodiment shown, the radiating layer 30 has eight radiating antenna elements 31, symmetrically distributed in two rows on both sides of the radiating layer 30. Each radiating antenna element 31 contains eight radiating slots 301, spaced apart along the longitudinal direction of the radiating antenna element 31. Each of the multiple radiating antenna elements 31 is connected to a corresponding waveguide branch 201, meaning each waveguide branch 201 is connected to one radiating antenna element 31, allowing each radio frequency signal distributed by the waveguide power divider 21 to be independently input to its corresponding radiating antenna element 31. After the radio frequency signal enters the radiating antenna element 31, it radiates outward through the radiating slot 301, forming a total radiation pattern in space composed of the superposition of the radiation fields of each radiating slot.

[0029] It should be noted that the number of radiating antenna elements 31 and the number of radiating slots 301 can be flexibly configured according to actual application requirements. The scheme of 8 radiating antenna elements and 8 radiating slots per element shown in this embodiment is only a preferred implementation method. In other implementation methods, adjustments can be made according to the specific requirements of the application scenario.

[0030] This application provides a waveguide antenna array 100, which is formed by sequentially stacking an RF interface layer 10, a waveguide power divider network layer 20, and a radiation layer 30 to form an integrated structure. A waveguide-to-microstrip transition structure is provided in the RF interface layer 10 as an RF chip interface 11, enabling the waveguide antenna array 100 to directly interface with the output of the RF chip without the need for external connectors or additional transition structures for cascading. On the one hand, by eliminating the additional losses introduced by external connectors or transition structures, the interface compatibility between the waveguide antenna array 100 and the RF chip is improved, and the transmission efficiency of the RF signal between the two is effectively improved, thereby improving the overall radiation efficiency of the waveguide antenna array 100. On the other hand, through the design of the three-layer integrated stacked structure, the waveguide antenna array and the RF chip can achieve compact integrated integration without reserving additional installation space for external connectors, thereby reducing the size of the entire radar system and meeting the application requirements of miniaturization and high integration of millimeter-wave radar.

[0031] Please see Figure 3 and Figure 4 The resonant cavity layer 40 is stacked between the waveguide power divider network layer 20 and the radiation layer 30, serving as an intermediate layer through which the radio frequency signal output from the waveguide power divider network layer 20 passes before reaching the radiation layer 30.

[0032] The resonant cavity layer 40 includes multiple resonant cavity units 41, which are arranged in an array within the resonant cavity layer 40. The number of these units corresponds to the number of multiple waveguide branches 201 in the waveguide power divider network layer 20 and the number of multiple radiating antenna units 31 in the radiating layer 30. In the preferred embodiment shown in this example, the resonant cavity layer 40 has eight resonant cavity units 41, corresponding to the eight waveguide branches 201 and the eight radiating antenna units 31.

[0033] The input terminals of multiple resonant cavity units 41 are connected one-to-one with the multi-channel waveguide branches 201, meaning that the output terminal of each waveguide branch 201 is connected to the input terminal of a resonant cavity unit 41, allowing each radio frequency signal distributed by the waveguide power divider 21 to independently enter its corresponding resonant cavity unit 41. The output terminals of the multiple resonant cavity units 41 are then connected one-to-one with the multiple radiating antenna units 31, meaning that the output terminal of each resonant cavity unit 41 is connected to a radiating antenna unit 31, allowing the radio frequency signal regulated by the resonant cavity units 41 to be independently output to its corresponding radiating antenna unit 31 for outward radiation. Through this dual one-to-one correspondence connection design, the resonant cavity layer 40 forms eight independent signal transmission channels between the waveguide power divider network layer 20 and the radiation layer 30. Each channel undertakes the intermediary function of transmitting one waveguide branch input signal to the corresponding radiating antenna element, so that each RF signal can be effectively regulated by the resonant cavity unit 41 before reaching the radiation layer 30, ensuring that the signal reaching the radiation layer has the required electromagnetic field distribution characteristics.

[0034] In this embodiment, each resonant cavity unit 41 is further provided with an electromagnetic bandgap structure 42. The electromagnetic bandgap structure 42 forms a propagation control effect on radio frequency signals through a specific structural arrangement in the internal space of the resonant cavity unit 41.

[0035] Specifically, such as Figure 4 As shown, the electromagnetic bandgap structure 42 includes four types of components: multiple metal pillars 421, multiple rectangular slots 422, multiple trapezoidal structures 423, and multiple first protrusions 424. These four types of structures work together in different regions inside the resonant cavity unit 41 to achieve the complete function of the electromagnetic bandgap structure 42.

[0036] Multiple metal pillars 421 are periodically arranged along the inner edge of the resonant cavity unit 41, forming a continuous array of metal pillars in the edge region of the resonant cavity unit 41. In the preferred embodiment shown in this embodiment, the multiple metal pillars 421 are cylindrical and distributed at equal intervals along the inner wall edge of the resonant cavity unit 41, forming a "pin wall" structure surrounding the internal space of the resonant cavity unit 41. The multiple metal pillars 421 form an electromagnetic bandgap in the operating frequency band through their periodic arrangement, which is equivalent to constructing a "soft electromagnetic wall" at the edge of the resonant cavity unit 41, confining the radio frequency signal to propagate inside the resonant cavity unit 41, effectively preventing the radio frequency signal from leaking outward along the edge of the resonant cavity unit 41 into the region of adjacent resonant cavity units, thereby suppressing signal mutual coupling between adjacent resonant cavity units. At the same time, the periodically arranged metal pillars 421 can suppress higher-order modes in the resonant cavity unit 41, so that the radio frequency signal propagates stably in the form of the dominant mode in the resonant cavity unit 41, ensuring the mode purity of each signal transmission. It should be noted that the specific shape of the metal column 421 can be a cylinder, a square column, an elliptical column, or other regular columnar shapes. The cylindrical shape shown in this embodiment is only a preferred option. In other embodiments, it can be adjusted according to the processing technology and electromagnetic performance requirements. This application embodiment does not limit the specific shape of the metal column.

[0037] Multiple rectangular slots 422 are located in the central region of the resonant cavity unit 41 and are arranged sequentially along the signal propagation direction of the resonant cavity unit 41. In this embodiment, the signal propagation direction is the direction in which the radio frequency signal flows from the input end to the output end of the resonant cavity unit 41, and this direction is consistent with the longitudinal axis direction of the resonant cavity unit 41. The multiple rectangular slots 422 sequentially form a resonant unit array along the signal propagation direction. When the radio frequency signal flows through the resonant cavity unit 41 along the signal propagation direction, it will sequentially resonate and couple with each rectangular slot 422. Each rectangular slot 422 constitutes a resonant unit in the operating frequency band. Through its geometric design, it generates resonance in the operating frequency band, thereby coupling the radio frequency signal energy passing through that position to the corresponding position of the radiation layer 30. The cooperative operation of multiple rectangular slots 422 enables the radio frequency signal in the resonant cavity unit 41 to achieve stepwise energy coupling at multiple resonant points, forming an energy distribution along the signal propagation direction, providing a basis for the aperture distribution of the radiation layer 30. It should be noted that the specific number and size of the rectangular slots 422 can be designed to match the number and size of the radiation gaps 301 in the radiation layer 30. This embodiment does not limit the specific number of rectangular slots.

[0038] Multiple trapezoidal structures 423 are arranged sequentially along the signal propagation direction of the resonant cavity unit 41, with each trapezoidal structure 423 located between two adjacent rectangular slots 422 or at both ends of the multiple rectangular slots 422. Specifically, during the sequential arrangement of the multiple rectangular slots 422 along the signal propagation direction, trapezoidal structures 423 are provided in the interval area between two adjacent rectangular slots 422, so that the trapezoidal structures 423 and the rectangular slots 422 are arranged alternately along the signal propagation direction. In addition, trapezoidal structures 423 can also be provided at the beginning and end positions of the array of multiple rectangular slots 422 as the transition between the two ends of the entire rectangular slot array. The core function of the trapezoidal structure 423 in this embodiment includes two aspects. On the one hand, the trapezoidal structure 423 has two parallel sides, forming two waveguide segments with different cross-sections within the waveguide cavity. A stepped impedance transformation segment is formed through the dimensional transition between the two parallel sides, achieving multi-level impedance matching within the resonant cavity unit 41. This allows for a smooth impedance transition when the RF signal flows through each impedance transformation segment along the signal propagation direction, broadening the matching bandwidth within the operating frequency band. On the other hand, the trapezoidal structure 423, as a transition unit between adjacent rectangular slots 422, can distribute and adjust the RF signal energy between adjacent rectangular slots 422. By controlling the specific dimensions of each trapezoidal structure 423, the signal energy coupled by each rectangular slot 422 can be distributed according to a preset pattern, working in conjunction with the aperture-weighted design of the radiating layer 30 to optimize the radiation pattern characteristics.

[0039] Multiple first protrusions 424 are respectively disposed near multiple rectangular slots 422, serving as auxiliary structures for fine-tuning the resonant and radiation characteristics of the rectangular slots 422. In the preferred embodiment shown in this embodiment, each rectangular slot 422 has at least one corresponding first protrusion 424 disposed near it. The first protrusion 424 and the rectangular slot 422 are spatially tightly coupled to form a local disturbance to the electromagnetic field distribution around the rectangular slot. The core function of the first protrusion 424 is to achieve fine-tuning of the resonant frequency and radiation characteristics of the rectangular slot 422 by locally disturbing the electromagnetic field around the rectangular slot 422. Specifically, by adjusting the size, position, and shape of the first protrusion 424, the resonant frequency of the corresponding rectangular slot 422 can be finely adjusted to accurately match the center frequency of the operating frequency band, thereby improving signal coupling efficiency. At the same time, the first protrusion 424 can also adjust the energy coupling of the rectangular slot 422 towards the radiation layer 30, affecting the radiation characteristics at the corresponding position of the rectangular slot 422, and further optimizing the aperture distribution of the radiation layer 30. It should be noted that the specific shape of the first protrusion 424 can be a frustum, a square, or other regular protrusion shape. This embodiment does not limit the specific shape of the first protrusion.

[0040] By introducing the resonant cavity layer 40 and coordinating the four components in the electromagnetic bandgap structure 42, the waveguide antenna array 100 provided in this embodiment achieves the following technical effects.

[0041] Firstly, the resonant cavity layer 40 serves as an intermediary layer between the waveguide power divider network layer 20 and the radiation layer 30, allowing the radio frequency signal output from the waveguide power divider network layer 20 to be effectively regulated by the resonant cavity unit 41 before reaching the radiation layer 30, thereby improving the mode purity and energy distribution accuracy of the signal reaching the radiation layer.

[0042] Secondly, the metal pillars 421 in the electromagnetic bandgap structure 42 form the electromagnetic bandgap boundary through periodic arrangement, which effectively suppresses the signal mutual coupling between adjacent resonant cavity units and the higher-order modes within the resonant cavity units, thereby improving the working stability of the antenna array.

[0043] Third, the rectangular slot 422, trapezoidal structure 423, and first protrusion 424 work together to achieve resonant coupling, multi-level impedance matching, energy distribution adjustment, and fine-tuning of resonant characteristics within the resonant cavity unit, laying a solid structural foundation for the aperture weighting of the radiating layer 30. Fourth, the resonant cavity layer 40, as a newly added intermediary layer, together with the original RF interface layer 10, waveguide power divider network layer 20, and radiating layer 30, constitutes a four-layer integrated stacked structure, further improving the overall radiation performance of the antenna array while maintaining the high integration advantage of this invention.

[0044] Please see Figure 5 and Figure 6 In this embodiment, in addition to the plurality of radiating antenna elements 31, the surface of the radiating layer 30 is further provided with a first rectangular strip assembly 32 and a second rectangular strip assembly 33. The first rectangular strip assembly 32 and the second rectangular strip assembly 33 are distributed in the adjacent areas of the plurality of radiating antenna elements 31 on the surface of the radiating layer 30, serving as a surface wave suppression structure for the radiating layer 30, and jointly suppressing the propagation of the electromagnetic field along the surface of the radiating layer 30, thereby reducing the electromagnetic coupling between adjacent radiating antenna elements 31 and improving the overall radiation performance of the radiating layer 30.

[0045] The first rectangular strip assembly 32 includes a plurality of first rectangular strips 321. In the preferred embodiment shown in this embodiment, the plurality of first rectangular strips 321 are concentrated in the central region of the radiating layer 30 and arranged parallel to each other along the longitudinal direction of the radiating layer 30, forming a set of long rectangular strip arrays extending longitudinally. Each first rectangular strip 321 extends continuously along the longitudinal direction of the radiating layer 30, and its projection range in the length direction covers the corresponding positions of the plurality of radiating antenna elements 31 on the radiating layer 30. In other words, the length of a single first rectangular strip 321 extending longitudinally is sufficient to penetrate the corresponding height region of the plurality of radiating antenna elements 31, so that the first rectangular strip 321 forms a continuous high-impedance surface band in the central corridor of the radiating layer 30. In the preferred embodiment shown in this embodiment, the plurality of first rectangular strips 321 are arranged in parallel at equal intervals to form a dense long rectangular strip array, which together constitute a global surface wave suppression structure in the longitudinal direction of the radiating layer 30.

[0046] In this embodiment, the first rectangular strip assembly 32 serves to suppress surface waves propagating longitudinally from the surface of the radiating layer 30. In the millimeter-wave band, the electromagnetic field on the surface of the radiating layer 30 excites surface waves that propagate along the surface. These surface waves, when propagating longitudinally, can create global coupling between distant radiating antenna elements 31, leading to deterioration of the sidelobe level and decreased gain stability in the array pattern. The multiple first rectangular strips 321, through their periodic arrangement within the operating frequency band, create a periodic change in surface impedance, effectively constructing a high-impedance surface in the central corridor of the radiating layer 30. This effectively blocks and attenuates longitudinally propagating surface waves, thereby suppressing global surface wave coupling between distant radiating antenna elements 31 and maintaining the stability of the entire array pattern.

[0047] The second rectangular strip assembly 33 includes multiple second rectangular strips 331, which are respectively disposed near multiple radiating antenna elements 31. Unlike the concentrated distribution of the first rectangular strips 321 in the first rectangular strip assembly 32, the multiple second rectangular strips 331 in the second rectangular strip assembly 33 are dispersedly distributed on the surface of the radiating layer 30. That is, a corresponding second rectangular strip 331 is disposed in the vicinity of each radiating antenna element 31, so that the second rectangular strips 331 and the radiating antenna elements 31 form a locally accompanying spatial layout relationship. In addition, the length of each second rectangular strip 331 is less than the length of the first rectangular strip 321, that is, the extension range of the second rectangular strip 331 is relatively short, corresponding only to the width range of a single radiating antenna element 31, rather than spanning the corresponding positions of multiple radiating antenna elements.

[0048] The core function of the second rectangular strip assembly 33 in this embodiment is to suppress surface waves in the region surrounding the radiating antenna element 31. Specifically, during operation, the radiation field of each radiating antenna element 31 generates short-range surface waves that propagate along the surface of the radiating layer towards adjacent radiating antenna elements 31. This short-range surface wave propagation leads to local coupling between adjacent radiating antenna elements, affecting the independence of the radiation pattern of each radiating antenna element. By respectively setting multiple second rectangular strips 331 in the vicinity of each radiating antenna element 31, a local high-impedance boundary is formed around each radiating antenna element 31, blocking the short-range leakage of the radiation field of that radiating antenna element 31 along the surface towards adjacent radiating antenna elements 31, thereby suppressing local surface wave coupling between adjacent radiating antenna elements and improving the independence of the radiation pattern of each radiating antenna element 31.

[0049] The first rectangular strip assembly 32 and the second rectangular strip assembly 33 form a "global suppression + local suppression" relationship on the surface of the radiating layer 30. The first rectangular strip assembly 32 undertakes global surface wave suppression in the longitudinal direction of the radiating layer through a long rectangular strip array, while the second rectangular strip assembly 33 undertakes local surface wave suppression around each radiating antenna element through dispersed short rectangular strips. The two complement each other functionally and provide complete spatial coverage, together constituting a complete functional system for surface wave suppression in the radiating layer 30.

[0050] Please refer to further information. Figure 6 This embodiment provides a detailed design of the internal composition of the radiating antenna unit 31. In this embodiment, each radiating antenna unit 31 includes a groove 311 and a third rectangular strip 312. The groove 311 and the third rectangular strip 312 together constitute the specific structural form of the radiating antenna unit 31 within the radiating layer 30, and together with the radiating slot 301, they constitute the complete composition of the radiating antenna unit 31.

[0051] A groove 311 is disposed on the radiating layer 30 and surrounds a plurality of radiating slots 301. That is, the groove 311 has a sunken structure within the radiating layer 30, forming a surrounding distribution along the outer boundary of the array of radiating slots 301, so that the plurality of radiating slots 301 are located within the internal space defined by the groove 311. In the preferred embodiment shown in this embodiment, the groove 311 has a rectangular surrounding shape, forming a rectangular sunken region around the array of radiating slots 301. The boundary of this sunken region is the aperture boundary of the radiating antenna element 31. The core function of the groove 311 in this embodiment is to define the radiating aperture of the radiating antenna element 31.

[0052] Specifically, the groove 311, through its sunken structure, forms the physical boundary of the radiating antenna element 31 relative to other areas of the radiating layer 30, so that the radiation field of the radiating slot 301 can form a stable radiation pattern within the aperture range defined by the groove 311; at the same time, the edge of the groove 311 can also guide the radiation field to propagate in the normal direction of the radiating layer 30 through reflection, thereby improving the directivity and radiation efficiency of the radiating antenna element 31.

[0053] The third rectangular strip 312 is disposed within the groove 311 and extends along the arrangement direction of the plurality of radiating slots 301. In this embodiment, the arrangement direction of the radiating slots 301 is the sequential distribution direction of the plurality of radiating slots within the radiating antenna element 31, and this direction is generally consistent with the longitudinal axis direction of the radiating antenna element 31. The third rectangular strip 312 extends along this arrangement direction, so that it passes through the corresponding positions of the plurality of radiating slots 301 within the groove 311, forming a specific spatial fit with the radiating slot array. In the preferred embodiment shown in this embodiment, the third rectangular strip 312 is disposed at the central dividing position of the radiating slot array 301, dividing the radiating slot array within the radiating antenna element 31 into two symmetrically distributed sub-arrays, each sub-array being located on one side of the third rectangular strip 312.

[0054] The core function of the third rectangular bar 312 in this embodiment is to adjust the electromagnetic field distribution around the plurality of radiating slots 301. Specifically, during the operation of the radiating antenna element 31, the radiating field of each radiating slot 301 will form an uneven phase and amplitude distribution within the aperture defined by the groove 311. This unevenness will affect the shape and stability of the overall radiation pattern of the radiating antenna element 31. As a loading structure within the groove 311, the third rectangular bar 312, through local perturbation of the electromagnetic field around the radiating slots 301, achieves balanced adjustment of the excitation phase relationship of each radiating slot, improves the phase uniformity of the aperture field of the radiating antenna element 31, and thus maintains the stable pointing of the main beam of the radiation pattern.

[0055] It should be noted that the specific length, width and height of the third rectangular strip 312 can be optimized according to the operating frequency band and radiation performance requirements of the radiating antenna element 31. This embodiment does not limit the specific size of the third rectangular strip.

[0056] Through the arrangement of the first rectangular strip assembly 32 and the second rectangular strip assembly 33 on the surface of the radiation layer 30, and the specific composition design of the groove 311 and the third rectangular strip 312 inside the radiation antenna unit 31, the waveguide antenna array 100 provided in this embodiment further achieves the following technical effects.

[0057] First, the first rectangular strip assembly 32 and the second rectangular strip assembly 33 on the surface of the radiating layer 30 effectively suppress the propagation of surface waves on the surface of the radiating layer through the function of "global suppression + local suppression", reduce the electromagnetic coupling between adjacent radiating antenna elements 31, and improve the sidelobe level and gain stability of the array pattern.

[0058] Second, the groove 311 inside the radiating antenna unit 31 defines the radiation aperture through a sunken surrounding structure, providing a stable radiation boundary for the radiation slot 301 and improving the directivity and radiation efficiency of the radiating antenna unit.

[0059] Third, the third rectangular bar 312 improves the phase uniformity of the aperture field of the radiating antenna element 31 and optimizes the overall shape of the radiation pattern by locally adjusting the electromagnetic field around the radiating slot 301.

[0060] Figure 7 and Figure 8 The diagrams are for performance verification of this application, corresponding to the simulation results of the radiation pattern and the simulation results of the S11 parameters, respectively.

[0061] Please see Figure 7 , Figure 7 The figure shows the simulation results of the radiation pattern of the waveguide antenna array 100 provided in the embodiment of this application at the center frequency of the operating frequency band. The figure shows the radiation pattern curves of two orthogonal cross-sections, Phi=0° and Phi=90°. Figure 7 It can be observed that the waveguide antenna array 100 provided in this embodiment has a main beam pointing in the antenna normal direction at the center frequency, with a center gain of approximately 18.19 dBi. In the Phi=0° section, the gain in the ±15° direction is approximately 6.4 dB; in the Phi=90° section, the gain in the ±15° direction is approximately 14.1 dB, demonstrating good wide azimuth coverage capability. The sidelobe electrical values ​​in both sections are below -10 dB, exhibiting a significant low sidelobe performance advantage compared to conventional microstrip antenna schemes in the same frequency band. This radiation pattern characteristic indicates that the waveguide antenna array 100 provided in this embodiment can effectively suppress environmental clutter interference and improve the target identification accuracy of millimeter-wave radar.

[0062] Please see Figure 8 , Figure 8 The diagram shows the simulation results curves of the S11 parameters of the waveguide antenna array 100 provided in this embodiment within the operating frequency band. The horizontal axis represents the operating frequency, and the vertical axis represents the S11 parameter values. Figure 8It can be observed that the waveguide antenna array 100 provided in this application embodiment has an S11 parameter better than -12dB across the entire operating frequency band from 76GHz to 79GHz, with S11 approximately -14.2dB at 76GHz, approximately -16.3dB at 77GHz, approximately -12.1dB at 78GHz, and approximately -14.3dB at 79GHz. This S11 parameter characteristic indicates that the waveguide antenna array 100 provided in this application embodiment has good port matching performance within the operating frequency band, capable of covering the entire operating frequency band of vehicle-mounted millimeter-wave radar, and adaptable to the detection requirements of different application scenarios.

[0063] Please continue reading. Figure 5 and Figure 6 In this embodiment, a plurality of radiating slots 301 in each radiating antenna element 31 are arranged sequentially at intervals along the waveguide axis. In this embodiment, the waveguide axis direction is the longitudinal extension direction of the waveguide cavity inside the radiating antenna element 31, which is consistent with the propagation direction of the radio frequency signal within the radiating antenna element 31. The plurality of radiating slots 301 are distributed sequentially at a predetermined interval along the waveguide axis, forming an axially extending array of radiating slots. In the preferred embodiment shown in this embodiment, each radiating antenna element 31 includes eight radiating slots 301, and the eight radiating slots 301 are arranged along the waveguide axis at intervals of approximately half a waveguide wavelength. The spacing is evenly spaced, and the spacing design is based on the physical basis of the traveling wave propagation characteristics in the waveguide and is a preferred parameter.

[0064] It should be noted that the specific number and spacing of the radiation slots 301 can be optimized and adjusted according to the operating frequency band and radiation performance requirements. The scheme of 8 radiation slots and half a waveguide wavelength spacing shown in this embodiment is only a preferred embodiment. This application does not limit the specific number and spacing of the radiation slots.

[0065] Adjacent radiating slots 301 are alternately offset relative to the waveguide axis. That is, among the radiating slots 301 arranged sequentially along the waveguide axis, adjacent radiating slots are located on opposite sides of the waveguide axis. Specifically, among the eight radiating slots 301 numbered first, second, third to eighth along the waveguide axis, the first radiating slot is offset to one side of the waveguide axis, the second radiating slot is offset to the other side of the waveguide axis, the third radiating slot is again offset to the first side of the waveguide axis, the fourth radiating slot is again offset to the other side, and so on, forming an alternating offset arrangement pattern of "one side, the other side, one side, the other side" along the waveguide axis.

[0066] The physical basis of this alternating bias arrangement lies in the phase relationship of traveling wave propagation within the waveguide. When a rectangular waveguide operates in its dominant mode, the surface current on the inner wall of the wider side is distributed in opposite directions along both sides of the waveguide axis. When the spacing between adjacent radiating slots is set to approximately half a waveguide wavelength, the propagation phase difference of the traveling wave reaching the adjacent radiating slot is 180 degrees. By alternating the bias of adjacent radiating slots on both sides of the waveguide axis, the reverse characteristics of the surface currents on both sides of the waveguide axis can be used to compensate for this 180-degree propagation phase difference, ensuring that the final excitation phase of each radiating slot is consistent, thereby achieving in-phase superposition of the radiation fields from all radiating slots in the far field.

[0067] Furthermore, in this embodiment, the offset of the plurality of radiating slots 301 relative to the waveguide axis is non-uniformly distributed according to a preset weighting rule. That is, although adjacent radiating slots are alternately offset, the distances of each radiating slot from the waveguide axis are not the same, but are non-uniformly distributed according to a preset weighting rule. Specifically, the magnitude of the offset of each radiating slot determines the coupling strength between the radiating slot and the electromagnetic field inside the waveguide; the larger the offset, the higher the coupling strength, and the larger the corresponding excitation amplitude. By designing the offset of each radiating slot according to a preset weighting rule, precise control of the amplitude distribution on the aperture of the radiating antenna element 31 can be achieved.

[0068] In the preferred embodiment shown in this example, the preset weighting rule adopts the Taylor weighting method. That is, the bias of each radiating slot is optimized according to the aperture weighting function of the Taylor distribution. This results in the radiating slots located at the center of the radiating slot array having a larger bias and thus a stronger excitation amplitude, while the radiating slots located at both ends of the array have a smaller bias and thus a weaker excitation amplitude, forming an overall aperture amplitude distribution that is strong in the middle and weak at both ends. This Taylor-weighted aperture distribution can effectively suppress the sidelobe level of the radiation pattern, resulting in lower radiation intensity of the radiating antenna element 31 in the sidelobe direction outside the main beam, thereby reducing the interference of environmental clutter on the antenna detection performance. It should be noted that the preset weighting rule can be selected according to the actual radiation performance requirements, such as the Taylor weighting method, Chebyshev weighting method, binomial weighting method, or other possible weighting methods. The Taylor weighting method shown in this embodiment is only a preferred option, and the specific form of the preset weighting rule is not limited in this application embodiment.

[0069] Through the coordinated design of the arrangement and offset rules of the aforementioned radiating slots 301, the plurality of radiating slots 301 in this embodiment can radiate the radio frequency signals received by the radiating antenna element 31 outward in a manner of in-phase superposition and aperture weighting. "In-phase superposition" corresponds to the phase consistency of the excitation of each radiating slot achieved by the alternating offset arrangement, enabling the radiation fields of each radiating slot to achieve coherent superposition with the same phase in the far field, thereby forming a stable main beam of the radiation pattern. "Aperture weighting" corresponds to the distribution of the excitation amplitude of each radiating slot according to a preset rule achieved by the non-uniform distribution of the offset, resulting in a specific shape of amplitude distribution on the aperture of the radiating antenna element 31, thereby effectively suppressing the sidelobe level of the radiation pattern.

[0070] Please refer to further information. Figure 5 This embodiment further refines the design of the internal structure of the waveguide power divider 21 in the waveguide power divider network layer 20. In this embodiment, the waveguide power divider 21 includes multiple T-junctions 211. The multiple waveguide branches 201 are cascaded through multiple T-junctions 211 to form a symmetrically distributed branch structure. The T-junction 211 serves as the core power dividing node of the waveguide power divider 21. Its physical structure consists of one input waveguide divided into two mutually perpendicular or having a specific angle between them. The connection area between the input waveguide and the two output waveguides inside the T-junction 211 forms a "T"-shaped geometry. Through the matching steps or inductor protrusions inside the T-junction 211, the two output waveguides can achieve equal amplitude and in-phase power distribution.

[0071] Multiple T-junctions 211 are cascaded within the waveguide power divider 21 to form a multi-stage one-to-two power distribution network. Specifically, the first-stage T-junction 211 splits the input RF signal from the RF chip interface 11 into two equal-amplitude, in-phase output signals, which then enter the two T-junctions 211 of the second stage. Each T-junction 211 of the second stage further splits its input signal into two equal-amplitude, in-phase output signals, resulting in four equal-amplitude, in-phase signals after the second-stage distribution. This process continues, with multiple T-junctions 211 distributing the signals step by step to ultimately form multiple equal-amplitude, in-phase output signals, which are then output to the radiation layer 30 through multiple waveguide branches 201. In the preferred embodiment shown in this implementation, the waveguide power divider 21 includes a three-stage T-junction 211 cascaded structure. After the three-stage one-to-two power distribution, it forms eight equal-amplitude and in-phase output signals, which correspond in quantity to the eight resonant cavity units 41 in the resonant cavity layer 40 and the eight radiating antenna units 31 in the radiating layer 30.

[0072] The physical layout of multiple T-junctions 211 within the waveguide power divider 21 adopts a symmetrical distribution, meaning that the multi-stage T-junctions 211 are symmetrically distributed with the geometric center of the waveguide power divider 21 as the center of symmetry, exhibiting a symmetrical branch structure. This symmetrical geometric layout ensures that the transmission path length from the RF chip interface 11 to the end of each waveguide branch 201 is approximately equal, thereby guaranteeing that each RF signal distributed by the waveguide power divider 21 has a consistent propagation phase when it reaches the radiation layer 30.

[0073] The core function of the multiple T-junctions 211 and the multiple waveguide branches 201 working together is to output the RF signal fed into the RF chip interface 11 to the radiating layer 30 in an equal-amplitude and in-phase manner. "Equal amplitude" refers to the equal power distribution characteristic achieved by the multiple T-junctions 211 in each stage of distribution, ensuring that the output signals maintain the same amplitude after multiple stages of distribution. "In-phase" refers to the phase consistency characteristic achieved by the symmetrical distribution of the multiple T-junctions 211 and the equal-length transmission of each waveguide branch 201, ensuring that the output signals have the same propagation phase when they reach the radiating layer 30. This equal-amplitude and in-phase power distribution method lays the foundation for the uniform excitation of each radiating antenna element 31 in the radiating layer 30 and is a key prerequisite for achieving the high-gain, low-sidelobe radiation pattern characteristics of the entire waveguide antenna array 100.

[0074] Through the optimized design of the arrangement of the radiation slots 301 and the optimized design of the T-junction cascade structure inside the waveguide power divider 21, the waveguide antenna array 100 provided in this embodiment further achieves the following technical effects on the basis of the aforementioned embodiments.

[0075] Firstly, the radiation slots 301 achieve precise compensation of the excitation phase of each radiation slot by arranging them at intervals along the waveguide axis and alternately offsetting adjacent slots, so that all radiation slots achieve stable in-phase superposition radiation in the far field, forming a main beam with a clear direction.

[0076] Secondly, the non-uniform distribution of the bias of the radiating slot 301 according to the preset weighting law realizes the amplitude weighting on the aperture of the radiating antenna element, effectively suppresses the sidelobe level of the radiation pattern, and improves the antenna's target recognition accuracy.

[0077] Third, the T-junction cascade structure and symmetrical distribution design inside the waveguide power divider 21 realizes the equal amplitude and in-phase distribution of each output signal, laying the structural foundation for the uniform excitation of each radiating antenna element in the radiating layer. Together with the in-phase superposition radiation of the radiating slot, it forms a functional chain, which supports the overall radiation performance of the waveguide antenna array 100.

[0078] In a preferred embodiment of this application, the waveguide antenna array 100 is manufactured entirely using a plastic-plated metallization process. Specifically, firstly, a plastic substrate is processed into the overall shape of the waveguide antenna array 100 using an injection molding process, so that the various structural features of the RF interface layer 10, waveguide power divider network layer 20, resonant cavity layer 40, and radiation layer 30 (including waveguide cavities, waveguide branches, resonant cavity units, electromagnetic bandgap structures, radiation slots, rectangular bar protrusions, and grooves, etc.) are integrally formed on the plastic substrate; then, a metal layer is plated on the surface of the plastic substrate, so that the surface of each structural feature has good conductivity, meeting the electromagnetic requirements for RF signal transmission and radiation. Compared with traditional metal machining processes, this plastic plating metal process has the following advantages: good process consistency, enabling mass production through molds and ensuring consistent dimensional accuracy between different products; suitable for large-scale mass production, with a significantly lower unit production cost than metal machining processes, which is conducive to the industrialization and promotion of the waveguide antenna array provided in this application embodiment in large-scale application scenarios such as vehicle-mounted millimeter-wave radar; and lightweight products, which helps reduce the overall weight of millimeter-wave radar and meet the requirements for lightweight equipment in vehicle-mounted, airborne, and other application scenarios.

[0079] In this embodiment, the radio frequency (RF) chip, as the core signal processing component of the millimeter-wave radar, is responsible for the generation, modulation, transmission and reception of RF signals, as well as the processing of echo signals. It is the signal source for the millimeter-wave radar to achieve target detection. The RF chip is typically integrated into the circuit board in a chip package within the millimeter-wave radar. It outputs multi-channel RF excitation signals through multiple output terminals and receives echo signals from the antenna array through multiple receiving terminals. The waveguide antenna array 100, as the core radiating and receiving component of the millimeter-wave radar, is responsible for converting the RF signals generated by the RF chip into spatially radiated electromagnetic waves, and for receiving target-reflected echoes and feeding them back to the RF chip. It is the key carrier for the millimeter-wave radar to achieve electromagnetic wave radiation and reception.

[0080] In this embodiment, the RF chip interface 11 of the waveguide antenna array 100 is connected to the output terminal of the RF chip. Specifically, the RF chip interface 11, as a transition structure from waveguide to microstrip, can directly achieve physical connection and electrical connection with the microstrip output terminal of the RF chip, without the need for additional connectors or transition structures between them. Compared with the cascaded method of "RF chip, connector, antenna array" in traditional millimeter-wave radar, this direct connection method fundamentally eliminates the interface loss introduced by external connectors, allowing the RF signal to flow from the RF chip to the waveguide antenna array with higher transmission efficiency. At the same time, the direct connection method also eliminates the need to reserve space for connectors between the RF chip and the waveguide antenna array, making the internal structure of the entire millimeter-wave radar more compact and significantly reducing the overall size.

[0081] In the preferred embodiment shown in this example, the radio frequency (RF) chip is a millimeter-wave radar-specific RF chip with multi-channel output capability, and the number of its output terminals matches the number of RF chip interfaces 11 in the waveguide antenna array 100. For example, when the waveguide antenna array 100 contains 8 RF chip interfaces 11, the RF chip should have at least 8 output channels, so that each output channel can independently connect to one RF chip interface 11 in the waveguide antenna array 100, realizing parallel transmission of multi-channel RF signals. It should be noted that the specific model, number of channels, and internal architecture of the RF chip can be selected according to the specific application requirements of the millimeter-wave radar, and this embodiment does not limit the specific type of RF chip.

[0082] The overall workflow of the millimeter-wave radar is as follows: The radio frequency (RF) chip first generates an RF excitation signal within the operating frequency band. This signal is output to the RF chip interface 11 of the waveguide antenna array 100 via the RF chip output terminal. After entering the RF interface layer 10 through the RF chip interface 11, the RF signal propagates and is regulated sequentially through the waveguide power divider network layer 20, the resonant cavity layer 40, and the radiation layer 30. Finally, it is radiated into space through the radiation slots 301 of each radiating antenna element 31 in the radiation layer 30, forming an electromagnetic beam with specific radiation pattern characteristics. When this electromagnetic beam encounters a target object during its propagation in space, it is reflected from the surface of the target object. The reflected echo returns to the waveguide antenna array 100 along the opposite path and is received through the radiation slots 301. After being received, it propagates in reverse through the radiation layer 30, the resonant cavity layer 40, the waveguide power divider network layer 20, and the RF interface layer 10, finally returning to the receiving end of the RF chip. The radio frequency chip demodulates and processes the received echo signal to extract parameters such as the distance, speed, and angle of the target object, thereby realizing the target detection function of millimeter-wave radar.

[0083] By integrating the waveguide antenna array 100 of this invention into a millimeter-wave radar product, the millimeter-wave radar provided in this embodiment eliminates the interface loss introduced by external connectors in conventional solutions compared to conventional millimeter-wave radars in the prior art. This improves the radio frequency signal transmission efficiency of the millimeter-wave radar, thereby enhancing the detection range and sensitivity of the radar system. Furthermore, the waveguide antenna array 100 adopts a four-layer integrated stacked structure, with high overall integration and compact size, which significantly reduces the overall size of the millimeter-wave radar. This facilitates installation and integration in space-constrained applications such as automobiles, drones, and industrial sensing equipment. The high gain and low sidelobe pattern characteristics achieved by the design of the resonant cavity layer, the surface wave suppression structure of the radiation layer, and the weighted arrangement of radiation slots in the waveguide antenna array 100 enable the millimeter-wave radar to have higher angular resolution and anti-interference capability during target detection, achieving stable target identification in complex environments.

[0084] It should be noted that the millimeter-wave radar provided in this embodiment can be applied to various practical scenarios, including but not limited to advanced driver assistance systems (ADAS) for vehicles, autonomous driving systems, industrial automation sensing, intelligent traffic monitoring, drone obstacle avoidance, and smart home sensing. This application does not limit the specific application scenarios of the millimeter-wave radar; any millimeter-wave radar product that uses the waveguide antenna array 100 of this invention as both a radiating and receiving component falls within the protection scope of this application.

[0085] In addition to the radio frequency chip and waveguide antenna array 100, the millimeter-wave radar provided in this embodiment may further include other auxiliary components according to actual application requirements, such as signal processing module, power management module, heat dissipation module, mechanical housing and external communication interface, etc. The specific form and connection relationship of these auxiliary components are well known to those skilled in the art, and will not be described in detail in this embodiment.

[0086] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A waveguide antenna array, characterized in that, include: The radio frequency interface layer is provided with at least one radio frequency chip interface, which is used to interface with the output terminal of the radio frequency chip. A waveguide power divider network layer is stacked on top of the radio frequency interface layer. The waveguide power divider network layer includes a waveguide power divider that is connected to the radio frequency chip interface. The waveguide power divider includes multiple waveguide branches, which are used to distribute the power of the radio frequency signal fed into the radio frequency chip interface. A radiating layer is stacked on top of the waveguide power divider network layer. The radiating layer includes multiple radiating antenna elements, each of which is provided with several radiating slots. The multiple radiating antenna elements are respectively connected to the multiple waveguide branches to receive the radio frequency signals distributed by the waveguide power divider and radiate them outward through the radiating slots.

2. The waveguide antenna array according to claim 1, characterized in that, The waveguide antenna array further includes a resonant cavity layer, which is stacked between the waveguide power divider network layer and the radiation layer. The resonant cavity layer includes multiple resonant cavity units, the input terminals of which are respectively connected to the multiple waveguide branches, and the output terminals of which are respectively connected to the multiple radiating antenna units.

3. The waveguide antenna array according to claim 2, characterized in that, The resonant cavity unit has an electromagnetic bandgap structure inside, which includes a plurality of metal pillars arranged periodically along the inner edge of the resonant cavity unit. The plurality of metal pillars are used to confine the radio frequency signal to propagate inside the resonant cavity unit in order to suppress higher-order modes within the resonant cavity unit.

4. The waveguide antenna array according to claim 3, characterized in that, The electromagnetic bandgap structure also includes multiple rectangular slots, which are located in the central region of the resonant cavity unit and arranged sequentially along the signal propagation direction of the resonant cavity unit. The multiple rectangular slots are used to resonantly couple the passing radio frequency signals.

5. The waveguide antenna array according to claim 4, characterized in that, The electromagnetic bandgap structure further includes multiple trapezoidal structures and multiple first protrusions. The multiple trapezoidal structures are arranged sequentially along the signal propagation direction of the resonant cavity unit, and each trapezoidal structure is located between two adjacent rectangular slots or at both ends of the multiple rectangular slots. The plurality of first protrusions are respectively disposed in the vicinity of the plurality of rectangular slots. The plurality of trapezoidal structures are used to form multi-level impedance matching in the resonant cavity unit and to distribute and adjust the radio frequency signal energy between the plurality of rectangular slots. The plurality of first protrusions are used to adjust the resonant characteristics and radiation characteristics of the plurality of rectangular slots.

6. The waveguide antenna array according to any one of claims 1 to 5, characterized in that, The surface of the radiating layer is further provided with a first rectangular strip assembly and a second rectangular strip assembly. The first rectangular strip assembly includes a plurality of first rectangular strips, which are arranged in parallel along the longitudinal direction of the radiating layer. The first rectangular strips extend continuously along the longitudinal direction of the radiating layer, and their projection range in the length direction covers the corresponding positions of the plurality of radiating antenna elements on the radiating layer. The second rectangular strip assembly includes a plurality of second rectangular strips, which are respectively disposed in the vicinity of the plurality of radiating antenna elements, and the length of each second rectangular strip is less than the length of the first rectangular strip; The first rectangular strip assembly is used to suppress surface waves propagating along the longitudinal direction on the surface of the radiating layer, and the second rectangular strip assembly is used to suppress surface waves in the area surrounding the radiating antenna element.

7. The waveguide antenna array according to claim 6, characterized in that, The radiating antenna element is provided with a groove and a third rectangular strip. The groove is disposed in the radiating layer and surrounds the plurality of radiating slots. The third rectangular strip is disposed in the groove and extends along the arrangement direction of the plurality of radiating slots. The groove is used to define the radiating aperture of the radiating antenna element, and the third rectangular strip is used to adjust the electromagnetic field distribution around the plurality of radiating slots.

8. The waveguide antenna array according to claim 6, characterized in that, Each of the radiating antenna elements has several radiating slots arranged sequentially at intervals along the waveguide axis. Two adjacent radiating slots are alternately offset relative to the waveguide axis, and the offset of the several radiating slots relative to the waveguide axis is non-uniformly distributed according to a preset weighting law. The several radiating slots are used to radiate the radio frequency signals received by the radiating antenna element outward in a manner that is in-phase superimposed and aperture-weighted.

9. The waveguide antenna array according to claim 1, characterized in that, The waveguide power divider includes multiple T-junctions. The multiple waveguide branches are cascaded through the multiple T-junctions to form a symmetrically distributed branch structure. The multiple T-junctions are used to perform multi-stage one-to-two power distribution on the RF signal fed into the RF chip interface. The multiple waveguide branches are used to output the RF signal distributed by the multiple T-junctions to the radiating layer in an equal amplitude and in phase manner.

10. A millimeter-wave radar, characterized in that, The millimeter-wave radar includes a radio frequency chip and a waveguide antenna array according to any one of claims 1 to 9, wherein the radio frequency chip interface of the waveguide antenna array is connected to the output terminal of the radio frequency chip, and the waveguide antenna array is used to radiate the radio frequency signal output by the radio frequency chip outward through the radiation gap.

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