WO2020258214A1

WO2020258214A1 - Back-fed traveling wave antenna array, radar, and movable platform

Info

Publication number: WO2020258214A1
Application number: PCT/CN2019/093557
Authority: WO
Inventors: 唐哲; 汤一君; 蔡铭
Original assignee: 深圳市大疆创新科技有限公司
Priority date: 2019-06-28
Filing date: 2019-06-28
Publication date: 2020-12-30
Also published as: CN111684657B; CN111684657A

Abstract

The present application provides a back-fed traveling wave antenna array, a radar, and a movable platform. The back-fed traveling wave antenna array comprises: a first dielectric substrate, a feed unit being provided on the surface of the first dielectric substrate; a first ground layer, the first ground layer being provided with a first gap; an intermediate dielectric substrate; a second ground layer, the second ground layer being provided with a second gap; a second dielectric substrate, the side of the second dielectric substrate facing away from the second ground layer being provided with a radiation unit; a plurality of first metal vias, the plurality of first metal vias penetrating 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 enclose the first gap and the second gap, wherein the first gap and the second gap are used for coupling the energy of the feed unit to the middle of the radiation unit. The back-fed traveling wave antenna array provided in the present application has a wide working bandwidth, and satisfies the requirements of good gain flatness and stable beam pointing within broadband.

Description

Back-fed traveling wave antenna array, radar and movable platform

Technical field

This application relates to the field of antenna technology, and in particular to a back-fed traveling wave antenna array, radar, and movable platform.

Background technique

The vehicle-mounted millimeter wave radar transmits millimeter waves to the outside through the antenna, receives the reflected signal from the target, and obtains the physical environment information around the car body quickly and accurately after data processing (such as the relative distance, relative speed, angle, movement between the car and other objects) Direction etc.). Wideband millimeter-wave radar can greatly improve the range resolution compared to narrowband low-band radars, and is suitable for application scenarios with high range resolution. As an important part of the radar front end, the antenna needs to have broadband working capabilities.

Summary of the invention

In order to solve the above technical problems, 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 that can have a wider bandwidth.

In a first aspect, an embodiment of the present application provides a back-fed traveling wave antenna array, including: a first dielectric substrate, a feeding unit is provided on the surface of the first dielectric substrate; a first ground layer is provided on the first dielectric substrate; The surface of a dielectric substrate facing away from the power feeding unit, the first ground layer is provided with a first gap; an intermediate dielectric substrate is provided on the surface of the first ground layer facing away from the first dielectric substrate; The second grounding layer is provided on the surface of the intermediate dielectric substrate facing away from the first grounding layer, the second grounding layer is provided with a second gap; the second dielectric substrate is provided on the second grounding layer A radiation unit is arranged on the side of the second dielectric substrate facing away from the second ground layer; a plurality of first metal vias, the plurality of first metal vias Pass 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 are enclosed in the Around the first slot and the second slot; wherein the first slot and the second slot are used to couple the energy of the feeding unit to the middle of the radiation unit.

In a second aspect, an embodiment of the present application provides a radar including a power supply and the back-fed traveling wave antenna array in the various embodiments of the first aspect, and the power supply is used to supply power to the back-fed traveling wave antenna array.

In a third aspect, an embodiment of the present application provides a movable platform, including a fuselage and the radar provided in the second aspect, and the radar is arranged on the movable platform.

The back-fed traveling wave antenna array provided by the first aspect of the present application adopts the form of a traveling wave antenna, supplemented by slot coupling and a feeding structure fed from the middle of the radiating unit, combined with a plurality of second wave antennas that can be equivalent to a waveguide structure. A metal via can make the antenna array have a wider working bandwidth, and meet the requirements of good gain flatness and stable beam pointing in the broadband.

Description of the drawings

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

2 is a schematic diagram of the planar structure of the radiation unit and the second dielectric substrate in FIG. 1;

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

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

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

6 is a schematic diagram of the three-dimensional structure of the power 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 the patch of an embodiment;

FIG. 10 is a schematic diagram of a partial structure of a second ground layer according to an embodiment;

11 is a schematic diagram of a cross-sectional structure of a back-fed traveling wave antenna array according to an embodiment;

FIG. 12 is a simulation curve diagram of return loss of a back-fed traveling wave antenna array according to an embodiment;

Fig. 13 is a view of the elevation plane of a back-fed traveling wave antenna array according to an embodiment;

Fig. 14 is an azimuth plane pattern of a back-fed traveling wave antenna array according to an embodiment.

Specific embodiment

The technical solutions in the embodiments of the present application will be clearly described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of this application.

It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or a central component may also exist. When a component is considered to be "connected" to another component, it can be directly connected to another component or there may be a centered component at the same time.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field of this application. The terms used in the description of the application herein are only for the purpose of describing specific embodiments, and are not intended to limit the application. The term "and/or" as used herein includes any and all combinations of one or more related listed items. Hereinafter, some embodiments of the present application will be described in detail with reference to the accompanying drawings. In the case of no conflict, the following embodiments and features in the embodiments can be combined with each other.

Various countries plan to apply the 77-81GHz frequency band with 79GHz as the center frequency to vehicle-mounted millimeter-wave broadband radars. The 77～81GHz wideband radar can greatly improve the range resolution compared with the 76～77GHz narrowband frequency band. It is suitable for short-range detection and high range resolution (0.15m～0.3m) application scenarios. The antenna is an important component of the radar front end Part of it needs to have the ability to work in broadband, including impedance matching in a wide frequency range, sidelobe suppression, beam pointing and gain flatness.

1) Impedance matching: Antennas can be divided into traveling wave antennas and standing wave antennas. The existing antennas are mainly standing wave antennas, whose impedance characteristics change drastically with frequency, and there is a problem of narrow impedance bandwidth (relative bandwidth about 3%);

2) Sidelobe suppression bandwidth: The existing technology can achieve sidelobe suppression better than 20dB in a narrowband range, but achieving sidelobe suppression in a wideband is a difficult point in broadband radar antenna design;

3) Beam pointing: The beam pointing refers to the pointing position of the point of maximum gain in the antenna pattern. The beam pointing of the antenna array is determined by the phase of each radiating element. The existing one-end side feed mode can only guarantee the beam in the narrow band Pointing is stable at the normal point;

4) Gain flatness: In the prior art, the gain flatness of the broadband internal antenna is about 4 to 5 dB. This value is too large, making the radar detection range insufficient.

To solve at least one of the above-mentioned problems, an embodiment of the present application provides a back-fed traveling wave antenna array. Please refer to FIG. 1, an embodiment of the present application provides a back-fed traveling wave antenna array, the structure of which is laminated and includes in order from top to bottom: a radiating unit 10, a second dielectric substrate 20, a second ground layer 21, and a middle The dielectric substrate 30, the first ground layer 41, the first dielectric substrate 40 and the power feeding unit 50 pass through 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的 is provided with a plurality of first metal vias 60. The power feeding unit 50 is disposed on the surface of the first dielectric substrate 40. Specifically, the power feeding unit 50 may be adhered to the surface of the first dielectric substrate 40, or may be disposed on the surface of the first dielectric substrate 40 by etching. The first ground layer 41 is provided with a first gap 411. The second ground layer 21 is provided with a second gap 211. A plurality of first metal vias 60 are enclosed around the first gap 411 and the second gap 211. Among them, 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 radiation unit 10.

The back-fed traveling wave antenna array in this embodiment adopts the form of a traveling wave antenna, supplemented by slot coupling and a feeding structure fed from the middle of the radiating unit 10, combined with a plurality of first wave antenna structures that can be equivalent to a waveguide structure. The metal via 60 can make the antenna array have a wider working bandwidth, and meet the requirements of good gain flatness and stable beam pointing in the broadband.

Wherein, the energy of the feeding unit 50 is propagated to the first slot 411 through slot coupling, and a plurality of first metal vias 60 are enclosed around the first slot 411 and the second slot 211 to form an equivalent waveguide structure, so that The energy coupled by a slot 411 propagates to the second slot 211 through the equivalent waveguide structure, and the second slot 211 propagates the energy to the middle of the radiating unit 10 by coupling, and then the energy is transmitted to the space in the form of electromagnetic waves through the radiating unit 10 radiation.

A plurality of first metal vias 60 are provided to form an equivalent waveguide structure. When energy propagates in the equivalent waveguide structure, the attenuation is reduced, which can ensure the efficiency of the antenna. When the energy propagates on the radiating unit 10, it is radiated step by step from the middle of the radiating unit 10 to both ends, so as to achieve the effect of stable beam pointing.

The shape and structure of the first slot 411 are the same as that of the second slot 211, so that energy attenuation is small during the process of coupling energy to the radiation unit 10 through the first slot 411 and the second slot 211.

Among them, the first slit 411 or the second slit 211 is any one of a rectangle, an H shape, a dumbbell shape, a bow tie shape, and an hourglass shape.

Specifically, in an embodiment, referring to FIGS. 3, 8 and 10, the first slit 411 or the second slit 211 is H-shaped. Please refer to FIG. 10, taking the second slot 211 as an example, and the first slot 411 can be referred to. The H-shaped slit of the second slit 211 has a central slit width W1 of 0.055λ _g -0.075λ _g , an end slit width W2 of 0.14λ _g -0.24λ _g , and a central slit length L1 of 0.24λ _g -0.44λ _g . The slit length L2 is 0.055λ _g -0.098λ _g . Among them, λ _g is the equivalent medium wavelength at the center frequency point. Setting the reasonable size makes the coupling efficiency of the energy of the feeding unit 50 in the H-shaped slot of the second slot 211 high, or the coupling efficiency of the energy of the H-shaped slot of the first slot 411 to the radiation unit 10 is high.

Further, referring to FIG. 1, the positions of the first slit 411 correspond to the positions of the second slit 211. Specifically, on the plate surface of the first dielectric substrate 40, the orthographic projections of the first slit 411 and the second slit 211 overlap. Further, the extending direction of the plurality of first metal vias 60 is perpendicular to the surface of the first dielectric substrate 40, and the equivalent waveguide structure formed by the plurality of first metal vias 60 is perpendicular to the surface of the first dielectric substrate 40. The cross-sectional shape in the direction is rectangular. By providing 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 energy loss in the medium can be effectively reduced.

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

In other embodiments, in the direction parallel to the surface of the first dielectric substrate 40, the cross-sectional shape of the equivalent waveguide structure formed by the space enclosed by the plurality of first metal vias 60 may also be the same as that of the first gap 411. Or the second gap 211 may be different. For example, the cross-sectional shape may be any one of rectangle, circle, parallelogram, trapezoid, etc. In this embodiment, the distance between each first metal via 60 and the first slit 411 or the second slit 211 may be set differently or completely different.

Referring to FIGS. 1 to 8, the plurality of first metal vias 60 are formed by opening corresponding vias on the dielectric substrate and the ground layer of each layer, and filling the vias with a metal material. Specifically, referring to FIG. 3, a plurality of through holes 212 are opened on the second ground layer 21. Please refer to FIG. 4, a plurality of through holes 301 are opened on the intermediate dielectric substrate 30. Referring to FIG. 7, a plurality of through holes 401 are opened on the first dielectric substrate 40. Please refer to FIG. 8, a plurality of through holes 412 are opened on the first ground layer 41. Please refer to FIG. 1 and FIG. 2, a plurality of through holes are also opened on the first dielectric substrate 40. The positions of the multiple through holes of the above-mentioned layers correspond to each other, and the shapes are the same. After the layers are stacked to form a whole, a layer of metal is plated on the inner walls of the multiple through holes of each layer, or the through holes of each layer are filled with metal, thereby forming the first metal via 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 materials, 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 laminates. For example, the materials of the first dielectric substrate 40 and the second dielectric substrate 20 are high-frequency and low-loss materials (such as Rogers Ro 4835, Rogers Ro 3003, etc.) The material of the intermediate dielectric substrate 30 is FR4.

The material selection of the above-mentioned layers is divided according to the purpose. The first dielectric substrate 40 is used as the base of the feeding unit 50. On the one hand, it is used to give the feeding unit 50 enough support, and on the other hand, it is used to isolate the feeding unit 50 from The first ground layer 41 enables the first slot 411 to be coupled with the feeding unit 50. Therefore, the first dielectric substrate selects a high-frequency and low-loss material to reduce energy loss and improve coupling efficiency. The second dielectric substrate 20 is similar to the first dielectric substrate 40, and high-frequency and low-loss materials are also selected. 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 slot and the second slot is increased. The part enclosed by the plurality of first metal vias 60 constitutes an equivalent waveguide structure. The energy coupled by the first slot 411 can be more concentratedly transmitted to the second slot 211. Considering the cost factor, a common FR4 material can be selected for the intermediate dielectric substrate.

In an embodiment, please refer to FIG. 1, the number of intermediate dielectric substrates 30 is multiple. Specifically, the number of intermediate dielectric substrates 30 can be set to 5 layers, that is, intermediate

dielectric substrates

31, 32, 33, 34, and 35. The number of the intermediate dielectric substrates 30 is related to the amplitude and phase characteristics of the energy. When the energy coupled to the first slot 411 by the feeding unit 50 propagates to the second slot 211, the amplitude and phase characteristics should be kept unchanged as much as possible. In other embodiments, the number of intermediate dielectric substrates 30 is not limited to 5 layers, and the number of intermediate dielectric substrates 30 can be 1 layer, 2 layers, 3 layers, 4 layers, 5 layers, 6 layers...N layers, where N is Positive integer. In addition, the thickness of each intermediate dielectric substrate is not limited.

In an embodiment, referring to FIGS. 1 and 2, the radiation 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 to couple the energy of the feeding unit 50 to the first microstrip line 121 in the middle of the radiation unit 10, and the first microstrip line 121 is one of the multiple microstrip lines 12 .

The radiation unit 10 is a structure in the form of microstrip patch series feed. The energy transmitted by the second slot 211 is coupled to the first microstrip line 121, and the energy flows to both ends of the radiation unit 10, and radiation is generated on the patch 11. , Flowing on the microstrip line 12. In the orthographic projection on the plate surface of the first dielectric substrate 40, the second gap 211 intersects the first microstrip line 121 at an angle of 90°. In other words, the microstrip line 12 (including the first microstrip line The extension direction of 121) and the length direction of the second slit 211 are perpendicular to each other. It is understandable that in actual products, due to manufacturing tolerances and other reasons, the angle between the length direction of the second gap 211 and the microstrip line 12 (including the first microstrip line 121) is allowed to float slightly, for example, the clip When the angle is between 85° and 95°, it can also be considered that the length direction of the second slit 211 is perpendicular to the first microstrip line 121. Setting this angle allows the second slot 211 to couple with the first microstrip line 121 to transmit energy. The radiating unit 10 adopts the form of a microstrip patch structure, and radiates step by step from the first microstrip line 121 in the middle to the two ends, ensuring that the beam pointing is stable at the normal point in the broadband range, and the stability is good.

Further, the radiation unit 10 has a symmetrical structure with respect to the first microstrip line 121. The symmetrical radiation unit 10 allows energy to be radiated on the patches 11 on both sides of the first microstrip line 121 in the same form, and the obtained antenna pattern has a symmetrical structure, and the beam is stably directed to the normal point in the broadband range.

In an embodiment, please refer to FIG. 2, a plurality of patches 11 are provided with first grooves 111. The first groove 111 is preferably opened in the middle of one end of the patch 111. Opening the first groove 111 can adjust the impedance, thereby adjusting the energy distribution on each patch 11, which can effectively suppress side lobes while meeting the electromagnetic wave radiation requirement of the preset frequency band. One end of the microstrip line 12 connecting two adjacent patches 11 is connected to the bottom wall of the first groove 111, and the other end is connected to the end of the adjacent patch 11 facing away from the first groove 111 .

Further, referring to FIG. 2, the first groove 111' opened by the patch 11' at the end of the radiation unit 10 faces the middle of the radiation unit 10, and the first grooves 111 opened by the other patches 11 face away from the radiation unit 10. Central. The first groove 111' of the patch 11' at the end is used to adjust impedance matching to realize the radiation characteristics of the traveling wave antenna.

In an embodiment, please refer to FIGS. 2 and 9, the patch 11 is rectangular, in the extension direction of the microstrip line 12, the length LP of the patch 11 is 0.5λ _g , and the depth of the first groove 111 is 0.06 λ _g . In the extending direction perpendicular to the microstrip line 12, the width WP of the patch 11 is 2.3λ _g -3.4λ _g , and the width WS from the side wall of the first groove 111 to the side wall of the microstrip line 12 opposite to it Is 0.24λ _g , λ _g is the equivalent medium wavelength at the center frequency. A reasonable size of the patch 11 is set so that when energy is radiated on the patch 11, the generated resonance frequency and bandwidth are within a preset range, and the energy is reasonably distributed on the patch 11, which can achieve the characteristics of low side lobe.

In an embodiment, referring to FIG. 2, multiple patches 11 have the same structure, or multiple patches 11 have a gradual structure. When multiple patches 11 have the same structure, the radiation unit 11 is easy to process. When the multiple patches 11 have a gradual structure, it can satisfy that the energy distribution on each patch 11 is better and the side lobes are lower. Since the energy from the first microstrip line 121 in the middle of the radiating unit 10 is radiated to the two ends, the energy is gradually attenuated. The more it is transmitted to the two ends, the weaker the energy is. Therefore, setting a gradual structure can make each sticker The energy distribution of the film is more reasonable. Specifically, the structure of the multiple patches 11 arranged from the middle to the two ends of the radiation unit 10 gradually increases.

In an embodiment, please continue to refer to FIG. 2, the microstrip line 12 is provided with an impedance matching structure (not shown in the figure), and the impedance matching structure has a polygonal shape. The impedance matching structure is used to adjust impedance matching so that the energy radiated by the radiating unit 10 meets the preset bandwidth. The impedance matching structure is sheet-shaped, and the overall extension plane is 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 quadrilateral, a pentagon, a hexagon, or the like.

1 and FIG. 2, the radiation unit 10 includes a second metal sheet 14, and the second metal sheet 14 is connected to the first metal via 60. Around the first microstrip line 121 in the middle of the radiation unit 10, a second metal sheet 14 is provided for fixing a plurality of first metal vias 60. The second metal sheet 14 is provided with a slit 141 and a through hole 142. The slit 141 corresponds to the position of the first slit 411 and is used to expose the coupling space of the first slit 411 to avoid shielding. The inner wall of the through hole 142 is connected to the plurality of first metal via holes 60.

In an embodiment, please refer to FIG. 1, FIG. 5 and FIG. 6, the power feeding unit 50 includes a microstrip line 52. In the orthographic projection of the surface of the first dielectric substrate 40, the microstrip line 52 and the first gap 411 The intersection and the included angle is 90°. In other words, the extension direction of the microstrip line 52 and the length direction of the first slot 411 are perpendicular to each other. The form in which the feeding unit 50 couples energy to the first slot 411 is the same as the form in which the second slot 211 couples energy to the first microstrip line 121 of the radiating unit 10, both of which are slot coupling modes.

1 and FIG. 6, the structure of the microstrip line 52 may be a long strip, and the width of the front end of the energy flow may be set to be wider for impedance matching. The front end of the energy flow of the microstrip line 52 is used to connect to a feeder line for receiving energy from the radio frequency chip. The energy flows through the microstrip line 52 and couples energy to the second gap 211 at the end of the energy flow.

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

In other embodiments, the structure for coupling energy to the second slot 211 is not limited to the microstrip line structure, but can also adopt the coplanar waveguide form (GCPW), the substrate integrated waveguide form (SIW), etc., and the structure refers to the prior art. Yes, I won’t repeat it.

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, and the plurality of second metal vias 53 are provided on the first metal sheet 51 facing away from the second recess. On one side edge of the opening direction of the slot 511, the second metal via 53 is connected between the first metal sheet 51 and the first ground layer 41. In FIG. 5, the first metal sheet 51 is provided with a through hole 513, the second metal via 53 is connected to the sidewall of the through hole 513, and the second metal via 53 forms a barrier shielding structure to reduce the energy along the microstrip line 52 The self-extension direction is transmitted, so that energy is coupled to the first gap 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 plurality of through holes 512 are connected with the first metal via 60 to connect and fix the first metal via 60 together with the second metal sheet 14.

Please refer to Figures 1 and 11. The arrows in Figure 11 indicate the propagation direction of energy. The energy is coupled from the feeding unit 50 to the first gap 411 of the first ground layer 41, which is enclosed by a plurality of first metal vias 60 In the equivalent waveguide structure formed by space, the energy coupled by the first slot 411 propagates to the second slot 211 of the second ground layer 21, and the energy propagated by the second slot 211 is coupled to the middle of the radiating unit 10 and radiates from The middle part of the unit 10 propagates to both ends, and when the energy propagates on the radiation unit 10, electromagnetic waves are radiated to the surrounding space, so as to realize the propagation process of the energy to the electromagnetic waves.

In summary, in the back-fed traveling wave antenna array provided by the present application, by setting the first slot 411, the second slot 211, and each layer of dielectric substrate and ground layer, energy is radiated from the middle of the radiation unit 10 to both ends, and the radiation unit 10 Adopting the microstrip patch structure, the structure design of each patch makes the energy distribution reasonable, which can realize the amplitude and phase characteristics of the traveling wave antenna, the impedance bandwidth is wide, and the working frequency band covers 77GHz-81GHz. The beam pointing can be stabilized at the normal point. The gain flatness is less than 1dB. By setting the shape and structure of the patch 11 and adjusting the energy distribution of the patch, side lobe suppression can be achieved in a wider bandwidth. In addition, the structure of this application is simple and easy to manufacture.

Please refer to FIG. 12 to simulate the antenna array of the present application, and it is obtained that the return loss in the 77GHz-81GHz bandwidth range is less than -10dB, which meets the energy radiation requirement in the bandwidth range.

Please refer to FIG. 13 to simulate the antenna array of the present application, and it is obtained that the sidelobe suppression of the elevation plane at the frequency points of 77GHz, 79GHz and 81GHz is less than 20dB, and the sidelobe suppression is good.

Please refer to FIG. 14 to simulate the antenna array of the present application, and it is obtained that the sidelobe suppression on the horizontal plane at the frequency points of 77GHz, 79GHz and 81GHz is less than 20dB, and the sidelobe suppression is good.

Please refer to FIG. 1, an embodiment of the present application also provides a radar, which is a millimeter wave radar. The radar includes a power supply and the back-fed traveling wave antenna array provided in the embodiment of the application, and the power supply is used to supply power to the back-fed traveling wave antenna array.

Among them, on the intermediate dielectric substrate of the back-fed traveling wave antenna array, a structure such as a data line can also be provided for power supply or transmission of control signals. The radar may also include a signal processor, which may include a radio frequency chip, which can be used to feed energy to the back-fed traveling wave antenna array. The signal processor can also process the electrical signals received by the back-fed traveling wave antenna.

The embodiment of the present application also provides a movable platform, such as a car, a ship, a train, etc. The movable platform includes a fuselage and the radar provided in the embodiment of the present application, and the radar is set on the movable platform.

The embodiments of the application are described in detail above, and specific examples are used in this article to illustrate the principles and embodiments of the application. The descriptions of the above embodiments are only used to help understand the methods and core ideas of the application; Those skilled in the art, based on the ideas of the present application, will have changes in the specific embodiments and application scope. In summary, the content of this specification should not be construed as limiting the present application.

Claims

A back-fed traveling wave antenna array is characterized in that it comprises:

A first dielectric substrate, the surface of the first dielectric substrate is provided with a power feeding unit;

The first ground layer is provided on the surface of the first dielectric substrate facing away from the feeding unit, and the first ground layer is provided with a first gap;

The intermediate dielectric substrate is arranged on the surface of the first ground layer facing away from the first dielectric substrate;

The second ground layer is arranged on the surface of the intermediate dielectric substrate facing away from the first ground layer, and the second ground layer is provided with a second gap;

A second dielectric substrate is arranged on the surface of the second ground layer facing away from the intermediate dielectric substrate, and a radiation unit is arranged on the side of the second dielectric substrate facing away from the second ground layer;

A plurality of first metal vias, the plurality of first metal vias penetrating the first dielectric substrate, the first ground layer, the intermediate dielectric substrate, the second ground layer, and the second dielectric A substrate, and the plurality of first metal vias are enclosed around the first gap and the second gap;

Wherein, the first slot and the second slot are used to couple the energy of the feeding unit to the middle of the radiation unit.
The back-fed traveling wave antenna array according to claim 1, wherein the first slot or the second slot is any one of a rectangular shape, an H-shape, a dumbbell shape, a bow tie shape, and an hourglass shape.
The back-fed traveling wave antenna array according to claim 2, wherein the first slot or the second slot is H-shaped, and the middle of the H-shaped slot has a width of 0.055λ g -0.075λ g , The end slit width is 0.14λ g -0.24λ g , the middle slit length is 0.24λ g -0.44λ g , and the end slit length is 0.055λ g -0.098λ g , where λ g is the equivalent medium at the center frequency point wavelength.
The back-fed traveling wave antenna array according to claim 1, wherein the position of the first slot corresponds to the position of the second slot.
The back-fed traveling wave antenna array according to claim 1, wherein the shape and structure of the first slot are the same as the second slot.
The back-fed traveling wave antenna array of claim 1, wherein the first ground layer and the second ground layer are made of metal, and the first dielectric substrate, the intermediate dielectric substrate, and the The second dielectric substrate is a laminate.
The back-fed traveling wave antenna array according to claim 1, wherein the number of the intermediate dielectric substrate is multiple.
The back-fed traveling wave antenna array according to claim 1, wherein the radiating unit comprises a plurality of patches and a plurality of microstrip lines connecting the plurality of patches, the first slot and the The second slot is used to couple the energy of the feeding unit to the first microstrip line in the middle of the radiation unit, and the first microstrip line is one of the multiple microstrip lines.
8. The back-fed traveling wave antenna array according to claim 8, wherein the radiating unit has a symmetrical structure with respect to the first microstrip line.
9. The back-fed traveling wave antenna array of claim 9, wherein the plurality of patches are provided with first grooves.
The antenna assembly back-fed traveling wave antenna array according to claim 10, wherein the first groove opened in the patch at the end of the radiating unit faces the middle of the radiating unit, and other patches are opened The first groove faces away from the middle of the radiation unit.
The back-fed traveling wave antenna array of claim 11, wherein the patch is rectangular, and the length of the patch is 0.5λ g in the extension direction of the microstrip line, and The depth of the first groove is 0.06λ g ; in the direction perpendicular to the extension of the microstrip line, the width of the patch is 2.3λ g -3.4λ g , and the sidewall of the first groove The width of the opposite side wall of the microstrip line is 0.24λ g , and λ g is the equivalent medium wavelength at the center frequency point.
8. The back-fed traveling wave antenna array according to claim 8, wherein a plurality of the patches have the same structure, or a plurality of the patches have a gradual structure.
8. The back-fed traveling wave antenna array according to claim 8, wherein an impedance matching structure is provided on the microstrip line, and the impedance matching structure has a polygonal shape.
The back-fed traveling wave antenna array according to claim 1, wherein the radiating unit comprises a second metal sheet, and the second metal sheet is connected to the first metal via.
The back-fed traveling wave antenna array according to claim 1, wherein the feeding unit comprises a microstrip line, and the extension direction of the microstrip line is perpendicular to the length direction of the first slot.
The back-fed traveling wave antenna array according to claim 16, wherein the feeding unit further comprises a first metal sheet, the first metal sheet is provided with a second groove, and the microstrip line extends Into the second groove and spaced from the inner wall of the second groove.
The back-fed traveling wave antenna array of claim 1, wherein the first dielectric substrate is provided with a plurality of second metal vias, and the plurality of second metal vias are provided in the first An edge of the metal sheet facing away from the opening direction of the second groove, and the second metal via is connected between the first metal sheet and the first ground layer.
A radar, characterized by comprising a power supply and the back-fed traveling wave antenna array according to any one of claims 1 to 18, and the power supply is used to supply power to the back-fed traveling wave antenna array.
A movable platform, characterized by comprising a fuselage and the radar according to claim 19, the radar being arranged on the movable platform.