WO2021136187A1

WO2021136187A1 - Array antenna and communication device

Info

Publication number: WO2021136187A1
Application number: PCT/CN2020/140206
Authority: WO
Inventors: 罗兵; 覃雯斐; 李建平; 廖志强
Original assignee: 华为技术有限公司
Priority date: 2019-12-31
Filing date: 2020-12-28
Publication date: 2021-07-08
Also published as: CN113131194A; CN113131194B

Abstract

The present application discloses an array antenna, comprising a metal reflector, at least one first antenna unit, and at least one second antenna unit. The operating frequency of the second antenna unit is lower than that of the first antenna unit, and the first antenna unit and the second antenna unit are disposed on the metal reflector. The first antenna unit comprises a first transmission line having a first winding structure, and a first radiator. The first transmission line has a first end connected to a first signal feed inlet on the metal reflector, and a second end connected to the first radiator. The first transmission line forms a first equivalent inductor and a first parasitic capacitor by means of the first winding structure. The first equivalent inductor and the first parasitic capacitor constitute a first resonant circuit. The difference between the self-resonant frequency of the first resonant circuit and the operating frequency of the second antenna unit is within a preset range. The configuration constitutes a band-stop filter pertaining to the operating frequency of the second antenna unit, suppresses common-mode induced current, and alleviates the problem of secondary radiation.

Description

Array antenna and communication equipment

This application claims the priority of a Chinese patent application filed with the Chinese Patent Office, the application number is 201911415534.X, and the invention title is "an array antenna and communication equipment" on December 31, 2019, the entire content of which is incorporated herein by reference. Applying.

Technical field

This application relates to the field of communication technology, and in particular to an array antenna and communication equipment.

Background technique

With the continuous development of wireless communication technology, the types of antennas have become more diverse. Multi-frequency array antennas usually include two or more antenna units with different operating frequency bands. Early multi-frequency array antennas are usually large in size and weight, which makes deployment and application very inconvenient. Later, through the common aperture technology, the array antennas of different frequency bands were arranged in the same plane, which can greatly reduce the overall size of the multi-frequency array antenna, and realize the design requirements of the multi-frequency array antenna that is miniaturized, lightweight, and easy to deploy.

In the design of a common aperture array antenna, antenna units of different operating frequency bands need to be placed close to each other, as shown in Figure 1(a), for example. The multi-frequency array antenna shown in Figure 1(a) includes a low-frequency antenna unit (working in the f1 frequency band) and two high-frequency antenna units (working in the f2 frequency band). The signal radiated by the low-frequency antenna unit is coupled to the high-frequency antenna unit, causing the high-frequency antenna unit to resonate in common mode, generating low-frequency common-mode induced current, which is formed by the metal reflector between the low-frequency antenna unit and the high-frequency antenna unit The connection structure forms an induction loop, which induces secondary radiation. When the low-frequency antenna unit is placed alone, its pattern is shown in Fig. 1(b), and when the low-frequency antenna unit is placed in the manner shown in Fig. 1(a), its pattern is shown in Fig. 1(c). From the comparison of the directional patterns shown in Figure 1(b) and Figure 1(c), it can be seen that the common mode resonance of the high-frequency antenna unit placed next to the low-frequency antenna under the excitation of the radiation signal of the low-frequency antenna unit causes a secondary Radiation, the pattern of the low-frequency antenna unit is seriously degraded.

In order to solve the problem of secondary radiation caused by the common mode induced current to deteriorate the pattern of the low-frequency antenna unit, there are currently many solutions, such as changing the ground path length of the high-frequency antenna unit and extending the balun length of the high-frequency antenna unit radiator. Or load a circuit with a specific structure on the radiator of the high-frequency antenna unit. These solutions can move the resonance point of the common mode resonance of the high-frequency antenna unit to outside the working frequency band of the low-frequency antenna unit, so when the low-frequency antenna unit is working, the high-frequency antenna unit will not resonate in the common mode. However, these solutions have problems such as impedance mismatch, complex structure, and high processing cost of the high-frequency antenna unit.

Summary of the invention

The embodiment of the present application provides an array antenna. The structure of the array antenna has the effect of suppressing the common-mode induced current and alleviates the secondary radiation problem caused by the common-mode induced current. The embodiment of the present application also provides a communication device.

In a first aspect, an embodiment of the present application provides the array antenna, which includes: a metal reflector, at least one first antenna unit, and at least one second antenna unit. Wherein, the working frequency of the second antenna unit is lower than that of the first antenna unit, and the first antenna unit and the second antenna unit are arranged on the metal reflector. The first antenna unit includes a first transmission line with a first winding structure and a first radiator. The first end of the first transmission line is connected to the first signal feed inlet on the metal reflector, and the second end is connected to the first radiator. , The first transmission line forms a first equivalent inductance and a first parasitic capacitance through the first winding structure. Further, the first equivalent inductance and the first parasitic capacitance constitute a first resonant circuit, and the difference between the self-resonant frequency of the first resonant circuit and the operating frequency of the second antenna unit is within a preset range.

It can be seen from the above first aspect that, in contrast, the first antenna unit is a high-frequency antenna unit, and the second antenna unit is a low-frequency antenna unit. The difference between the self-resonant frequency of the first resonant circuit and the operating frequency of the second antenna unit is within a preset range, and a band rejection filter for the operating frequency of the second antenna unit is formed. When the first radiator on the first antenna unit is affected by the low-frequency radiation signal of the second antenna unit, common-mode resonance occurs, and a low-frequency common-mode induced current is generated. Due to the band-stop characteristic of the first resonant circuit, the common mode When the induced current flows from the first radiator to the first transmission line, it will be greatly hindered by the first resonant circuit. Therefore, the common-mode induced current cannot flow smoothly through the metal reflector to other adjacent first antenna units. The secondary radiation problem caused by the common mode induced current is alleviated, and the directivity pattern of the second antenna unit is prevented from seriously degrading.

Optionally, in the first possible implementation manner of the first aspect, the first antenna unit further includes a second transmission line having a second winding structure, and the first end of the second transmission line is connected to the second transmission line on the metal reflector. The two signal feed inlets are connected. The second end of the second transmission line is connected to the first radiator. The second transmission line forms a second equivalent inductance and a second parasitic capacitance through the second winding structure. The second equivalent inductance is connected to the second radiator. The parasitic capacitance forms the second resonant circuit, and the difference between the self-resonant frequency of the second resonant circuit and the operating frequency of the second antenna unit is within a preset range. In this solution, the first antenna unit is a dual-polarized antenna, the first transmission line and the second transmission line are two different feeders, and the common mode induced current can form an induction loop through the second transmission line. However, the difference between the self-resonant frequency of the second resonant circuit on the second transmission line and the operating frequency of the second antenna unit is within a preset range, and a band-stop filter for the operating frequency of the second antenna unit is formed. When the first radiator on the first antenna unit is affected by the low-frequency radiation signal of the second antenna unit, common mode resonance occurs, and a low-frequency common-mode induced current is generated. Due to the band-stop characteristic of the second resonant circuit, the common mode When the induced current flows from the first radiator to the second transmission line, it will be hindered by the second resonant circuit. Therefore, the common-mode induced current cannot flow smoothly through the metal reflector to other adjacent first antenna units, which reduces Secondary radiation problem caused by common mode induced current.

Optionally, in the second possible implementation manner of the first aspect, the first transmission line is a coaxial cable.

Optionally, in a third possible implementation manner of the first aspect, when the first transmission line is a coaxial cable, the first winding structure is a structure in which the first transmission line is spirally wound along the first winding axis direction. The first direction around the axis is perpendicular or parallel to the metal reflector to meet different engineering installation requirements.

Optionally, in the fourth possible implementation manner of the first aspect, when the first transmission line is a coaxial cable, the first winding structure may also be such that the first transmission line is in the first plane in a serpentine or bent shape. A structure in which one of a folded shape and a flat spiral shape is wound, and the first plane is vertical or parallel to the metal reflector. Different forms of the first winding structure can meet more diversified engineering installation requirements.

Optionally, in a fifth possible implementation manner of the first aspect, the second transmission line and the first transmission line are also coaxial cables, and the second winding structure of the second transmission line is such that the second transmission line runs along the first winding. The structure is spirally wound in the axial direction, and the second winding structure and the first winding structure form a staggered spiral structure. The staggered spiral structure can enhance the mutual inductance between the first transmission line and the second transmission line, and can obtain a larger equivalent inductance value within a limited size.

Optionally, in the sixth possible implementation manner of the first aspect, when the first transmission line or the second transmission line is a coaxial cable, the diameter of the outer conductor of the coaxial cable is less than or equal to 5 mm, so that the finite size of the A transmission line or a second transmission line forms a larger equivalent inductance value through the winding structure.

Optionally, in the seventh possible implementation manner of the first aspect, the first transmission line may also be a microstrip line or a strip line.

Optionally, in the eighth possible implementation manner of the first aspect, when the first transmission line is a microstrip line or a strip line, due to the structural characteristics of the microstrip line and the strip line, the first winding structure is the first winding structure. A structure in which a transmission line is wound in the shape of a flat spiral bend in the second plane.

Optionally, in a ninth possible implementation manner of the first aspect, the second transmission line and the first transmission line are both microstrip lines or strip lines, and the second winding structure of the second transmission line is such that the second transmission line is In the second plane, the winding structure is wound in the shape of a plane spiral bending. The second winding structure of the second transmission line and the first winding structure of the first transmission line form a plane staggered spiral bending structure, which enhances The mutual inductance between the first transmission line and the second transmission line.

Optionally, in the tenth possible implementation manner of the first aspect, when the first transmission line and the second transmission line are microstrip lines or strip lines, the width of the ground conductor and the width of the signal conductor of the microstrip line are both less than or equal to 5 mm, the width of the ground conductor of the strip line and the width of the signal conductor are both less than or equal to 5 mm.

In a second aspect, an embodiment of the present application provides a communication device, which includes the array antenna described in the foregoing first aspect or any one of the possible implementation manners of the first aspect. The communication device is specifically a wireless communication base station or other communication device that radiates and receives signals through an array antenna.

In the technical solution of the present application, the first antenna unit in the array antenna includes a first transmission line having a first winding structure and a first radiator, and the first end of the first transmission line is connected to the first signal on the metal reflector. The feed inlet is connected, the second end is connected to the first radiator, the first transmission line forms a first equivalent inductance and a first parasitic capacitance through the first winding structure, and the first equivalent inductance and the first parasitic capacitance form a first resonant circuit If the difference between the self-resonant frequency of the first resonant circuit and the operating frequency of the second antenna unit is within a preset range, a band-stop filter for the operating frequency of the second antenna unit is formed. The first antenna unit is a high-frequency antenna unit. When the first radiator on the first antenna unit is affected by the low-frequency radiation signal of the second antenna unit, common mode resonance occurs, and low-frequency common-mode induced current is generated. The band-stop characteristic of a resonant circuit. When the common-mode induced current flows from the first radiator to the first transmission line, it will be greatly hindered by the first resonant circuit, so the common-mode induced current cannot pass through the metal smoothly. The reflector flows to other adjacent first antenna units, which alleviates the secondary radiation problem caused by the common mode induced current and avoids serious deterioration of the pattern of the second antenna unit.

At the same time, the technical solution of the present application only needs to adjust the structure of the transmission line used for feeding in the array antenna, and does not need to change the original structure of the array antenna, such as the length of the grounding path, the arrangement of antenna units of different operating frequencies, etc. , So there will be no problems such as impedance mismatch. In addition, the technical solution of the present application can also use the existing transmission line to process according to a specific winding structure, which reduces the processing difficulty and processing cost.

Description of the drawings

In order to explain the technical solutions in the embodiments of the present invention more clearly, the following will briefly introduce the drawings needed in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work.

Figure 1(a) is a schematic diagram of the structure of a common aperture array antenna;

Figure 1(b) is the normal pattern of the low-frequency antenna unit in the stand-alone state;

Figure 1(c) is the pattern of the low-frequency antenna unit in the common-aperture array antenna when placed side by side with the high-frequency antenna unit;

FIG. 2 is a schematic diagram of the structure of an array antenna provided by an embodiment of the application;

3 is a schematic diagram of a winding structure of a transmission line in an embodiment of the application;

FIG. 4 is a schematic diagram of a structure of a resonant circuit in an embodiment of the application;

Figure 5 is a schematic diagram of an electromagnetic simulation software interface;

FIG. 6 is a directional diagram of the low-frequency antenna unit in the array antenna provided by the embodiment of the application when placed in parallel with the high-frequency antenna unit;

FIG. 7 is a schematic diagram of an installation method of the first transmission line in an embodiment of the application;

FIG. 8 is a schematic diagram of another installation method of the first transmission line in an embodiment of the application;

FIG. 9 is a schematic diagram of several winding structures of the transmission line in an embodiment of the application;

10 is a schematic diagram of the simulation results of the suppression effect of the resonance circuit corresponding to different inductance values;

FIG. 11 is a schematic diagram of another array antenna structure provided by an embodiment of this application;

FIG. 12 is a schematic diagram of another winding structure of a transmission line provided by an embodiment of the application;

FIG. 13 is a schematic diagram of another array antenna structure provided by an embodiment of the application;

FIG. 14 is a schematic diagram of the winding structure of a traditional strip line and the strip line in an embodiment of the present application.

Detailed ways

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

The terms "first", "second", etc. in the description and claims of the application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific sequence or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances so that the embodiments described herein can be implemented in a sequence other than the content illustrated or described herein. In addition, the terms "including" and "having" and any variations of them are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or device that includes a series of steps or modules is not necessarily limited to those clearly listed. Those steps or modules may include other steps or modules that are not clearly listed or are inherent to these processes, methods, products, or equipment. The division of modules presented in this application is a logical division. In actual applications, there may be other divisions. For example, multiple modules can be combined or integrated in another system, or some features can be ignored , Or do not execute.

In addition, in this application, unless expressly stipulated and limited otherwise, the terms "connected", "connected", "arranged" and other terms should be understood in a broad sense. For example, it may be a fixed connection or a detachable connection, or It can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above-mentioned terms in the present invention can be understood according to specific situations.

In the common-aperture array antenna, antenna units of different working frequency bands are arranged in adjacent positions. Because the signal radiated by the low-frequency antenna unit is coupled to the high-frequency antenna unit, common-mode resonance occurs in the high-frequency antenna unit, resulting in a common-mode induced current. In addition, an induction loop is formed through the connection structure between the low-frequency antenna unit and the high-frequency antenna unit, which causes secondary radiation, which will seriously deteriorate the pattern of the low-frequency antenna unit and seriously affect the parameter performance of the array antenna.

In order to solve the foregoing problem, an embodiment of the present application provides an array antenna.

Referring to FIG. 2, the array antenna provided by the embodiment of the present application may include: a metal reflector 10, at least one first antenna unit 20 and at least one second antenna unit 30. The working frequency of the second antenna unit 30 is lower than that of the first antenna unit 20, and the first antenna unit 20 and the second antenna unit 30 are arranged on the metal reflector 10.

It should be understood that, as an example, in the array antenna structure shown in FIG. 2, the number of the first antenna unit 20 is two, and the number of the second antenna unit 30 is one. The specific number and arrangement of the second antenna units are not specifically limited.

In the array antenna, the first antenna unit 20 includes a first transmission line 201 having a first winding structure and a first radiator 202. The first end of the first transmission line 201 is connected to the first signal feed port on the metal reflector 10 Connected, the second end of the first transmission line 201 is connected to the first radiator 202. The first transmission line is a transmission line used for feeding power in the first antenna unit 20. The first transmission line is preferably a transmission line in a Transverse Electromagnetic Wave (TEM) mode or a quasi-TEM mode, such as a coaxial cable, a microstrip line, and a belt. Shape lines and so on. The transmission line of TEM mode or quasi-TEM mode can achieve a smaller size, which can reduce the space occupation.

The first transmission line 201 undergoes bending and winding processing to form a first winding structure. When the first transmission line 201 is a coaxial cable, the first winding structure may be a spiral winding structure similar to an air core inductor, for example, as shown in FIG. 3, and may also be other types of winding structures. Through the first winding structure, a first equivalent inductance L1 can be formed on the first transmission line 201, and at the same time, the first transmission line 201 inevitably includes a first parasitic capacitance C1. Without considering the conductor loss, the first transmission line 201 can be simplified and equivalent to a first resonant circuit formed by the first equivalent inductance L1 and the first parasitic capacitance C1.

It should be noted that in some possible designs, the first resonant circuit may be a series resonant circuit or a parallel resonant circuit as shown in FIG. 4. In the embodiment of the present application, the first resonant circuit is configured as a parallel resonant circuit.

When the difference between the self-resonant frequency of the first resonant circuit and the operating frequency of the second antenna unit 30 is within a preset range, that is, when the self-resonant frequency of the first resonant circuit is close to the operating frequency of the second antenna unit 30, A band-stop filter for the operating frequency of the second antenna unit 30 is formed, and the size of the preset range can be set according to actual conditions. When the first radiator 202 on the first antenna unit 20 is affected by the radiation signal emitted by the second antenna unit 30, common mode resonance occurs, and a common mode induced current is generated, because the frequency of the common mode induced current is different from that of the second antenna. The working frequency of the unit 30 is the same. When the common-mode induced current flows from the first radiator 202 to the first transmission line 201, it will be greatly hindered by the first resonant circuit, so the common-mode induced current cannot pass smoothly. The first transmission line 201 flows to other adjacent first antenna units, which alleviates the secondary radiation problem caused by the common-mode induced current, and prevents the pattern of the second antenna unit 30 from being seriously degraded.

The self-resonant frequency of the first resonant circuit can be determined according to the inductance value of the first equivalent inductor L1 and the capacitance value of the first parasitic capacitor C1. The specific calculation formula is:

The inductance value of the first equivalent inductance L1 and the capacitance value of the first parasitic capacitor C1 can be simulated by simulation software such as commercial electromagnetic simulation software (ANSYS Electronics) and shared air core inductance calculation software (Air Cored Calculator), or The first winding structure is modeled and calculated to obtain the values of the first equivalent inductance L1 and the first parasitic capacitance C1.

As an example, assume that the array antenna shown in FIG. 2 is a dual-frequency array antenna including one second antenna element and two first antenna elements. The operating frequency band of the second antenna unit is 690 MHz to 960 MHz. The first transmission line in the first antenna unit is a coaxial cable with an outer conductor diameter of 2 millimeters (mm), and the first winding structure is shown in FIG. 3, which is similar to the spiral winding structure of an air core inductor. Input the parameters of the coil formed by the first winding structure into the shared air-core inductance calculation software (Air Cored Calculator) to calculate the inductance formed by the first transmission line through the first winding structure (that is, the above-mentioned first equivalent inductance) L1), self-distributed capacitance (that is, the above-mentioned first parasitic capacitance C1), self-resonant frequency and other parameters are shown in Fig. 5. It can be seen from the interface shown in Figure 5 that the self-resonant frequency of the first resonant circuit formed by the first transmission line through the first winding structure is approximately equal to 679MHz, while the operating frequency of the second antenna unit is not a fixed value. The frequency is between 690 MHz and 960 MHz. In order to make the difference between the self-resonant frequency of the first resonant circuit and the operating frequency of the second antenna unit always be within a preset range, the self-resonant frequency of the first resonant circuit The frequency is also preferably between 690 MHz and 960 MHz. The first winding structure is fine-tuned so that the self-resonant frequency of the first resonant circuit reaches about 800 MHz, and a better decoupling effect (ie, induced current suppression effect) can be obtained. Through this design, the directional pattern simulation result of the second antenna unit is shown in FIG. 6. Comparing the pattern shown in Fig. 1(c) and Fig. 6, it can be seen that in the pattern shown in Fig. 6, the gain is greater than 8dB and the polarization suppression ratio is greater than 15dB, which is closer to the pattern shown in Fig. 1(b). The performance parameters of the directional pattern, therefore, the directional pattern of the second antenna unit (ie, the low-frequency antenna unit) of the embodiment of the present application can be used to obtain a significant improvement effect.

In a possible design, the first winding structure is that the first transmission line 201 is spirally wound along the first winding axis direction to form a spiral winding structure similar to an air core inductor as shown in FIG. 3. The first direction around the axis may be perpendicular to the metal reflector 10 or parallel to the metal reflector 10. When the first winding axis direction is perpendicular to the metal reflector 10, the installation method of the first transmission line 201 in the first antenna unit 20 is shown in FIG. 7. When the first axis direction is parallel to the metal reflector 10, the installation method of the first transmission line 201 in the first antenna unit 20 is shown in FIG. 8. The first transmission line installation method shown in Figure 7 and Figure 8 can better match different engineering installation requirements.

In a possible design, in addition to the spiral winding structure similar to the air core inductor, the first winding structure can also be the first transmission line 201 in the first plane, in a serpentine, bent, and planar spiral shape. A structure in which the shape is wound, as shown in Figure 9. The first plane can be perpendicular or parallel to the metal reflector, and can better match different engineering installation requirements.

However, it should be noted that, in principle, the embodiment of the present application does not limit the winding mode of the first winding structure, only the self-resonant frequency and the first resonant frequency of the first resonant circuit formed by the first winding structure are required. The difference between the operating frequencies of the two antenna units is within a preset range, which can suppress the common-mode induced current. When the first winding structure adopts an irregular winding structure, if you want to calculate the equivalent inductance and parasitic capacitance formed by it, you can build the corresponding winding structure model through the modeling tool, and use the model to perform Simulation calculation.

If a broadband common-mode induced current suppression effect needs to be obtained, the first transmission line needs to use a coaxial cable as thin as possible. Referring to Figure 10, it can be seen from the simulation results of the band-stop filter circuit (resonant circuit) in Figure 10 that different inductance values match different capacitance values. When the product of the inductance value and the capacitance value is approximately equal, the self-resonant frequency is also approximately The same, but different inductance values correspond to different high impedance bandwidths. When the inductance value is larger, the capacitance value is smaller, the high impedance bandwidth is larger, that is, the filter circuit can obtain the ideal common-mode induced current suppression effect in a larger bandwidth range. As an example, the filter circuit represented by the suppression curve 1 in FIG. 10 can achieve a common-mode induced current suppression effect of more than 20dB in the first bandwidth, and the filter circuit represented by the suppression curve 2 can achieve 20dB in the second bandwidth. For the above common mode induced current suppression effect, the filter circuit represented by the suppression curve 3 can obtain a common mode induced current suppression effect of more than 20 dB in the third bandwidth, but the first bandwidth is significantly larger than the second bandwidth and the third bandwidth. Therefore, the first transmission line can use a coaxial cable as thin as possible, so that the larger the inductance value of the first equivalent inductance formed by the first winding structure, the ideal common mode induced current suppression effect can be obtained in a larger frequency range. , The structure of the first antenna unit is also miniaturized. However, in engineering practice, a coaxial cable that is too thin has problems such as poor workability and low power capacity. Through practical verification, it is found in the embodiment of the present application that when the first transmission line adopts a coaxial cable, the diameter of the outer conductor of the coaxial cable is preferably between 0.5 mm and 5 mm.

The embodiment of the present application also provides an array antenna, and the antenna unit in the array antenna is a dual-polarized antenna. In mobile communication networks, dual-polarized antennas are one of the most commonly used antenna types. Referring to FIG. 11, as a simplified schematic diagram, the structure of the array antenna provided by the embodiment of the present application is compared with the array antenna structure shown in FIG. 2. The difference is that the first antenna unit 20 further includes a second winding structure having a second winding structure. Transmission line 203, the first end of the second transmission line 203 is connected to the second signal feed inlet on the metal reflector 10, the second end of the second transmission line 203 is connected to the first radiator 202, and the second transmission line 203 passes through the second winding The structure forms a second equivalent inductance L2 and a second parasitic capacitance C2. The second equivalent inductance L2 and the second parasitic capacitance C2 form a second resonant circuit, and the self-resonant frequency of the second resonant circuit is the same as that of the second antenna unit 30. The difference between the operating frequencies is also within the above preset range.

In a dual-polarized antenna, a common-mode induced current can pass through the first transmission line 201 and the second transmission line 203 to form an induction loop. With the second winding structure, a second equivalent inductance L2 can be formed on the second transmission line 203, and at the same time, the second transmission line 203 inevitably includes a second parasitic capacitance C2. Without considering the conductor loss, the second transmission line 203 can be simplified and equivalent to a second resonant circuit formed by the second equivalent inductance L2 and the second parasitic capacitance C2. When the difference between the self-resonant frequency of the second resonant circuit and the operating frequency of the second antenna unit 30 is within the preset range, that is, the self-resonant frequency of the second resonant circuit is also close to the operating frequency of the second antenna unit 30 At this time, another band rejection filter for the operating frequency of the second antenna unit 30 is formed. When the common-mode induced current flows from the first radiator 202 to the second transmission line 203, it will be greatly hindered by the second resonant circuit. Therefore, the common-mode induced current cannot flow smoothly through the second transmission line 203 to the neighboring other The first antenna unit alleviates the secondary radiation problem caused by the common mode induced current, and prevents the pattern of the second antenna unit 30 from being seriously degraded.

In a possible design, the second transmission line 203 and the first transmission line 201 may simultaneously use coaxial cables of the same specification. When the above-mentioned second winding structure is a structure in which the second transmission line 203 is spirally wound in the first winding direction, and the first winding structure is a structure in which the first transmission line 201 is spirally wound in the first winding direction, the first winding structure is The second winding structure and the first winding structure form a staggered spiral structure, as shown in FIG. 12. Due to the mutual inductance between the first transmission line 201 and the second transmission line 203, this staggered spiral structure can increase the inductance formed when the first transmission line 201 or the second transmission line 203 is wound individually, and can be used in fewer winding turns. Get the ideal inductance value and capacitance value in a few minutes, so as to achieve the design goal of miniaturization and low loss.

It should be noted that when the first transmission line and the second transmission line form a staggered spiral structure through the first winding structure and the second winding structure, it is necessary to calculate that the first transmission line and the second transmission line pass through the first winding structure and the second winding structure. When the inductance value and capacitance value formed by the winding structure, the mutual inductance between the first transmission line and the second transmission line needs to be substituted into the simulation calculation.

In a possible design, the first transmission line 201 and the second transmission line 203 may also be microstrip lines or strip lines. When the first transmission line 201 adopts a microstrip line or a strip line, due to the structural characteristics of the microstrip line and the strip line, the first winding structure is preferably the first transmission line 201 in a plane, in the shape of a plane spirally bent shape The structure for winding.

Referring to FIG. 13, FIG. 13 is a schematic structural diagram of an antenna unit provided by an embodiment of the application, and the antenna unit is the first antenna unit in the array antenna provided by the embodiment of the application. The first antenna unit shown in FIG. 13 further includes a supporting structure 204. The first transmission line 201 and the second transmission line 203 are both strip lines. The first winding structure is preferably the first transmission line 201 in the second plane. The second winding structure is a winding structure in which the second transmission line 203 is also wound in the shape of a planar spiral bend in the second plane. The second plane is located above the metal reflector 10 and parallel to the upper surface of the metal reflector 10. The first winding structure and the second winding structure form a plane staggered spiral bending structure. The first transmission line 201 and the second transmission line 203 may be fixed in the upper surface of the metal reflective plate 10. This planar interlaced winding structure can enhance the mutual inductance between the first transmission line and the second transmission line, thereby increasing the inductance formed by each transmission line through the winding structure. The antenna connection solder joint (that is, the solder joint between the first end of the first transmission line and the second transmission line and the first radiator on the first antenna unit) is located in the middle of the plane staggered winding structure, and the signal input solder joint (that is, the first The second ends of the transmission line and the second transmission line are respectively connected to the first signal feed-in point and the second signal feed-in point on the metal reflector plate) located outside the planar interlaced winding structure.

In the first antenna unit shown in FIG. 13, the strip lines used in the first transmission line and the second transmission line include signal conductors located on the inner layer of a printed circuit board (PCB) and grounding located on the lower layer of the PCB. conductor. Different from the traditional strip line, the ground conductor of the traditional strip line is generally a large area conductor plane, and the size is much larger than the signal conductor. Referring to FIG. 14, the traditional strip line winding structure means that the signal conductor is bent or spirally wound in a large-sized ground conductor plane; and the strip line ground conductor size used in the embodiment of the application It is limited, and its width is about 2 to 5 times that of the signal conductor, and the ground conductor is bent or spirally wound in the same path as the signal conductor. The purpose of this design is to limit the width of the ground conductor in order to obtain greater inductance under the same winding structure, so that the first transmission line and the second transmission line can achieve an ideal common-mode induced current suppression effect in a larger bandwidth And the structure in which the signal conductor and the ground conductor are wound in the same path ensures the impedance continuity of the transmission line itself.

An embodiment of the present application also provides a communication device. The communication device includes the array antenna in any of the embodiments shown in FIG. 2 to FIG. 13. The communication device may be a wireless communication base station or other devices that radiate and receive signals through an array antenna. communication device.

Finally, it should be noted that specific examples are used in this article to illustrate the principles and implementation of the application. The descriptions of the above examples are only used to help understand the methods and core ideas of the application, not to limit them; although The technical solutions of the present application have been described in detail with reference to the foregoing embodiments. Those of ordinary skill in the art should understand that the protection scope of the present application is not limited to this. Anyone familiar with the technical field in the technical scope disclosed in the present invention Any changes or replacements that can be easily conceived shall be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

An array antenna, characterized in that it comprises:

The metal reflector, at least one first antenna unit and at least one second antenna unit, the working frequency of the second antenna unit is lower than that of the first antenna unit, the at least one first antenna unit and the at least one second antenna unit The antenna unit is arranged on the metal reflector;

The first antenna unit includes a first transmission line having a first winding structure and a first radiator. A first end of the first transmission line is connected to a first signal feed inlet on the metal reflector. The second end of a transmission line is connected to the first radiator, the first transmission line forms a first equivalent inductance and a first parasitic capacitance through the first winding structure, and the first equivalent inductance is connected to the first radiator. The first parasitic capacitance constitutes a first resonant circuit, and the difference between the self-resonant frequency of the first resonant circuit and the operating frequency of the second antenna unit is within a preset range.
The array antenna according to claim 1, wherein the first antenna unit further comprises a second transmission line having a second winding structure, and a first end of the second transmission line is connected to the metal reflector. The second signal feed inlet is connected, the second end of the second transmission line is connected to the first radiator, and the second transmission line forms a second equivalent inductance and a second parasitic capacitance through the second winding structure, The second equivalent inductance and the second parasitic capacitance constitute a second resonant circuit, and the difference between the self-resonant frequency of the second resonant circuit and the operating frequency of the second antenna unit is set in the preset Within range.
The array antenna according to claim 1 or 2, wherein the first transmission line is a coaxial cable.
The array antenna according to claim 3, wherein the first winding structure is a structure in which the first transmission line is spirally wound along a first winding axis direction, and the first winding axis direction is perpendicular or parallel to The metal reflector.
The array antenna according to claim 3, wherein the first winding structure is that the first transmission line is in a first plane in one of a serpentine shape, a bent shape, and a planar spiral shape. In a wound structure, the first plane is perpendicular or parallel to the metal reflector.
The array antenna according to claim 4, wherein the second transmission line is the coaxial cable, and the second winding structure is that the second transmission line is spirally wound along the first axis direction The first winding structure and the second winding structure form a staggered spiral structure.
The array antenna according to any one of claims 2-6, wherein the diameter of the outer conductor of the coaxial cable is less than or equal to 5 mm.
The array antenna according to claim 1 or 2, wherein the first transmission line is a microstrip line or a strip line.
8. The array antenna according to claim 8, wherein the first winding structure is a structure in which the first transmission line is wound in a second plane in a plane spirally bent shape.
The array antenna according to claim 9, wherein the second transmission line is the microstrip line or the strip line, and the second winding structure is the second transmission line in the second In a plane, a winding structure that is wound in the shape of the plane spirally bent shape, and the first winding structure and the second winding structure form a plane interlaced spirally bent structure.
The array antenna according to claim 9, wherein the width of the ground conductor and the width of the signal conductor of the microstrip line are both less than or equal to 5 mm, and the width of the ground conductor and the width of the signal conductor of the strip line are both less than or Equal to 5 millimeters.
A communication device, characterized in that the communication device comprises the array antenna according to any one of claims 1 to 11.