Ridge waveguide slot antenna array and device with high gain, wide band and high cross-pole ratio

Abstract

The invention relates to the technical field of microwave antennas, and particularly discloses a ridge waveguide slot antenna array and device with high gain, wide band and high cross-pole ratio, and the structure of the antenna array is as follows: an antenna radiation linear array layer is formed by linear array sub-arrays, and one linear array sub-array is composed of two linear array units; the first feed network layer is composed of a plurality of first feed networks corresponding to the linear array sub-arrays, the center of the first feed network layer is provided with a probe insertion structure, a feed probe is inserted into the first feed network layer, and the first feed networks and the feed probe are in non-contact coupling feed; the second feed network layer is composed of a second feed power division network, a second feed power division channel of the second feed network layer corresponds to the first feed network, the feed probe and the second feed power division channel are in non-contact coupling feed, and a radio frequency signal port is formed in the middle of the bottom face of the second feed power division network layer. On the basis of ensuring the antenna gain performance, the complexity of the feed network is reduced, the impedance matching design of the antenna is simplified, the standing-wave ratio of the antenna is optimized, and the working bandwidth of the antenna is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of microwave antennas, in particular to a high-gain, wide-band, high-cross-polarization-ratio ridge waveguide slot antenna array and device. BACKGROUND

[0002] A standing wave waveguide slot antenna achieves electromagnetic wave radiation by opening a series of slots on the waveguide wall and exciting the slots by using the standing wave formed by the superposition of incident and reflected waves in the waveguide, and has the characteristics of high gain, low sidelobe and compact structure, and is suitable for application in radar and communication systems. However, for a specific standing wave waveguide slot antenna, its physical structure is designed based on a specific center frequency, and only in the vicinity of the center frequency can all the slots be in a resonant state; when the frequency deviates, the change in the wavelength in the waveguide causes the designed slot spacing and terminal short-circuit position to mismatch the wavelength, destroying the resonance condition, and the impedance mismatch of the slots accumulates along the waveguide, causing the overall standing wave ratio (VSWR) of the antenna to rapidly increase, resulting in a narrow usable working bandwidth of the standing wave waveguide slot antenna, generally between 1% and 3%. Improving the working bandwidth of the standing wave waveguide slot antenna as much as possible is one of the main goals of the technical personnel.

[0003] In antenna design, a structure in which a large antenna array is formed by a plurality of smaller sub-arrays is often used. Independent feeding of the sub-arrays can reduce impedance mismatch accumulation, thereby improving the working bandwidth; and the grouping of multiple sub-arrays can achieve co-directional radiation, thereby improving the gain of the antenna.

[0004] However, as the number of sub-arrays increases, the feeding network structure becomes more complex and occupies more space resources, making it difficult to satisfy the layout of the feeding network and the impedance matching network in the space resources of the grouping, making the design of the impedance matching network difficult, affecting the implementation of the impedance matching, and further hindering the optimization of the working bandwidth. Especially in the case where the number of sub-arrays is large due to a clear limitation on the size of the antenna or a clear requirement for the gain of the antenna, the shortage of space resources makes it difficult to arrange the feeding network and the impedance matching network in space. In addition, in order to achieve a specific polarization direction of the antenna, for example, to achieve horizontal polarization and ensure high polarization purity, the position, direction and structure of the slots need to be designed accordingly, which further affects the design of the impedance matching of the feeding structure.

[0005] In summary, the performance requirements of antenna gain, working bandwidth, cross-polarization purity and other performance requirements jointly restrict the design of the antenna, and the performance indicators of the existing antenna design scheme have bottlenecks. SUMMARY

[0006] The application aims to overcome the deficiencies of the prior art, and provide a high-gain, wide-band, high-interdigital ratio ridge waveguide slot antenna array, which can reduce the complexity of the feed network, realize the feed network configuration of the antenna subarray in limited space, simplify the design of impedance matching of the antenna, optimize the standing wave ratio of the antenna, and improve the working bandwidth of the antenna.

[0007] In a first aspect, the application provides a high-gain, wide-band, high-interdigital ratio ridge waveguide slot antenna array, which adopts the following technical scheme: The antenna array comprises an antenna radiation array layer and a feed network layer. The antenna radiation array layer is composed of 2 n arrayed line array subarrays, each of which is composed of two parallel line array units, the bottom surface of the line array unit is provided with a feed coupling slot, and the top surface of the line array unit is provided with a radiation slot. The feed network layer comprises a first feed network layer and a second feed network layer. The first feed network layer is composed of a plurality of first feed networks arranged in an array, and each first feed network is located below a corresponding line array subarray and is coupled to the two line array units of the line array subarray through the feed coupling slot. The central part of the first feed network is provided with a probe insertion structure, and a feed probe is inserted into the probe insertion structure. The first feed network and the feed probe are non-contact coupled. The second feed network layer is composed of a second feed power division network, and the second feed power division network is provided with a second feed power division channel corresponding to each first feed network. The feed probe is inserted into the second feed power division channel and is non-contact coupled to the second feed power division channel to realize the signal connection between the first feed network layer and the second feed network layer. The bottom surface of the second feed power division network layer is provided with a radio frequency signal port.

[0008] Through the above technical scheme, a layered feed network structure is adopted, each subarray has two line array units sharing a first feed network, all the first feed networks are connected to the second feed power division network to realize a total and division type coupling feed network, which can improve the space utilization of the feed network, reduce the number of slots of a single line array unit, suppress the long line effect, and optimize the impedance matching; the first feed network and the line array unit are coupled through the feed coupling slot, and the first feed network and the second feed power division network for signal distribution are connected through the feed probe, which simplifies the structure of the feed network, enables the impedance matching to be designed independently between layers, simplifies the design and implementation of the impedance matching, thereby improving the working bandwidth performance of the antenna array and reducing the profile height of the antenna.

[0009] As a preferred, the linear array unit is a ridge waveguide antenna, the feed coupling slot is an H-shaped slot, the H-shaped slot is provided with symmetrically arranged a plurality of groups of radiation slots on both sides of the top surface projection of the linear array unit, each group of radiation slots is composed of two parallelogram slots symmetrically arranged about the center line of the length direction of the top surface of the linear array unit, forming a V-shaped radiation slot, and the opening direction of any two adjacent V-shaped radiation slots is opposite.

[0010] Through the above technical solution, the ridge waveguide antenna can obtain wider working bandwidth and better impedance matching performance; the H-shaped feed coupling slot can realize impedance matching and expand the working bandwidth through specific structural design of the H-shaped structure; the V-shaped radiation slot can optimize the polarization direction and ensure high polarization purity, and on this basis, the design difficulty of impedance matching of the feed network is reduced.

[0011] As a preferred, the bottom surface of the linear array unit is provided with one feed coupling slot on both sides, and the two feed coupling slots are symmetrically arranged about the center of the bottom surface.

[0012] Through the above technical solution, the feed coupling slots are arranged on both sides of the bottom surface of the linear array unit, and the feed is coupled from both sides, which can shorten the distance from the feed point to the radiation slot, suppress the long line effect, provide stronger coupling and more abundant tuning means, and thus realize better impedance matching performance, wider matching bandwidth and higher design flexibility.

[0013] As a preferred, the first feed network is a ridge waveguide feed network, the first feed network is provided with two linear array unit power division channels corresponding to the two linear array units symmetrically arranged, the linear array unit power division channel is provided with two feed coupling slot power division channels corresponding to the two feed coupling slots symmetrically arranged, the feed coupling slot power division channel is connected with a stepped ridge waveguide feed channel, and the width of the stepped ridge waveguide feed channel gradually narrows in a stepped manner, and the narrowest section is located below the feed coupling slot.

[0014] Through the above technical solution, the first feed network with a planar structure feeds two linear array units of one linear array unit through the linear array unit power division channel, which optimizes the spatial layout of the feed network; the two feed coupling slot power division channels correspond to the two feed coupling slots, realizing equal-amplitude and same-direction feeding of the two-side feed coupling slots; by adjusting the ridge waveguide feed channel with a width changing in a stepped manner, impedance matching can be realized, and the standing wave ratio can be reduced.

[0015] Preferably, the probe insertion structure includes a probe insertion through hole and a probe connector located on the top surface of the first power supply network layer and covering the probe insertion through hole. The probe connector has a probe mounting blind hole. The diameter of the probe insertion through hole is larger than the diameter of the probe mounting blind hole. The power supply probe is inserted into the probe mounting blind hole and extends downward through the probe insertion through hole into the second power supply power divider channel.

[0016] The above technical solution achieves non-contact fixation of the feed probe to the waveguide wall of the first feed network through the probe connector, and enables the feed probe to achieve non-contact coupling feed with the first feed network and the second feed power divider channel respectively. The coupling method is near-field radiation coupling, without physical contact and wear, which has high mechanical reliability. It can also avoid overheating and arc discharge at the contact point, improve power capacity, and is not affected by contact resistance. It can facilitate impedance matching optimization and improve the operating bandwidth.

[0017] Preferably, the power supply probe is an L-shaped probe, consisting of a vertical section and a horizontal section. The vertical and horizontal sections have circular cross-sections with the same diameter. The vertical section is inserted into the probe connector and extends downward through the probe insertion through-hole into the second power supply distribution channel. It then transitions to the horizontal section within the second power supply distribution channel. The impedance matching of the power supply probe is adjusted by adjusting the diameter of the cross-section, the depth of the vertical section extending into the second power supply distribution channel, and the length of the horizontal section.

[0018] The above technical solution achieves wave-to-wave conversion using an L-shaped probe. The length, height, diameter, coupling distance, and other parameters of the L-shaped probe can be adjusted independently. By optimizing the structural dimensions of the L-shaped probe, impedance matching can be flexibly achieved without adding an additional impedance matching network, which simplifies the antenna structure and impedance matching design, and ensures the operating bandwidth under the premise of limiting the space of the feed network.

[0019] Preferably, the end face of the horizontal section of the L-shaped probe is provided with a stepped impedance matching structure.

[0020] By using the above technical solution, a multi-section impedance transformer is formed through the stepped impedance matching structure at the end face, which can achieve a smooth transition of wave-to-wave conversion and maintain good impedance matching over a wider frequency range, thereby expanding the operating bandwidth.

[0021] Preferably, the second power distribution network is a waveguide power distribution network. Each second power distribution channel of the second power distribution network forms a multi-level power distribution network. Several adjacent second power distribution channels form a second power distribution channel group. Two adjacent second power distribution channels or two adjacent second power distribution channel groups of the same level are interconnected through a power distribution interface. Each power distribution interface is provided with a metal partition wall.

[0022] Through the technical solution, the multi-stage feeding power division network is constructed through the second feeding power division channel to realize the feeding distribution of each feeding point; the metal partition wall is arranged at each power division interface, and the amplitude distribution of each linear array unit of the antenna array can be optimized by adjusting the size of the metal partition wall to realize fine adjustment, thereby optimizing the gain, sidelobe and other radiation characteristics of the array pattern.

[0023] Preferably, a group of metal tuning probes are symmetrically arranged in the two branches of any one power division interface.

[0024] Through the technical solution, the capacitive reactance or inductive reactance is introduced by arranging the metal tuning probes to change the electric field vector transmitted in the waveguide and offset the reactance generated by the feeding network itself, thereby further optimizing the impedance matching.

[0025] In the second aspect, the radar antenna device provided by the application adopts the ridge waveguide slot antenna array.

[0026] In summary, the application has at least one of the following beneficial technical effects: 1. The application adopts a double-layer feeding network layer, the first feeding network corresponds to two linear array sub-arrays, all the first feeding networks are connected to the second feeding power division network layer to form a total and divided feeding network structure, which optimizes the spatial layout and improves the space utilization rate, and can meet the spatial arrangement requirements of the antenna array.

[0027] 2. The application simplifies the structure of the feeding network, reduces the complexity and design difficulty of realizing the impedance matching between the radiation layer and the feeding layer and between different feeding layers, and can flexibly realize the impedance matching by adjusting the structure, thereby expanding the working bandwidth of the antenna.

[0028] 3. The application can meet the requirements of antenna gain and polarization direction, and achieve the design requirements of antenna working bandwidth through structural adjustment and impedance matching design, thereby realizing the antenna design that meets the performance requirements of gain, working bandwidth, polarization direction and polarization purity. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 FIG. 1 is a structure schematic diagram of a high-gain, wide-band, high-cross-pole ratio ridge waveguide slot antenna array three-layer structure in an embodiment of the application; Figure 2 FIG. 2 is a top view of an antenna radiation linear array layer 1 of a high-gain, wide-band, high-cross-pole ratio ridge waveguide slot antenna array in an embodiment of the application; Figure 3 FIG. 3 is a schematic diagram of a ridge waveguide cross section of a linear array unit 11 in an embodiment of the application; Figure 4The bottom view of the linear array unit 11 in the embodiment of the present application is shown in the figure. Figure 5 The H-shaped feed coupling slot of the linear array unit 11 in the embodiment of the present application is shown in the figure. Figure 6 The top view of the linear array unit 11 in the embodiment of the present application is shown in the figure. Figure 7 The first feed network layer 2 of the ridge waveguide slot antenna array with high gain, wide frequency band and high cross-polarization ratio in the embodiment of the present application is shown in the figure. Figure 8 The structure of the first feed network 21 in the embodiment of the present application is shown in the figure. Figure 9 The structure of the first feed network 21 in the embodiment of the present application is shown in the figure. Figure 10 The side view of the first feed network 21 in the embodiment of the present application is shown in the figure. Figure 11 The structure of the L-shaped feed probe in the embodiment of the present application is shown in the figure. Figure 12 The structure of the L-shaped feed probe in the embodiment of the present application is shown in the figure. Figure 13 The second feed network layer 3 of the ridge waveguide slot antenna array with high gain, wide frequency band and high cross-polarization ratio in the embodiment of the present application is shown in the figure. Figure 14 The side view of the second feed network 31 in the embodiment of the present application is shown in the figure. Figure 15 The antenna standing wave ratio curve of the ridge waveguide slot antenna array with high gain, wide frequency band and high cross-polarization ratio in the embodiment of the present application is shown in the figure. Figure 16 The antenna normal gain curve of the ridge waveguide slot antenna array with high gain, wide frequency band and high cross-polarization ratio in the embodiment of the present application is shown in the figure. Figure 17 The antenna main polarization and cross-polarization pattern of the antenna in the low frequency range of the ridge waveguide slot antenna array with high gain, wide frequency band and high cross-polarization ratio in the embodiment of the present application is shown in the figure. Figure 18 The antenna main polarization and cross-polarization pattern of the antenna in the medium frequency range of the ridge waveguide slot antenna array with high gain, wide frequency band and high cross-polarization ratio in the embodiment of the present application is shown in the figure. Figure 19 The antenna main polarization and cross-polarization pattern of the antenna in the high frequency range of the ridge waveguide slot antenna array with high gain, wide frequency band and high cross-polarization ratio in the embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0030] The specific embodiments are merely explanatory of this application, and are not intended to limit this application, and those skilled in the art can make modifications to the embodiments without creative contribution after reading this specification, but as long as it is within the scope of this application, it is protected by the patent law.

[0031] To make the purpose, technical solutions and advantages of the embodiments of the application clearer, the technical solutions in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are some of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative contribution fall within the scope of protection of the application. It should be noted that in the optional embodiments of the application, the object information and other related data involved in the embodiments of the application when applied to specific products or technologies need to obtain the permission or consent of the object, and the collection, use and processing of the related data need to comply with the relevant laws, regulations and standards of the country and region. That is, if the embodiments of the application involve data related to the object, the data needs to be obtained with the authorization and consent of the object, the authorization and consent of the relevant department, and in compliance with the relevant laws, regulations and standards of the country and region. If the embodiments involve personal information, the consent of the individual needs to be obtained for the collection of all personal information, and the individual consent needs to be obtained for the collection of sensitive information, and the embodiments also need to be implemented with the authorization and consent of the object.

[0032] The embodiments of the application will be described in further detail below with reference to the drawings of the specification.

[0033] The embodiments of the application are used to realize the design requirements of an array antenna, wherein the antenna array size (length* width* height) is 370mm*370mm*25mm, the antenna operating frequency band is X frequency band, the operating bandwidth BW is greater than or equal to 12%, the antenna standing wave ratio VSWR in the operating frequency band is less than 1.7, and the antenna array gain G is greater than 30dBi.

[0034] Please refer to Figure 1 To realize the above performance index requirements, the embodiments of the application select to use a ridge waveguide slot antenna array, and the specific structure includes an antenna radiation line array layer 1 composed of a ridge waveguide slot antenna and a layered feed network layer, wherein the feed network layer is divided into a first feed network layer 2 and a second feed network layer 3.

[0035] Please refer to Figure 2In the embodiment of the present application, the antenna radiation line array layer 1 is composed of 2*16 (column*row) 32 line array units 11 arranged in an array. Among them, the line array units 11 on any column are grouped into a line array sub-array every two rows, and share a first feeding network located in the first feeding network layer 2. All the first feeding networks of the first feeding network layer 2 are connected to the second feeding power dividing network of the second feeding network layer 3, and the signal is input or output through the radio frequency signal port located in the center of the second feeding power dividing network.

[0036] Please refer to Figure 3 The line array unit 11 adopts a ridge waveguide form. The main mode cutoff frequency of the slot antenna in the form of ridge waveguide is significantly lower than that of the rectangular waveguide under the same cross-sectional size, so the ridge waveguide can avoid the inconvenience caused by the oversize of the rectangular waveguide; the ratio of the high-order mode cutoff frequency to the main mode cutoff frequency of the ridge waveguide is larger, so the working bandwidth is wider than that of the rectangular waveguide; in addition, the characteristic impedance of the ridge waveguide is relatively low, usually between 20Ω-100Ω, which is closer to the impedance of coaxial line, microstrip line and other commonly used transmission lines, which is conducive to impedance matching and further optimization of bandwidth performance. In the embodiment of the present application, the width of the outer wall of the wide side of the ridge waveguide D1=9.9mm, the width of the inner wall of the wide side D2=8.9mm, the height of the ridge H=6mm, and the ridge width D3=2.1mm.

[0037] Please refer to Figure 4 and Figure 5 The bottom surface of the line array unit 11 is symmetrically provided with an H-shaped feeding coupling slot 111 on both sides, which is used for coupling and feeding with the first feeding network. For the H-shaped feeding coupling slot 111, the two parallel edges and the middle connecting edge of the H-shaped structure can be adjusted in size, so as to flexibly adjust the impedance characteristics, better realize impedance matching, and improve the energy transmission efficiency; the coupling areas of the two parallel edges of the H-shaped structure can be coupled on both sides of the ridge of the ridge waveguide, the coupling area is larger, and the cooperative coupling can be formed through the connecting edge in the middle, which enhances the energy coupling strength between the feeding network and the line array unit, and at the same time, the coupling characteristics are less affected by the external environment and have higher stability; the multi-section structure of the H-shaped slot can produce multiple resonance points, and by optimizing the size of the H-shaped structure to make the resonance points close to each other, the working bandwidth of the antenna can be effectively expanded. In the embodiment of the present application, the length of the two parallel edges of the H-shaped feeding coupling slot 111 is Lh1=8.6mm, the width is Bh1=2.6mm, the length of the connecting edge is Lh2=2.8mm, and the width is Bh2=0.8mm.

[0038] Please refer to Figure 6, the H-shaped feed coupling slot 111 of the linear array unit 11 is provided with symmetrically arranged a plurality of groups of radiation slots on both sides of the top surface projection of the linear array unit 11, each group of radiation slots is composed of two parallelogram slots 112 which are symmetric about the center line of the length direction of the top surface of the linear array unit, forming a V-shaped radiation slot, and the opening directions of any two adjacent V-shaped radiation slots are opposite. In the embodiment of the present application, the included angle between the hypotenuse of the two parallelogram slots 112 and the axial direction of the linear array unit is 60° or 120°, the slot width is 2.6 mm, and the depth is 5 mm. The two parallelogram slots 112 at a certain angle can effectively cancel the cross-polarization component, and can make the main polarization and cross-polarization ratio of the antenna array in the normal direction ≥70 dB, with extremely high polarization purity. By changing the included angle of the V-shaped radiation slot, the radiation pattern can be adjusted in a wide range, especially suitable for specific directivity scenarios such as directional communication and radar detection. By adjusting the structural size and angle of the parallelogram slot, the resonance points can be made close and superimposed, thereby widening the working bandwidth of the antenna. The V-shaped radiation slot can also realize flexible design of linear polarization, elliptical polarization or even circular polarization by adjusting the length ratio and angle of the two parallelogram slots 112, and adapt to different polarization requirements of the communication scene. The V-shaped slot can realize multi-resonance characteristics in a limited space through angle design, without the need to increase the length of the additional slot, and is more compact than the combination structure of multiple independent conventional slots, which is beneficial to the miniaturization and array integration of the waveguide antenna.

[0039] It should be noted that, since the antenna of the embodiment of the present application can simplify the design scheme of the feed network structure and facilitate the realization of the array of a larger number of linear array units, the number of radiation slots on a single linear array unit can be reduced to meet the performance requirements of the antenna gain. In the embodiment of the present application, the top surface of the linear array unit 11 is provided with only 8 groups of V-shaped radiation slots, and each feed coupling slot corresponds to 4 groups of V-shaped radiation slots. Reducing the number of radiation slots on a single linear array unit 11 can avoid the problems of impedance mismatch and narrow bandwidth caused by the increase in the number of radiation slots, and can also avoid the problems of complex mutual coupling and pattern deterioration caused by too many radiation slots.

[0040] Based on the design of the antenna radiation linear array layer 1 of the embodiment of the present application, the feed network structure of the embodiment of the present application is described in detail.

[0041] Please refer to Figure 7 , the first feed network 21 of the first feed network layer 2 corresponds to one linear array unit 11 of the linear array subarray one by one, forms a 2*8 (column*row) array, adopts a ridge waveguide form, and has a height of 2.2 mm.

[0042] Compared with the technical solution of realizing power division coupling feeding of a linear array unit by one feeding network, the embodiment of the application realizes coupling feeding of two linear array units 11 of one linear array subarray by one first feeding network, which can greatly reduce the number of required first feeding networks and can fully utilize the spacing space when the same column adjacent two rows of linear array units 11 are arranged, thereby providing convenience for subsequent access of the first feeding network to the second feeding power division network and improving the space utilization.

[0043] Please refer to Figures 8 to 10 The first feeding network 21 is symmetrically provided with two linear array unit power division channels 211 corresponding to two linear array units, the linear array unit power division channel 211 is symmetrically provided with two feeding coupling gap power division channels 212 corresponding to two H-shaped feeding coupling gaps, the feeding coupling gap power division channel 212 is connected with a stepped ridge waveguide feeding channel 213, the width of the stepped ridge waveguide feeding channel 213 is gradually narrowed in a stepped manner, and the narrowest section is located below the H-shaped feeding coupling gap. By adjusting the structural size of the stepped ridge waveguide feeding channel in the form of a planar structure, impedance matching of the first feeding network and the linear array unit can be realized, and the standing wave ratio can be optimized, while the occupied space is small, and the antenna profile height can be reduced.

[0044] The central part of the first feeding network is provided with a probe insertion structure, including a probe insertion through hole 214 and a probe connector 215 located on the top surface of the first feeding network layer and covering the probe insertion through hole, the probe connector 215 is provided with a probe mounting blind hole, and the aperture of the probe insertion through hole 214 is larger than the aperture of the probe mounting blind hole. The L-shaped feeding probe 216 is inserted into the probe mounting blind hole through the connecting section, and the connection mode can adopt threaded connection or interference fit, and the L-shaped feeding probe 216 passes through the probe insertion through hole 214 downward into the range of the second feeding network layer.

[0045] It should be noted that although the probe insertion structure has a certain height, the projection of the probe insertion structure in the vertical direction is located in the mounting gap between the adjacent two linear array units 11 arranged side by side, so that the accommodation space for the probe insertion structure can be arranged in the antenna radiation linear array layer 1 without affecting the arrangement of the linear array unit 11. The above structure can fully utilize the space of the mounting gap and improve the space utilization.

[0046] Through the above structure, the L-shaped feeding probe 216 can be connected with the first feeding network layer and the second feeding network layer in a non-contact manner, realizing non-contact coupling feeding with the first feeding network and the second feeding power division network respectively. Non-contact feeding coupling does not require physical contact, reduces wear and tear, avoids contact resistance, facilitates impedance matching adjustment, is beneficial to expanding bandwidth, and does not require an additional impedance matching network, simplifies the antenna structure, and saves space.

[0047] More specifically, the L-shaped feeding probe 216 is composed of a vertical section and a horizontal section, the cross sections of which are circular with the same diameter, the vertical section is inserted into the probe connecting piece 215 and extends downward through the probe insertion hole 214 into the second feeding network layer, and the horizontal section transitions to the second feeding network layer. The L-shaped feeding probe 216 is adjusted in impedance matching by adjusting the diameter of the cross section, the depth of the vertical section into the second feeding network layer, and the length of the horizontal section, so as to optimize the standing wave ratio. In the embodiment of the present application, the diameter of the L-shaped feeding probe 216 is 2 mm, and the depth of the probe into the second feeding network layer is 8 mm. The L-shaped feeding probe is adapted to the multi-layer structure of the embodiment of the present application, can be flexibly adapted to different interlayer distances, realizes energy transmission through non-contact coupling, effectively avoids the interlayer connection problem caused by direct feeding, and enhances the degree of freedom of structural design.

[0048] In another embodiment, referring to Figure 11 and Figure 12 , the end surface of the horizontal section of the L-shaped feeding probe 216 is provided with a stepped impedance matching structure. The stepped impedance matching structure forms a multi-section impedance transformer, can realize smooth transition of wave conversion, can maintain good impedance matching in a wider frequency range, and thus expands the working bandwidth.

[0049] Referring to Figure 13 and Figure 14 , the second feeding network layer 3 is composed of a second feeding power division network 31, which adopts a waveguide form and has a height of 11 mm. The second feeding power division network 31 is provided with a second feeding power division channel 311 corresponding to any one of the first feeding networks, the L-shaped feeding probe 216 extends into the second feeding power division channel 311 and is non-contact coupled with the second feeding power division channel 311 to realize the connection of the feeding signals between the first feeding network layer and the second feeding network layer. The distances from each second feeding power division channel 311 to the radio frequency signal port 312 arranged in the middle of the bottom surface of the second feeding power division network layer are equal, so that the signals transmitted by each second feeding power division channel 311 have the same phase.

[0050] More specifically, the 16 second feeding power division channels 311 of the second feeding power division network 31 in the embodiment of the present application form a three-stage feeding power division network. Two adjacent second feeding power division channels 311 form a first-stage second feeding power division channel group, which is connected through a first-stage power division interface; two adjacent first-stage second feeding power division channel groups form a second-stage second feeding power division channel group, which is connected through a second-stage power division interface; two second-stage second feeding power division channel groups form a third-stage second feeding power division channel group, which is connected through a third-stage power division interface; two third-stage power division interfaces are connected to each other, and the central part of the power division channel formed thereby is provided with a radio frequency signal port 312.

[0051] A metal partition wall 313 is arranged at each power division interface, which makes the power division channel at the power division interface concave and narrow. By setting the length, width and specific position of the metal partition wall, the amplitude distribution of each linear array unit of the antenna array can be optimized, so that the gain, sidelobe and other radiation characteristics of the array pattern are optimized.

[0052] Further, a group of metal tuning probes 314 is symmetrically arranged in the two branches of each power division interface. The metal tuning probes 314 can further reduce the standing wave and improve the bandwidth by introducing capacitive reactance or inductive reactance, increasing disturbance, changing the electric field vector transmitted in the waveguide, and offsetting the reactance generated by the network itself to make the total impedance close to the matching state.

[0053] The specific processing and production method of the high-gain, wide-band and high-interdecile ratio ridge waveguide slot antenna array of the embodiment of the present application is as follows: The antenna array is divided into three layers, the first layer is an antenna radiation linear array layer 1, the second layer is a first feed network layer 2, and the third layer is a second feed network layer 3.

[0054] The above three layers are respectively machined on a high-precision numerical control machining center using a metal aluminum plate. At the same time, in order to ensure the accuracy of the welding assembly after machining of each layer, high-precision positioning pins are added to each layer.

[0055] The above-mentioned machined antenna radiation linear array layer, first feed network layer and second feed network layer are cleaned and assembled using the positioning pins.

[0056] The above-mentioned assembled semi-finished antenna is integrally welded into one body using a vacuum furnace brazing process to form a ridge waveguide slot antenna array. Vacuum aluminum brazing is a high-precision connection process for brazing aluminum alloy in a vacuum environment, which is suitable for aluminum and aluminum alloy parts that require high strength, high airtightness and good surface quality, and has the advantages of high connection quality, excellent surface quality, strong adaptability and good precision control.

[0057] Finally, the above-mentioned ridge waveguide slot antenna array is surface conductive oxidized or surface plated with silver or gold to ensure the stability of the electrical and structural performance of the antenna and complete the assembly of the ridge waveguide slot antenna array.

[0058] Please refer to Figures 15-19 The performance of the high-gain, wide-band and high-interdecile ratio ridge waveguide slot antenna array of the embodiment of the present application is described.

[0059] Figure 15 For the antenna standing wave ratio curves under different radio frequency reference frequencies, it can be seen that the VSWR of the antenna array surface of the embodiment of the present application is less than 1.7 in the frequency range of 9.2GHZ to 10.4GHZ, and the relative bandwidth BW is greater than or equal to 12.24%.

[0060] Figure 16 For the antenna normal gain curves at different radio frequency reference frequencies, it can be seen that the antenna array surface of the embodiment of the present application has an antenna normal gain G>31dBi in different frequency ranges.

[0061] Figure 17 Figure 19 For the antenna directional patterns of the antenna array surface of the embodiment of the present application at different frequencies, it can be seen that the antenna can achieve a high cross-pole ratio in different frequency bands.

[0062] In another embodiment, the present application provides a radar antenna device which adopts the ridge waveguide slot antenna array in the above-mentioned embodiment. It should be noted that in the implementation of the specific radar antenna device, the number of linear array units and the array arrangement mode can be expanded according to the space conditions and performance requirements of the antenna device.

[0063] Unless otherwise defined, technical or scientific terms used in the present application should be understood as having the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The use of "first", "second", "third" and similar words in the specification and claims of the present application does not indicate any order, number or importance, but is only used to distinguish different components. "One" or "a" and similar words do not indicate a quantity limitation, but indicate the existence of at least one. "Include" or "contain" and similar words mean that the elements or objects appearing before "include" or "contain" cover the elements or objects listed after "include" or "contain" and their equivalents, and do not exclude other elements or objects. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships, and when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0064] The above embodiments are only used to illustrate the technical solutions of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.​

Claims

1. A high-gain, wide-band, high-cross-polarization ridge waveguide slot antenna array, comprising an antenna array layer and a feed network layer, characterized in that: The antenna radiation line array layer is composed of 2 n arrayed line array subarrays, each of which is composed of two parallel line array units, the bottom surface of the line array unit is provided with a feed coupling gap, and the top surface of the line array unit is provided with a radiation gap. the feed network layer comprises a first feed network layer and a second feed network layer; the first feed network layer is composed of a plurality of first feed networks arranged in an array, each first feed network is located below and corresponds to one of the array of linear array elements, and each first feed network is coupled to two linear array elements through the feed coupling slots; the central part of each first feed network is provided with a probe insertion structure, and a feed probe is inserted into the probe insertion structure; the first feed network and the feed probe are non-contact coupled; the second feed network layer is composed of a second feed power division network, and each first feed network is provided with a second feed power division channel in the second feed power division network; the feed probe is inserted into the second feed power division channel and is non-contact coupled to the second feed power division channel, thereby realizing the connection of the feed signals between the first feed network layer and the second feed network layer; the bottom surface of the second feed power division network layer is provided with a radio frequency signal port.

2. The high-gain, wide-band, high-cross-polarization-ratio slotted ridge waveguide antenna array of claim 1, wherein, each linear array element is a ridge waveguide antenna, and each feed coupling slot is an H-shaped slot; each H-shaped slot is provided with a plurality of groups of radiation slots on both sides of the projection of the top surface of the linear array element; each group of radiation slots is composed of two parallelogram slots which are symmetric about the center line of the length direction of the top surface of the linear array element, forming a V-shaped radiation slot; the opening directions of any two adjacent V-shaped radiation slots are opposite.

3. The high-gain, wide-band, high-cross-polarization-ratio slotted ridge waveguide antenna array of claim 1, wherein, each linear array element is provided with one feed coupling slot on each side of the bottom surface, and the two feed coupling slots are symmetric about the center of the bottom surface.

4. The high-gain, wide-band, high-crosspolarization-ratio slotted ridge waveguide antenna array of claim 3, wherein, each first feed network is a ridge waveguide feed network; each first feed network is provided with two linear array element power division channels which are symmetric about the two linear array elements; each linear array element power division channel is provided with two feed coupling slot power division channels which are symmetric about the two feed coupling slots; each feed coupling slot power division channel is connected to a stepped ridge waveguide feed channel; the width of the stepped ridge waveguide feed channel gradually narrows in a stepped manner, and the narrowest section is located below the feed coupling slot.

5. The high-gain, wide-band, high-cross-polarization-ratio slotted ridge waveguide antenna array of claim 1, wherein, the probe insertion structure comprises a probe insertion through-hole and a probe connector located on the top surface of the first feed network layer and covering the probe insertion through-hole; the probe connector is provided with a probe mounting blind hole; the diameter of the probe insertion through-hole is larger than the diameter of the probe mounting blind hole; the feed probe is inserted and fixed in the probe mounting blind hole and extends downward through the probe insertion through-hole into the second feed power division channel.

6. The high-gain, wide-band, high-crosspolarization-ratio slotted ridge waveguide antenna array of claim 5, wherein, the feed probe is an L-shaped probe composed of a vertical section and a horizontal section; the cross sections of the vertical section and the horizontal section are circular with the same diameter; the vertical section is inserted into the probe connector and extends downward through the probe insertion through-hole into the second feed power division channel; the feed probe is impedance matched by adjusting the diameter of the cross section, the depth of the vertical section inserted into the second feed power division channel, and the length of the horizontal section.

7. The high-gain, wide-band, high-cross-polarization-ratio slotted ridge waveguide antenna array of claim 6, wherein, the end surface of the horizontal section of the L-shaped probe is provided with a stepped impedance matching structure.

8. The high-gain, wide-band, high-cross-polarization-ratio slotted ridge waveguide antenna array of claim 1, wherein, The second feeding power division network is a waveguide power division network, each second feeding power division channel of the second feeding power division network forms a multi-stage feeding power division network, a plurality of adjacent second feeding power division channels form a second feeding power division channel group, and adjacent two second feeding power division channels or adjacent two second feeding power division channel groups at the same stage are connected to each other through a power division interface, and each power division interface is provided with a metal partition wall.

9. The high-gain, wide-band, high-cross-polarization-ratio slotted ridge waveguide antenna array of claim 8, wherein, A set of metal tuning probes is symmetrically arranged in two branches of any one power division interface.

10. A radar antenna device, characterized by The ridge waveguide slot antenna array according to any one of claims 1-9.

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