CN106911013B

CN106911013B - Array antenna and antenna system

Info

Publication number: CN106911013B
Application number: CN201510979037.8A
Authority: CN
Inventors: 黄国书; 萧兴隆
Original assignee: Wistron Neweb Corp
Current assignee: Wistron Neweb Corp
Priority date: 2015-12-23
Filing date: 2015-12-23
Publication date: 2020-06-12
Anticipated expiration: 2035-12-23
Also published as: CN106911013A

Abstract

An array antenna and an antenna system. The array antenna forms a main beam, the main beam faces a beam direction, and the array antenna comprises: the radiator comprises a plurality of radiators, a first antenna, a second antenna and a third antenna, wherein the radiators are provided with a plurality of central lines and are arranged on a straight line, and the straight line penetrates through the central lines; and a plurality of meanders connecting the plurality of radiators; the array antenna is arranged on a first plane, a non-zero offset angle is formed between the beam direction and a normal direction, and the normal direction is perpendicular to the first plane. The antenna system of the invention can achieve the same detection range in the horizontal plane and the vertical plane.

Description

Array antenna and antenna system

Technical Field

The present invention relates to an array antenna and an antenna system, and more particularly, to an array antenna and an antenna system that achieve the same detection range in the horizontal direction and the vertical direction.

Background

The array antenna is an antenna system formed by arranging a plurality of same antennas according to a certain rule, and the array antenna can achieve a specific radiation pattern by adjusting the arrangement mode of antenna components in the array antenna, so that a main beam is concentrated in a specific direction to transmit signals. For example, for a radar system for a vehicle, the array antenna is usually configured to detect a horizontal direction in two dimensions. However, in practical applications, only two-dimensional detection in the horizontal direction may be reflected from objects above the horizontal plane (e.g., billboards, traffic signs, bridges, buildings, etc.), often resulting in False alarms (False Alarm) due to hardware limitations, which reduce system performance. In this case, if a radio frequency system with a three-dimensional scanning function is provided for the vehicle radar system and the horizontal and vertical directions are detected simultaneously, it is helpful to distinguish the reflection from the horizontal or vertical direction, increase the reliability of the system, and further reduce the false alarm rate.

Conventionally, the most intuitive way to add the detection function in different directions is to add another array antenna and adjust the placement of the antenna elements to perform the detection in the vertical direction. However, in the radar system for a vehicle, a wireless signal transceiver is installed inside a bumper or a fan grill cover of the vehicle, and is used for ranging, information exchange, and the like. Since the bumper of a vehicle is usually installed with a shock-absorbing Styrofoam or fiberglass, the available space is very limited, and it is difficult to add an additional array antenna. Furthermore, if the car radar system is sold in the aftermarket, i.e. radar suppliers cannot participate in the decision of the material and thickness of the bumper, in this case, the design requirements of the gain, area, radiation pattern, etc. of the array antenna are more strict in order to be suitable for most cars as much as possible.

Dual polarized antenna systems including horizontally polarized antennas and vertically polarized antennas have been developed in the prior art to provide three-dimensional scanning functions in the horizontal and vertical directions. However, the horizontal polarization antenna and the vertical polarization antenna of the conventional dual-polarization antenna system cannot achieve the same detection range, so that the system performance is reduced. In addition, the horizontal polarization antenna and the vertical polarization antenna of the dual-polarization antenna system need to be designed individually, and need to be realized through a special stack structure in the manufacturing process, which has higher design complexity and production cost.

Therefore, how to achieve the same detection range in the horizontal direction and the vertical direction has become one of the goals of the industry.

Accordingly, there is a need to provide an array antenna and an antenna system to meet the above-mentioned needs.

Disclosure of Invention

Therefore, it is a primary objective of the claimed invention to provide an array antenna and an antenna system that achieve the same detection range in the horizontal direction and the vertical direction, so as to improve the disadvantages of the prior art.

The invention discloses an array antenna, which forms a main beam facing to a beam direction and comprises: the radiator comprises a plurality of radiators, a first antenna, a second antenna and a third antenna, wherein the radiators are provided with a plurality of central lines and are arranged on a straight line, and the straight line penetrates through the central lines; and a plurality of meanders (meanders) connecting the plurality of radiators; the array antenna is arranged on a first plane, a non-zero offset angle is formed between the beam direction and a normal direction, and the normal direction is perpendicular to the first plane.

The invention also discloses an antenna system which is arranged on a first plane and comprises at least one offset array antenna and at least one offset main beam, wherein the at least one offset main beam faces to the direction of the at least one offset beam; and at least one first array antenna forming at least one first main beam, the at least one first main beam facing at least one first beam direction; wherein the at least one first beam direction and the at least one offset beam direction have a non-zero angular difference.

The invention also discloses an antenna system, which is arranged on a first plane and comprises: at least one array antenna, wherein the at least one array antenna forms at least one main beam, and the at least one main beam faces to at least one beam direction; and at least one offset array antenna, the at least one offset array antenna forming at least one offset main beam, the at least one offset main beam facing at least one offset beam direction; wherein the at least one beam direction and the at least one offset beam direction have a non-zero angular difference.

The invention uses the meander to connect with a plurality of radiators in series, so that the beam direction of the main beam deviates from the normal direction of the setting plane, and uses the array antennas forming different beam directions to scan and detect in the vertical direction, so that the antenna system of the invention can reach the same detection range in the horizontal plane and the vertical plane.

Drawings

Fig. 1A is a top view of an array antenna according to an embodiment of the invention.

Fig. 1B is an isometric view of an array antenna in accordance with an embodiment of the present invention.

Fig. 2 is a top view of an antenna system according to an embodiment of the invention.

Fig. 3 is a diagram of an antenna radiation pattern of the antenna system of fig. 2.

Fig. 4 is a top view of an antenna system according to an embodiment of the invention.

Fig. 5 is a top view of an antenna system according to an embodiment of the invention.

Fig. 6 is an antenna radiation pattern diagram of the array antenna of fig. 1A.

Fig. 7 is a schematic diagram of a difference and ratio of the antenna system of fig. 2.

Description of the main component symbols:

10. 200, 202, 204, 402, 504, array antenna

600～616、701～708

20. 40, 50, 60, 70 antenna system

FD _ a, FD _ b, FD _1 feed points

MLB _ a, MLB _ b, MLB _2, MLB _4 Main Beam

D _ a, D _ b, D _2, D _4 beam directions

N normal direction

θ_a、θ_bAngle of rotation

Angle difference of theta

PA, PA0, PA2 and PA4 radiators

MD serpentine

LS center line

LN, LN0, LN2, LN4 straight line

Phase centers of PC, PC0, PC2 and PC4

PCL phase center line

Distance of DS straight line

X, Y, Z coordinate axes

S1 first side

S2 second side

DE. DA direction

Detailed Description

Referring to fig. 1A and 1B, fig. 1A and 1B are a top view and an isometric view of an array antenna 10 according to an embodiment of the present invention, and for convenience of description, fig. 1A and 1B are indicated by a coordinate system with an axis X, Y, Z. The array antenna 10 includes a plurality of radiators PA and a plurality of meanders (meanders) MD, the plurality of meanders MD are used to connect the plurality of radiators PA, the plurality of radiators PA are arranged on a straight line LN, each radiator PA has a center line LS (i.e., the plurality of radiators PA have a plurality of center lines LS), the straight line LN runs through (or is connected in series with) the plurality of center lines LS, the plurality of meanders MD connect the plurality of radiators PA, and both ends of the plurality of meanders MD are respectively connected to the center lines LS of the radiators PA. The array antenna 10 has a phase center PC, and the pair of array antennas 10Referred to as the phase center PC. The radiators PA have a linear distance DS between them, the serpentine MD has a length L _ MD which is greater than the linear distance DS and a length difference delta between the length L _ MD and the linear distance DS, the length difference delta being greater than zero. In one embodiment, the length difference δ may be related to the wavelength λ of the electromagnetic wave transmitted by the array antenna 10, for example, the length difference δ may be 0.11 times the wavelength. The plurality of meanders MD may form a phase difference between the plurality of radiators PA

Phase difference

Proportional to the length L _ MD of the serpentine MD, i.e., the longer the length L _ MD of the serpentine MD, the phase difference

The larger. Specifically, referring to fig. 6, fig. 6 is a diagram of an antenna radiation pattern of the array antenna 10, wherein a dotted line and a thick black line represent the radiation pattern when the length L _ MD of the meandering element MD of the array antenna 10 is greater than the linear distance DS between the radiators PA (i.e. the length difference δ is greater than zero), and a thin black line represents the radiation pattern when the length difference δ is equal to zero, as can be seen from fig. 6, the length difference δ between the length L _ MD of the meandering element MD and the linear distance DS can cause a phase difference

Thereby causing the main beam formed by the array antenna 10 to have an angular offset.

Specifically, the array antenna 10 may be disposed on a first plane formed by the X-axis and the Y-axis, and the first plane has a normal direction N, which is perpendicular to the first plane (i.e., parallel to the Z-axis). Generally, the array antenna 10 forms a main beam (Mainlobe) MLB, and the main beam MLB faces a beam direction D having an offset angle θ different from zero degrees from the normal direction N. Taking fig. 1B as an example, when the array antenna 10 is fed from a feeding point FD _ B (i.e. an end of the array antenna 10), the array antenna 10 may form a main beam MLB _ a and the main beam MLBA is directed to a beam direction D _ a having an offset angle theta between the beam direction D _ a and the normal direction N which is non-zero_a(ii) a When the array antenna 10 is fed from a feeding point FD _ a (i.e. the other end of the array antenna 10), the array antenna 10 may form a main beam MLB _ b, and the main beam MLB _ b faces a beam direction D _ b, and an offset angle θ between the beam direction D _ b and the normal direction N is different from zero_b。

In short, the array antenna 10 uses the meanders MD to form the phase difference between the radiators PA

In this way, the beam direction D of the main beam MLB formed by the array antenna 10 can be shifted from the normal direction N of the first plane. The array antenna 10 may be used in an antenna system. Referring to fig. 2 and 3, fig. 2 is a top view of an antenna system 20 according to an embodiment of the present invention, fig. 3 is a diagram of an antenna radiation pattern of the antenna system 20, and fig. 2 and 3 also indicate a coordinate system with an axis X, Y, Z. The antenna system 20 is a one-transmit-two-receive Frequency-Modulated Continuous Wave (FMCW) radar antenna system, which is disposed on a first plane formed by an X-axis and a Y-axis. The antenna system 20 may be applied to a vehicle radar system, which may be vertically disposed inside a bumper or a fan grill cover of a vehicle, the antenna system 20 includes a transmitting array antenna 200, an array antenna 202, and an offset array antenna 204, the offset array antenna 204 may be implemented by using the array antenna 10, the transmitting array antenna 200 is used for transmitting a signal, and the array antenna 202 and the offset array antenna 204 are used for receiving a reflected signal. Specifically, the array antenna 202 forms a main beam MLB _2, the main beam MLB _2 faces a beam direction D _2, and the offset array antenna 204 forms an offset main beam MLB _4, the offset main beam MLB _4 faces an offset beam direction D _4, the beam direction D _2 and the offset beam direction D _4 have a non-zero angle difference θ.

In detail, the tx array antenna 200 includes a plurality of tx radiators PA0 and a plurality of linear connectors CN, a plurality of tx radiators PA0 are arranged on a straight line LN0, the tx array antenna 200 has a tx phase center PC0, and the tx array antenna 200 is symmetrical to the tx phase center PC 0; the array antenna 202 includes a plurality of radiators PA2, the radiators PA2 are arranged on a straight line LN2, the array antenna 202 has a phase center PC2, and the array antenna 202 is symmetrical to the phase center PC 2; the offset array antenna 204 includes a plurality of offset radiators PA4 and a plurality of meanders MD, the plurality of offset radiators PA4 are arranged on an offset straight line LN4, the offset array antenna 204 has an offset phase center PC4, and the offset array antenna 204 is symmetrical to the offset phase center PC 4. Lines LN0, LN2, LN4 are parallel to each other, and the transit phase center PC0, the phase center PC2, and the offset phase center PC4 are aligned with each other on a phase center line PCL perpendicular to the lines LN0, LN2, LN 4.

It should be noted that the plurality of radiators PA2 in the array antenna 202 are connected in series by a plurality of straight connectors CN, so that the beam direction D _2 corresponding to the main beam MLB _2 is parallel to the normal direction N of the first plane (i.e. the Z-axis direction); the offset radiators PA4 of the offset array antenna 204 are connected in series by the meanders MD, and the meanders MD form a phase difference between the radiators PA

Such that there is a non-zero angular difference θ between the offset beam direction D _4 and the beam direction D _2 of the corresponding offset main beam MLB _ 4.

Further, the antenna system 20 further includes a processing unit 206, wherein the processing unit 206 is coupled to the transmit array antenna 200, the array antenna 202, and the offset array antenna 204, i.e., the processing unit 206 is coupled to the transmit array antenna 200, the array antenna 202, and the offset array antenna 204 through a plurality of feed points FD _ 1. In the antenna system 20, the feeding points FD _1 are located at a first side S1 of the antenna system 20, i.e., the transmitting array antenna 200, the array antenna 202, and the offset array antenna 204 are all fed from the first side S1 of the antenna system 20. The processing unit 206 may operate in an Amplitude-contrast Mono-Pulse mode or a Phase-contrast Mono-Pulse mode. In one embodiment, the antenna system 20 is disposed in an XY plane, and since the array antenna 202 and the offset array antenna 204 have different angles of the main beams MLB _2 and MLB _4 in a first direction DE parallel to an XZ plane, the antenna system 20 can operate in a amplitude-comparison single-pulse mode through the transmitting array antenna 200, the array antenna 202 and the offset array antenna 204 to perform the target object detection and angle identification on the XZ plane (the first direction DE). Meanwhile, the main beams MLB _2 and MLB _4 have no angular difference in a second direction DA parallel to a YZ plane, so that the antenna system 20 can operate in a phase-contrast monopulse mode through the transmitting array antenna 200, the array antenna 202 and the offset array antenna 204 to perform object detection and angular recognition on the YZ plane (the second direction DA). Specifically, when the antenna system 20 is vertically disposed on a vertical plane, i.e., the XY plane is a vertical plane, the YZ plane is a horizontal plane, the first Direction DE is a vertical Direction (Elevation Direction), and the second Direction DA is a horizontal Direction (Azimuth Direction), the first Direction DE is perpendicular to the second Direction DA.

Referring to fig. 7, fig. 7 is a schematic diagram of a Delta-sum ratio (Δ/Σ) when the antenna system 20 operates in the amplitude-comparison single-pulse mode, and as can be seen from fig. 7, the antenna system 20 can perform target object detection and angle identification on the XZ plane, and the angle identification range is about plus or minus 10 degrees.

In addition, referring to fig. 4, fig. 4 is a top view of an antenna system 40 according to an embodiment of the invention, and fig. 4 also shows a coordinate system with X, Y, Z axes. The antenna system 40 is similar to the antenna system 20 and like components are labeled with like reference numerals. Unlike the antenna system 20, the antenna system 40 further includes an array antenna 402, the array antenna 402 is used for receiving the reflected signal, i.e. the antenna system 40 is a one-transmit-three-receive antenna system, the array antenna 402 has the same structure as the array antenna 202, i.e. the main beam formed by the

array antennas

202 and 402 is oriented in the beam direction parallel to the Z-axis. Antenna system 40 may operate in a phase-contrast monopulse mode with transmit array antenna 200 and

array antennas

202, 402, while antenna system 40 may operate in a phase-contrast monopulse mode with transmit array antenna 200 and array antenna 202 and offset array antenna 204 (or with transmit array antenna 200 and array antenna 402 and offset array antenna 204). Similarly, when the antenna system 40 is disposed on the vertical plane, the antenna system 40 can perform the detection and angle recognition of the target object in the second direction DA parallel to the YZ plane by using the single pulse mode, and the antenna system 40 can perform the detection and angle recognition of the target object in the XZ plane by using the single pulse mode. Note that, in the antenna system 20, the component on the YZ plane that offsets the array antenna 204 has a smaller gain than the array antenna 202, resulting in a shorter detection distance; in contrast, the antenna system 20 increases the gain parallel to the YZ plane with the

array antennas

202, 402, increasing the detection distance on the YZ plane. In addition, the antenna system 40 utilizes three

array antennas

202 and 402 and the offset array antenna 204 to receive the reflected signals, and utilizes different array antennas to operate in the phase single pulse mode and the amplitude single pulse mode, respectively, so that the antenna system 40 has better isolation for detecting the angles in the first direction DE and the second direction DA than the antenna system 20.

Referring to fig. 5, fig. 5 is a top view of an antenna system 50 according to an embodiment of the invention, and fig. 5 also shows a coordinate system with X, Y, Z axes. Antenna system 50 is similar to antenna system 40, and like components are labeled with like numerals. Unlike the antenna system 40, the antenna system 50 further includes an offset array antenna 504, the offset array antenna 504 has the same structure as the offset array antenna 204, and the offset array antenna 504 is also used for receiving the reflected signal, i.e. the antenna system 50 is a one-transmit four-receive antenna system. In addition, the feeding position of the offset array antenna 504 is different from the feeding positions of the transmitting array antenna 200, the

array antennas

202 and 402, and the offset array antenna 204, in other words, the feeding point of the transmitting array antenna 200, the

array antennas

202 and 402, and the offset array antenna 204 is located on a first side S1 (i.e., coupled to a processing unit 506 of the antenna system 50 by the first side S1) from the feeding point of the antenna system 50, and the offset array antenna 504 is located on a second side S2 (i.e., coupled to the processing unit 506 of the antenna system 50 by the second side S2) from the feeding point of the antenna system 50. It should be noted that the different feeding positions of the offset array antenna 204 and the offset array antenna 504 cause the main beams formed by the offset

array antennas

204 and 504 to be respectively offset by a positive angle and a negative angle from the Z axis, and for different applications, the antenna system 50 can operate in the amplitude-comparison single-pulse mode through the transmitting array antenna 200 and the offset

array antennas

204 and 504, so that the antenna system 50 has a wider scanning and detecting angle in the XZ plane than the antenna system 40.

It should be noted that the foregoing embodiments are provided to illustrate the concept of the present invention, and those skilled in the art should be able to make various modifications thereto without being limited thereto. For example, in fig. 4, the antenna system 40 is not limited to operating in the phase-comparison monopulse mode through the transmitting array antenna 200 and the

array antennas

202 and 402, and as long as the antenna system 40 receives the reflected signals through two of the

array antennas

202 and 402 and the offset array antenna 204, the processing unit 206 of the antenna system 40 can control the antenna system 40 to operate in the phase-comparison monopulse mode, that is, the antenna system 40 operates in the phase-comparison monopulse mode through any two of the

array antennas

202 and 402 and the offset array antenna 204, and it also falls within the scope of the present invention.

In addition, in fig. 5, the antenna system 50 is not limited to operating in the amplitude monopulse mode through the transmitting array antenna 200 and the offset

array antennas

204 and 504, and the processing unit 206 of the antenna system 50 may control the antenna system 50 to operate in the amplitude monopulse mode as long as the antenna system 50 receives the reflected signals through any two array antennas that can form different beam directions. For example, it is within the scope of the present invention that the antenna system 50 may receive the reflected signal through one of the

array antennas

202, 402 and one of the offset

array antennas

204, 504, and that the antenna system 50 may operate in a single-pulse-amplitude mode. In addition, the antenna system 50 may receive the reflected signals through any two of the

array antennas

202, 402 and the offset

array antennas

204, 504, and the processing unit 206 of the antenna system 50 may control the antenna system 50 to operate in the phase comparison monopulse mode, which also falls within the scope of the present invention.

In summary, the present invention uses the meander element to connect a plurality of radiators in series, so that the beam direction of the main beam is shifted from the normal direction of the setting plane, and the array antenna forming different beam directions is used to perform scanning and detection in the vertical direction, so that the antenna system of the present invention can achieve the same detection range in the horizontal plane and the vertical plane.

The above-described embodiments are merely exemplary embodiments of the present invention, and all equivalent changes and modifications made according to the claims of the present invention should be covered by the scope of the present invention.

Claims

1. An array antenna forming a main beam, the main beam being directed in a beam direction, the array antenna comprising:

the plurality of radiators are arranged on a first plane and arranged on a straight line, and the straight line penetrates through the plurality of central lines; and

a plurality of meanders connecting the plurality of radiators on the first plane such that the plurality of meanders and the plurality of radiators are connected in series with each other along the straight line;

the array antenna is arranged on the first plane, a non-zero offset angle is formed between the beam direction and a normal direction, and the normal direction is perpendicular to the first plane.

2. The array antenna of claim 1, wherein the array antenna has a phase center, the array antenna being symmetric to the phase center.

3. The array antenna of claim 1, wherein the lengths of the plurality of meanders are related to the magnitude of the offset angle.

4. The array antenna of claim 1, wherein the array antenna is fed from one end of the array antenna.

5. An antenna system disposed in a first plane, the antenna system comprising:

at least one array antenna, wherein the at least one array antenna forms at least one main beam, and the at least one main beam faces to at least one beam direction; and

at least one offset array antenna, wherein the at least one offset array antenna forms at least one offset main beam, and the at least one offset main beam faces to at least one offset beam direction;

wherein the at least one beam direction and the at least one offset beam direction have a non-zero angular difference;

wherein each of the at least one offset array antenna comprises:

the plurality of offset radiators are arranged on the first plane and arranged on an offset straight line, and the offset straight line penetrates through the plurality of central lines; and

a plurality of meanders connecting the plurality of offset radiators on the first plane such that the plurality of meanders and the plurality of offset radiators are connected in series with each other along the offset straight line;

wherein the at least one offset beam direction has at least one offset angle with a non-zero degree with a normal direction, and the normal direction is perpendicular to the first plane.

6. The antenna system of claim 5, wherein the lengths of the meanders are related to the magnitude of the at least one offset angle.

7. The antenna system of claim 5, wherein each of the at least one array antenna comprises a plurality of first radiators arranged in a first straight line and a plurality of straight connectors connecting the plurality of first radiators, and the first straight line and the offset straight line are parallel to each other.

8. The antenna system of claim 5, wherein the at least one offset array antenna has at least one offset phase center, the at least one array antenna has at least one first phase center, and the at least one offset phase center and the at least one first phase center are aligned with each other.

9. The antenna system of claim 5, wherein the at least one offset array antenna comprises a first offset array antenna and a second offset array antenna, the first offset array antenna being fed at a first side of the antenna system, the second offset array antenna being fed at a second side of the antenna system.

10. The antenna system of claim 5, further comprising:

a transmit array antenna for transmitting a signal;

a processing unit coupled to the at least one offset array antenna, the at least one array antenna, and the transmit array antenna;

wherein the processing unit controls the at least one offset array antenna, the at least one array antenna, and the transmit array antenna such that the antenna system operates in an amplitude monopulse mode or a phase monopulse mode.

11. The antenna system of claim 10, wherein the antenna system performs angular discrimination in a first direction when the antenna system is operating in the single pulse mode.

12. The antenna system of claim 11, wherein the antenna system performs angular discrimination in a second direction perpendicular to the first direction when the antenna system operates in the phase-comparison monopulse mode.

13. The antenna system of claim 10, wherein the antenna system operates in the amplitude-comparison monopulse mode using a first offset array antenna of the at least one offset array antenna and a first array antenna of the at least one array antenna; the antenna system operates in the phase-comparison monopulse mode using the first offset array antenna and the first array antenna.

14. The antenna system of claim 10, the antenna system operating in the amplitude-modulated monopulse mode using one of a first array antenna, a second array antenna, and a first offset array antenna of the at least one offset array antenna; the antenna system operates in the phase-comparison monopulse mode by using two of the first array antenna, the second array antenna, and the first offset array antenna.

15. The antenna system of claim 10, the antenna system operating in the amplitude-modulated monopulse mode using one of a first array antenna and a second array antenna of the at least one array antenna, and one of a first offset array antenna and a second offset array antenna of the at least one offset array antenna; the antenna system operates in the phase-comparison monopulse mode by using two of the first array antenna, the second array antenna, the first offset array antenna and the second offset array antenna.

16. The antenna system of claim 10, the antenna system operating in the amplitude-modulated monopulse mode with a first and a second offset array antenna of the at least one offset array antenna; the antenna system operates in the phase comparison monopulse mode by using two of a first array antenna of the at least one array antenna, a second array antenna of the at least one array antenna, the first offset array antenna and the second offset array antenna, wherein the feeding position of the first offset array antenna is a first side of the antenna system, and the feeding position of the second offset array antenna is a second side of the antenna system.