Antenna device and radar

Abstract

An antenna device and a radar. The antenna device comprises a decoupling network and at least two antenna units. Each antenna unit comprises a radiator and a feed line; and one end of the feed line is connected to the radiator for feeding a radio frequency signal to the radiator. A preset distance is formed between feed lines of two adjacent antenna units. The decoupling network is arranged between the feed lines of the two adjacent antenna units and is indirectly coupled to the feed lines for enabling phases of currents transmitted from the feed lines of the two adjacent antenna units to the decoupling network to be opposite. According to the present application, by providing the decoupling network, coupled currents generated by the feed lines of the two adjacent antenna units can be led to the decoupling network, and the two coupled currents from different feed lines can be mutually cancelled out on the decoupling network, thereby achieving the purpose of decoupling. In addition, by providing the decoupling network, decoupling of two adjacent antenna units having a distance less than 0.5 λ can be achieved, thereby increasing the isolation degree of a high-density array antenna.

Description

Antenna devices and radars

[0001] This invention claims priority to the Chinese patent application filed with the State Intellectual Property Office on December 15, 2023, with application number 202311737720.1 and application name “Antenna Device and Radar”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of communication technology, and in particular to an antenna device and a radar. Background Art

[0003] As millimeter-wave radar applications expand, they are developing toward long-range, large-aperture, and high-angular resolution. Currently, in the millimeter-wave radar field, the spacing between millimeter-wave antenna arrays is typically greater than 1.5 times the free-space wavelength, which is a non-high-density array configuration. In this non-high-density configuration, the array antenna's pattern will have multiple grating lobes, which can cause false images when encountering reflective targets with large radar cross sections (RCS), directly impacting overall system performance.

[0004] To reduce the problem of false images caused by high grating sidelobe energy and achieve high angular resolution, a high-density array arrangement with unit antenna spacing less than 0.5 wavelengths and increased number of transmit and receive channels can be considered. However, using antenna spacing less than 0.5 wavelengths results in poor isolation, causing mutual interference between unit antennas and affecting antenna performance. Summary of the Invention

[0005] In view of this, the present application provides an antenna device and a radar to solve the above-mentioned problem of poor isolation between antennas arranged in a high-density array in the prior art.

[0006] In a first aspect, the present application provides an antenna device comprising a decoupling network and at least two antenna units. Each antenna unit comprises a radiator and a feeder line, one end of the feeder line being connected to the radiator for feeding a radio frequency signal to the radiator; the feeders of two adjacent antenna units are spaced apart by a preset distance. A decoupling network is disposed between the feeders of two adjacent antenna units, with both ends of the decoupling network indirectly coupled to the feeders of the two adjacent antenna units, so as to cause the currents transmitted from the feeders of the two adjacent antenna units to the decoupling network to have opposite phases.

[0007] The antenna device provided herein, by providing a decoupling network between two adjacent antenna elements, can introduce the coupled currents generated by the feeder lines of the two adjacent antenna elements into the decoupling network. This allows the two coupled currents from different feeder lines to cancel each other out on the decoupling network, thereby achieving decoupling. Furthermore, the decoupling network can decouple adjacent antenna elements with a spacing of less than 0.5λ, improving the isolation of high-density array antennas.

[0008] In one possible design, the decoupling network includes a first coupling branch and a second coupling branch. A first coupling gap is defined between the first coupling branch and an adjacent feeder line, and the first coupling branch includes a first coupling port. A second coupling gap is defined between the second coupling branch and another adjacent feeder line, and the second coupling branch includes a second coupling port. The first coupling port is coupled to the second coupling port, and the currents in the first coupling port and the second coupling port are in opposite phases. The current on the feeder line adjacent to the first coupling branch can be coupled to the first coupling branch and transmitted to the first coupling port, and the current generated by the feeder line adjacent to the second coupling branch can be coupled to the second coupling branch and transmitted to the second coupling port. The current at the first coupling port and the current at the second coupling port are in opposite directions. Therefore, when the currents on the first coupling port and the second coupling port are coupled to each other, they can cancel each other out, achieving decoupling.

[0009] In one possible design, the feeder includes an input port and an output port. The feeder is connected to the RF front end via the input port, and is coupled to the radiator via the output port. The first coupling port is provided at an end of the first coupling branch that is close to the input port; and / or the second coupling port is provided at an end of the second coupling branch that is close to the input port. The RF signal can be input to the feeder via the input port of the RF front end and fed into the radiator via the output port. When the distance between two adjacent antenna units is relatively close, for example, when the distance between the feeders of two adjacent antenna units is less than 0.5λ, a coupled electric field will be generated on the feeder without a decoupling network. Therefore, a decoupling network can be provided at a position corresponding to the feeder and can be indirectly coupled to the feeder to attract the coupled current caused by the feeder to the decoupling network, thereby achieving a decoupling effect between the feeders. Among them, a strong coupling electric field is easily generated near the input port on the feeder, and the coupling current on the decoupling network mainly achieves the effect of current cancellation at the first coupling port and the second coupling port. Therefore, making the first coupling port and the second coupling port closer to the input port of the feeder can enable the coupling current near the input port to be quickly and efficiently decoupled through the decoupling network.

[0010] In one possible design, the first coupling gap and / or the second coupling gap is greater than or equal to 0.01 mm. For example, the gap may be between 0.05 mm and 0.15 mm. Maintaining the gap within this range facilitates manufacturing while ensuring coupling between the decoupling network and the feeder, thereby ensuring decoupling.

[0011] In one possible design, the decoupling network further includes a first decoupling branch and a second decoupling branch, wherein the first end of the first decoupling branch is electrically connected to the first coupling port, the first end of the second decoupling branch is electrically connected to the second coupling port, and the second end of the first decoupling branch is electrically connected to the second end of the second decoupling branch. The first decoupling branch and the second decoupling branch can achieve a direct electrical connection between the first coupling port and the second coupling port, which is beneficial for achieving a cancellation effect of the coupled current on the decoupling branch. At the same time, by configuring the first decoupling branch and the second decoupling branch, the impedances of the two feed lines can be matched, so that the decoupling effect of the two feed lines meets the operating frequency band of the antenna unit.

[0012] In one possible design, the electrical length between the first end of the first decoupling branch and the second end of the first decoupling branch is 0.5Nλ, and the electrical length between the first end of the second decoupling branch and the second end of the second decoupling branch is 0.5Nλ, where N is a positive odd number and λ is the wavelength of the dielectric. This enables the decoupling network to generate current coupling with the feeder, and creates a current coupling path on the decoupling network.

[0013] In one possible design, the end of the first coupling branch away from the first coupling port further includes a first isolation port, and the end of the second coupling branch away from the second coupling port further includes a second isolation port, with the first isolation port and the second isolation port being coupled to each other. The majority of the current coupled from the feeder line to the decoupling network will cancel each other out of phase through the first decoupling branch and the second decoupling branch, while very little or no current will be coupled between the first isolation port and the second isolation port. The first isolation port and the second isolation port can match the impedance between the decoupling network and the feeder line, allowing the coupled current generated by the feeder line to be coupled to the decoupling network, thereby achieving a decoupling effect.

[0014] In one possible design, the decoupling network further includes a regulating branch, with both ends of the regulating branch electrically connected to the first isolated port and the second isolated port, respectively. The regulating branch enables direct electrical connection between the first isolated port and the second isolated port. By configuring appropriate regulating branches, impedance adjustment can be achieved, allowing the coupling current generated by the feeder to be coupled to the decoupling network, thereby achieving a decoupling effect.

[0015] In one possible design, the electrical length between the first isolated port and the first coupled port is 0.25Nλ, and the electrical length between the second isolated port and the second coupled port is 0.25Nλ, where N is a positive odd number and λ is the wavelength of the dielectric. This allows the decoupling network to generate current coupling with the feeder, creating a current coupling path on the decoupling network.

[0016] In one possible design, the first coupling branch includes a first section, a second section, and a third section. The two ends of the second section are connected to the first section and the third section respectively, and the first section and the third section are bent toward the side of the second section away from the adjacent feeder line. The end of the first section away from the second section forms the first coupling port, and the end of the third section away from the second section forms the first isolation port. The first section, the second section, and the third section can form a C-shaped structure, and the length of the second section can be relatively longer, which is conducive to introducing the coupling current generated by the adjacent feeder line into the first coupling branch. The first section protrudes toward one side of the second section, which is conducive to guiding the coupling current to the first coupling port, so as to cancel the reverse current at the second coupling port and achieve decoupling. The third section can achieve impedance matching by cooperating with the second coupling branch.

[0017] In one possible design, the second coupling branch includes a fourth segment, a fifth segment, and a sixth segment. The two ends of the fifth segment are connected to the fourth segment and the sixth segment, respectively. The fourth segment and the sixth segment are bent toward the side of the fifth segment away from the adjacent feeder line. The end of the fourth segment away from the fifth segment forms the second coupling port, and the end of the sixth segment away from the fifth segment forms the second isolation port. The fourth segment, the fifth segment, and the sixth segment can also form a C-shaped structure. The length of the fifth segment can be relatively longer, which is conducive to introducing the coupling current generated by the adjacent feeder line into the second coupling branch. The fourth segment protrudes toward one side of the fifth segment, which is conducive to introducing the coupling current into the second coupling port, so as to cancel the reverse current at the first coupling port and achieve decoupling. The sixth segment can achieve impedance matching by cooperating with the third segment.

[0018] In one possible design, the spacing between the feed lines of two adjacent antenna units is greater than or equal to 0.4λ, where λ is the free space wavelength. Thus, by providing a decoupling network, decoupling of high-density array antennas and non-high-density array antennas can be achieved, thereby improving isolation.

[0019] In one possible design, the decoupling network is integrally formed, that is, the first coupling branch, the second coupling branch, the first decoupling branch, the second decoupling branch and the adjustment branch are all integrally formed during the preparation process of the decoupling network, so that the decoupling network constitutes an integral structure, which is convenient for processing. At the same time, it can also avoid the generation of splicing gaps at the connections of each branch that affect the current distribution, thereby ensuring the decoupling effect.

[0020] In a second aspect, the present application further provides a radar comprising the antenna device provided in the first aspect of the present application. The radar comprising the aforementioned antenna device also has similar technical effects as the aforementioned antenna device, and will not be described in detail here.

[0021] It should be understood that the foregoing general description and the following detailed description are merely illustrative and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments. 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 paying any creative labor.

[0023] FIG1 is a schematic structural diagram of an antenna device provided by an embodiment of the present application;

[0024] FIG2 is a schematic structural diagram of an antenna device provided in another embodiment of the present application;

[0025] FIG3 is a partial schematic diagram of an antenna device provided by an embodiment of the present application;

[0026] FIG4 is a partial schematic diagram of an antenna device provided in another embodiment of the present application;

[0027] FIG5 is a schematic diagram of electric field distribution of the antenna device provided in the present application when no decoupling network is provided;

[0028] FIG6 is a schematic diagram of electric field distribution of the antenna device provided in the present application when a decoupling network is provided;

[0029] FIG7 is a comparison diagram of S11 simulation curves of an antenna device provided by an embodiment of the present application before and after a decoupling network is provided;

[0030] FIG8 is a comparison diagram of horizontal plane radiation patterns of an antenna device provided by an embodiment of the present application before and after a decoupling network is provided;

[0031] FIG9 is a comparison diagram of vertical plane radiation patterns of an antenna device provided by an embodiment of the present application before and after a decoupling network is provided;

[0032] FIG10 is a comparison diagram of gain curves of an antenna device provided by an embodiment of the present application before and after a decoupling network is provided;

[0033] FIG11 is a comparison diagram of isolation simulation curves of an antenna device provided by an embodiment of the present application before and after a decoupling network is provided;

[0034] FIG12 is a comparison diagram of S11 simulation curves of an antenna device provided by another embodiment of the present application before and after a decoupling network is provided;

[0035] FIG13 is a comparison diagram of horizontal plane radiation patterns of an antenna device provided by another embodiment of the present application before and after a decoupling network is provided;

[0036] FIG14 is a comparison diagram of vertical plane radiation patterns of an antenna device provided by another embodiment of the present application before and after a decoupling network is provided;

[0037] FIG15 is a comparison diagram of isolation simulation curves of an antenna device provided by another embodiment of the present application before and after a decoupling network is provided;

[0038] FIG16 is a schematic structural diagram of a first coupling branch provided in an embodiment of the present application;

[0039] FIG17 is a schematic structural diagram of a second coupling branch provided in an embodiment of the present application.

[0040] Reference numerals:

[0041] 1-antenna unit;

[0042] 11-Radiator;

[0043] 12-feeder;

[0044] 121-input port;

[0045] 122-output port;

[0046] 1A-first antenna unit;

[0047] 1A1-first feeder;

[0048] 1B-second antenna unit;

[0049] 1B1-second feeder;

[0050] 2- Decoupling network;

[0051] 21-first coupling branch;

[0052] 211- first paragraph;

[0053] 211A-first coupling port;

[0054] 212-Second paragraph;

[0055] 213- third paragraph;

[0056] 213A-first isolation port;

[0057] 22-second coupling branch;

[0058] 221-4th paragraph;

[0059] 221A-second coupling port;

[0060] 222-5th paragraph;

[0061] 223-6th paragraph;

[0062] 223A-second isolation port;

[0063] 23-first decoupling branch;

[0064] 24-Second decoupling branch;

[0065] 25-regulate branches;

[0066] H-spacing;

[0067] a1-first coupling gap;

[0068] a2 - second coupling gap. DETAILED DESCRIPTION

[0069] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0070] It should be clear that the embodiments described 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 work are within the scope of protection of this application.

[0071] The terms used in the embodiments of the present application are for the purpose of describing specific embodiments only and are not intended to limit the present application. The singular forms "a", "an", "the" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise.

[0072] It should be understood that the term "and / or" as used herein simply describes a relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A alone, A and B together, or B alone. Furthermore, the character " / " in this document generally indicates an "or" relationship between the associated objects.

[0073] In the description of this application, unless otherwise specified or limited, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance; unless otherwise specified or explained, the term "plurality" refers to two or more; the terms "connected" and "fixed" should be understood in a broad sense. For example, "connected" can mean a fixed connection, a detachable connection, an integral connection, or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0074] Radiator: A device in an antenna used to receive / send electromagnetic wave radiation. In some cases, the narrow meaning of "antenna" is the radiator, which converts the guided wave energy from the transmitter into radio waves, or converts radio waves into guided wave energy, used to radiate and receive radio waves. The modulated high-frequency current energy (or guided wave energy) generated by the transmitter is transmitted to the transmitting radiator via the feeder line, where it is converted into a certain polarized electromagnetic wave energy and radiated in the desired direction. The receiving radiator converts the electromagnetic wave energy of a certain polarization from a specific direction in space into modulated high-frequency current energy and transmits it to the receiver input via the feeder line.

[0075] The radiator can be a conductor with a specific shape and size, such as a wire antenna. A wire antenna is an antenna composed of one or more metal wires with a wire diameter much smaller than the wavelength and a length comparable to the wavelength, and can be used as a transmitting or receiving antenna. The main forms of wire antennas include dipole antennas, half-wave oscillator antennas, monopole antennas, loop antennas, inverted F antennas (also known as IFA, Inverted F Antenna), planar inverted F antennas (also known as PIFA, Planar Inverted F Antenna), slot antennas or slot antennas, antenna arrays, etc. For example, for a dipole antenna, each dipole antenna typically includes two radiating branches, and each branch is fed by a feeding part from the feeding end of the radiating branch. For example, for a slot antenna or a slot antenna, a single radiating branch can be included, and both ends of the branch are grounded to form a slot or slot.

[0076] The radiator can also be a slot or slit formed in a conductor. For example, an antenna formed by a slit in a conductor surface can also be called a slot antenna or slot antenna. In some embodiments, the slot is elongated. In some embodiments, the slot is approximately half a wavelength long. In some embodiments, the slot can be fed by a transmission line spanning one or both sides, or by a waveguide or resonant cavity. A radio frequency electromagnetic field is excited in the slot, and electromagnetic waves are radiated into space.

[0077] Feeder: Also called a transmission line, it refers to the connection between an antenna's transceiver and the radiator. The system connecting the antenna's radiator and transceiver is called the feed system. Feeders are categorized by frequency, including wire transmission lines, coaxial transmission lines, waveguides, or microstrip lines. The feed point is the point on the radiator where the feeder connects to the radiator.

[0078] Wavelength: Or operating wavelength, this can be the wavelength corresponding to the center frequency of the resonant frequency or the center frequency of the operating frequency band supported by the antenna. For example, if the center frequency of the B1 uplink frequency band (resonant frequency 1920MHz to 1980MHz) is 1955MHz, the operating wavelength can be the wavelength calculated using 1955MHz. "Operating wavelength" is not limited to the center frequency; it can also refer to the wavelength corresponding to a non-center frequency of the resonant frequency or operating frequency band.

[0079] Electrical length: Electrical length can be expressed as the ratio of the physical length (i.e., mechanical length or geometric length) multiplied by the propagation time of an electrical or electromagnetic signal in a medium to the time required for the signal to travel a distance equal to the physical length of the medium in free space. Alternatively, electrical length can also refer to the ratio of the physical length (i.e., mechanical length or geometric length) to the wavelength of the transmitted electromagnetic wave. In some embodiments of the present application, the physical length of a radiator can be understood as the electrical length of the radiator ±10%. In embodiments of the present application, the wavelength in a certain wavelength mode of an antenna (such as a half-wavelength mode, etc.) can refer to the wavelength of the signal radiated by the antenna.

[0080] Coupling: can be understood as direct coupling and / or indirect coupling, and "coupling connection" can be understood as direct coupling connection and / or indirect coupling connection. Direct coupling can also be referred to as "electrical connection", which is understood as the physical contact and electrical conduction between components; it can also be understood as the form in which different components in the circuit structure are connected through physical lines such as printed circuit board (PCB) copper foil or wires that can transmit electrical signals; "indirect coupling" can be understood as two conductors being electrically conductive in an airless / non-contact manner. In one embodiment, indirect coupling can also be referred to as capacitive coupling, for example, signal transmission is achieved by forming an equivalent capacitance through coupling between the gap between two conductive parts.

[0081] Millimeter-wave radar can not only distinguish small targets but also identify multiple targets simultaneously. Millimeter-wave radar can be used in vehicles as onboard radar, but it can also be used in other vehicles. Antennas are key components of millimeter-wave radar systems, and their performance directly affects the radar system's detection range, detection angle, anti-interference capabilities, and resolution.

[0082] With the expansion of millimeter-wave radar application scenarios (urban scenarios, high-speed scenarios, etc.), millimeter-wave radar is developing towards long-range, large-aperture, and high-angular resolution. Currently, in the field of millimeter-wave radar, the spacing between millimeter-wave antenna arrays is usually greater than 1.5 times the wavelength, which is a non-high-density array method. In a non-high-density array method, the array antenna's radiation pattern will have multiple grating lobes, which will cause the problem of virtual scene when encountering reflective targets with large radar cross sections (RCS), directly affecting the overall performance of the system.

[0083] To reduce the problem of false images caused by high grating sidelobe energy and achieve high angular resolution, a high-density array arrangement with unit antenna spacing less than 0.5 wavelengths and increased number of transmit and receive channels can be considered. Although this arrangement offers the characteristics of no grating lobes, low sidelobes, and high angular resolution, the use of antenna spacing less than 0.5 wavelengths results in poor isolation, causing mutual interference between unit antennas and affecting antenna performance.

[0084] An embodiment of the present application provides an antenna device, which can be used in radar systems such as millimeter wave radars. The antenna device includes at least two antenna units 1, and at least two antenna units 1 can constitute an antenna array. For example, Figure 1 is a structural schematic diagram of the antenna device provided by an embodiment of the present application. Referring to Figure 1, when two antenna units 1 are provided, a dual-element antenna array can be formed. When three antenna units 1 are provided, a three-element antenna array can be formed. Figure 2 is a structural schematic diagram of the antenna device provided by another embodiment of the present application. Referring to Figure 2, when five antenna units 1 are provided, a five-element antenna array can be formed. Each antenna unit 1 includes a radiator 11 and a feeder 12, one end of the feeder 12 is connected to the radiator 11, and is used to feed a radio frequency signal to the radiator 11 so that the radiator 11 radiates energy.

[0085] Referring to Figure 1 , to ensure that adjacent antenna units can operate independently and properly and to reduce mutual interference between adjacent antenna units 1, a preset spacing H is provided between the feed lines 12 of two adjacent antenna units 1. In one embodiment, the preset spacing H can be greater than 1.5λ, where λ is the free space wavelength, thereby enabling the antenna units 1 to form a non-high-density antenna array. In another embodiment, the preset spacing H can also be between 0.4λ and 1.5λ, thereby enabling the antenna units 1 to form a high-density antenna array.

[0086] FIG3 is a partial schematic diagram of an antenna device provided by one embodiment of the present application, and FIG4 is a partial schematic diagram of an antenna device provided by another embodiment of the present application. Referring to FIG3 and FIG4, a decoupling network 2 is provided between the feeder lines 12 of two adjacent antenna units 1. The two ends of the decoupling network 2 are indirectly coupled to the feeder lines 12 of the two adjacent antenna units 1, respectively, to cause the currents transmitted from the feeder lines 12 of the two adjacent antenna units 1 to the decoupling network 2 to have opposite phases. In the arrangement direction of the two adjacent antenna units 1, there is a gap between the two ends of the decoupling network 2 and the feeder lines 12 of the two antenna units 1. The gap can form an indirect coupling connection between the decoupling network 2 and the feeder lines 12. The coupling current generated by the feeder lines 12 of the two adjacent antenna units 1 can be introduced into the decoupling network 2. The two coupling currents from the two feeder lines 12 have opposite phases, that is, the transmission directions of the two coupling currents are opposite, so that the two coupling currents can cancel each other out on the decoupling network 2, thereby achieving decoupling. Among them, the decoupling network 2 is a structure independent of the feed line 12 and does not contact the adjacent feed line 12. The decoupling network 2 can be independently adjusted, for example, the width, length, and distance between the decoupling network 2 and the adjacent feed line 12 can be adjusted, so that the decoupling network 2 can match the operating frequency of the antenna unit 1, the impedance between the antennas, etc., to achieve decoupling between the antenna units 1 that resonate in different operating frequency bands.

[0087] Thus, the antenna device provided in the embodiment of the present application, by providing a decoupling network 2 between two adjacent antenna units 1, can introduce the coupling current generated by the feed lines 12 of the two adjacent antenna units 1 into the decoupling network 2, and can cancel out the two coupling currents from different feed lines 12 on the decoupling network 2, thereby achieving the purpose of decoupling. At the same time, by providing the decoupling network 2, decoupling can be achieved between two adjacent antenna units 1 with a spacing H less than 0.5λ, thereby improving the isolation of high-density array antennas.

[0088] In one embodiment, referring to FIG1 , an example is provided in which two antenna units 1 are provided. For ease of explanation, in this embodiment, the two antenna units 1 are defined as a first antenna unit 1A and a second antenna unit 1B, respectively. The feeder 12 of the first antenna unit 1A is the first feeder 1A1, and the feeder 12 of the second antenna unit 1B is the second feeder 1B1. FIG5 is a schematic diagram of the electric field distribution of the antenna device provided in this application when the decoupling network 2 is not provided. The distance between the feeders 12 of the two antenna units 1 shown in FIG5 is less than 0.5λ, and the decoupling network 2 provided in this application is not provided. Referring to FIG5 , when the radiator 11 of the first antenna unit 1A is fed by the first feeder 1A1 (feeding at Port 1 in FIG5 ), a strong coupled electric field will be generated on the second feeder 1B1 and the radiator 11 of the second antenna unit 1B (refer to the portion of the second antenna unit 1B in the wire frame M in FIG5 ). This coupled electric field will adversely affect the radiation performance of the antenna.

[0089] In one embodiment, FIG6 is a schematic diagram of the electric field distribution of the antenna device provided by the present application when a decoupling network 2 is provided. The structural layout and feeding conditions of the antenna unit 1 shown in FIG6 and FIG5 are the same, except that a decoupling network 2 is provided between the adjacent first antenna unit 1A and the second antenna unit 1B in FIG6. Referring to FIG6, the decoupling network 2 can introduce the coupling current on the first antenna unit 1A and the second antenna unit 1B into the decoupling network 2, and can cancel each other out on the decoupling network 2, thereby achieving decoupling. Compared with the area with a strong coupling electric field shown in FIG5, the coupling electric field in the area corresponding to the second feeder 1B1 in FIG6 is significantly reduced (refer to the portion of the second antenna unit 1B in the wire frame N in FIG6), and the coupling electric field on the radiator 11 of the second antenna unit 1B is also well suppressed. Therefore, under the condition that the distance between the two adjacent antenna units 1 is less than 0.5λ, there is good isolation between the two antenna units 1, and good radiation performance can be obtained.

[0090] FIG7 is a comparison diagram of the S11 simulation curves of the antenna device before and after the decoupling network 2 is provided according to an embodiment of the present application. Curve a shown in FIG7 is the S11 curve of the dual-element antenna array shown in FIG5 (without the decoupling network 2), and curve b is the S11 curve of the dual-element antenna array shown in FIG6 (with the decoupling network 2). The horizontal axis represents the frequency, and the vertical axis represents the return loss S11. Referring to FIG7, in the frequency band of 79.5 GHz to 80.5 GHz, the S11 of curve a and curve b are both below -15 dB, that is, after the decoupling network 2 is provided, the S11 of the antenna device can still meet the requirements.

[0091] Figure 8 compares the horizontal plane patterns of an antenna device according to an embodiment of the present application before and after the decoupling network 2 is installed. Curve c (solid line) represents the horizontal plane pattern of the dual-element antenna array shown in Figure 5 (without the decoupling network 2), and curve d (dashed line) represents the horizontal plane pattern of the dual-element antenna array shown in Figure 6 (with the decoupling network 2). Referring to Figure 8 , the antenna device has minimal impact on the horizontal plane pattern before and after the decoupling network 2 is installed.

[0092] Figure 9 compares the vertical plane patterns of an antenna device provided by an embodiment of the present application before and after the decoupling network 2 is installed. Curve e (solid line) represents the vertical plane pattern of the dual-element antenna array shown in Figure 5 (without the decoupling network 2), and curve f (dashed line) represents the vertical plane pattern of the dual-element antenna array shown in Figure 6 (with the decoupling network 2). Referring to Figure 9 , the vertical plane pattern of the antenna device is minimally affected before and after the decoupling network 2 is installed.

[0093] Figure 10 compares the gain curves of an antenna device provided by an embodiment of the present application before and after the decoupling network 2 is installed. Curve g (solid line) represents the antenna gain curve of the dual-element antenna array shown in Figure 5 (without the decoupling network 2), and curve h (dashed line) represents the antenna gain curve of the dual-element antenna array shown in Figure 6 (with the decoupling network 2). Referring to Figure 10 , the effect of the decoupling network 2 on the antenna gain before and after installation is negligible.

[0094] Figure 11 is a comparison diagram of the isolation simulation curves of the antenna device before and after the decoupling network 2 is set according to an embodiment of the present application. The curve j shown in Figure 11 is the isolation curve of the dual-element antenna array shown in Figure 5 (without the decoupling network 2), and the curve k is the isolation curve of the dual-element antenna array shown in Figure 6 (with the decoupling network 2). Among them, the horizontal axis represents the frequency and the vertical axis represents the isolation. Referring to Figure 11, in the frequency band of 79.5GHz to 80.5GHz, the isolation of curve j is less than 25dB, and the corresponding isolation at a frequency of 79.5GHz is 22dB; the isolation of curve k is greater than 25dB, and the corresponding isolation at a frequency of 79.5GHz is 28.9dB. In other words, after the decoupling network 2 is set in the antenna device, the isolation can be significantly improved. In the frequency band of 79.5GHz to 80.5GHz, the isolation is improved by at least greater than or equal to 6dB.

[0095] It can be seen from this that compared with the antenna device before the decoupling network 2 is set, the isolation between two adjacent antenna units 1 is significantly improved after the decoupling network 2 is set, while the performance other than isolation, such as S11, horizontal and vertical plane directional patterns, antenna gain, etc., can still meet the requirements.

[0096] In one embodiment, for the five-element array antenna shown in FIG2 , various aspects of antenna performance before and after the decoupling network 2 is provided will be described in detail below with reference to the diagram.

[0097] Figure 12 is a comparison diagram of the S11 simulation curves of the antenna device provided by another embodiment of the present application before and after the decoupling network 2 is set, wherein Figure 12 (a) shows the S11 curve when the decoupling network 2 is not set in the five-element array antenna, and in the 79.5GHz to 80.5GHz frequency band, S11 is below -15dB. Figure 12 (b) shows the S11 curve when the decoupling network 2 is set in the five-element array antenna (refer to Figure 2), and in the 79.5GHz to 80.5GHz frequency band, S11 is below -15dB. In other words, before and after the decoupling network 2 is set, the S11 of the antenna device is basically the same and can still meet the requirements.

[0098] FIG13 is a comparison of the horizontal plane patterns of an antenna device provided by another embodiment of the present application before and after the decoupling network 2 is installed. Curve m (solid line) represents the horizontal plane pattern of the five-element antenna array without the decoupling network 2, and curve n (dashed line) represents the horizontal plane pattern of the five-element antenna array shown in FIG2 with the decoupling network 2 installed (see FIG2 ). Referring to FIG13 , the antenna device has little effect on the horizontal plane pattern before and after the decoupling network 2 is installed.

[0099] FIG14 is a comparison of the vertical plane patterns of an antenna device provided by another embodiment of the present application before and after the decoupling network 2 is installed. Curve p (solid line) represents the vertical plane pattern of the five-element antenna array without the decoupling network 2, and curve q (dashed line) represents the vertical plane pattern of the five-element antenna array shown in FIG2 with the decoupling network 2 installed (see FIG2 ). Referring to FIG14 , the vertical plane pattern of the antenna device is minimally affected before and after the decoupling network 2 is installed.

[0100] FIG15 is a comparison diagram of the isolation simulation curves of the antenna device provided by another embodiment of the present application before and after the decoupling network 2 is set, wherein FIG15(a) shows the isolation curve when the decoupling network 2 is not set in the five-element array antenna, and in the 79.5GHz to 80.5GHz frequency band, the isolation between some adjacent two antenna units 1 is less than 25dB, and the corresponding isolation at a frequency of 79.5GHz is 22dB; FIG15(b) shows the isolation curve when the decoupling network 2 is set in the five-element array antenna (refer to FIG2 ), and it can be seen that in the 79.5GHz to 80.5GHz frequency band, the isolation is greater than 25dB, and the corresponding isolation at a frequency of 79.5GHz is 28dB. In other words, after the decoupling network 2 is set in the antenna device, the isolation can be significantly improved, and in the 79.5GHz to 80.5GHz frequency band, the isolation is improved by at least greater than or equal to 6dB.

[0101] It can be seen from this that compared with the antenna device before the decoupling network 2 is set, the isolation between two adjacent antenna units 1 is significantly improved after the decoupling network 2 is set, while the performance other than isolation, such as S11, horizontal and vertical plane directional patterns, antenna gain, etc., can still meet the requirements.

[0102] Of course, in some other embodiments, for multi-element array antennas including other numbers, the isolation between two adjacent antenna units 1 can be significantly improved by providing a decoupling network 2 , which will not be detailed here one by one.

[0103] In one embodiment, the feeder 12 and decoupling network 2 can be disposed on a dielectric board, such as a printed circuit board (PCB). In one embodiment, the feeder 12, radiator 11, and decoupling network 2 are etched onto the PCB. In one embodiment, the feeder 12, radiator 11, and decoupling network 2 can also be metal sheets, such as copper sheets, which can be disposed on a dielectric material.

[0104] In one embodiment, referring to FIG3 , the decoupling network 2 includes a first coupling branch 21 and a second coupling branch 22. A first coupling gap a1 is defined between the first coupling branch 21 and an adjacent feeder line 12, and the first coupling branch 21 includes a first coupling port 211A. A second coupling gap a2 is defined between the second coupling branch 22 and another adjacent feeder line 12, and the second coupling branch 22 includes a second coupling port 221A. The first coupling port 211A is coupled to the second coupling port 221A, and the currents in the first coupling port 211A and the second coupling port 221A are in opposite phases. Among them, the coupling current generated by the feeding line 12 adjacent to the first coupling branch 21 can be coupled to the first coupling branch 21 and can be transmitted to the first coupling port 211A. The coupling current generated by the feeding line 12 adjacent to the second coupling branch 22 can be coupled to the second coupling branch 22 and can be transmitted to the second coupling port 221A. The current at the first coupling port 211A and the current at the second coupling port 221A are in opposite directions. Therefore, when the current on the first coupling port 211A and the current on the second coupling port 221A are coupled with each other, they can offset each other to achieve decoupling.

[0105] In one embodiment, referring to FIG3 , the feeder 12 includes an input port 121 and an output port 122. The feeder 12 is connected to an RF front end via the input port 121. The RF front end may include components such as a power amplifier and a filter. The feeder 12 is coupled to the radiator 11 via the output port 122. A first coupling port 211A is provided at an end of the first coupling branch 21 proximate to the input port 121; and / or a second coupling port 221A is provided at an end of the second coupling branch 22 proximate to the input port 121. For ease of illustration, this embodiment uses the example of the first coupling port 211A being provided at an end of the first coupling branch 21 proximate to the input port 121, and the second coupling port 221A being provided at an end of the second coupling branch 22 proximate to the input port 121. RF signals can be input from the RF front end into the feeder 12 via the input port 121 of the feeder 12 and fed into the radiator 11 via the output port 122. When the distance between two adjacent antenna units 1 is relatively close, for example, when the distance between the feed lines 12 of the two adjacent antenna units 1 is less than 0.5λ, a coupled electric field will be generated on the feed line 12 if a decoupling network 2 is not provided. Therefore, the decoupling network 2 can be provided at a position corresponding to the feed line 12 and can be indirectly coupled with the feed line 12, directing the coupled current generated by the feed line 12 to the decoupling network 2, thereby achieving a decoupling effect between the feed lines 12. A stronger coupled electric field is likely to be generated near the input port 121 on the feed line 12, while the coupled current on the decoupling network 2 primarily achieves a current cancellation effect at the first coupling port 211A and the second coupling port 221A. Therefore, by placing the first coupling port 211A and the second coupling port 221A closer to the input port 121 of the feed line 12, the coupled current near the input port 121 can be quickly and efficiently decoupled by the decoupling network 2.

[0106] In one embodiment, referring to FIG3 , the first coupling gap a1 and / or the second coupling gap a2 are greater than or equal to 0.01 mm. For example, the gaps may be between 0.05 mm and 0.15 mm. Maintaining the gaps within these ranges facilitates manufacturing while ensuring coupling between the decoupling network 2 and the feeder 12, thereby ensuring a good decoupling effect.

[0107] In one embodiment, referring to FIG4 , the decoupling network 2 further includes a first decoupling branch 24 and a second decoupling branch 24 . The first end of the first decoupling branch 24 is electrically connected to the first coupling port 211A, the first end of the second decoupling branch 24 is electrically connected to the second coupling port 221A, and the second end of the first decoupling branch 24 is electrically connected to the second end of the second decoupling branch 24 . The first decoupling branch 24 and the second decoupling branch 24 can achieve a direct electrical connection between the first coupling port 211A and the second coupling port 221A, which facilitates cancellation of coupled currents on the decoupling branches. Furthermore, by configuring the first decoupling branch 24 and the second decoupling branch 24 , the impedances of the two feed lines 12 can be matched, so that the decoupling effect of the two feed lines 12 meets the operating frequency band of the antenna unit 1 .

[0108] In one embodiment, in order to enable the decoupling network 2 to produce a current coupling effect with the feed line 12 and to generate a current coupling path on the decoupling network 2, the electrical length between the first end of the first decoupling branch 24 and the second end of the first decoupling branch 24 is 0.5Nλ, and the electrical length between the first end of the second decoupling branch 24 and the second end of the second decoupling branch 24 is 0.5Nλ, where N is a positive odd number, for example, N=1, 3, 5, 7, 9..., and λ is the wavelength of the medium.

[0109] In one embodiment, referring to FIG3 , the end of the first coupling branch 21 away from the first coupling port 211A further includes a first isolation port 213A, and the end of the second coupling branch 22 away from the second coupling port 221A further includes a second isolation port 223A. The first isolation port 213A is coupled to the second isolation port 223A. The current coupled from the feeder 12 to the decoupling network 2 is mostly phase-cancelled through the first decoupling branch 24 and the second decoupling branch 24, while very little or no current is coupled between the first isolation port 213A and the second isolation port 223A. The first isolation port 213A and the second isolation port 223A can match the impedance between the decoupling network 2 and the feeder 12, so that the coupling current generated by the feeder 12 can be coupled to the decoupling network 2, thereby achieving a decoupling effect.

[0110] In one embodiment, referring to FIG4 , the decoupling network 2 further includes an adjustment branch 25, the two ends of which are electrically connected to the first isolation port 213A and the second isolation port 223A, respectively. The adjustment branch 25 can achieve direct electrical connection between the first isolation port 213A and the second isolation port 223A, and impedance adjustment can be achieved by configuring appropriate adjustment branches 25. Impedance adjustment can be achieved by adjusting the width and shape of the adjustment branch 25, so as to achieve impedance matching between the decoupling network 2 and the feed line 12 at different operating frequency bands. Of course, the width or shape of the first coupling branch 21, the second coupling branch 22, the first decoupling branch 24, and the second decoupling branch 24 can also be adaptively adjusted to coordinately adjust the impedance of the decoupling network 2.

[0111] In one embodiment, in order to ensure that the decoupling network 2 between any two adjacent feeders 12 has a decoupling effect and can generate a current coupling path on the decoupling network 2, the electrical length between the first isolated port 213A and the first coupled port 211A is 0.25Nλ, and the electrical length between the second isolated port 223A and the second coupled port 221A is 0.25Nλ, where N is a positive odd number, for example, N=1, 3, 5, 7, 9, etc., and λ is the wavelength of the medium.

[0112] In one embodiment, the decoupling network 2 is an integrally formed structure, that is, the first coupling branch 21, the second coupling branch 22, the first decoupling branch 24, the second decoupling branch 24 and the adjustment branch 25 are all integrally formed during the preparation process of the decoupling network 2, so that the decoupling network 2 constitutes an integral structure, which is convenient for processing. At the same time, it can also avoid the generation of splicing gaps at the connections between the branches that affect the current distribution, and can ensure the decoupling effect.

[0113] In one embodiment, FIG16 is a schematic structural diagram of a first coupling branch 21 provided in an embodiment of the present application. Referring to FIG16 , the first coupling branch 21 includes a first section 211, a second section 212, and a third section 213. The second section 212 is connected to the first section 211 and the third section 213 at both ends, respectively. The first section 211 and the third section 213 are bent toward the side of the second section 212 away from the adjacent feeder line 12. The end of the first section 211 away from the second section 212 forms a first coupling port 211A, and the end of the third section 213 away from the second section 212 forms a first isolation port 213A. The first section 211, the second section 212, and the third section 213 can form a C-shaped structure, and the second section 212 can be relatively longer, which facilitates the introduction of coupling currents generated by the adjacent feeder line 12 into the first coupling branch 21. The first section 211 protrudes toward the second section 212 to guide the coupled current to the first coupling port 211A, thereby canceling the reverse current at the second coupling port 221A and achieving decoupling. The third section 213 can achieve impedance matching by cooperating with the second coupling branch 22.

[0114] Similarly, in one embodiment, FIG17 is a schematic structural diagram of a second coupling branch 22 provided in an embodiment of the present application. Referring to FIG17 , the second coupling branch 22 includes a fourth segment 221, a fifth segment 222, and a sixth segment 223. The ends of the fifth segment 222 are connected to the fourth segment 221 and the sixth segment 223, respectively. The fourth segment 221 and the sixth segment 223 are bent toward the side of the fifth segment 222 away from the adjacent feeder line 12. The end of the fourth segment 221 away from the fifth segment 222 forms a second coupling port 221A, and the end of the sixth segment 223 away from the fifth segment 222 forms a second isolation port 223A. The fourth segment 221, the fifth segment 222, and the sixth segment 223 may also form a C-shaped structure, and the length of the fifth segment 222 may be relatively longer, which facilitates the introduction of the coupling current generated by the adjacent feeder line 12 into the second coupling branch 22. The length of the fifth segment 222 must satisfy 0.25Nλ, where N is a positive odd number, for example, N = 1, 3, 5, 7, 9, etc., and λ is the dielectric wavelength. The fourth segment 221 protrudes toward one side of the fifth segment 222, facilitating the directing of coupled current to the second coupled port 221A, thereby canceling the reverse current at the first coupled port 211A and achieving decoupling. The sixth segment 223 can achieve impedance matching by cooperating with the third segment 213.

[0115] Among them, the first coupling branch 21 and the second coupling branch 22 are both integral structures. In order to facilitate the description of the various parts of the first coupling branch 21 and the second coupling branch 22, this embodiment divides the first coupling branch 21 into a first section 211, a second section 212 and a third section 213, and divides the second coupling branch 22 into a fourth section 221, a fifth section 222 and a sixth section 223. However, there is no clear boundary between the first section 211, the second section 212 and the third section 213, and there is no clear boundary between the fourth section 221, the fifth section 222 and the sixth section 223.

[0116] The above are merely preferred embodiments of the present application and are not intended to limit the present application. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. An antenna device, characterized in that: include: At least two antenna units, each of which comprises a radiator and a feeder, one end of the feeder is connected to the radiator for feeding a radio frequency signal to the radiator; There is a preset distance between the feed lines of two adjacent antenna units; A decoupling network is arranged between the feeder lines of two adjacent antenna units, and both ends of the decoupling network are indirectly coupled to the feeder lines of the two adjacent antenna units respectively, so as to make the current phases transmitted from the feeder lines of the two adjacent antenna units to the decoupling network opposite.

2. The antenna device according to claim 1, characterized in that The decoupling network comprises a first coupling branch and a second coupling branch, a first coupling gap is provided between the first coupling branch and an adjacent one of the feed lines, and the first coupling branch comprises a first coupling port; There is a second coupling gap between the second coupling branch and another adjacent feeding line, and the second coupling branch includes a second coupling port; The first coupling port is coupled to the second coupling port, and currents in the first coupling port and the second coupling port are in opposite phases.

3. The antenna device according to claim 2, characterized in that The feeder includes an input port and an output port, the feeder is connected to the RF front end via the input port, and the feeder is coupled to the radiator via the output port; The first coupling port is arranged at an end of the first coupling branch close to the input port; and / or the second coupling port is arranged at an end of the second coupling branch close to the input port.

4. The antenna device according to claim 2, characterized in that: The first coupling gap and / or the second coupling gap is greater than or equal to 0.01 mm.

5. The antenna device according to any one of claims 2 to 4, characterized in that: The decoupling network also includes a first decoupling branch and a second decoupling branch, wherein the first end of the first decoupling branch is electrically connected to the first coupling port, the first end of the second decoupling branch is electrically connected to the second coupling port, and the second end of the first decoupling branch is electrically connected to the second end of the second decoupling branch.

6. The antenna device according to claim 5, characterized in that The electrical length between the first end of the first decoupling branch and the second end of the first decoupling branch is 0.5Nλ, and the electrical length between the first end of the second decoupling branch and the second end of the second decoupling branch is 0.5Nλ, where N is a positive odd number and λ is a medium wavelength.

7. The antenna device according to any one of claims 2 to 6, characterized in that: The end of the first coupling branch away from the first coupling port further includes a first isolation port, the end of the second coupling branch away from the second coupling port further includes a second isolation port, and the first isolation port is coupled to the second isolation port.

8. The antenna device according to claim 7, characterized in that: The decoupling network further includes a regulating branch, and two ends of the regulating branch are electrically connected to the first isolation port and the second isolation port respectively.

9. The antenna device according to claim 7 or 8, characterized in that: The electrical length between the first isolated port and the first coupled port is 0.25Nλ, and the electrical length between the second isolated port and the second coupled port is 0.25Nλ, where N is a positive odd number and λ is a medium wavelength.

10. The antenna device according to any one of claims 7 to 9, characterized in that: The first coupling branch includes a first section, a second section and a third section, two ends of the second section are connected to the first section and the third section respectively, and the first section and the third section are bent toward a side of the second section away from an adjacent feeder line, an end of the first section away from the second section forms the first coupling port, and an end of the third section away from the second section forms the first isolation port.

11. The antenna device according to any one of claims 7 to 10, characterized in that: The second coupling branch includes a fourth section, a fifth section and a sixth section, two ends of the fifth section are connected to the fourth section and the sixth section respectively, and the fourth section and the sixth section are bent toward a side of the fifth section away from an adjacent feeder line, an end of the fourth section away from the fifth section forms the second coupling port, and an end of the sixth section away from the fifth section forms the second isolation port.

12. The antenna device according to any one of claims 1 to 11, characterized in that: The spacing between the feed lines of two adjacent antenna units is greater than or equal to 0.4λ, where λ is the free space wavelength.

13. The antenna device according to any one of claims 1 to 12, characterized in that: The decoupling network is integrally formed.

14. A radar, characterized in that: The invention comprises the antenna device as claimed in any one of claims 1 to 13.

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