Base station antenna and base station

Abstract

The present application belongs to the technical field of communications. Disclosed are a base station antenna and a base station. The base station antenna comprises a reflecting plate and an antenna array provided on the reflecting plate, working frequency bands of the antenna array comprising a first frequency band and a second frequency band, the first frequency band being higher than the second frequency band; a first decoupling surface, which is arranged above the antenna array and is used for performing decoupling elimination on a coupled wave at the first frequency band by reflecting a portion of electromagnetic waves at the first frequency band transmitted by the antenna array; and a second decoupling surface, which is arranged above the first decoupling surface and is used for performing decoupling elimination on a coupled wave at the second frequency band by reflecting a portion of electromagnetic waves at the second frequency band transmitted by the antenna array.

Description

Base station antennas and base stations

[0001] Cross-references

[0002] This application claims priority to the Chinese patent application filed with the China Patent Office on August 7, 2023, with application number 202310993553.0 and application name “Base Station Antenna and Base Station”. The entire contents of the application are incorporated by reference into this application. Technical Field

[0003] The present application belongs to the field of communication technology, and specifically relates to a base station antenna and a base station. Background Art

[0004] With the rapid development of mobile communication systems, fifth-generation mobile communication technology (5G) has achieved full commercialization. However, there is still a significant demand for communication in the third-generation mobile communication technology (3G) / fifth-generation mobile communication technology (4G) frequency bands. This means that communication systems will face the coexistence of multiple communication systems, including 3G / 4G and 5G, for a long time. As a key component of mobile communication systems, base station antenna design will cover more frequency bands, and array applications will also tend to be multi-frequency. In practical applications, due to deployment space limitations, to achieve miniaturized array design, antennas are closely arranged with a unit spacing of less than half a wavelength. Excessively close spacing will cause inter-unit coupling. In multi-frequency arrays, inter-unit coupling exists simultaneously in every frequency band, seriously affecting the array's radiation performance, leading to poor impedance matching, pattern distortion, and reduced radiation efficiency. Currently, the decoupling technologies proposed include array antenna decoupling surfaces, metasurface decoupling methods, self-decoupling arrays, electromagnetically transparent antennas, and isolation walls. However, the above decoupling technologies mainly focus on single-band operation and cannot achieve independent decoupling in multiple frequency bands.

[0005] Summary of the Invention

[0006] The embodiments of the present application provide a base station antenna and a base station, which can solve the problem of how to independently decouple in multiple frequency bands.

[0007] In the first aspect, an embodiment of the present application provides a base station antenna, comprising: a reflector, an antenna array arranged on the reflector, the operating frequency band of the antenna array comprising a first frequency band and a second frequency band, wherein the first frequency band is higher than the second frequency band; a first decoupling surface, arranged above the antenna array, for decoupling and eliminating coupled waves of the first frequency band by reflecting part of the electromagnetic waves of the first frequency band sent by the antenna array; a second decoupling surface, arranged above the first decoupling surface, for decoupling and eliminating coupled waves of the second frequency band by reflecting part of the electromagnetic waves of the second frequency band sent by the antenna array.

[0008] In a second aspect, an embodiment of the present application provides a base station, comprising the base station antenna described in the first aspect.

[0009] In an embodiment of the present application, after setting a first decoupling surface above the antenna array set on the reflecting plate, the first decoupling surface can decouple and eliminate the coupled waves of the first frequency band by reflecting part of the electromagnetic waves in the first frequency band sent by the antenna array. At the same time, a second decoupling surface is set above the first decoupling surface. The second decoupling surface can decouple and eliminate the coupled waves of the second frequency band by reflecting part of the electromagnetic waves in the second frequency band sent by the antenna array. The first decoupling surface and the second decoupling surface are respectively connected to the reflecting plate, and the first frequency band is higher than the second frequency band, thereby realizing the control of spatial waves by two layers of decoupling surfaces, so that the base station antenna can be decoupled in two frequency bands at the same time, or independently decoupled, with simple operation, non-interference and high repeatability. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG1 is a schematic structural diagram of a base station antenna provided in an embodiment of the present application;

[0011] FIG1a is a schematic diagram of a base station antenna according to an embodiment of the present application;

[0012] FIG2 is a schematic structural diagram of a first decoupling surface provided in an embodiment of the present application;

[0013] FIG2 a is a schematic diagram of a metal pattern of a first decoupling unit provided in an embodiment of the present application;

[0014] FIG2 b is another schematic diagram of the metal pattern of the first decoupling unit provided in an embodiment of the present application;

[0015] FIG2 c is another schematic diagram of the metal pattern of the first decoupling unit provided in an embodiment of the present application;

[0016] FIG2 d is a schematic structural diagram of a first decoupling unit provided in an embodiment of the present application;

[0017] FIG2e is another schematic structural diagram of the first decoupling surface provided in an embodiment of the present application;

[0018] FIG2 f is a schematic diagram of the affine result of the first decoupling surface provided in an embodiment of the present application;

[0019] FIG3 is a schematic structural diagram of a second decoupling surface provided in an embodiment of the present application;

[0020] FIG3 a is a schematic structural diagram of a second decoupling unit provided in an embodiment of the present application;

[0021] FIG3 b is another structural schematic diagram of a second decoupling surface provided in an embodiment of the present application;

[0022] FIG3 c is a schematic diagram of a metal pattern of a second decoupling unit provided in an embodiment of the present application;

[0023] FIG3 d is a schematic diagram of the affine result of the second decoupling surface provided in an embodiment of the present application;

[0024] FIG4 is another structural diagram of a base station antenna provided in an embodiment of the present application;

[0025] FIG4a is another working schematic diagram of a base station antenna provided in an embodiment of the present application;

[0026] FIG5 is a front view of an original array provided in an embodiment of the present application;

[0027] FIG6 is a top view of the original array provided in an embodiment of the present application;

[0028] FIG7 is a schematic diagram of port numbering provided in an embodiment of the present application;

[0029] FIG8 is a schematic diagram of an array loaded with a first decoupling surface provided in an embodiment of the present application;

[0030] FIG9 is a comparison diagram of co-polarization coupling between low-frequency ports before and after loading the first decoupling surface according to an embodiment of the present application;

[0031] FIG10 is a comparison diagram of the polarization coupling between low-frequency ports before and after loading the first decoupling surface according to an embodiment of the present application;

[0032] FIG11 is a comparison diagram of co-polarization coupling between high-frequency ports before and after loading the first decoupling surface according to an embodiment of the present application;

[0033] FIG12 is a comparison diagram of the high-frequency port polarization coupling before and after loading the first decoupling surface according to an embodiment of the present application;

[0034] FIG13 is a schematic diagram of an array of loaded composite decoupling surfaces provided in an embodiment of the present application;

[0035] FIG14 is a comparison diagram of co-polarization coupling between low-frequency ports before and after loading the composite decoupling surface provided in an embodiment of the present application;

[0036] FIG15 is a comparison diagram of the polarization coupling between low-frequency ports before and after loading the composite decoupling surface provided in an embodiment of the present application;

[0037] FIG16 is a comparison diagram of co-polarization coupling between high-frequency ports before and after loading the composite decoupling surface provided in an embodiment of the present application;

[0038] FIG17 is a comparison diagram of the high-frequency port polarization coupling before and after loading the composite decoupling surface provided in an embodiment of the present application;

[0039] FIG18 is a comparison diagram of the low-frequency radiation patterns before and after loading the composite decoupling surface provided in an embodiment of the present application;

[0040] FIG19 is a comparison diagram of the high-frequency radiation patterns before and after loading the composite decoupling surface provided in an embodiment of the present application. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0042] The terms "first," "second," and the like in the specification and claims of this application are used to distinguish similar objects, and are not used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of this application can be implemented in an order other than that illustrated or described herein, and that the objects distinguished by "first," "second," and the like are generally of the same type, and do not limit the number of objects; for example, the first object can be one or more. In addition, the term "and / or" in the specification and claims refers to at least one of the connected objects, and the character " / " generally indicates that the objects connected are in an "or" relationship.

[0043] In order to better understand the technical solution provided by this application, the technology involved in this application is first introduced.

[0044] 1. Array antenna decoupling surface

[0045] Array-Antenna Decoupling Surface (ADS) technology involves placing a substrate printed with multiple small electrically dimensioned metal patches directly above the antenna array. This technology introduces a second signal transmission path by reflecting electromagnetic waves. The resulting diffracted waves, with equal amplitude and opposite phase to the original coupled waves, cancel each other out, achieving decoupling. In a two-dimensional 2×2 dual-polarized antenna array, decoupling of multiple paths is possible across the 3.3-3.8 GHz frequency band.

[0046] Decoupling surfaces can achieve good decoupling effects with a simple structure, are applicable to a variety of coupling types, and can be designed independently of the antenna. They can be used in large arrays, but they only have a good decoupling effect for a single operating frequency band. When faced with multi-frequency situations, especially when the operating frequency band span is large (such as 2 times the frequency), they will face greater limitations. Specifically, one surface will find it difficult to cover all operating frequency bands. When multiple layers of decoupling surfaces working in different frequency bands are stacked, there will be a greater impact between the multiple surfaces, which is not conducive to independent control of each frequency band.

[0047] 2. Metasurface decoupling method

[0048] The decoupling device of the metasurface-based decoupling method (MDM) consists of a dielectric substrate and several metal patches placed above the antenna. The metal patches of different lengths create dual-band characteristics. By regulating the surface coupling current between antennas, this device can achieve decoupling within the 2.5GHz and 3.5GHz frequency bands in the Multiple-Input Multiple-Output (MIMO) system, significantly reducing the Envelope Correlation Coefficient (ECC) between antennas.

[0049] The MDM method can achieve dual-band decoupling and has a simple structure. However, the method only involves microstrip antennas and does not introduce more types of antenna forms in practical applications. In addition, the method only targets single-polarization arrays and faces certain limitations in dual-polarization or multi-polarization arrays.

[0050] 3. Self-decoupling dual-band base station antenna array

[0051] A self-decoupling dual-band base station antenna array refers to a dual-band common-aperture antenna system in which decoupling structures are added to multiple radiators of the low-frequency antenna. This design creates a partially reflective surface (PRS) for high-frequency electromagnetic waves. By adjusting the reflection and wave transmission characteristics of the low-frequency antenna located above the array, some high-frequency electromagnetic waves can be reflected, thereby achieving coupled wave cancellation and decoupling.

[0052] Self-decoupling dual-band base station antenna arrays integrate decoupling structures with the antennas, eliminating the need for additional decoupling structures and simplifying the array structure. However, this approach only achieves co-frequency decoupling of high-frequency antennas and does not address the co-frequency coupling of low-frequency antennas in larger arrays. Furthermore, low-frequency antennas have both radiation and high-frequency wave transmission capabilities, which can limit the freedom of antenna design.

[0053] In view of this, the present application proposes a base station antenna and a base station. The base station antenna and the base station provided in the embodiments of the present application are described below using multiple columns of antenna units as horizontal columns of antenna units and vertical columns of antenna units as examples.

[0054] FIG1 is a schematic structural diagram of a base station antenna provided in an embodiment of the present application. As shown in FIG1 , the base station antenna comprises: a reflector 110, an antenna array 120 arranged on the reflector, a first decoupling surface 130, and a second decoupling surface 140, wherein the operating frequency band of the antenna array 120 comprises a first frequency band and a second frequency band, wherein the first frequency band is higher than the second frequency band; the first decoupling surface 130 is connected to the reflector 110 via a non-metallic support structure such as a dielectric column, and is arranged above the antenna array 120, and is used to decouple and eliminate coupled waves in the first frequency band by reflecting part of the electromagnetic waves in the first frequency band transmitted by the antenna array 120; the second decoupling surface 140 is connected to the reflector 110 via a non-metallic support structure such as a dielectric column, and is arranged above the first decoupling surface 130, and is used to decouple and eliminate coupled waves in the second frequency band by reflecting part of the electromagnetic waves in the second frequency band transmitted by the antenna array 120.

[0055] The antenna array 120 may be formed by interlacing high-frequency oscillator units, dual-frequency oscillator units, and low-frequency oscillator units in an aperture plane. The array forms include but are not limited to the following three types:

[0056] (1) A high-frequency antenna array consisting only of high-frequency oscillator units, and a low-frequency antenna array consisting only of low-frequency oscillator units.

[0057] (2) A high-frequency antenna array consisting of a high-frequency oscillator unit and a dual-frequency oscillator unit, and a low-frequency antenna array consisting of a low-frequency oscillator unit and a dual-frequency oscillator unit.

[0058] (3) A high-frequency antenna array composed of a high-frequency oscillator unit and a dual-frequency oscillator unit, and a low-frequency antenna array composed only of a dual-frequency oscillator unit.

[0059] Among them, the working frequency band corresponding to the high-frequency antenna array in (1) to (3) above is the first frequency band, and the working frequency band corresponding to the low-frequency antenna array 120 is the second frequency band. The embodiment of the present application takes the array form in (3) above as an example for explanation, and the decoupling method of this array form can be applied to the other two forms mentioned above. As shown in Figure 1a, it is a schematic diagram of the decoupling work of the first decoupling surface 130 and the second decoupling surface 140. The low-frequency antenna composed of several dual-frequency vibrator units and the high-frequency antenna composed of high-frequency vibrator units are alternately placed on the same reflector 110 to form an antenna array 120. The first decoupling surface 130 and the second decoupling surface 140 are placed parallel above the antenna array 120. The two layers of decoupling surfaces can be connected to the reflector 110 through non-metallic support structures such as dielectric columns. When the antenna array 120 operates in the first frequency band, the first decoupling surface 130 decouples and eliminates the coupled waves in the first frequency band by reflecting part of the electromagnetic waves in the first frequency band transmitted by the antenna array 120. The electromagnetic waves may be high-frequency reflected waves. That is, when the antenna array 120 operates in the first frequency band, i.e., the high frequency band, part of the high-frequency reflected waves is introduced by the first decoupling surface 130. When the high-frequency reflected waves and the high-frequency coupled waves have equal amplitudes and opposite phases, high-frequency electromagnetic wave cancellation and decoupling can be achieved. At the same time, most of the electromagnetic waves in the first frequency band other than the electromagnetic waves used for decoupling, i.e., high-frequency transmitted waves, penetrate the first decoupling surface 130 and the second decoupling surface 140 and radiate into free space. When the antenna array 120 operates in the second frequency band, the second decoupling surface 140 reflects a portion of the electromagnetic waves in the second frequency band transmitted by the antenna array 120 to decouple and eliminate the coupled waves in the second frequency band. The electromagnetic waves can be low-frequency reflected waves. That is, when the antenna array 120 operates in the second frequency band, i.e., the low-frequency band, when the low-frequency reflected waves and the low-frequency coupled waves have equal amplitudes and opposite phases, low-frequency electromagnetic wave cancellation and decoupling can be achieved. At the same time, most of the electromagnetic waves in the second frequency band other than the electromagnetic waves used for decoupling, i.e., low-frequency transmitted waves, penetrate the first decoupling surface 130 and the second decoupling surface 140 and radiate into free space. It can be understood that the first decoupling surface 130 and the second decoupling surface 140 both exhibit wave-transmitting characteristics in the non-operating frequency band, which can achieve independent regulation of the two frequency bands. In addition, since only a portion of the electromagnetic waves are introduced, most of the electromagnetic waves can still penetrate the decoupling surface and radiate into free space. Therefore, the directional pattern of the antenna array 120 after decoupling is less deformed than before decoupling. In one implementation, the decoupling method corresponding to the base station antenna can also be applied to a dual-polarization dual-frequency array base station antenna, and the dual-frequency decoupling work is decomposed into independent high-frequency and low-frequency decoupling work of each frequency band.It is understandable that the antenna array 120 can also provide a dual-polarization dual-band base station antenna array loaded with a decoupling device, wherein the dual-polarization dual-band base station antenna array includes a reflector, a radiating unit mounted on the reflector, and the decoupling device; the radiating unit includes a plurality of common radiators working at low-frequency radiating units and a plurality of common radiators working at high-frequency radiating units, wherein the decoupling device includes a first decoupling surface and a second decoupling surface. Furthermore, the dual-polarization dual-band base station antenna array includes a first subarray and a second subarray, wherein the first subarray includes a plurality of dual-frequency radiating units and high-frequency radiating units alternately arranged in a row along the horizontal direction of the reflector, and the second subarray includes a plurality of high-frequency radiating units arranged in a row along the horizontal direction of the reflector, and a plurality of first subarrays and second subarrays are alternately arranged in multiple rows along the vertical direction of the reflector, and adjacent subarrays are parallel to each other.

[0060] In an embodiment of the present application, after setting a first decoupling surface above the antenna array set on the reflecting plate, the first decoupling surface can reflect part of the electromagnetic waves in the first frequency band sent by the antenna array to decouple and eliminate the coupled waves in the first frequency band. At the same time, a second decoupling surface is set above the first decoupling surface. The second decoupling surface can reflect part of the electromagnetic waves in the second frequency band sent by the antenna array to decouple and eliminate the coupled waves in the second frequency band. The first decoupling surface and the second decoupling surface are respectively connected to the reflecting plate, and the first frequency band is higher than the second frequency band. The electromagnetic waves are controlled by two layers of decoupling surfaces, so that the base station antenna can be decoupled in two frequency bands at the same time or independently, with simple operation, no interference and high scalability.

[0061] It should be noted that, in addition to the first decoupling surface and the second decoupling surface, the base station antenna can also integrate multiple other decoupling surfaces to eliminate coupled waves in different frequency bands. The embodiment of the present application only uses two decoupling surfaces as an example. That is, no matter how many decoupling surfaces the base station antenna includes, the decoupling method in the embodiment of the present application is also applicable.

[0062] FIG2 is a schematic structural diagram of a first decoupling surface provided in an embodiment of the present application. As shown in FIG2 , the first decoupling surface may include: a first dielectric plate 210 and a plurality of first decoupling units 220 disposed on the upper surface of the first dielectric plate 210, wherein the vertical projection of any one of the first decoupling units 220 on the reflector overlaps with the first radiating unit operating in the first frequency band, and the first decoupling units 220 correspond one-to-one with the first radiating unit. It is understood that the vertical projection of any one of the first decoupling units 220 on the reflector overlaps with the first radiating unit operating in the first frequency band means that when the first decoupling unit 220 is connected to the reflector via a non-metallic support structure such as a dielectric column and projected in a direction above the reflector, the image formed by the projection overlaps with the first radiating unit. That is, when the first radiating unit is disposed on the reflector, the vertical projection of the first decoupling unit 220 and the first radiating unit have the same center position, but are different in size and shape. In addition, the first dielectric plate 210 may be made of FR4 material with a dielectric constant of 4.4. The thickness of the first dielectric plate 210 may be 1 mm, and the size may be the same as that of the reflective plate 110 in FIG. 1 .

[0063] In another implementation, as shown in FIG2a , the first decoupling unit 220 includes a metal pattern composed of multiple metal strips 221, where the length of any one of the metal strips is less than k1 times the wavelength of the first frequency band, where k1 is a rational number greater than 0 and less than 1. It will be appreciated that the metal pattern of each first decoupling unit 220 can be a combination of multiple metal strips 221, and the length of a single metal strip 221 needs to be less than k1 times the wavelength of the high frequency band, i.e., the wavelength of the first frequency band, to avoid resonance within the operating frequency band. k1 can be 0.25.

[0064] Among them, in another implementation, the metal pattern composed of multiple metal strips is a symmetrical pattern. It can be understood that the distortion of the radiation pattern of the antenna unit below caused by the asymmetric decoupling unit can be avoided. Exemplarily, as shown in Figures 2b, 2c and 2d, multiple metal strips form a symmetrical pattern. It should be noted that the number and position of the metal strips can be used to adjust the intensity of the decoupling reflected wave. Exemplarily, as shown in Figure 2e, it is a structural schematic diagram of the first decoupling surface in space, including a first dielectric plate and a first decoupling unit arranged on the upper surface of the first dielectric plate. The first decoupling surface includes a FR4 dielectric substrate with a thickness of 1 mm and a plurality of strip metal patches etched on the upper surface. The strip metal patches are mainly composed of rectangular metal patches and L-shaped metal patches. The rectangular metal patches are distributed in a cross shape and an X shape, and the L-shaped metal patches are distributed in a square shape.

[0065] In the above embodiment, the first decoupling surface may decouple and eliminate coupled waves in the first frequency band by reflecting a portion of electromagnetic waves in the first frequency band transmitted by the antenna array.

[0066] In one implementation, the transmission coefficient of the first decoupling surface for electromagnetic waves in the second frequency band is in the range of [0.5, 1]. It is understandable that the first decoupling surface needs to produce a decoupling effect on the high-frequency array antenna without having any effect on the low-frequency antenna array, that is, it needs to be able to completely transmit low-frequency electromagnetic waves. Therefore, when designing the first decoupling surface, the transmission coefficient for the low-frequency band can be designed to be in the range of [0.5, 1]. The transmission coefficient refers to the degree of attenuation of the decoupling surface to electromagnetic waves. Usually, the transmission coefficient is around -1.5dB and the reflection coefficient is around -7dB. If the coupled wave is large, the reflection coefficient will be greater than -7dB. As shown in Figure 2f, in the embodiment of the present application, in the low-frequency band of 2.49-2.69GHz, the transmission coefficient is close to 0dB, achieving wave transmission characteristics. That is, in the low-frequency band, the first decoupling surface has very low or no loss to electromagnetic waves, that is, the ideal transmission coefficient is in the range of [0.5, 1]. In the high frequency band of 4.8-4.9GHz, the transmission coefficient is -1.4~-1.3dB and the reflection coefficient is -7.3~-7.0dB, achieving partial reflection characteristics.

[0067] In one implementation, the distance between the first decoupling surface and the radiating surface of the antenna array is k2 times the wavelength of the first frequency band, where k2 is a rational number greater than 0.1 and less than 0.5. It is understood that the radiating surface refers to the plane where the high-frequency oscillator unit and the dual-frequency oscillator unit are located. The first decoupling unit of the first decoupling surface can be arranged above each high-frequency oscillator unit and the dual-frequency oscillator unit, and the distance to the radiating surface can be k2 times the wavelength of the first frequency band, so as to control the phase of the decoupled reflected wave and the direct coupling wave to be opposite to each other, thereby achieving cancellation. The value range of k2 can be (0.1, 0.5).

[0068] FIG3 is a schematic structural diagram of a second decoupling surface provided in an embodiment of the present application. As shown in FIG3 , the second decoupling surface includes: a second dielectric plate 310 and a plurality of second decoupling units 320 disposed on the second dielectric plate 310, wherein the vertical projection of any second decoupling unit 320 on the reflector overlaps with the second radiating unit operating in the second frequency band, and the second decoupling unit 320 corresponds one-to-one with the second radiating unit. It can be understood that the vertical projection of any second decoupling unit 320 on the reflector overlaps with the second radiating unit operating in the second frequency band means that when the second decoupling unit 320 is connected to the reflector through a non-metallic support structure such as a dielectric column and is projected in a direction above the reflector, the image formed by the projection overlaps with the second radiating unit. That is, the second radiating unit is disposed on the reflector, and the vertical projection of the second decoupling unit 320 has the same center position as the second radiating unit, but has different sizes and shapes. In addition, the second dielectric plate 310 may be made of FR4 material with a dielectric constant of 4.4. The thickness of the second dielectric plate 310 may be 1 mm, and the size may be the same as that of the reflective plate 110 in FIG. 1 .

[0069] In another implementation, as shown in FIG3a , the second decoupling unit includes: a metal layer 321 disposed on the upper surface of the second dielectric plate 310, the metal layer having a predetermined-shaped slot etched therein; and a metal patch 322 of the predetermined shape disposed on the lower surface of the second dielectric plate. FIG3b , for example, illustrates a schematic structural diagram of a second decoupling surface in space. Specifically, the second decoupling surface comprises a 1 mm thick FR4 dielectric substrate, the upper pattern of which is a square-ring slot, and the lower pattern is a ring-shaped metal patch. It is understood that the second decoupling unit comprises a decoupling metal pattern unit etched on both sides of the dielectric substrate. The metal pattern comprises a slot etched in a metal layer and a metal patch. The slot can be in the shape of a square ring, a circular ring, a cross, or the like, and the metal patch can be in the shape of a square, a circle, a cross, or the like. FIG3c , for example, illustrates an alternative pattern for the second decoupling unit.

[0070] In another implementation, the length of the second decoupling unit is less than k3 times the wavelength of the second frequency band, where k3 is a rational number greater than 0 and less than 1. It will be appreciated that the length of each second decoupling unit needs to be less than k3 times the wavelength of the low-frequency band, i.e., the wavelength of the second frequency band, to avoid resonance within the operating frequency band. k3 can be 0.3.

[0071] In another implementation, the transmission coefficient of the second decoupling surface for electromagnetic waves in the first frequency band ranges from [0.5, 1]. It is understandable that the second decoupling surface needs to have a decoupling effect on the low-frequency array antenna without any impact on the high-frequency antenna array, that is, it needs to be able to completely transmit low-frequency electromagnetic waves. Therefore, when designing the second decoupling surface, the transmission coefficient for the high-frequency band needs to be equal to 1; and the low-frequency electromagnetic waves need to be partially reflected to offset the coupled wave signal. For example, as shown in Figure 3d, the simulation results show that in the low-frequency band of 2.49-2.69GHz, the transmission coefficient is -1 to -2dB and the reflection coefficient is -7.7 to -4.2dB, achieving partial reflection characteristics. In the high-frequency band of 4.8-4.9GHz, the transmission coefficient is close to 0dB, achieving wave transmission characteristics. In other words, in the high-frequency band, the second decoupling surface has very low or no loss of electromagnetic waves, that is, the ideal transmission coefficient ranges from [0.5, 1].

[0072] In another implementation, the distance between the second decoupling surface and the radiating surface of the antenna array is k4 times the wavelength of the second frequency band, where k4 is a rational number greater than 0.1 and less than 0.5. It is understood that the radiating surface refers to the plane where the high-frequency oscillator unit and the dual-frequency oscillator unit are located. The second decoupling unit of the second decoupling surface can be arranged above each high-frequency oscillator unit and the dual-frequency oscillator unit, and the distance from the radiating surface can be k4 times the wavelength of the second frequency band, so as to control the phase of the decoupled reflected wave and the direct coupling wave to be opposite to each other, thereby achieving cancellation. The value range of k4 can be (0.1, 0.5).

[0073] In the above embodiment, the second decoupling surface can decouple and eliminate coupled waves in the second frequency band by reflecting part of the electromagnetic waves in the second frequency band transmitted by the antenna array.

[0074] FIG4 is another structural schematic diagram of a base station antenna provided in an embodiment of the present application. As shown in FIG4 , the operating frequency band of the antenna array 420 further includes: a third frequency band, wherein the second frequency band is higher than the third frequency band; the base station antenna further includes: a third decoupling surface 450, connected to the reflector 410, disposed above the second decoupling surface 440, for decoupling and eliminating the coupled waves in the third frequency band by reflecting part of the electromagnetic waves in the third frequency band transmitted by the antenna array 420. Exemplarily, referring to FIG4a , the working principle of the base station antenna is described. The three-band array is composed of three types of antenna units, namely, a high-frequency antenna, an intermediate-frequency antenna, and a low-frequency antenna. Three layers of decoupling surfaces are provided above the three-band array, wherein the bottom first decoupling surface 430 is used to reflect part of the high-frequency electromagnetic waves, thereby achieving decoupling of the high-frequency antenna, while ensuring transmission of the intermediate and low-frequency electromagnetic waves; similarly, the second decoupling surface 440 and the third decoupling surface 450 are respectively used to reflect part of the intermediate-frequency electromagnetic waves and the low-frequency electromagnetic waves, thereby achieving decoupling of the corresponding frequency bands, while ensuring normal transmission of electromagnetic waves in other frequency bands.

[0075] A specific embodiment of the present application is described below with reference to Figures 5 to 19.

[0076] As shown in FIG5 , a main view of the original array without adding a decoupling structure is provided in an embodiment of the present application. FIG6 is a top view of the original array, including two groups of first sub-arrays 610 and one group of second sub-arrays 620. The first sub-array 610 includes three dual-frequency units 601 and two high-frequency units 602 placed alternately. The second sub-array includes five high-frequency units 602 placed side by side. The array can be expanded into a dual-frequency array of any size. Among them, the high-frequency unit 602 includes four radiating arms composed of zigzag lines and two microstrip feeding baluns. The dual-frequency unit 601 includes four annular radiating arms and a zigzag resonant ring located above the radiating arm, four angular metal columns located at the tail of the radiating arm, and two dual-frequency feeding baluns. The metal flange located around the dual-frequency antenna is used to control the beam stability of the dual-frequency unit. The feed lines of all units are connected to a common reflector. When the dual-frequency array is laid out, the spacing between the radiating units of antennas in different frequency bands is different. The 0.3-0.8 wavelength at the center frequency of each working frequency band is a reasonable unit spacing. Furthermore, the original array in this embodiment can be applied to a compact dual-antenna array. Setting the minimum element spacing to less than or equal to 0.5 times the center wavelength helps improve array aperture utilization. In this dual-band array, the dual-band radiating elements can be considered a combination of high-frequency and low-frequency radiating elements. The horizontal spacing d1 of the low-frequency elements is 58 mm, and the vertical spacing d3 is 77 mm. The horizontal spacing d2 of the high-frequency elements is 29 mm, and the vertical spacing d4 is 38.5 mm.

[0077] In this embodiment, as shown in FIG. 7 , ports L1 to L12 operate in a low frequency band of 2.49 to 2.69 GHz, and ports 1 to 30 operate in a high frequency band of 4.8 to 4.9 GHz.

[0078] As shown in FIG8 , a first decoupling surface is provided 6.5 mm above the array.

[0079] 9 and 10 , the dotted lines represent the simulation results of the isolation between the low-frequency ports of the original array without the addition of the decoupling structure, and the solid lines represent the simulation results of the isolation between the low-frequency ports after the first decoupling surface is loaded. With the exception of S(L1, L3), the addition of the first decoupling surface slightly improves the low-frequency isolation, but has no significant effect.

[0080] As shown in Figures 11 and 12, the dashed lines represent the simulated isolation between the high-frequency ports of the original array, while the solid lines represent the simulated isolation between the high-frequency ports after adding the first decoupling surface. The addition of the first decoupling surface increases the isolation between co-polarized ports from a maximum of 14dB to over 22dB, and the isolation between heteropolarized ports from a maximum of 15.5dB to over 19dB. This shows that the first decoupling surface has little impact on the antenna array's performance in the low-frequency band, but has a significant decoupling effect in the high-frequency band. By manipulating the first decoupling surface, independent decoupling of the array's high-frequency band can be achieved.

[0081] 13 , a second decoupling surface is superimposed 10 mm above the array on which the first decoupling surface is provided as shown in FIG8 .

[0082] Referring to Figures 14 and 15 , the dotted lines represent the simulation results of the isolation between the low-frequency ports of the original array, and the dashed lines represent the simulation results of the isolation between the low-frequency ports after loading the composite decoupling surface. The addition of the second decoupling surface increases the isolation between the co-polarized ports from a maximum of 19 dB to over 22 dB, and the isolation between the heteropolarized ports from a maximum of 14 dB to over 20.5 dB.

[0083] As shown in Figures 16 and 17, the dashed lines represent the simulation results of the isolation between the high-frequency ports of the original array. The simulation results of the isolation between the high-frequency ports after adding the composite decoupling surface are essentially the same as those after adding only the first decoupling surface. This shows that the second decoupling surface has a significant decoupling effect on the low-frequency ports without affecting the operating performance of the high-frequency ports. Independent decoupling of the array's low-frequency band can be achieved by controlling the second decoupling surface.

[0084] As shown in Figure 18, ports L1, L3 and L5 are fed. The curves in the figure are the low-frequency normalized radiation patterns of the array without and with the composite decoupling structure. The radiation patterns before and after the decoupling structure is loaded are smooth and stable, with little deformation.

[0085] As shown in Figure 19, power is fed to ports 11, 13, 15, 17, and 19. The curves in the figure show the normalized radiation patterns in the high-frequency band of the array without and with the composite decoupling structure. Compared with the original array, the beamwidth of the pattern with the decoupling structure is slightly narrower, but the gain is higher and the directivity is better. This shows that the addition of the decoupling structure has little impact on the array's radiation performance and helps improve overall directivity.

[0086] In this embodiment, by loading two layers of composite decoupling surfaces above the antenna array, the port isolation between the radiating units is improved, the good radiation performance of the array is maintained, and the decoupling surfaces are isolated from each other and can work independently. The decoupling device has a simple structure, is easy to integrate, and is effective for multiple coupling types, and is suitable for large multi-band arrays.

[0087] The present application also provides a base station, which includes the base station antenna provided in the above-mentioned embodiments. The various processes of the embodiments shown in Figures 1 to 19 can be implemented and achieve the same technical effects. To avoid repetition, they are not described here.

[0088] It should be noted that, in this article, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element. In addition, it should be pointed out that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in the opposite order according to the functions involved. For example, the described method may be performed in an order different from that described, and various steps may also be added, omitted or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0089] Through the description of the above embodiments, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of a computer software product plus a necessary general-purpose hardware platform, or of course, by hardware. The computer software product is stored in a storage medium (such as ROM, RAM, magnetic disk, optical disk, etc.) and includes a number of instructions for enabling a terminal or network-side device to execute the methods described in each embodiment of the present application.

[0090] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of this application, ordinary technicians in this field can also make many forms of implementation methods without departing from the purpose of this application and the scope of protection of the claims. These implementation methods are all within the protection of this application.

Claims

1. A base station antenna, comprising: Reflective panels, An antenna array is arranged on the reflector, wherein the working frequency band of the antenna array includes a first frequency band and a second frequency band, wherein the first frequency band is higher than the second frequency band; A first decoupling surface is arranged above the antenna array and is used to decouple and eliminate coupled waves in the first frequency band by reflecting part of the electromagnetic waves in the first frequency band sent by the antenna array; The second decoupling surface is arranged above the first decoupling surface, and is used for decoupling and eliminating the coupled waves in the second frequency band by reflecting part of the electromagnetic waves in the second frequency band sent by the antenna array.

2. The base station antenna according to claim 1, wherein: The first decoupling surface includes: a first dielectric plate and a plurality of first decoupling units arranged on the upper surface of the first dielectric plate, wherein a vertical projection of any first decoupling unit on the reflective plate overlaps with a first radiating unit operating in the first frequency band, and the first decoupling unit corresponds one-to-one to the first radiating unit.

3. The base station antenna according to claim 2, wherein: The first decoupling unit includes a metal pattern composed of a plurality of metal strips, and the length of any one of the metal strips is less than k1 times the wavelength of the first frequency band, where k1 is a rational number greater than 0 and less than 1.

4. The base station antenna according to claim 3, wherein: The metal pattern formed by a plurality of the metal strips is a symmetrical pattern.

5. The base station antenna according to any one of claims 1 to 4, wherein: The transmission coefficient of the first decoupling surface to the electromagnetic waves in the second frequency band has a value range of [0.5, 1].

6. The base station antenna according to any one of claims 1 to 4, wherein: The distance between the first decoupling surface and the radiation surface of the antenna array is k2 times the wavelength of the first frequency band, where k2 is a rational number greater than 0.1 and less than 0.

5.

7. The base station antenna according to claim 1, wherein: The second decoupling surface includes: a second dielectric plate and a plurality of second decoupling units arranged on the second dielectric plate, wherein a vertical projection of any second decoupling unit on the reflecting plate overlaps with a second radiating unit operating in the second frequency band, and the second decoupling unit corresponds one-to-one to the second radiating unit.

8. The base station antenna according to claim 7, wherein: The second decoupling unit comprises: A metal layer is arranged on the upper surface of the second dielectric plate, and a gap of a predetermined shape is etched on the metal layer; The metal patch of the predetermined shape is arranged on the lower surface of the second dielectric plate.

9. The base station antenna according to claim 7, wherein: The length of the second decoupling unit is less than k3 times the wavelength of the second frequency band, where k3 is a rational number greater than 0 and less than 1.

10. The base station antenna according to any one of claims 7 to 9, wherein: The transmission coefficient of the second decoupling surface to the electromagnetic waves in the first frequency band has a value range of [0.5, 1].

11. The base station antenna according to any one of claims 7 to 9, wherein: The distance between the second decoupling surface and the radiation surface of the antenna array is k4 times the wavelength of the second frequency band, where k4 is a rational number greater than 0.1 and less than 0.

5.

12. The base station antenna according to claim 1, wherein: The working frequency band of the antenna array further includes: a third frequency band, wherein the second frequency band is higher than the third frequency band; The base station antenna also includes: a third decoupling surface, connected to the reflector, and arranged above the second decoupling surface, for decoupling and eliminating coupled waves in the third frequency band by reflecting part of the electromagnetic waves in the third frequency band sent by the antenna array.

13. A base station, comprising the base station antenna according to any one of claims 1 to 12.

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