Filtering antenna and antenna system for vehicle-mounted millimeter wave radar

Abstract

The invention relates to the technical field of radar antennas, and provides a filtering antenna and an antenna system for a vehicle-mounted millimeter wave radar, the filtering antenna comprises a microstrip array antenna structure, a parasitic branch filtering structure and a feed transmission line, and the parasitic branch filtering structure is connected with the microstrip array antenna structure through the feed transmission line; a parasitic stub filtering structure of a short stub is added to a single side of the antenna, and a fan-shaped patch structure is arranged to form an adjusting circuit capacitive element by changing the radius of an open circuit fan-shaped stub structure; an inductive adjusting element is formed by combining a microstrip structure and a ground connection copper-clad hole, high-frequency coupling signal filtering is achieved, the influence on the amplitude and phase performance of the microstrip array antenna structure is small, more MIMO antenna channels are arranged on a low-cost and small-size radar PCB, meanwhile, the problems that coupling is serious and isolation is poor between the antenna channels are solved, and the antenna performance is improved. A miniaturized and high-isolation millimeter wave radar MIMO technology is realized, and the isolation between MIMO antenna channels of the whole board can be improved to 30 db or more.

Description

Technical Field

[0001] The present invention relates to the technical field of radar antennas, and in particular to a filtering antenna and an antenna system for a vehicle-mounted millimeter-wave radar. Background Art

[0002] With the rapid development of today's social economy and people's daily travel needs, the total number of cars in my country has increased year by year and has reached a relatively high level. With the increase in the number of cars, the number of traffic accidents has also gradually increased, which has an adverse impact on people's health and property safety. With the development of industrial intelligence, the application of vehicle-mounted radar can help drivers make correct decisions in some emergency situations and avoid traffic accidents. Vehicle-mounted radar can realize real-time detection of the distance, speed and position of objects around the car, and can realize auxiliary functions such as blind spot monitoring, lane change assistance, and emergency braking. At present, the main technologies of vehicle-mounted radar include ultrasonic, laser, infrared and millimeter wave. Because millimeter-wave radar has high resolution and measurement accuracy, and can work stably in harsh environments such as rain, snow, and fog, millimeter-wave radar has been widely developed and applied.

[0003] Among existing radar products, 77GHz millimeter-wave radar has higher measurement accuracy and smaller size than 24GHz radar, so it has become the main development trend of millimeter-wave radar today. Antenna, as the transceiver component at the front end of the radar system, is an important component of the radar system. At present, the main forms of millimeter-wave radar antennas are dielectric integrated waveguide antennas, lens antennas, and microstrip patch antennas. Microstrip patch antennas are widely used because of their low profile, light weight, and low cost.

[0004] As an indispensable part of the intelligent driving assistance system (ADAS), the application of millimeter wave radar has upgraded the active safety warning system of automobiles, provided safety protection for automobile driving, and to a certain extent ensured that the driver's life and property were not infringed. The application of millimeter wave anti-collision radar to automobiles can conveniently detect the distance, speed, angle and other information of the target, and timely issue warnings in case of danger.

[0005] Since the power coverage of corner radar is mainly required to be directly behind and to the side of the vehicle, the detection distance of the target directly behind needs to reach 100-200m, and the detection distance of the target to the side needs to reach 50-60m. Based on this distance requirement, it is necessary to increase the number of antenna elements to improve the gain, thereby increasing the radar detection distance, but this will increase the size of the antenna and reduce the beam width of the antenna elevation plane; and the radar is installed at the corner of the vehicle, and the detection distance in the normal direction is not required. The traditional design will cause the gain in the normal radiation direction of the antenna to be wasted. Therefore, considering a certain installation angle range, in order to meet this power coverage requirement, it is particularly necessary to reduce the design pressure of antenna gain, beam width and size on the basis of the existing radar structure, and study the beamforming of the radar antenna and the simultaneous MIMO transmission phase modulation method.

[0006] Millimeter-wave radar systems now generally use MIMO to further improve gain, reduce antenna design difficulties and increase detection distance, while using multiple MIMO antenna channels to improve angular resolution. In order to achieve a certain high resolution on the horizontal and vertical planes and avoid grating lobes within the required detection FOV range, the distance design between MIMO antenna channels is limited, and there is often a minimum unit distance requirement. Therefore, miniaturized, low-cost radars will have serious coupling and poor isolation between antenna channels when more MIMO antenna arrays are arranged on a small PCB size. Summary of the invention

[0007] The present invention provides a filtering antenna and an antenna system for a vehicle-mounted millimeter-wave radar, which solves the technical problem that the existing miniaturization cannot be balanced with multiple MIMO channels to achieve high resolution, resulting in severe coupling and poor isolation between antenna channels.

[0008] In order to solve the above technical problems, the present invention provides a filtering antenna for a vehicle-mounted millimeter-wave radar, comprising a microstrip array antenna structure, a parasitic branch filter structure and a feeding transmission line, wherein the parasitic branch filter structure is connected to the microstrip array antenna structure through the feeding transmission line;

[0009] The parasitic branch filtering structure includes a fan-shaped patch structure, a microstrip structure and a ground connection copper-clad hole. One end of the microstrip structure is connected to one side of the feeding transmission line, and the other end is respectively connected to the fan-shaped patch structure and the ground connection copper-clad hole; the fan-shaped patch structure connected to the end of the microstrip array antenna structure forms a capacitive adjustment element, and is combined with the microstrip structure and the ground connection copper-clad hole to form an inductive adjustment element for performing high-frequency coupled signal filtering.

[0010] This basic solution connects a parasitic branch filter structure to the feed transmission line at the end of the existing microstrip array antenna structure, wherein a fan-shaped patch structure is arranged at the end of the parasitic branch filter structure, and a capacitive element of the adjustment circuit is formed by changing the radius r of the open-circuit fan-shaped branch structure; at the same time, the microstrip structure and the ground connection copper-clad hole are combined to form an inductive adjustment element to achieve high-frequency coupling signal filtering, and has little effect on the amplitude and phase performance of the microstrip array antenna structure, and is suitable for low-cost, small-size radar PCB (Printed Circuits Board) to arrange more MIMO (multiinput multi output) antenna channels, while solving the problems of severe coupling and poor isolation between antenna channels, and realizing miniaturized, high-isolation millimeter-wave radar MIMO technology.

[0011] In a further embodiment, the microstrip structure includes a first microstrip branch and a second microstrip branch; one end of the first microstrip branch is connected to the fan-shaped patch structure to form a capacitive adjustment element, and the other end is connected to one side of the feeding transmission line; one end of the second microstrip branch is connected to a side of the first microstrip branch away from the microstrip array antenna structure, and the other end is connected to the ground connection copper hole.

[0012] In this scheme, a first microstrip branch is arranged on one side of the feeding transmission line to access the fan-shaped patch structure to form a capacitive adjustment element. At the same time, a second microstrip branch is added on the side of the first microstrip branch away from the microstrip array antenna structure to connect to the ground copper-clad hole (for connecting the reference ground), which is combined with the fan-shaped patch structure to form an inductive adjustment element, thereby reducing interference between antenna channels through high-frequency filtering to improve isolation; the parasitic fan-shaped patch structure and microstrip structure are small in size, which are fully adapted to the miniaturized design of the radar.

[0013] In a further embodiment, an impedance transformation structure is also included, one end of the impedance transformation structure is connected to the feeding transmission line, and the other end is connected to the microstrip array antenna structure, and the feeding transmission line is connected to the microstrip array antenna structure through the impedance transformation structure.

[0014] In a further embodiment, the impedance transformation structure has a length of one quarter wavelength.

[0015] This solution sets an impedance transformation structure connected in series between the feeding transmission line and the microstrip array antenna structure. Through impedance transformation, the influence of the internal resistance of the signal source and the negative resistance on the resonant circuit can be effectively reduced, thereby ensuring the stability and performance of the circuit.

[0016] In a further embodiment, the microstrip array antenna structure includes a microstrip comb patch array antenna, including a microstrip feed line and a plurality of radiators, wherein the plurality of radiators are cross-distributed on opposite sides of the microstrip feed line along the length direction of the microstrip feed line.

[0017] This solution uses a microstrip comb patch array antenna, which has engineering practicality such as miniaturization, low cost, light weight, easy integration, and low cost.

[0018] In a further embodiment, the microstrip array antenna structure also includes a matching structure, which is arranged between the impedance transformation structure and the microstrip comb patch array antenna, and the feeding transmission line is connected to the microstrip comb patch array antenna through the impedance transformation structure and the matching structure in sequence.

[0019] In a further embodiment, the matching structure is a square structure.

[0020] This solution connects a series matching structure between the impedance transformation structure and the microstrip comb patch array antenna, which can ensure better signal transmission.

[0021] In a further embodiment, the feeding transmission line is a microstrip transmission line, and the microstrip transmission line is a 50 ohm microstrip feeding line.

[0022] The scheme sets up a 50 ohm microstrip feed line to ensure that the designed antenna can be integrated with the chip.

[0023] The present invention provides an antenna system for a vehicle-mounted millimeter-wave radar, comprising a dielectric substrate and a four-channel antenna array, wherein the four-channel antenna array adopts a MIMO array layout, and the antenna array is a filtering antenna as described above;

[0024] The filtering antenna comprises a microstrip array antenna structure, a parasitic branch filtering structure and a feeding transmission line; the parasitic branch filtering structure comprises a fan-shaped patch structure, a first microstrip branch, a second microstrip branch and a ground connection copper-clad hole;

[0025] The fan-shaped patch structure, the first microstrip branch, the second microstrip branch and the ground connection copper-clad hole are distributed on the upper surface of the dielectric substrate, and the lower surface is used as a ground reference plane and is connected to the second microstrip branch through the ground connection copper-clad hole.

[0026] In a further embodiment, it further includes a grounded coplanar waveguide and an electronic chip distributed on the upper surface of the dielectric substrate, and the filtering antenna is connected to the electronic chip via the grounded coplanar waveguide.

[0027] The beneficial effects of this basic program are as follows:

[0028] (1) The above-mentioned filter antenna is used to form an arbitrary MIMO array layout design. The parasitic branch filter structure is small in size. The filter antenna array is used to realize the MIMO radar working mode, which has little impact on the layout area of ​​the entire board, so as to eliminate the tight coupling caused by the adjacent antenna channels, greatly improve the MIMO radar antenna isolation, thereby miniaturizing the radar and simplifying the design of multi-channel MIMO antenna channels.

[0029] (2) Since the added parasitic filter structure has little effect on the antenna performance and the parasitic branches do not affect the antenna size, it is conducive to the miniaturization design of the antenna system (radar).

[0030] (3) By adding a parasitic branch filter structure with short branches on one side of the antenna, the isolation between the channels of the entire MIMO antenna can be improved by 30db or more; and the horizontal beam of the antenna is pointed to the front or rear side of the vehicle body, and the gain of the antenna on the front or rear side of the vehicle body is improved to increase the detection distance of the radar on the front or rear side of the vehicle body.

[0031] (4) At the same time, the high-frequency stopband filter covers 80-90 GHz, and the antenna gain bandwidth covers the radar operating frequency band of 76.5-78.5 GHz, which fully meets the radar broadband design and greatly improves the ranging resolution. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a schematic diagram of a filtering antenna for a vehicle-mounted millimeter-wave radar provided by an embodiment of the present invention;

[0033] Figure 2 The embodiment of the present invention provides Figure 1 Structural diagram of the parasitic branch filter structure;

[0034] Figure 3 The embodiment of the present invention provides Figure 1 Structural diagram of the microstrip array antenna structure;

[0035] Figure 4 It is a schematic diagram of the layout of a whole board of a MIMO multi-path transmit filter antenna in an antenna system for a vehicle-mounted millimeter-wave radar provided by an embodiment of the present invention;

[0036] Figure 5 is a reflection and transmission coefficient diagram provided by an embodiment of the present invention;

[0037] Figure 6 : are the horizontal plane radiation patterns of antennas with and without filtering provided by the embodiments of the present invention;

[0038] Figure 7 The vertical plane radiation diagrams of antennas with and without filtering provided by the embodiments of the present invention;

[0039] Figure 8 It is a diagram of the whole-board isolation coefficient of the MIMO multi-channel transmit filter antenna provided in an embodiment of the present invention.

[0040] Among them: microstrip array antenna structure 1, microstrip feed line 11, radiator 12; parasitic branch filter structure 2, first microstrip branch 21, second microstrip branch 22, fan-shaped patch structure 23, ground connection copper hole 24; feeding transmission line 3; impedance transformation structure 4; matching structure 5; dielectric substrate 6, ground reference plane 61; grounded coplanar waveguide 7; electronic chip 8. DETAILED DESCRIPTION

[0041] The following specifically illustrates the implementation mode of the present invention in conjunction with the accompanying drawings. The embodiments are provided for illustrative purposes only and cannot be understood as limiting the present invention. The accompanying drawings are provided for reference and illustration only and do not constitute a limitation on the scope of patent protection of the present invention, because many changes can be made to the present invention without departing from the spirit and scope of the present invention.

[0042] Example 1

[0043] An embodiment of the present invention provides a filtering antenna for a vehicle-mounted millimeter-wave radar, such as Figure 1 , Figure 2 , Figure 3 As shown, in this embodiment, it includes a microstrip array antenna structure, a parasitic branch filter structure and a feeding transmission line, and the parasitic branch filter structure is connected to the microstrip array antenna structure through the feeding transmission line;

[0044] The parasitic branch filter structure is arranged on the upper surface and the lower surface of the dielectric substrate, and includes a fan-shaped patch structure, a microstrip structure and a ground connection copper-clad hole. One end of the microstrip structure is connected to one side of the feeding transmission line, and the other end is respectively connected to the fan-shaped patch structure and the ground connection copper-clad hole; the fan-shaped patch structure connected to the end of the microstrip array antenna structure forms a capacitive adjustment element, and is combined with the microstrip structure and the ground connection copper-clad hole to form an inductive adjustment element for performing high-frequency coupling signal filtering.

[0045] In this embodiment, the microstrip structure includes a first microstrip branch and a second microstrip branch; one end of the first microstrip branch is connected to the fan-shaped patch structure to form a capacitive adjustment element, and the other end is connected to one side of the feeding transmission line; one end of the second microstrip branch is connected to a side of the first microstrip branch away from the microstrip array antenna structure, and the other end is connected to the ground connection copper hole.

[0046] Preferably, the radius range of the fan-shaped patch structure is designed to be r=0.3-0.28mm; the length and width of the first microstrip branch are set to w1=0.1mm:s1=0.2mm respectively; the length and width of the second microstrip branch are set to w2=0.1mm:s2=0.3mm respectively; the diameter of the ground connection copper hole is D=0.2mm.

[0047] In this embodiment, a first microstrip branch is arranged on one side of the feeding transmission line to access the fan-shaped patch structure to form a capacitive adjustment element. At the same time, a second microstrip branch is added on the side of the first microstrip branch away from the microstrip array antenna structure to connect to the ground copper-clad hole (for connecting the reference ground), which is combined with the fan-shaped patch structure to form an inductive adjustment element, thereby reducing interference between antenna channels through high-frequency filtering to improve isolation; the parasitic fan-shaped patch structure and microstrip structure are small in size, which are fully adapted to the miniaturized design of the radar.

[0048] In this embodiment, an impedance transformation structure is also included, one end of the impedance transformation structure is connected to the feeding transmission line, and the other end is connected to the microstrip array antenna structure, and the feeding transmission line is connected to the microstrip array antenna structure through the impedance transformation structure.

[0049] In this embodiment, the length of the impedance transformation structure is one quarter of a wavelength.

[0050] This embodiment provides an impedance transformation structure connected in series between the feeding transmission line and the microstrip array antenna structure. Through impedance transformation, the influence of the internal resistance of the signal source and the negative resistance on the resonant circuit can be effectively reduced, thereby ensuring the stability and performance of the circuit.

[0051] In this embodiment, the microstrip array antenna structure includes a microstrip comb patch array antenna, including a microstrip feed line and a plurality of radiators, wherein the plurality of radiators are cross-distributed on opposite sides of the microstrip feed line along the length direction of the microstrip feed line, and the plurality of radiators are connected in series through the microstrip feed line to form a linear array structure.

[0052] This embodiment uses a microstrip comb patch array antenna, which has engineering practicality such as miniaturization, low cost, light weight, easy integration, and low cost.

[0053] In this embodiment, the microstrip array antenna structure also includes a matching structure, which is arranged between the impedance transformation structure and the microstrip comb patch array antenna, and the feeding transmission line is connected to the microstrip comb patch array antenna through the impedance transformation structure and the matching structure in sequence.

[0054] In this embodiment, the matching structure is a square structure.

[0055] In this embodiment, a series matching structure is provided between the impedance transformation structure and the microstrip comb-shaped patch array antenna, which can ensure better signal transmission.

[0056] In this embodiment, the feeding transmission line is a microstrip transmission line, and the microstrip transmission line is a 50 ohm microstrip feeding line.

[0057] In this embodiment, a 50-ohm microstrip feed line is provided to ensure that the designed antenna can be integrated with the chip.

[0058] In the embodiment of the present invention, a parasitic branch filter structure is connected to a feeding transmission line at the end of an existing microstrip array antenna structure, wherein a fan-shaped patch structure is arranged at the end of the parasitic branch filter structure, and a capacitive element of an adjustment circuit is formed by changing the radius r of the open-circuit fan-shaped branch structure; at the same time, a microstrip structure and a ground connection copper-clad hole are combined to form an inductive adjustment element, so as to realize high-frequency coupling signal filtering, and have little influence on the amplitude and phase performance of the microstrip array antenna structure, so as to adapt to the low-cost and small-size radar PCB (Printed Circuits Board) to arrange more MIMO (multiinput multi output) antenna channels, and solve the problems of severe coupling and poor isolation between antenna channels, so as to realize miniaturized and high-isolation millimeter-wave radar MIMO technology.

[0059] Example 2

[0060] An embodiment of the present invention provides an antenna system for a vehicle-mounted millimeter-wave radar, such as Figure 4 , comprising a dielectric substrate and a four-channel antenna array, the four-channel antenna array adopts a MIMO array layout, and the antenna array is the filtering antenna described in the above embodiment;

[0061] The closer the distance between the four-channel antenna arrays is, the stronger the coupling is and the worse the isolation is.

[0062] The filtering antenna comprises a microstrip array antenna structure, a parasitic branch filtering structure and a feeding transmission line; the parasitic branch filtering structure comprises a fan-shaped patch structure, a first microstrip branch, a second microstrip branch and a ground connection copper-clad hole;

[0063] The fan-shaped patch structure, the first microstrip branch, the second microstrip branch and the ground connection copper-clad hole are distributed on the upper surface of the dielectric substrate, and the lower surface is used as a ground reference plane and is connected to the second microstrip branch through the ground connection copper-clad hole.

[0064] The specifications of the dielectric substrate are as follows: dielectric dk=3.1: thickness h=0.127 mm.

[0065] In this embodiment, it also includes a grounded coplanar waveguide and an electronic chip distributed on the upper surface of the dielectric substrate. The filtering antenna is connected to the electronic chip through the grounded coplanar waveguide. The filtering antenna A is adjacent to the filtering antenna B, and the filtering antenna C is adjacent to the filtering antenna D.

[0066] See also Figure 5 The filter reflection S11 and transmission S21 coefficients of this embodiment show that in the stopband bandwidth range of 80GHz-90GHz, it has good high-frequency filtering characteristics, transmission loss>-2dB, and reflection loss>-8Db. Among them, in the normal working frequency range of 60-80GHz, the reflection coefficient of this embodiment is <-8dB, which has good transmission performance.

[0067] See also Figure 6 , obtain the horizontal plane direction diagram, and compare the present embodiment (such as Figure 6 with filter) and antennas without parasitic branch filtering structures (such as Figure 6 The gain of the antenna with filter and the antenna without filter varies little. In the operating frequency range of 76.5-78.5GHz, the maximum gain fluctuation is about 1.4dB (12.722dB-11.324dB=1.398dB at 52 degrees in the horizontal plane), and the maximum beam points to -50 degrees. The antenna 0dB gain beam width angle is -100° to 100°, and the beam width is 200 degrees.

[0068] See also Figure 7 , obtain the vertical plane direction diagram, and compare the present embodiment (such as Figure 7 with filter) and antennas without parasitic branch filtering structures (such as Figure 7 The gain of the antenna with filter and the antenna without filter varies little. In the operating frequency range of 76.5-78.5GHz, the maximum gain fluctuation is about 1.4dB (at 0 degrees in the vertical plane, 9.678dB-8.2673dB = 1.4107dB), the maximum beam pointing is 0 degrees, the 3dB beam width is 16 degrees, and the first null coverage angle of the radiation pattern is -20° to 20°. The beam width is ±20°.

[0069] See also Figure 8 , obtain the isolation coefficient diagram of the whole board MIMO multi-path transmission channel, this embodiment (such as Figure 7 Compared with the antenna without parasitic branch filtering structure (such as Figure 7The isolation of the whole board is significantly improved. In the operating frequency range of 76.5-78.5GHz of the automotive millimeter-wave radar, the isolation is improved to about 28-30dB. The isolation of adjacent antenna channels that are close to each other is improved by more than 5dB from about -23-24dB.

[0070] In summary, the antenna system composed of filtering in this embodiment has a horizontal plane radiation pattern covering ±100° and a vertical plane radiation pattern covering ±20° FOV, that is, the added parasitic filtering structure has little effect on the antenna performance, but the isolation is significantly improved.

[0071] The beneficial effects of the embodiments of the present invention are as follows:

[0072] (1) The above-mentioned filter antenna is used to form an arbitrary MIMO array layout design. The parasitic branch filter structure is small in size. The filter antenna array is used to realize the MIMO radar working mode, which has little impact on the layout area of ​​the entire board, so as to eliminate the tight coupling caused by the adjacent antenna channels, greatly improve the MIMO radar antenna isolation, thereby miniaturizing the radar and simplifying the design of multi-channel MIMO antenna channels.

[0073] (2) Since the added parasitic filter structure has little effect on the antenna performance and the parasitic branches do not affect the antenna size, it is conducive to the miniaturization design of the antenna system (radar).

[0074] (3) By adding a parasitic branch filter structure with short branches on one side of the antenna, the isolation between the channels of the entire MIMO antenna can be improved by 30db or more. The horizontal beam of the antenna is pointed to the front or rear side of the vehicle body. By improving the gain of the antenna on the front or rear side of the vehicle body, the detection distance of the radar on the front or rear side of the vehicle body can be increased.

[0075] (4) At the same time, the high-frequency stopband filter covers 80-90 GHz, and the antenna gain bandwidth covers the radar operating frequency band of 76.5-78.5 GHz, which fully meets the radar broadband design and greatly improves the ranging resolution.

[0076] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A filtering antenna for a vehicle-mounted millimeter-wave radar, characterized in that: It comprises a microstrip array antenna structure, a parasitic branch filter structure and a feeding transmission line, wherein the parasitic branch filter structure is connected to the microstrip array antenna structure through the feeding transmission line; The parasitic branch filter structure includes a fan-shaped patch structure, a microstrip structure and a ground connection copper-clad via, one end of the microstrip structure is connected to one side of the feeding transmission line, and the other end is respectively connected to the fan-shaped patch structure and the ground connection copper-clad via; The fan-shaped patch structure connected to the end of the microstrip array antenna structure forms a capacitive adjustment element, and is combined with the microstrip structure and the ground connection copper-clad hole to form an inductive adjustment element for performing high-frequency coupling signal filtering.

2. The filtering antenna for vehicle-mounted millimeter-wave radar according to claim 1, characterized in that: The microstrip structure includes a first microstrip branch and a second microstrip branch; one end of the first microstrip branch is connected to the fan-shaped patch structure to form a capacitive adjustment element, and the other end is connected to one side of the feeding transmission line; one end of the second microstrip branch is connected to a side of the first microstrip branch away from the microstrip array antenna structure, and the other end is connected to the ground connection copper hole.

3. The filtering antenna for vehicle-mounted millimeter-wave radar according to claim 1, characterized in that: It also includes an impedance transformation structure, one end of which is connected to the feeding transmission line, and the other end is connected to the microstrip array antenna structure. The feeding transmission line is connected to the microstrip array antenna structure through the impedance transformation structure.

4. The filtering antenna for vehicle-mounted millimeter-wave radar according to claim 3, characterized in that: The length of the impedance transformation structure is one quarter of a wavelength.

5. The filtering antenna for vehicle-mounted millimeter-wave radar according to claim 3, characterized in that: The microstrip array antenna structure comprises a microstrip comb patch array antenna, which comprises a microstrip feed line and a plurality of radiators, wherein the plurality of radiators are cross-distributed on opposite sides of the microstrip feed line along the length direction of the microstrip feed line.

6. The filtering antenna for vehicle-mounted millimeter-wave radar according to claim 5, characterized in that: The microstrip array antenna structure also includes a matching structure, which is arranged between the impedance transformation structure and the microstrip comb-shaped patch array antenna. The feeding transmission line is connected to the microstrip comb-shaped patch array antenna through the impedance transformation structure and the matching structure in sequence.

7. The filtering antenna for vehicle-mounted millimeter-wave radar according to claim 6, characterized in that: The matching structure is a square structure.

8. The filtering antenna for vehicle-mounted millimeter-wave radar according to claim 1, characterized in that: The feeding transmission line is a microstrip transmission line, and the microstrip transmission line is a 50-ohm microstrip feeding line.

9. An antenna system for a vehicle-mounted millimeter-wave radar, comprising a dielectric substrate and a four-channel antenna array, wherein the four-channel antenna array adopts a MIMO array layout, and is characterized in that: The antenna array is a filtering antenna as claimed in any one of claims 1 to 8; The filtering antenna comprises a microstrip array antenna structure, a parasitic branch filtering structure and a feeding transmission line; the parasitic branch filtering structure comprises a fan-shaped patch structure, a first microstrip branch, a second microstrip branch and a ground connection copper-clad hole; The fan-shaped patch structure, the first microstrip branch, the second microstrip branch and the ground connection copper-clad hole are distributed on the upper surface of the dielectric substrate, and the lower surface is used as a ground reference plane and is connected to the second microstrip branch through the ground connection copper-clad hole.

10. The antenna system for a vehicle-mounted millimeter-wave radar according to claim 9, characterized in that: It also includes a grounded coplanar waveguide and an electronic chip distributed on the upper surface of the dielectric substrate, and the filtering antenna is connected to the electronic chip through the grounded coplanar waveguide.

Images