CN111684657A

CN111684657A - Backfeed traveling wave antenna array, radar and movable platform

Info

Publication number: CN111684657A
Application number: CN201980007788.XA
Authority: CN
Inventors: 唐哲; 汤一君; 蔡铭
Original assignee: SZ DJI Technology Co Ltd
Current assignee: Shenzhen Zhuoyu Technology Co ltd
Priority date: 2019-06-28
Filing date: 2019-06-28
Publication date: 2020-09-18
Anticipated expiration: 2039-06-28
Also published as: CN111684657B; WO2020258214A1

Abstract

The application provides a back-fed traveling wave antenna array, radar and movable platform, should back-fed traveling wave antenna array include: the surface of the first dielectric substrate is provided with a feed unit; the first grounding layer is provided with a first gap; an intermediate dielectric substrate; the second grounding layer is provided with a second gap; a second dielectric substrate, wherein a radiation unit is arranged on one side of the second dielectric substrate, which is back to the second grounding layer; the first dielectric substrate, the first ground layer, the intermediate dielectric substrate, the second ground layer and the second dielectric substrate are arranged in a surrounding manner, and the first gap and the second gap are surrounded by the first metal via holes; wherein the first slot and the second slot are used for coupling the energy of the feed unit to the middle part of the radiation unit. The back feed type traveling wave antenna array has wider working bandwidth, and meets the requirements of good gain flatness and stable beam pointing in the broadband.

Description

Backfeed traveling wave antenna array, radar and movable platform

Technical Field

The application relates to the technical field of antennas, in particular to a back feed type traveling wave antenna array, a radar and a movable platform.

Background

The vehicle-mounted millimeter wave radar transmits millimeter waves outwards through the antenna, receives a target reflection signal, and quickly and accurately acquires physical environment information (such as relative distance, relative speed, angle, movement direction and the like between an automobile and other objects) around the automobile body after data processing. Compared with a narrow-band low-frequency-band radar, the broadband millimeter-wave radar can greatly improve the range resolution and is suitable for application scenes with high range resolution. The antenna is an important component of the radar front end and needs to have broadband operation capability.

Disclosure of Invention

In order to solve the above technical problem, embodiments of the present application provide a back-fed traveling-wave antenna array, a radar, and a movable platform, and provide a traveling-wave antenna, which can have a wider bandwidth.

In a first aspect, an embodiment of the present application provides a back-fed traveling-wave antenna array, including: the surface of the first dielectric substrate is provided with a feed unit; the first grounding layer is arranged on the surface, back to the power feeding unit, of the first dielectric substrate and provided with a first gap; the intermediate medium substrate is arranged on the surface of the first grounding layer, which is opposite to the first medium substrate; the second grounding layer is arranged on the surface of the intermediate medium substrate, which is opposite to the first grounding layer, and a second gap is formed in the second grounding layer; the second dielectric substrate is arranged on the surface, back to the intermediate dielectric substrate, of the second grounding layer, and a radiating unit is arranged on one side, back to the second grounding layer, of the second dielectric substrate; a plurality of first metal vias, the plurality of first metal vias penetrating through the first dielectric substrate, the first ground layer, the intermediate dielectric substrate, the second ground layer and the second dielectric substrate, and the plurality of first metal vias enclosing around the first slot and the second slot; wherein the first slot and the second slot are used for coupling the energy of the feed unit to the middle part of the radiation unit.

In a second aspect, embodiments of the present application provide a radar including a power supply and the array of backfeed traveling wave antennas in various embodiments of the first aspect, wherein the power supply is configured to supply power to the array of backfeed traveling wave antennas.

In a third aspect, an embodiment of the present application provides a movable platform, which includes a body and the radar provided in the second aspect, where the radar is disposed on the movable platform.

According to the back-fed traveling wave antenna array provided by the first aspect of the application, by adopting a traveling wave antenna form, assisting with a slot coupling and a feed structure fed from the middle of a radiation unit, and combining with a plurality of first metal via holes which can be equivalently used as a waveguide structure, the antenna array can have a wider working bandwidth, and the requirements of good gain flatness and stable beam pointing can be met in a broadband.

Drawings

Fig. 1 is a schematic diagram of an explosion structure of a back-fed traveling-wave antenna array according to an embodiment;

fig. 2 is a schematic plan view of the radiating element and the second dielectric substrate of fig. 1;

fig. 3 is a schematic plan view of the second ground layer of fig. 1;

FIG. 4 is a schematic plan view of the intermediate dielectric substrate of FIG. 1;

fig. 5 is a schematic plan view of the feeding unit and the first dielectric substrate of fig. 1;

fig. 6 is a schematic perspective view of the feeding unit of fig. 1;

FIG. 7 is a schematic plan view of the first dielectric substrate of FIG. 1;

fig. 8 is a schematic plan view of the first ground layer of fig. 1;

FIG. 9 is a schematic diagram of the structure of a patch of an embodiment;

fig. 10 is a partial structural schematic diagram of a second ground plane according to an embodiment;

fig. 11 is a schematic cross-sectional view of a backfeed traveling-wave antenna array according to an embodiment;

FIG. 12 is a graph of a simulation of return loss for an embodiment of a back-fed traveling wave antenna array;

figure 13 is a elevation pattern of an embodiment of a backfeed traveling wave antenna array;

figure 14 is an azimuth plane pattern of a backfeed traveling wave antenna array of an embodiment.

Detailed Description

The technical solutions in the embodiments of the present application will be described below clearly with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When a component is referred to as being "connected" to another component, it can be directly connected to the other component or intervening components may also be present.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. Some embodiments of the present application will be described in detail below with reference to the accompanying drawings. The embodiments described below and the features of the embodiments can be combined with each other without conflict.

The planning of each country applies a 77-81 GHz frequency band with 79GHz as a center frequency to a vehicle-mounted millimeter wave broadband radar. Compared with a 76-77 GHz narrow-band frequency band, the 77-81 GHz broadband radar can greatly improve range resolution, is suitable for application scenes with high range resolution (0.15-0.3 m) in short-distance detection, and an antenna serving as an important component of a radar front end needs to have broadband working capacity, including impedance matching in a broadband range, side lobe suppression, beam pointing and gain flatness.

1) Impedance matching: the antenna can be divided into a traveling wave antenna and a standing wave antenna, the existing antenna mainly adopts the standing wave antenna, the impedance characteristic of the existing antenna is changed along with the frequency, and the problem of narrow impedance bandwidth (the relative bandwidth is about 3 percent) exists;

2) side lobe suppression bandwidth: in the prior art, the side lobe suppression in a narrow-band range is better than 20dB, but the realization of the side lobe suppression in a wide band is a difficult point of designing a wide-band radar antenna;

3) beam pointing: the beam direction refers to the direction position of the point with the maximum gain in the antenna directional diagram, the beam direction of the antenna array is determined by the phase of each radiation unit, and the existing one-end side feed mode can only ensure that the beam direction is stabilized at a normal point in a narrow band;

4) gain flatness: in the prior art, the gain flatness of the antenna in the broadband is about 4-5 dB, and the value is too large, so that the radar detection distance is insufficient.

To solve at least one of the above problems, embodiments of the present application provide a back-fed traveling-wave antenna array. Referring to fig. 1, an embodiment of the present invention provides a back-fed traveling-wave antenna array, which has a stacked structure, and sequentially includes, from top to bottom: the radiating element 10, the second dielectric substrate 20, the second ground layer 21, the intermediate dielectric substrate 30, the first ground layer 41, the first dielectric substrate 40, and the power feeding unit 50 are provided with a plurality of first metal vias 60 penetrating the first dielectric substrate 40, the first ground layer 41, the intermediate dielectric substrate 30, the second ground layer 21, and the second dielectric substrate 20. The feeding unit 50 is disposed on the surface of the first dielectric substrate 40, and specifically, the feeding unit 50 may be adhered to the surface of the first dielectric substrate 40, or disposed on the surface of the first dielectric substrate 40 by etching. The first ground layer 41 is provided with a first slot 411. The second ground layer 21 is provided with a second slot 211. A plurality of first metal vias 60 surround the first slot 411 and the second slot 211. Wherein the first slot 411 and the second slot 211 are used to couple the energy of the feeding unit 50 to the middle of the radiating unit 10.

In the back-fed traveling-wave antenna array in this embodiment, a traveling-wave antenna is adopted, a slot coupling and a feeding structure feeding from the middle of the radiation unit 10 are used, and a plurality of first metal via holes 60 equivalent to a waveguide structure are combined, so that the antenna array has a wider operating bandwidth, and the requirements of good gain flatness and stable beam pointing are met in a broadband.

The energy of the feed unit 50 is propagated to the first slot 411 in a slot coupling manner, the plurality of first metal via holes 60 surround the first slot 411 and the second slot 211 to form an equivalent waveguide structure, so that the energy coupled to the first slot 411 is propagated to the second slot 211 through the equivalent waveguide structure, the second slot 211 propagates the energy to the middle of the radiation unit 10 in a coupling manner, and the energy is radiated to the space in an electromagnetic wave manner through the radiation unit 10.

The plurality of first metal via holes 60 are arranged to form an equivalent waveguide structure, so that attenuation is low when energy is transmitted in the equivalent waveguide structure, and the efficiency of the antenna can be ensured. When the energy is transmitted on the radiation unit 10, the energy is radiated from the middle of the radiation unit 10 to the two ends step by step, so that the effect of stable beam pointing is realized.

The first slot 411 has the same shape and structure as the second slot 211, so that energy is less attenuated during the energy coupling to the radiation unit 10 through the first slot 411 and the second slot 211.

The first slit 411 or the second slit 211 may be rectangular, H-shaped, dumbbell-shaped, bow-tie-shaped, or hourglass-shaped.

Specifically, in an embodiment, referring to fig. 3, 8 and 10, the first slot 411 or the second slot 211 is H-shaped. Referring to fig. 10, taking the second slot 211 as an example, the first slot 411 may be referred to. The H-shaped slit of the second slit 211 has a central slit width W1 of 0.055 lambda_g-0.075λ_gThe end slit width W2 is 0.14 lambda_g-0.24λ_gThe length L1 of the middle slot is 0.24 lambda_g-0.44λ_gThe length L2 of the end slot is 0.055 lambda_g-0.098λ_g. Wherein λ is_gIs the equivalent medium wavelength at the central frequency point. The reasonable size is set so that the coupling efficiency of the energy of the feeding unit 50 in the H-shaped slot of the second slot 211 or the coupling efficiency of the energy of the H-shaped slot of the first slot 411 to the radiating unit 10 is high.

Further, referring to fig. 1, the first gap 411 corresponds to the second gap 211. Specifically, orthographic projections of the first slit 411 and the second slit 211 are overlapped on the plate surface of the first dielectric substrate 40. Furthermore, the extending direction of the plurality of first metal vias 60 is perpendicular to the plate surface of the first dielectric substrate 40, and the cross-sectional shape of the equivalent waveguide structure formed by the plurality of first metal vias 60 in the direction perpendicular to the plate surface of the first dielectric substrate 40 is rectangular. By arranging a plurality of metal vias 60, which can be equivalent to a waveguide structure, around the first slot 411 and the second slot 211, the loss of energy in a medium can be effectively reduced.

In this embodiment, when the plurality of first metal vias 60 are provided, the cross-sectional shape of the equivalent waveguide structure formed by the space surrounded by the plurality of first metal vias 60 may be the same as the first slot 411 or the second slot 211 in the direction parallel to the plate surface of the first dielectric substrate 40. For example, the cross-sectional shape may be any one of a rectangle, an H-shape, a dumbbell shape, a bow tie shape, and an hourglass shape. Further, each of the first metal vias 60 and the first slot 411 or the second slot 211 may be disposed at equal intervals.

In other embodiments, the cross-sectional shape of the equivalent waveguide structure formed by the spaces surrounded by the plurality of first metal vias 60 in the direction parallel to the plate surface of the first dielectric substrate 40 may be different from the first slot 411 or the second slot 211, and may be any one of a rectangle, a circle, a parallelogram, a trapezoid, and the like, for example. In this embodiment, the distances between each first metal via 60 and the first slot 411 or the second slot 211 may not be all the same or all the same.

Referring to fig. 1 to 8, the plurality of first metal vias 60 are formed by forming corresponding through holes on each of the dielectric substrate and the ground layer, and filling a metal material in the through holes. Specifically, referring to fig. 3, a plurality of through holes 212 are formed on the second ground layer 21. Referring to fig. 4, a plurality of through holes 301 are formed on the intermediate dielectric substrate 30. Referring to fig. 7, a plurality of through holes 401 are formed on the first dielectric substrate 40. Referring to fig. 8, a plurality of through holes 412 are formed on the first ground layer 41. Referring to fig. 1 and 2, a plurality of through holes are also formed on the first dielectric substrate 40. The through holes of the layers correspond in position and are identical in shape. After the layers are stacked to form a whole, a layer of metal is plated on the inner walls of the through holes of each layer, or the through holes of each layer are filled with metal, so as to form the first metal via holes 60. The metal material of the first metal via 60 may be copper, aluminum, silver, or the like.

The first ground layer 41 and the second ground layer 21 are made of metal, such as copper foil, aluminum foil, silver foil, and the like. The first dielectric substrate 40, the intermediate dielectric substrate 30 and the second dielectric substrate 20 are laminated plates, for example, the first dielectric substrate 40 and the second dielectric substrate 20 are made of high-frequency low-loss materials (such as Rogers Ro4835 and Rogers Ro 3003); the material of the intermediate dielectric substrate 30 is FR 4.

The material of each layer is selected according to the application, and the first dielectric substrate 40 is used as a bearing base of the power feeding unit 50, on one hand, to provide sufficient support for the power feeding unit 50, and on the other hand, to isolate the power feeding unit 50 from the first ground layer 41, so that the first slot 411 can be coupled with the power feeding unit 50, and therefore, the first dielectric substrate is made of a high-frequency low-loss material, energy loss is reduced, and coupling efficiency can be improved. The second dielectric substrate 20 is similar to the first dielectric substrate 40, and is also made of a high-frequency low-loss material. The intermediate dielectric substrate can be used for radar wiring, due to the introduction of the intermediate dielectric substrate, the longitudinal distance between the first gap and the second gap is increased, an equivalent waveguide structure is formed by the part enclosed by the plurality of first metal via holes 60, the energy coupled by the first gap 411 can be transmitted to the second gap 211 more intensively, and the intermediate dielectric substrate can be made of a common FR4 material in consideration of cost.

In one embodiment, referring to fig. 1, the number of the intermediate dielectric substrates 30 is plural. Specifically, the number of the intermediate dielectric substrates 30 may be set to 5, that is, the intermediate

dielectric substrates

31, 32, 33, 34, 35. The number of the intermediate dielectric substrates 30 is related to the amplitude-phase characteristics of the energy, and the amplitude-phase characteristics need to be kept as constant as possible when the energy coupled to the first slot 411 by the power feeding unit 50 propagates to the second slot 211. In other embodiments, the number of the intermediate dielectric substrates 30 is not limited to 5, and the number of the intermediate dielectric substrates 30 may be 1, 2, 3, 4, 5, 6, … … N layers, where N is a positive integer. In addition, the thickness of each layer of the intermediate dielectric substrate is not limited.

In an embodiment, referring to fig. 1 and fig. 2, the radiating unit 10 includes a plurality of patches 11 and a plurality of microstrip lines 12 connecting the plurality of patches 11. The first slot 411 and the second slot 211 are used for coupling the energy of the feeding unit 50 to the first microstrip line 121 in the middle of the radiating unit 10, where the first microstrip line 121 is one of the plurality of microstrip lines 12.

The radiation unit 10 is a microstrip patch series feed structure, energy transmitted by the second slot 211 is coupled to the first microstrip line 121, and the energy flows to two ends of the radiation unit 10, generates radiation on the patch 11, and flows on the microstrip line 12. In an orthographic projection of the first dielectric substrate 40 on the plate surface, the second slot 211 intersects with the first microstrip line 121 at an angle of 90 °, in other words, the extension direction of the microstrip line 12 (including the first microstrip line 121) is perpendicular to the length direction of the second slot 211. It can be understood that, in an actual product, due to manufacturing tolerances and the like, the angle between the length direction of the second slot 211 and the microstrip line 12 (including the first microstrip line 121) is allowed to slightly float, for example, when the angle is 85 ° to 95 °, the length direction of the second slot 211 can also be considered to be perpendicular to the first microstrip line 121. The angle is set so that the second slot 211 can couple with the first microstrip line 121 to propagate energy. The radiation unit 10 adopts a microstrip patch structure form, and radiates from the first microstrip line 121 in the middle to the two ends step by step, so that the beam pointing is ensured to be stabilized at a normal point in a broadband range, and the stability is good.

Further, the radiating element 10 is symmetrical with respect to the first microstrip line 121. The symmetrical radiation units 10 enable energy to be radiated on the patches 11 on the two sides of the first microstrip line 121 in the same form, the obtained antenna directional diagram is in a symmetrical structure, and the wave beam stably points to a normal point in a broadband range.

In one embodiment, referring to fig. 2, the patches 11 are formed with a first groove 111. The first recess 111 is preferably open in the middle of one end of the patch 111. The first groove 111 is formed to adjust impedance, so that energy distribution on each patch 11 is adjusted, and side lobes can be effectively suppressed while the radiation requirement of electromagnetic waves in a preset frequency band is met. One end of the microstrip line 12 connecting the two adjacent patches 11 is connected to the bottom wall of the first groove 111, and the other end is connected to an end portion of the adjacent patch 11 facing away from the first groove 111.

Further, with continued reference to fig. 2, the first grooves 111 'of the patches 11' at the end portions of the radiating unit 10 face the middle portion of the radiating unit 10, and the first grooves 111 of the other patches 11 face away from the middle portion of the radiating unit 10. The first groove 111 'of the patch 11' at the end portion is used for adjusting impedance matching, and the radiation characteristic of the traveling wave antenna is realized.

In one embodiment, referring to fig. 2 and 9, the patch 11 is rectangular, and the length LP of the patch 11 is 0.5 λ in the extending direction of the microstrip line 12_gThe depth of the first groove 111 is 0.06 lambda_g. In an extension perpendicular to microstrip line 12In the direction of width WP of patch 11 is 2.3 λ_g-3.4λ_gThe width WS from the sidewall of the first groove 111 to the sidewall of the microstrip line 12 opposite thereto is 0.24 λ_g，λ_gIs the equivalent medium wavelength at the central frequency point. Set up reasonable paster 11's size for when the energy radiated on paster 11, resonant frequency and the bandwidth of production are in predetermineeing the within range, and, the energy distributes rationally on paster 11, can realize the characteristics of low side lobe.

In one embodiment, referring to fig. 2, the plurality of patches 11 are identical in structure, or the plurality of patches 11 are gradually changed in structure. The radiating elements 11 are easy to process when the plurality of patches 11 are identical in structure. When the patches 11 are of a gradual change structure, the energy distribution on each patch 11 is better, and the side lobe is lower. In the process of radiating the energy from the first microstrip line 121 in the middle of the radiating unit 10 to the two ends, the energy is attenuated step by step, and the energy is weaker when the energy is transmitted to the two ends, so that the energy distribution of each patch can be more reasonable by arranging the gradual change structure. Specifically, the plurality of patches 11 arranged from the middle of the radiation unit 10 to both ends are gradually increased in structure.

In an embodiment, referring to fig. 2, an impedance matching structure (not shown) is disposed on the microstrip line 12, and the impedance matching structure is in a polygonal shape. The impedance matching structure is used to adjust impedance matching so that the energy radiated by the radiation unit 10 satisfies a preset bandwidth. The impedance matching structure is sheet-like with an overall extension plane parallel to the plane of the patch 11. In the orthographic projection of the first dielectric substrate 10, the shape of the impedance matching structure may be a triangle, a quadrangle, a pentagon, a hexagon, or the like.

Referring to fig. 1 and 2, the radiating element 10 includes a second metal plate 14, and the second metal plate 14 is connected to the first metal via 60. Around the first microstrip line 121 in the middle of the radiating element 10, a second metal plate 14 is disposed for fixing a plurality of first metal vias 60. The second metal sheet 14 is provided with a gap 141 and a through hole 142, and the gap 141 corresponds to the first gap 411 in position and is used for exposing the coupling space of the first gap 411 to avoid shielding. The inner walls of the through holes 142 are connected to the plurality of first metal vias 60.

In an embodiment, referring to fig. 1, fig. 5 and fig. 6, the feeding unit 50 includes a microstrip line 52, and in an orthogonal projection of the board surface of the first dielectric substrate 40, the microstrip line 52 intersects the first slot 411 at an angle of 90 °, in other words, an extending direction of the microstrip line 52 is perpendicular to a length direction of the first slot 411. The feeding unit 50 couples energy to the first slot 411 in the same manner as the second slot 211 couples energy to the first microstrip line 121 of the radiating unit 10, which is a slot coupling manner.

Referring to fig. 1 and 6, the microstrip line 52 may be in a long strip shape, and a wider width may be set at a front position where energy flows, so as to perform impedance matching. The front end of the energy flow of the microstrip line 52 is used for connecting with a feeder line and receiving the energy of the radio frequency chip, and the energy flows in the microstrip line 52 and is coupled to the second slot 211 at the tail end of the energy flow.

Referring to fig. 1, 5 and 6, the feeding unit 50 further includes a first metal plate 51, the first metal plate 51 is provided with a second groove 511, and the microstrip line 52 extends into the second groove 511 and has a gap with an inner wall of the second groove 511. The second groove 511 is arranged to surround the microstrip line 52, so as to prevent the energy of the microstrip line 52 from radiating to both sides, and reduce the energy loss, so that the more energy is coupled to the second slot 211.

In other embodiments, the structure for coupling energy to the second slot 211 is not limited to a microstrip line structure, and a coplanar waveguide form (GCPW), a substrate integrated waveguide form (SIW), and the like may also be adopted.

Further, referring to fig. 1, fig. 5 and fig. 6, the first dielectric substrate 40 is provided with a plurality of second metal vias 53, the plurality of second metal vias 53 are disposed on a side edge of the first metal sheet 51 facing away from the opening direction of the second groove 511, and the second metal vias 53 are connected between the first metal sheet 51 and the first ground layer 41. In fig. 5, a through hole 513 is formed in the first metal sheet 51, the second metal via 53 is connected to a sidewall of the through hole 513, and the second metal via 53 forms a blocking and shielding structure, so that energy of the microstrip line 52 is reduced to be transmitted along an extending direction thereof, and the energy is coupled to the first slot 411 as much as possible.

The first metal sheet 51 is further provided with a plurality of through holes 512, and the sidewalls of the through holes 512 are connected to the first metal vias 60, so as to fix the first metal vias 60 together with the second metal sheet 14.

Referring to fig. 1 and 11, arrows in fig. 11 indicate propagation directions of energy, the energy is coupled from the feeding unit 50 to the first slot 411 of the first ground layer 41, in an equivalent waveguide structure formed by a space surrounded by the plurality of first metal vias 60, the energy coupled by the first slot 411 propagates to the second slot 211 of the second ground layer 21, the energy propagated by the second slot 211 is further coupled to the middle of the radiating unit 10 and propagates from the middle to both ends of the radiating unit 10, and when the energy propagates on the radiating unit 10, electromagnetic waves are radiated to the surrounding space, thereby implementing a propagation process from the energy to the electromagnetic waves.

In summary, in the back-fed traveling-wave antenna array provided by the present application, by providing the first slot 411, the second slot 211, and each layer of dielectric substrate and ground layer, energy is radiated from the middle portion to both ends of the radiation unit 10, and the radiation unit 10 adopts a microstrip patch structure, so that energy distribution is reasonable through the structural design of each patch, and the amplitude-phase characteristic, the impedance bandwidth and the working frequency band coverage of the traveling-wave antenna are 77GHz-81 GHz. The beam pointing can be stabilized at the normal point. The gain flatness is less than 1 dB. By setting the shape and structure of the patch 11, the energy distribution of the patch is adjusted, and sidelobe suppression can be achieved within a wide bandwidth. In addition, the structure of the device is simple, and the device is easy to process and manufacture.

Referring to fig. 12, simulation is performed on the antenna array of the present application, and the return loss in the bandwidth range of 77GHz-81GHz is less than-10 dB, which satisfies the energy radiation requirement in the bandwidth range.

Referring to fig. 13, the antenna array of the present application is simulated, and the sidelobe suppression on the pitch surface at the frequency points of 77GHz, 79GHz, and 81GHz is less than 20dB, and the sidelobe suppression is good.

Referring to fig. 14, by performing simulation on the antenna array of the present application, it is obtained that the sidelobe suppression at the horizontal planes of the frequency points of 77GHz, 79GHz, and 81GHz is less than 20dB, and the sidelobe suppression is good.

Referring to fig. 1, an embodiment of the present application further provides a radar, where the radar is a millimeter-wave radar. The radar comprises a power supply and the back feed type traveling wave antenna array provided by the embodiment of the application, wherein the power supply is used for supplying power to the back feed type traveling wave antenna array.

The intermediate medium substrate of the back-fed traveling wave antenna array can be further provided with structures such as data lines and the like for supplying power or transmitting control signals and the like. The radar may further comprise a signal processor, and the signal processor may comprise a radio frequency chip, and may be configured to feed energy to the back-fed traveling-wave antenna array. The signal processor may also process electrical signals received by the backfeed traveling-wave antenna.

The embodiment of the application also provides a movable platform, such as an automobile, a ship, a train and the like, which comprises a machine body and the radar provided by the embodiment of the application, wherein the radar is arranged on the movable platform.

The foregoing detailed description of the embodiments of the present application has been presented to illustrate the principles and embodiments of the present application, and the above description of the embodiments is only provided to help understand the method and the core concept of the present application; meanwhile, for a person skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.

Claims

1. A back-fed traveling-wave antenna array, comprising:

the surface of the first dielectric substrate is provided with a feed unit;

the first grounding layer is arranged on the surface, back to the power feeding unit, of the first dielectric substrate and provided with a first gap;

the intermediate medium substrate is arranged on the surface of the first grounding layer, which is opposite to the first medium substrate;

the second grounding layer is arranged on the surface of the intermediate medium substrate, which is opposite to the first grounding layer, and a second gap is formed in the second grounding layer;

the second dielectric substrate is arranged on the surface, back to the intermediate dielectric substrate, of the second grounding layer, and a radiating unit is arranged on one side, back to the second grounding layer, of the second dielectric substrate;

a plurality of first metal vias, the plurality of first metal vias penetrating through the first dielectric substrate, the first ground layer, the intermediate dielectric substrate, the second ground layer and the second dielectric substrate, and the plurality of first metal vias enclosing around the first slot and the second slot;

wherein the first slot and the second slot are used for coupling the energy of the feed unit to the middle part of the radiation unit.

2. The back-fed traveling wave antenna array of claim 1, wherein the first slot or the second slot is any one of rectangular, H-shaped, dumbbell-shaped, bow-tie-shaped, and hourglass-shaped.

3. The back-fed traveling wave antenna array of claim 2, wherein the first slot or the second slot is H-shaped, and a middle slot width of the H-shaped slot is 0.055 λ_g-0.075λ_gThe width of the end seam is 0.14 lambda_g-0.24λ_gThe length of the middle seam is 0.24 lambda_g-0.44λ_gThe length of the end slot is 0.055 lambda_g-0.098λ_gWherein λ is_gIs the equivalent medium wavelength at the central frequency point.

4. The back-fed traveling wave antenna array of claim 1, wherein the first slot corresponds in position to the second slot.

5. The back-fed traveling wave antenna array of claim 1, wherein the first slot is the same shape and structure as the second slot.

6. The back-fed traveling wave antenna array of claim 1, wherein the first ground plane and the second ground plane are metal, and the first dielectric substrate, the intermediate dielectric substrate, and the second dielectric substrate are laminated boards.

7. The back-fed traveling wave antenna array of claim 1, wherein the number of the intermediate dielectric substrates is plural.

8. The backfeed traveling wave antenna array of claim 1, wherein the radiating element comprises a plurality of patches and a plurality of microstrip lines connecting the plurality of patches, the first slot and the second slot are used for coupling the energy of the feed element onto a first microstrip line in a middle portion of the radiating element, and the first microstrip line is one of the plurality of microstrip lines.

9. The back-fed traveling wave antenna array of claim 8, wherein the radiating elements are symmetrical with respect to the first microstrip line.

10. The back-fed traveling-wave antenna array of claim 9, wherein the plurality of patches are formed with a first groove.

11. The antenna assembly backfeed traveling wave antenna array of claim 10, wherein the first slots formed in the patches at the ends of the radiating elements face a middle portion of the radiating elements, and the first slots formed in the other patches face away from the middle portion of the radiating elements.

12. The back-fed traveling wave antenna array of claim 11, wherein the patches are rectangular, and the length of the patches in the extending direction of the microstrip line is 0.5 λ_gThe depth of the first groove is 0.06 lambda_g(ii) a The width of the patch is 2.3 lambda in the extending direction perpendicular to the microstrip line_g-3.4λ_gSaidThe width from the side wall of the first groove to the side wall of the microstrip line opposite to the first groove is 0.24 lambda_g，λ_gIs the equivalent medium wavelength at the central frequency point.

13. The back-fed traveling wave antenna array of claim 8, wherein a plurality of the patches are identical in structure or have a tapered structure.

14. The back-fed traveling wave antenna array of claim 8, wherein the microstrip line is provided with an impedance matching structure, and the impedance matching structure is in a shape of a polygon.

15. The back-fed traveling wave antenna array of claim 1, wherein the radiating element comprises a second metal sheet connected with the first metal via.

16. The back-fed traveling-wave antenna array of claim 1, wherein the feeding unit comprises a microstrip line, and an extending direction of the microstrip line is perpendicular to a length direction of the first slot.

17. The back-fed traveling-wave antenna array of claim 16, wherein the feed unit further comprises a first metal plate, the first metal plate is formed with a second groove, and the microstrip line extends into the second groove and has a gap with an inner wall of the second groove.

18. The back-fed traveling-wave antenna array as claimed in claim 1, wherein the first dielectric substrate has a plurality of second metal vias formed therein, the plurality of second metal vias are disposed on a side edge of the first metal plate facing away from the opening of the second notch, and the second metal vias are connected between the first metal plate and the first ground layer.

19. A radar comprising a power supply and a back-fed travelling wave antenna array as claimed in any one of claims 1 to 18, the power supply being arranged to power the back-fed travelling wave antenna array.

20. A movable platform comprising a body and a radar according to claim 19, the radar being disposed on the movable platform.