A dual-polarized wideband small aperture base station antenna

Abstract

The application discloses a kind of dual-polarized wideband small aperture base station antennas, including at least one antenna unit, antenna unit is from bottom to top sequentially including reflector, feed structure, vertical lower bend radiating body, horizontal radiating body and vertical upper bend radiating body, wherein, reflector is formed by a layer of metal copper-clad patch printing on the top of dielectric substrate;Feed structure is arranged on the top of reflector, including two first vertical dielectric substrates placed in cross, respectively printed with feed connector, η-shaped microstrip baron and ground metal sheet on the two sides of each first vertical dielectric substrate;Vertical lower bend radiating body is arranged below horizontal radiating body, formed by inner layer dielectric substrate and outer metal copper-clad, four groups of vertical lower bend radiating body are vertically placed below horizontal radiating body respectively;Vertical upper bend radiating body is arranged around horizontal radiating body.The base station antenna is simple in process, stable in structure, high in yield, and suitable for mass production.

Description

Technical Field

[0001] This invention belongs to the field of wireless communication technology, specifically relating to a dual-polarized broadband small-aperture base station antenna. Background Technology

[0002] In the course of mobile communication development, the technology of base station antennas has been rapidly innovating. Currently, mobile communication technology has become a crucial industry for improving socio-economic levels and accelerating modernization, permeating all aspects of people's lives, while people's desire for improved mobile communication environment quality continues to grow.

[0003] Miniaturization of base station antennas can effectively reduce wind load and minimize the negative impact of the environment on antenna radiation performance. Miniaturization of base station antenna aperture is conducive to the development of base station integration technology, facilitates integrated antenna design, improves communication system capacity, and enhances the user's communication environment. Furthermore, after reducing the antenna aperture, it is required that the antenna radiation performance will not be adversely affected. This saves the footprint of the base station system, conserves increasingly scarce site resources, and enables the system to still have excellent information transmission capabilities within a limited space.

[0004] To further meet the demand for miniaturization of base station antennas, researchers have conducted much related work, including antenna aperture miniaturization and low-profile antenna design. Low-profile antenna design primarily aims to break the height limitations of directional base station antennas and reduce antenna weight. Existing research on low-profile technology is limited, with most methods using metasurfaces to replace metal reflectors. However, current metasurface designs are complex, and research indicates that using metasurfaces has a negative impact on the antenna's cross-polarization ratio. Therefore, base station antennas are typically only one-quarter wavelength high.

[0005] On the other hand, with the development of mobile communication technology, the demand for large capacity and multi-user function makes the number of base station antennas increase sharply. If the antenna unit occupies too much space, no matter whether the array is uniformly or staggered arranged, due to the existence of space limitation and strong coupling effect, the spacing between the antenna units cannot be further reduced. At the same time, if the distance between the units is small, it is difficult to deploy any decoupling structure in the array. Therefore, for large-scale MIMO array, especially in the base station, antenna unit miniaturization is crucial. Base station antenna aperture miniaturization can effectively reduce the space occupation area of the antenna and effectively reduce the wind load area of the antenna. Most of the existing technologies are to realize additional resonance mode by using parasitic structure or to realize it by changing the structure of the radiator; however, most of the base station antenna miniaturization is at the expense of antenna bandwidth and gain. On the one hand, the decrease of antenna aperture leads to the decrease of effective radiation area of the antenna, thereby reducing the gain of the antenna, on the other hand, the decrease of antenna aperture leads to the decrease of effective resonance length, thereby causing the resonance of the antenna to shift to high frequency, and more seriously, causing mismatch. Therefore, it is a key challenge to research the small size while ensuring the wideband operation and high gain characteristics of the antenna. SUMMARY

[0006] In order to solve the above problems existing in the prior art, the application provides a dual-polarized wideband small-aperture base station antenna. The technical problem to be solved by the application is solved by the following technical scheme:

[0007] The application provides a dual-polarized wideband small-aperture base station antenna, which comprises at least one antenna unit, and the antenna unit comprises a reflecting plate, a feeding structure, a vertical lower bent radiator, a horizontal radiator and a vertical upper bent radiator, wherein,

[0008] The reflecting plate is square and is composed of a layer of metal copper-clad patch printed on the upper side of a dielectric substrate and is located below the entire antenna unit.

[0009] The feeding structure is arranged above the reflecting plate and comprises two first vertical dielectric substrates arranged in cross, and a feeding connector, an η-shaped microstrip balun and a ground metal sheet are respectively printed on both sides of each first vertical dielectric substrate.

[0010] The vertical lower bent radiator is arranged below the horizontal radiator and is formed by an inner layer dielectric substrate and a metal copper-clad printed on the outer side of the upper end of the inner layer dielectric substrate, and four groups of vertical lower bent radiators are respectively arranged vertically below four corners of the horizontal radiator.

[0011] The horizontal radiator is formed by four annular dipoles arranged in cross above a square dielectric substrate to form cross dipoles, and each cross dipole is connected with the vertical lower bent radiator and the vertical upper bent radiator.

[0012] The vertical upper bent radiation body is arranged around the horizontal radiation body, and an S-shaped metal copper-clad patch of the vertical upper bent radiation body is located above the metal patch of the horizontal radiation body (4) and connected with the metal patch of the horizontal radiation body.

[0013] In one embodiment of the present application, the feeding terminals and the η-shaped microstrip barrons are located on the front surface of the first vertical dielectric substrate, the ground metal sheets are located on the back surface of the first vertical dielectric substrate, the η-shaped microstrip barrons arranged on different first vertical dielectric substrates have a height difference in the vertical direction, and the bottom parts of each η-shaped microstrip barron are connected with the corresponding feeding terminals (21) respectively.

[0014] In one embodiment of the present application, the η-shaped microstrip barron comprises three-order microstrip lines with different widths and different lengths.

[0015] In one embodiment of the present application, the vertical lower bent radiation body comprises four second vertical dielectric substrates forming a cuboid structure, two first metal sheets are respectively arranged on the outer surface of each second vertical dielectric substrate, the two first metal sheets are symmetrically arranged on the upper left and right sides of the second vertical dielectric substrate, each first metal sheet comprises an S-shaped part and a protruding part arranged above the S-shaped part, and the protruding part is used for being inserted into the horizontal radiation body located above.

[0016] In one embodiment of the present application, the first metal sheets located above different second vertical dielectric substrates are spaced from each other.

[0017] In one embodiment of the present application, a rectangular slot with different sizes is arranged on each cross-dipole for connecting the vertical lower bent radiation body and the vertical upper bent radiation body.

[0018] In one embodiment of the present application, the vertical upper bent radiation body comprises four third vertical dielectric substrates forming a cuboid structure, two S-shaped second metal sheets are respectively arranged on the inner surface of each third vertical dielectric substrate, and the two second metal sheets are symmetrically arranged on the upper left and right sides of the third vertical dielectric substrate.

[0019] In one embodiment of the present application, the second metal sheets arranged above different third vertical dielectric substrates are spaced from each other.

[0020] Compared with the prior art, the present application has the following beneficial effects:

[0021] The base station antenna of the present application realizes the reduction of the aperture of the antenna while the working frequency band is still kept within 1.7GHz-2.7GHz by loading the vertical lower bending radiators and the vertical upper bending radiators around the horizontal radiators, can cover the frequency bands of 2G / 3G / 4G, compared with the traditional antenna unit working in the frequency band, the aperture size of the unit is reduced by about 25%, and the radiation pattern is good, the reflection coefficient and the transmission coefficient in the working frequency band are good, the cross polarization ratio is low, the actual gain in the whole frequency band is about 7.7dBi, and the spatial advantage for forming a large-scale MIMO array is obtained.

[0022] Meanwhile, the base station antenna has simple design process, low cost, stable structure, mature processing technology, high yield and is suitable for large-scale mass production.

[0023] The present application will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 A structure schematic diagram of an antenna unit of a wideband dual-polarized base station antenna provided by the embodiment of the present application is shown in the figure.

[0025] Figure 2 A structure schematic diagram of a feeding structure provided by the embodiment of the present application is shown in the figure.

[0026] Figure 3 A structure schematic diagram of a vertical lower bending radiator provided by the embodiment of the present application is shown in the figure.

[0027] Figure 4 A structure schematic diagram of a horizontal radiator provided by the embodiment of the present application is shown in the figure.

[0028] Figure 5 A structure schematic diagram of a vertical upper bending radiator provided by the embodiment of the present application is shown in the figure.

[0029] Figure 6a And Figure 6b A current distribution diagram corresponding to the base station antenna provided by the embodiment of the present application at a frequency of 1.85GHz is shown in the figure.

[0030] Figure 7a And Figure 7b A current distribution diagram corresponding to the base station antenna provided by the embodiment of the present application at a frequency of 2.3GHz is shown in the figure.

[0031] Figure 8a And Figure 8b A current distribution diagram corresponding to the base station antenna provided by the embodiment of the present application at a frequency of 2.68GHz is shown in the figure.

[0032] Figure 9The S parameter response graph corresponding to the base station antenna unit model provided by the embodiment of the present application;

[0033] Figure 10 The input impedance simulation result graph of the base station antenna unit model provided by the embodiment of the present application;

[0034] Figure 11a The antenna directional diagram of the base station antenna unit model provided by the embodiment of the present application at 1.7GHz;

[0035] Figure 11b The antenna directional diagram of the base station antenna unit model provided by the embodiment of the present application at 2.2GHz;

[0036] Figure 11c The antenna directional diagram of the base station antenna unit model provided by the embodiment of the present application at 2.7GHz;

[0037] Figure 12 The full-band actual gain graph of the base station antenna unit model provided by the embodiment of the present application;

[0038] Figure 13a The 3D antenna directional diagram of the antenna unit model provided by the embodiment of the present application at 1.71GHz;

[0039] Figure 13b The 3D antenna directional diagram of the antenna unit model provided by the embodiment of the present application at 1.88GHz;

[0040] Figure 13c The 3D antenna directional diagram of the antenna unit model provided by the embodiment of the present application at 1.92GHz;

[0041] Figure 13d The 3D antenna directional diagram of the antenna unit model provided by the embodiment of the present application at 2.02GHz;

[0042] Figure 13e The 3D antenna directional diagram of the antenna unit model provided by the embodiment of the present application at 2.17GHz;

[0043] Figure 13f The 3D antenna directional diagram of the antenna unit model provided by the embodiment of the present application at 2.2GHz;

[0044] Figure 13g The 3D antenna directional diagram of the antenna unit model provided by the embodiment of the present application at 2.3GHz;

[0045] Figure 13h The 3D antenna directional diagram of the antenna unit model provided by the embodiment of the present application at 2.39GHz;

[0046] Figure 13iA 3D antenna pattern of the antenna unit model provided by the embodiment of the present application at 2.69GHz.

[0047] Figure 13j A 3D antenna pattern of the antenna unit model provided by the embodiment of the present application at 2.7GHz. DETAILED DESCRIPTION

[0048] In order to further illustrate the technical means and effects adopted by the present application to achieve the predetermined purposes, a dual-polarized wideband small-aperture base station antenna according to the present application is described in detail below in combination with the drawings and specific embodiments.

[0049] The foregoing and other technical contents, features and effects of the present application can be clearly presented in the following detailed description of specific embodiments in combination with the drawings. Through the description of specific embodiments, the technical means and effects adopted by the present application to achieve the predetermined purposes can be understood more deeply and specifically. However, the accompanying drawings are provided for reference and illustration only, and are not intended to limit the technical solutions of the present application.

[0050] It should be noted that, in this document, relational terms such as first and second, and the like, are used solely to distinguish one entity or action from another entity or action, without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without more limitations, an element defined by an "comprising... " statement is not excluded from a process, method, article, or apparatus that includes the element, even if the same process, method, article, or apparatus also includes other elements not mentioned in the "comprising... " statement.

[0051] Please refer to Figure 1 , Figure 1 The antenna unit structure diagram of a wideband dual-polarized base station antenna provided by the present application. The base station antenna comprises at least one antenna unit, which comprises a reflecting plate 1, a feed structure 2, a vertical lower bent radiator 3, a horizontal radiator 4 and a vertical upper bent radiator 5. The reflecting plate 1, as the reflecting plate of the antenna, is square, is composed of a layer of metal copper-clad patch printed on the upper side of the dielectric substrate, and is located below the entire antenna unit. The function of the reflecting plate is to make the antenna directional.

[0052] Please refer to Figure 2 , Figure 2A structural diagram of a feeding structure is provided for an embodiment of the present application. The feeding structure 2 of the embodiment is arranged above a reflecting plate 1 and comprises two first vertical dielectric substrates arranged in cross. A feeding terminal 21, an η-shaped microstrip balun 22 and a ground metal sheet 23 are respectively printed on both sides of each of the first vertical dielectric substrates. The feeding terminal 21 and the three-section η-shaped microstrip balun 22 are located on the front side of the first vertical dielectric substrate, and the ground metal sheet 23 is located on the back side of the first vertical dielectric substrate.

[0053] The η-shaped microstrip baluns 22 arranged on different first vertical dielectric substrates have a height difference in the vertical direction. The first stage (bottom) of each η-shaped microstrip balun 22 is connected to the corresponding feeding terminal 21. The η-shaped microstrip balun 22 comprises three-stage microstrip lines with different widths and lengths, realizes microstrip lines with different resistances, and thus realizes impedance transformation and impedance matching from the feeding port to the radiator. The ground metal sheets 23 arranged on different first vertical dielectric substrates have a gap between them. In other words, the feeding structure 2 of the embodiment comprises two mutually orthogonal η-shaped microstrip baluns 22. Each first vertical dielectric substrate on which the microstrip balun 22 is printed is fixed by jack welding of the top protruding part to the horizontal dielectric substrate of the horizontal radiator 4 arranged above it.

[0054] The vertical downwardly bent radiators 3 are arranged below the horizontal radiator 4 and are sleeved on the outside of the feeding structure 2. The vertical downwardly bent radiators 3 are formed by an inner layer dielectric substrate and a metal copper coating printed on the outside of the substrate. Four groups of vertical downwardly bent radiators 3 are vertically arranged below the four corners of the horizontal radiator 4. Each group is symmetrically distributed on one corner.

[0055] Specifically, please refer to Figure 3 , Figure 3 A structural diagram of a vertical downwardly bent radiator is provided for an embodiment of the present application. The vertical downwardly bent radiator 3 of the embodiment comprises four second vertical dielectric substrates 31 forming a quadrangular structure. Two first metal sheets 32 are respectively printed and arranged on the outer surface of each second vertical dielectric substrate 31. The two first metal sheets 32 are symmetrically arranged on the left and right sides above the second vertical dielectric substrate 31. Each first metal sheet 32 comprises an S-shaped part 321 and a protruding part 322 arranged above the S-shaped part. The protruding part 322 is used to be inserted into the horizontal radiator 4 above it. It should be noted that the first metal sheets 32 arranged above different second vertical dielectric substrates 31 are adjacent but not connected to each other, as shown by 321 and 323 in Figure 3 Exemplarily, the overall height of the S-shaped part 321 is 10 mm (0.07λ, λ represents the wavelength at the center frequency of 2.2 GHz). The protruding parts 322 are located on the upper edges of the S-shaped parts 321 and are connected to each other for connection to the horizontal radiator.

[0056] The first metal sheet 32 of the vertical down-bent radiator 3 is printed on the outer side of the second vertical dielectric substrate 31 and is connected to the horizontal radiator 4 through the hole of the horizontal dielectric substrate, wherein the contact points can be connected by soldering during processing. Each group of vertical down-bent radiators 3 is placed in the four corners, which can effectively utilize the orthogonality of polarization to improve the cross-polarization ratio. The length of the vertical down-bent radiator 3 can be calculated according to the half wavelength corresponding to the frequency of the resonant point of the path, and then further parameter optimization is performed to determine. It is worth noting that in the embodiment, the length of the first metal sheet 32 of the vertical down-bent radiator 3 is 10 mm (0.07λ, λ represents the wavelength at the center frequency point 2.2 GHz), and if the bent arm is lengthened, it cannot further reduce the aperture, because the too long down-bent radiation arm will interact with the radiation plate, which will cause the matching of the antenna to deteriorate, and the gain will also decrease.

[0057] Further, please refer to Figure 4 , Figure 4 A structure schematic diagram of a horizontal radiator is provided for the embodiment of the present application. The horizontal radiator 4 of the embodiment is formed by four annular dipoles which are cross-placed above the square horizontal dielectric substrate to form cross-dipoles, the periphery of each cross-dipole is connected with the S-shaped radiation body bottom of the vertical up-bent radiator 5, and the periphery of the horizontal radiator 4 is also provided with a rectangular slot for connecting the protrusion above the vertical down-bent radiator 3, so that the dielectric substrate of the vertical down-bent radiator 3 and the patch radiator can be inserted through the protrusion structure 322.

[0058] Preferably, different size rectangular slots 411, 413 are provided on the cross-dipole 41. The size of the horizontal radiator 4 is 40 mm x 40 mm, i.e. 0.29λ x 0.29λ (λ represents the wavelength at the center frequency point 2.2 GHz).

[0059] The horizontal radiator 4 is formed by four annular dipoles which are cross-placed, and due to the reduction of the aperture, only the length of the cross-dipole is difficult to form a resonant current, so a strip-shaped radiation metal sheet is loaded at the corner of the annular dipole for connecting the current connection between the horizontal radiator 4 and the vertical up-bent radiator 5. Finally, the aperture of the antenna unit is reduced to only 40 mm (0.29λ, λ represents the wavelength at the center frequency point 2.2 GHz).

[0060] The cross-dipole of the horizontal radiator 4 and the horizontal dielectric substrate are both provided with rectangular slots, wherein the small-size rectangular slot in the middle is used to fix the dielectric substrate in the feed structure 2, and the large-size rectangular slot in the periphery is used to fix the dielectric substrate in the vertical down-bent radiator 3.

[0061] Please refer to Figure 5, Figure 5 A structure diagram of a vertical upper bending radiator is provided for an embodiment of the present application. The vertical upper bending radiator 5 of the embodiment is entirely sleeved outside the vertical lower bending radiator 3, and includes four third vertical dielectric substrates 51 forming a cuboid structure. Two S-shaped second metal sheets 52 are respectively printed on the inner surface of each third vertical dielectric substrate 51. The two second metal sheets 52 are symmetrically arranged on the left and right sides above the third vertical dielectric substrate 51. It should be noted that the second metal sheets 52 arranged above different third vertical dielectric substrates 51 are adjacent but not connected to each other, as shown by 521 and 522 in FIG. 5. Figure 5 Exemplarily, the overall height of the vertical upper bending radiator 5 is 10 mm (0.07λ, λ represents the wavelength at the center frequency point 2.2 GHz).

[0062] The vertical upper bending radiator 5 is placed around the horizontal radiator 4. The S-shaped second metal sheets 52 are printed on the inner side of the third vertical dielectric substrate 51. The second metal sheets 52 are connected to the metal patches of the horizontal radiator 4, and there are four pairs of them placed in the four corners.

[0063] The vertical upper bending radiator 5 is composed of four groups of symmetrically structured S-shaped second metal sheets 52, which are printed on the inner side of the outer third vertical dielectric substrate 51. The S-shaped metal radiation parts are reasonably placed to increase the length of the generated resonant current by using the S shape, thereby effectively prolonging the resonant current and moving the resonant frequency point to the low-frequency operating frequency band. The length of the S-shaped second metal sheet 52 (vertical upper bending arm) can be calculated according to the half wavelength corresponding to the frequency at the resonant frequency point, and the parameters can be further optimized and determined.

[0064] The orthogonal characteristics of cross-polarization are utilized to make the isolation between the cross-polarization signal and the main polarization signal of the antenna good.

[0065] From the perspective of the entire antenna unit of the base station antenna, there are two layers of dielectric substrates installed around it. There is a distance difference between the placement of the dielectric substrates. The inner dielectric substrate (second vertical dielectric substrate 31) is fixedly installed through the openings around the horizontal dielectric substrate, and the outer dielectric substrate (third vertical dielectric substrate 51) is fixedly installed through the S-shaped upper bending radiation structure printed on the inner side and the rectangular strip welding on the edge of the horizontal radiation structure.

[0066] In summary, the horizontal radiator 4 is placed above the square dielectric substrate by four annular dipoles to form crossed dipoles, the periphery of each crossed dipole is connected with the S-shaped radiator bottom of the vertically upper bent radiator 5, and the periphery of the horizontal radiator 4 is also provided with a rectangular slot for connecting the protrusion above the vertically lower bent radiator 3. The dielectric substrate and the patch radiator of the vertically lower bent radiator 3 can be inserted into the jack through the protrusion 322 structure to connect the horizontal radiator 4. In addition, the vertically placed dielectric substrate has three groups in total, and from the inside to the outside, one group is used for printing a microstrip balun; the middle group is the inner layer vertical dielectric substrate used for printing the radiator of the vertically lower bent radiator; and the outermost group is the outer layer vertical dielectric substrate used for printing the radiator structure of the vertically upper bent radiator. The aperture size of the antenna unit is only 40mm x 40mm, i.e. 0.29λ x 0.29λ (λ is the wavelength corresponding to the center frequency point 2.2GHz).

[0067] According to the antenna theory, using a high dielectric constant medium can reduce the resonant frequency of the antenna, and the resonant frequency is inversely proportional to the electrical length of the antenna, which is equivalent to reducing the actual volume of the antenna.

[0068] The working mechanism of the base station antenna of the embodiment is designed by using the principle of prolonging the effective resonant current, and the current zero point is effectively prolonged to the end of the upper and lower vertical radiators (including the vertically lower bent radiator 3 and the vertically upper bent radiator 5) by being introduced to the end of the upper and lower vertical radiators (including the vertically lower bent radiator 3 and the vertically upper bent radiator 5). The radiator provides a resonant path for resonance, and according to the principle of half-wave resonance, The current distribution at 1.85GHz, 2.3GHz and 2.68GHz resonances in the working frequency band of 1.7-2.7GHz is shown in Figure 6a 、 Figure 6b 、 Figure 7a 、 Figure 7b 、 Figure 8a and Figure 8b . Among them, Figure 6a shows the current distribution on the horizontal radiator at 1.85GHz resonance, Figure 6b shows the current distribution on the vertical radiator (including the vertically lower bent radiator 3 and the vertically upper bent radiator 5) at 1.85GHz resonance, and it can be seen that at 1.85GHz resonance, the current is mainly generated along the crossed dipole of the horizontal radiator and the vertically upper bent radiator, which is generated by the structure in the excited polarization direction. Figure 7a shows the current distribution on the horizontal radiator at 2.3GHz resonance, Figure 7bThe current distribution on the vertical radiator at the 2.3GHz resonance is shown, and it can be seen that at the 2.3GHz resonance, the current is mainly distributed on the structure of the -45° polarization direction, which is generated by coupling, along the cross-dipole of the horizontal radiator and the resonant path of the vertical upper bending radiator; Figure 8a The current distribution on the horizontal radiator at the 2.68GHz resonance is shown, Figure 8b The current distribution on the vertical radiator at the 2.68GHz resonance is shown, and at the high frequency 2.68GHz resonance, the current is obviously distributed in a large range on the cross-dipole and the vertical upper bending radiator, and both are large current values. It can be seen that the current zero point at each resonance is located at the end of the upper and lower vertical bending radiators, and then a certain length of current is formed along the S shape to generate resonance. In this process, in addition to having a physical length to generate resonant current, a microstrip balun is also needed for impedance transformation, which involves a three-section eta-shaped microstrip balun and a coupler structure.

[0069] Further, the feeding structure 2 has the function of feeding in addition to the function of feeding, and more importantly, impedance transformation between the feeding joint and the radiator. When only one polarization is excited (taking +45° polarization as an example), the joint 21 of the other polarization feeding structure 2 is connected with a 50Ω load, the exciting current is impedance-transformed through the three-section eta-shaped microstrip balun 221, 222, 223, the gap 232 between the ground metal sheets on the back of the dielectric substrate corresponds to a coupler, and the signal is coupled and transmitted, and then connected to the horizontal radiator structure through the small protrusion 233 on the ground metal. In addition, the back metal sheet 231 is used to ground the radiator, thereby realizing the feeding of the antenna radiator.

[0070] Optionally, all the dielectric substrates involved in the base station antenna are Rogers RO4350 with a dielectric constant of 3.66, and the thickness is 0.762mm.

[0071] Please refer to Figure 9 and Figure 10 , Figure 9 the S parameter response graph corresponding to the base station antenna unit model provided by the embodiment of the application; Figure 10 the input impedance simulation result graph of the base station antenna unit model provided by the embodiment of the application. It can be seen that the introduction of the vertical upper bending radiator and the vertical lower bending radiator can make the antenna have a flat impedance matching in the 1.7-2.7GHz frequency band, generate three resonance frequency points, and the matching is below -12dB, and the port isolation is below -27dB. Although the antenna aperture is reduced to only 40mm (0.29λ, λ represents the wavelength at the center frequency 2.2GHz), the gain of the full-band antenna does not decrease much compared with the traditional large-aperture base station antenna operating in this frequency band. Please refer to Figure 12 , Figure 12The full-band actual gain diagram of the base station antenna unit model provided by the embodiment of the present application can be seen that the actual gain of the base station antenna is basically above 7.5dBi in the full-band.

[0072] Figures 13a to 13j The 3D radiation pattern of the antenna at low, medium and high frequencies is given, which can be seen that the radiation pattern is smooth and the radiation performance is good at each frequency, and the corresponding Figure 11a 、 Figure 11b and Figure 11c The 2D radiation pattern at 1.7GHz, 2.2GHz and 2.7GHz is given, which can clearly see that the cross-polarization ratio of the antenna is greater than 15 between ±60°, having good cross-polarization characteristics, which can be effectively applied to dual-polarized base station antennas.

[0073] The radiators in the antenna are printed on a Rogers RO4350 dielectric substrate with a dielectric constant of 3.66 and a thickness of 0.762mm, the antenna unit radiator aperture is only 40mm*40mm (0.29λ*0.29λ, λ represents the wavelength at the center frequency of 2.2GHz), and the profile height is 48mm (0.35λ, λ represents the wavelength at the center frequency of 2.2GHz). The horizontal radiator is composed of four cross-placed ring-shaped dipoles; the four periphery loaded upper and lower bent arc-shaped radiators are respectively located at the four corner ends of the horizontal radiator, and there are a total of four groups; the microstrip balun feeding network has two feeding points, and the feeding points are along the ±45° direction of the antenna; and the reflector is square and under the entire antenna. Finally, the small-aperture antenna unit is realized to cover the 1.7-2.7GHz frequency band of 2G / 3G, the operating bandwidth is 45.5% (VSWR<1.7), the polarization isolation is greater than 30dB, and the antenna gain is stable at 7.8dBi. The antenna has good radiation patterns in horizontal and vertical directions, and the half-power beamwidth is 77°±2°, which meets the index requirements of base station antennas.

[0074] The base station antenna of the embodiment loads vertical lower bent radiators and vertical upper bent radiators around the horizontal radiator to realize the reduction of the antenna aperture while keeping the operating frequency band within 1.7GHz-2.7GHz, which can cover the frequency band of 2G / 3G / 4G. Compared with the conventional antenna unit operating in this frequency band, the unit aperture size is reduced by about 25%, and the radiation pattern is good, the reflection coefficient and the transmission coefficient in the operating frequency band are good, the cross-polarization ratio is low, the actual gain in the entire frequency band is about 7.7dBi, and it has spatial advantages for forming a large-scale MIMO array. At the same time, the design process of the base station antenna is simple, the cost is low, the structure is stable, the processing technology is mature, the yield is high, and it is suitable for large-scale production.

[0075] The above description is further detailed in connection with specific preferred embodiments of the present application, and it is not to be construed that the specific implementation of the present application is limited to these descriptions. For those skilled in the art to which the present application belongs, without departing from the concept of the present application, a number of simple deductions or substitutions can be made, and all of them should be considered as falling within the protection scope of the present application.

Claims

1. A dual-polarized wideband small aperture base station antenna, characterized by, The base station antenna comprises at least one antenna unit, the antenna unit comprises a reflecting plate (1), a feed structure (2), a vertical lower bent radiator (3), a horizontal radiator (4) and a vertical upper bent radiator (5), wherein, The reflecting plate (1) is square, is composed of a layer of metal copper-clad patch printed on the upper side of the dielectric substrate, and is located below the entire antenna unit; The feeding structure (2) is arranged above the reflecting plate (1), comprising two first vertical dielectric substrates arranged in cross, a feeding connector (21) is respectively printed on both sides of each first vertical dielectric substrate, a microstrip balun (22) and a ground metal sheet (23). The vertical lower bent radiator (3) is arranged below the horizontal radiator (4), is formed by an inner layer of dielectric substrate and metal copper-clad printed on the outer side of the inner layer of dielectric substrate, and four groups of the vertical lower bent radiator (3) are vertically arranged at four corners below the horizontal radiator (4) respectively; The horizontal radiator (4) is arranged above the square dielectric substrate by four annular dipoles arranged in cross, to form a cross-dipole, and each cross-dipole is connected with the vertical lower bent radiator (3) and the vertical upper bent radiator (5); The vertical upper bent radiator (5) is arranged around the horizontal radiator (4), and the S-shaped metal copper-clad patch of the vertical upper bent radiator (5) is located above the metal patch of the horizontal radiator (4) and is connected with the metal patch of the horizontal radiator (4); The vertical lower bent radiator (3) comprises four second vertical dielectric substrates (31) surrounding a quadrangular structure, two first metal sheets (32) are respectively printed and arranged on the outer surface of each second vertical dielectric substrate (31), the two first metal sheets (32) are symmetrically arranged above and on the left and right sides of the second vertical dielectric substrate (31), each first metal sheet (32) comprises an S-shaped part (321) and a protruding part (322) arranged above the S-shaped part (321), and the protruding part (322) is used for being inserted into the horizontal radiator (4) above it; The first metal sheets (32) above different second vertical dielectric substrates (31) are spaced from each other; Each cross-dipole (41) is provided with rectangular slots (411, 413) of different sizes for connecting the vertical lower bent radiator (3) and the vertical upper bent radiator (5).

2. The dual-polarized wideband small aperture base station antenna according to claim 1, wherein, The feeding terminal (21) and the The first vertical dielectric substrate is provided with a plurality of feeding terminals (21) and a plurality of microstrip baluns (22) in a matrix form. The feeding terminal (21) and the The microstrip baluns (22) in the matrix form have a height difference in the vertical direction. Each The bottom of each microstrip balun (22) is connected with the corresponding feeding terminal (21).

3. The dual-polarized wideband small aperture base station antenna according to claim 2, wherein, The The shaped microstrip balun (22) includes three microstrip lines of different widths and different lengths.

4. The dual-polarized wideband small aperture base station antenna of claim 1, wherein, The vertical upper bent radiator (5) comprises four third vertical dielectric substrates (51) surrounding a quadrangular structure, two S-shaped second metal sheets (52) are respectively printed and arranged on the inner surface of each third vertical dielectric substrate (51), and the two second metal sheets (52) are symmetrically arranged above and on the left and right sides of the third vertical dielectric substrate (5).

5. The dual-polarized wideband small aperture base station antenna according to claim 4, wherein, The second metal sheets (52) arranged above different third vertical dielectric substrates (51) are spaced from each other.

Images