Antenna array and radar detection method

Abstract

The present application discloses an antenna array and a radar detection method. The antenna array includes: a unit antenna and a coupled power-dividing feed network, wherein the unit antenna is connected to the coupled power-dividing feed network; the unit antenna includes a main feed antenna and a slave feed antenna; the coupled power-dividing feed network includes a main feed section and a slave feed section, wherein both ends of the main feed section are respectively connected to an external RF port and the main feed antenna, and the slave feed section is connected to the slave feed antenna; the slave feed section includes a coupling section and a phase-adjusting section, wherein the coupling section is arranged in parallel with the main feed section, and the phase-adjusting section is connected to the coupling section. This can expand the power-dividing ratio range of the antenna array used for millimeter-wave radar, improve the range and stability of the output signal, and simplify the structure of the antenna array.

Description

Technical Field

[0001] The present invention relates to the field of antenna transmission, and in particular to an antenna array and a radar detection method. Background Art

[0002] Common functions of automotive millimeter-wave corner radars include blind spot detection (BSD), lane change assist (LCA), and rear cross traffic alert (RCTA). Different functions require different field of view (FOV) requirements for the corner radar. When the radar is mounted at the rear of the vehicle, the radar's normal direction is at a 45° angle to the rear, with the radar's normal direction parallel to the Y-axis, which is 0°. For lane change assist, the rear corner radar is required to have a long-range detection capability at -45° (i.e., directly behind the vehicle). For rear cross traffic alert (RCTA), the rear corner radar is also required to have a long-range detection capability at +45° (i.e., laterally of the vehicle). However, to reduce false targets and other issues in road conditions, the radar's normal detection range must be lower than the ±45° detection range. To achieve these functions, the radar's field of view (FOV) must have high gain in the ±45° direction while appropriately reducing the gain at 0°. Therefore, a microstrip antenna with a special beamforming function is required.

[0003] Antenna arrays for irregular beamforming require microstrip antenna arrays with widely varying power splitting ratios within each antenna element. These antenna arrays often have power splitting ratios exceeding 1:5, and in some cases, even reaching 1:10 or even greater. However, in 77GHz millimeter-wave radars, these high power splitting ratios often result in power splitter line widths less than 0.1mm, making it difficult to maintain precision in PCB manufacturing and failing to meet automotive electronics design specifications. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides an antenna array and a radar detection method, which can expand the power splitting ratio range of the antenna array used for millimeter-wave radar, improve the range and stability of the output signal, and simplify the structure of the antenna array.

[0005] To achieve the above-mentioned purpose, the present application provides an antenna array that can be used for special-shaped beamforming of millimeter-wave radar. The antenna array includes:

[0006] A unit antenna and a coupled power division feeding network, wherein the unit antenna is connected to the coupled power division feeding network;

[0007] The unit antenna includes a main feed antenna and a slave feed antenna;

[0008] The coupled power splitter feeding network includes a main feeding section and a slave feeding section, wherein two ends of the main feeding section are respectively connected to an external RF port and the main feeding antenna, and the slave feeding section is connected to the slave feeding antenna;

[0009] The slave feeding section includes a coupling section and a phase adjustment section. The coupling section is arranged in parallel with the main feeding section, and the phase adjustment section is connected to the coupling section.

[0010] On the other hand, the present application also provides a radar detection method, wherein the radar includes the above-mentioned antenna array, and the method includes:

[0011] generating an oscillation signal by using an oscillator, and sending the oscillation signal to the main feed section;

[0012] Using a coupling section and a phase modulation section to couple and phase-modulate the oscillation signal received by the main feeding section to form an antenna pattern;

[0013] When the target object reflects the radiated signal to generate a reflection signal, receiving the reflection signal;

[0014] The target object is detected according to the transmitted signal and the reflected signal.

[0015] The implementation of this application has the following beneficial effects:

[0016] The present application sets up an antenna array including: a unit antenna and a coupled power-dividing feeding network, wherein the unit antenna is connected to the coupled power-dividing feeding network; the unit antenna includes a main feed antenna and a slave feed antenna; the coupled power-dividing feeding network includes a main feed section and a slave feed section, wherein both ends of the main feed section are respectively connected to an external RF port and the main feed antenna, and the slave feed section is connected to the slave feed antenna; the slave feed section includes a coupling section and a phase-adjusting section, wherein the coupling section is arranged in parallel with the main feed section, and the phase-adjusting section is connected to the coupling section. This can expand the power-dividing ratio range of the antenna array used for millimeter-wave radar, improve the range and stability of the output signal, and simplify the structure of the antenna array. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solution of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0018] Figure 1 A side view of an antenna array provided in an embodiment of the present application;

[0019] Figure 2A schematic diagram of the structure of an antenna array provided in an embodiment of the present application;

[0020] Figure 3 A schematic structural diagram of a coupled power splitter feeding network 2 provided in an embodiment of the present application;

[0021] Figure 4 A schematic structural diagram of an antenna array provided in another embodiment of the present application;

[0022] Figure 5 A schematic structural diagram of a slave feeder section provided in an embodiment of the present application;

[0023] Figure 6 A schematic flow chart of a radar detection method provided in an embodiment of the present application;

[0024] Figure 7 A saddle-shaped directivity pattern is provided in an embodiment of the present application. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this application.

[0026] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way are interchangeable where appropriate so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or server that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0027] In order to implement the technical solution of this application and enable more engineering and technical workers to easily understand and apply this application, the working principle of this application will be further explained in combination with specific embodiments.

[0028] An antenna is a device used to transmit and receive electromagnetic energy. Based on its own directional pattern characteristics, an antenna can receive signals from all directions in space, acting as a spatial filter. An antenna array composed of multiple elements arranged in a specific manner can achieve a scanning antenna pattern or impart other special properties. Characteristic beam antenna arrays can be used in radar, navigation, communications, and other fields. Antenna arrays can adjust the amplitude, phase, and position of array elements to meet specific requirements for their directional pattern, such as creating a null at a preset depth, achieving a preset gain value, or achieving a preset power splitting ratio.

[0029] This application can be applied to the field of millimeter-wave radar. For example, common functions of automobiles include BSD (Blind Spot Detection), LCA (Lane Change Assist), and RCTA (Rear Cross Traffic Alert). Different functions have different requirements for the field of view of the corner radar, i.e., the millimeter-wave radar. When the corner radar is installed at the rear of the vehicle, the normal direction of the corner radar is at an angle of 45° to the rear direction of the vehicle. When the normal direction of the corner radar is parallel to the Y-axis, the angle with the rear direction of the vehicle is 0°. For the lane change assist function, the rear corner radar is required to have a long-range detection function at -45° (i.e., the vehicle's rearward direction). For the rear cross traffic alert function, the rear corner radar is required to have a long-range detection function at +45° (i.e., the vehicle's lateral direction). This requires the antenna array of the corner radar to have a large adjustable range of amplitude and phase, and at the same time requires the antenna array to have a large adjustable range of power splitter ratio, so that the generated beam can have high gain, low loss, long transmission distance, and stability.

[0030] The shaped beamforming antenna array in the embodiment of the present application is a microstrip antenna array used for 77GHz millimeter-wave radar. The microstrip antenna is a metal patch with a fixed shape. It is attached to a dielectric layer (such as a polytetrafluoroethylene glass fiber laminate) with a thin metal layer on one side as a ground plane and a metal patch of a certain shape on the other side using methods such as photolithography and etching. Figure 1 The side view of the antenna array shows a laminated structure of an antenna board. Figure 1 As shown, the antenna array includes an antenna copper clad plate 01, a dielectric layer 02 and a ground copper clad layer 03. The ground copper clad layer 03 is a ground plane. Metal patches of a certain shape can be made on the antenna copper clad plate 01 by using methods such as photolithography and etching.

[0031] The following describes an embodiment of an antenna array of the present application. Figure 2 The main structural diagram of the antenna array in the first embodiment is shown in FIG. Figure 2As shown, the antenna array may include a unit antenna 1 and a coupled power splitter feed network 2. Unit antenna 1 can be a shaped metal patch fabricated using methods such as photolithography and etching, and is used to transmit transmit signals from an external RF port. The coupled power splitter feed network 2 is used within the antenna array to feed the transmitted transmit signals to the unit antennas 1 in a manner consistent with a specific amplitude distribution and phase gradient, so that the radiated signals from the two unit antennas form a spatially shaped beam. The coupled power splitter feed network 2 and unit antenna 1 are coplanar, facilitating simultaneous photolithography and simplifying fabrication.

[0032] Figure 2 In the schematic diagram of the antenna array shown, element antenna 1 is connected to a coupled power splitter feed network 2. Element antenna 1 includes a primary feed antenna 11 and a secondary feed antenna 12. Coupled power splitter feed network 2 comprises a primary feed section 21 and a secondary feed section 22. Primary feed section 21 is connected to an external RF port and primary feed antenna 11 at both ends, respectively. Secondary feed section 22 is connected to secondary feed antenna 12. Figure 3 This is a schematic diagram of the structure of a coupled power splitter feeding network 2 provided in an embodiment of the present application. Figure 3 As shown, the slave feed section 22 may include a coupling section 221 and a phase-adjustment section 222. The coupling section 221 is arranged parallel to the main feed section 21, and the phase-adjustment section 222 is connected to the coupling section 221. In the coupled power splitter feeding network 2, power and energy are transferred between the main feed section 21 and the slave feed section 12 without direct contact. The main feed section 21 is directly connected to the chip and receives the transmit signal transmitted by the chip. The slave feed section 22 uses the coupling section 221 to split off part of the transmit signal from the main feed section 21. The phase-adjustment section 222 is used to adjust the phase difference Δφ between the coupling section 221 and the main feed section 21 within an adjustment range of 360°. When the length of the phase-adjustment section 222 changes, the phase changes accordingly.

[0033] Specifically, the main feed antenna 11 includes a main feed antenna feed line and a main feed patch, with the main feed patches distributed on both sides of the main feed antenna feed line. The slave feed antenna 12 includes a slave feed antenna feed line and a slave feed patch, with the slave feed patches distributed on both sides of the slave feed line. The main feed patch and the slave feed patch are comb-shaped patches on the main feed antenna feed line and the slave feed antenna feed line, respectively. The patches are fed using the antenna feed line and the coupled power splitter feeding network. The received energy can be first distributed through the coupled power splitter feeding network, and then distributed to each patch through the antenna feed line.

[0034] Preferably, the length L1 of the main feed section 21 ≥ λg, the length L2 of the coupling section 221 meets the condition λg / 4 <L2<L1, and the edge spacing d between the main feed section 21 and the coupling section 221 ≤ λg, where λg is the wavelength of the medium. When the other parameters remain unchanged, as the length L2 of the coupling section 221 decreases, the power division ratio of the antenna array decreases in an oscillatory manner. The length L1 of the main feed section 21 ≥ λg makes the phase difference between the main feed antenna 11 and the slave feed antenna 12 form 360 degrees. When the length L2 of the coupling section 221 is between λg / 4 and L1 and the edge spacing d between the main feed section 21 and the coupling section 221 is adjusted within λg, the power division ratio of the antenna array can be changed. In this application, the power division ratio of the antenna array is a value between 1:1 and 1:20. For example, when the length L2 of the coupling section 221 is close to λg / 4, the power division ratio of the antenna array can reach close to 1:20.

[0035] In the embodiment of the present application, the edge spacing d between the main feeding section 21 and the coupling section 221 meets the minimum process restriction of PCB (Printed Circuit Board) processing.

[0036] In another embodiment, the antenna array may include a unit antenna 1 and a coupled power splitter feeding network 2. The unit antenna 1 is connected to the coupled power splitter feeding network 2. The unit antenna 1 includes a main feed antenna 11 and a slave feed antenna 12, and the main feed antenna 11 and the slave feed antenna 12 can be arranged in parallel. The coupled power splitter feeding network 2 includes a main feed section 21 and a slave feed section 22, and the two ends of the main feed section 21 are respectively connected to the external RF port and the main feed antenna 11, and the slave feed section 22 is connected to the slave feed antenna 12. The slave feed section 22 may include a coupling section 221 and a phase adjustment section 222, and the coupling section 221 and the main feed section 21 are arranged in parallel, and the phase adjustment section 222 is connected to the coupling section 221. As shown in Figure 4, the slave feed section 22 may also include a bridging section 223, and the main feed section 21 and the coupling section 221 are connected via the bridging section 223. The bridging section 223 is used to improve the coupling efficiency between the main feeding section 21 and the coupling section 221. When the length of the coupling section 221 is short, the setting of the bridging section 223 can increase the power division ratio of the antenna array to 1:1.

[0037] Specifically, the distance p between the bridging section 223 and the lower edge of the coupling section 221 does not exceed λg. By setting this distance p, the power splitting ratio of the antenna array is adjusted. The shorter the distance between the bridging section 223 and the lower edge of the coupling section 221, the higher the power splitting ratio of the antenna array. For example, if the bridging section 223 is moved from the lower edge of the coupling section 221 to a distance L2 that is half the length of the coupling section 221, the power splitting ratio of the antenna array can be increased from 1:1 to 1:20. The line width of the bridging section 223 is 0.05λg to 0.1λg.

[0038] In some embodiments, there are at least two secondary feed antennas 12, and the secondary feed segments 22 include the same number of secondary feed segments as the secondary feed antennas 12. Taking two secondary feed antennas as an example, Figure 5 A schematic structural diagram of the slave feed section when there are two slave feed antennas 12 is shown. There are also two slave feed sections in the antenna array, namely 22a and 22b. The slave feed sections 22 can be arranged on both sides of the main feed section 21. Such an arrangement can make the phase difference between one slave feed antenna 12 and the main feed antenna 11 form 180 degrees, and the phase difference between the slave feed antenna 12 on the other side and the main feed antenna 11 also form 180 degrees.

[0039] Specifically, the coupling sections 221 of the slave feeding sections 22 , the number of which is equal to the number of the slave feeding antennas 12 , are connected to the main feeding section 21 via the bridging sections 223 .

[0040] In some embodiments, the antenna form of the unit antenna 1 may include a microstrip antenna array such as a comb antenna array, a rectangular antenna array, a wall line array, a circularly polarized circular patch array, a variable pole patch array, a back-fed circular patch array or a cross-fed circularly polarized array.

[0041] The following describes an embodiment of a radar detection method of the present application. Figure 6 This is a flowchart of a radar detection method provided in an embodiment of the present application. This specification provides the method operation steps described in the embodiment or flowchart, but based on routine or non-creative work, more or fewer operation steps may be included. The order of steps listed in the embodiment is only one way of executing the steps among many, and does not represent the only execution order. Specifically, Figure 6 As shown, the method may include:

[0042] S101: Generate an oscillation signal using an oscillator, and send the oscillation signal to the main feed section.

[0043] The antenna array of the present application can be applied to the FOV (field of view) design of the millimeter wave radar. First, the millimeter wave radar generates an oscillation signal using an oscillator and sends the oscillation signal to the main feed section.

[0044] S103: Using the coupling section and the phase modulation section to couple and phase-modulate the oscillation signal received by the main feeding section, and forming a transmission signal of a preset antenna pattern based on preset antenna array parameters.

[0045] Specifically, the millimeter-wave radar first uses an oscillator to generate an oscillation signal. The received energy can be first distributed through the coupled power division feeding network in the antenna array, and then the energy is distributed to each patch through the antenna feed line to form a transmission signal with a preset antenna pattern based on the preset antenna array parameters.

[0046] S105: When the target object reflects the radiated transmission signal and generates a reflection signal, the reflection signal is received.

[0047] The main feed antenna in the antenna array on the radar is used to radiate the first target signal, and the secondary feed antenna is used to radiate the second target signal. In this way, the radar can radiate signals of target angle and target distance in the target direction.

[0048] S107: Detect obstacles based on the transmitted signal and the reflected signal.

[0049] Specifically, if the obstacle is moving, the reflected signal is appended with a Doppler frequency proportional to the obstacle's speed. Combined with the oscillation signal, this frequency can be used to calculate the distance and speed of the obstacle from the radar. If the obstacle is stationary, the oscillation and reflected signals are combined to determine the distance from the obstacle to the radar.

[0050] The embodiment of the present application provides a saddle-shaped directional pattern obtained by implementing the present application according to the requirements of a power division ratio of 1:5 and a phase difference of 180° (the solid line shows the implementation result of the present application, and the dotted line shows the directional pattern of a traditional comb antenna). Figure 7 As can be seen, the saddle pattern achieves higher gain at ±45°, with a 5dB gain difference between 0° and ±45°. Comparison with the conventional microstrip antenna pattern (shown by the dotted line) reveals that the saddle pattern improves gain by at least 3dB at ±45° compared to conventional comb antennas. Meanwhile, the gain drop at 0° is minimal, ensuring radar detection capability at 0° and enabling better LCA and RCTA capabilities. Furthermore, the gain drop at 0° is minimal, ensuring radar detection capability at 0°.

[0051] It can be seen from the above embodiments that the present application sets an antenna array including: a unit antenna and a coupled power-dividing feeding network, wherein the unit antenna is connected to the coupled power-dividing feeding network; the unit antenna includes a main feed antenna and a slave feed antenna; the coupled power-dividing feeding network includes a main feed section and a slave feed section, and the two ends of the main feed section are respectively connected to the external RF port and the main feed antenna, and the slave feed section is connected to the slave feed antenna; the slave feed section includes a coupling section and a phase adjustment section, and the coupling section is arranged in parallel with the main feed section, and the phase adjustment section is connected to the coupling section. This can expand the power division ratio range of the antenna array used for millimeter-wave radar, improve the range and stability of the output signal, and simplify the structure of the antenna array.

[0052] In the description provided herein, numerous specific details are described. However, it is understood that embodiments of the present invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques are not shown in detail so as not to obscure the understanding of this description.

[0053] Similarly, it should be understood that in order to streamline the present disclosure and aid in understanding one or more of the various inventive aspects, in the above description of exemplary embodiments of the present invention, various features of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof. However, this disclosed method should not be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as reflected in the claims of the present invention, inventive aspects lie in less than all the features of the individual embodiments disclosed above. Accordingly, the claims that follow the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of the present invention.

[0054] Those skilled in the art will appreciate that the modules in the devices of the embodiments may be adaptively changed and arranged in one or more devices different from the embodiments. The modules or units or components in the embodiments may be combined into one module or unit or component, and furthermore may be divided into a plurality of submodules or subunits or subcomponents. All features disclosed in this specification (including the accompanying claims, abstracts and drawings) and all processes or units of any method or device disclosed herein may be combined in any combination, except that at least some of such features and / or processes or units are mutually exclusive. Unless expressly stated otherwise, each feature disclosed in this specification (including the accompanying claims, abstracts and drawings) may be replaced by an alternative feature providing the same, equivalent or similar purpose.

[0055] Furthermore, those skilled in the art will appreciate that although the embodiments described herein may include certain features that are included in other embodiments but not other features, combinations of features from different embodiments are intended to be within the scope of the present invention and to form different embodiments. For example, in the claims of the present invention, any of the claimed embodiments may be used in any combination.

[0056] The present invention may also be implemented as an apparatus or system program (e.g., a computer program or computer program product) for performing part or all of the methods described herein. Such a program implementing the present invention may be stored on a computer-readable medium or in the form of one or more signals. Such signals may be downloaded from an Internet website, provided on a carrier signal, or provided in any other form.

[0057] It should be noted that the above embodiments are illustrative rather than limiting of the present invention, and that those skilled in the art may devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference symbols placed between brackets should not be construed as limiting the claims. The word "comprising" does not exclude the presence of elements or steps etc. which are not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The present invention may be implemented by means of hardware comprising several different elements and by means of appropriately programmed computers. In a unit claim enumerating several systems, several of these systems may be embodied by the same item of hardware. The use of the words first, second and third etc. does not indicate any order and these words may be interpreted as names.

Claims

1. An antenna array, characterized in that: The antenna array comprises: A unit antenna and a coupled power division feeding network, wherein the unit antenna is connected to the coupled power division feeding network; The unit antenna includes a main feed antenna and a slave feed antenna; the main feed antenna includes a main feed antenna feed line and a main feed patch, and the slave feed antenna includes a slave feed antenna feed line and a slave feed patch; The coupled power splitter feeding network includes a main feeding section and a slave feeding section, wherein two ends of the main feeding section are respectively connected to an external RF port and the main feeding antenna, and the slave feeding section is connected to the slave feeding antenna; The slave feed section includes a coupling section and a phase adjustment section. The coupling section is arranged parallel to the main feed section, and the edge spacing between the coupling section and the main feed section is used to adjust the power division ratio of the antenna array within one medium wavelength; the phase adjustment section is connected to the coupling section, and the phase adjustment section is used to adjust the phase difference between the coupling section and the main feed section. When the length of the phase adjustment section changes, the phase changes accordingly.

2. The antenna array according to claim 1, wherein: The length of the main feeding section is not less than the medium wavelength, the length of the coupling section is less than the length of the main feeding section and greater than one quarter of the medium wavelength, and the edge spacing between the main feeding section and the coupling section is less than or equal to the medium wavelength.

3. The antenna array according to claim 1, wherein: There are at least two slave feed antennas; The secondary feeding section includes secondary feeding sections whose number is equal to the secondary feeding antennas.

4. The antenna array according to claim 1, wherein: The array forms of the unit antennas include comb antenna arrays, rectangular antenna arrays, wall line arrays, circular polarization circular patch arrays, variable polarity patch arrays, back-fed circular patch arrays or cross-fed circular polarization arrays.

5. A radar detection method, characterized in that: The radar comprises the antenna array according to any one of claims 1 to 4, and the method comprises: generating an oscillation signal by using an oscillator, and sending the oscillation signal to the main feed section; The oscillation signal received by the main feeding section is coupled and phase-adjusted by using the coupling section and the phase-adjustment section, and a transmission signal of a preset antenna pattern is formed based on preset antenna array parameters; When the target object reflects the transmitted signal to generate a reflected signal, receiving the reflected signal; The target object is detected according to the transmitted signal and the reflected signal.

6. The method according to claim 5, characterized in that The antenna array parameters include: Amplitude and phase matching of the antenna array.

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