阅读说明：本技术 一种天线阵列及基站 (Antenna array and base station ) 是由 王天祥 王光健 张晶 于 2020-04-22 设计创作，主要内容包括：本申请提供了一种天线阵列及基站,天线阵列包括：多个高频辐射单元,串联的第一移相器及第一衰减器,串联的第一移相器和第一衰减器与多个高频辐射单元一一对应连接；多个高频辐射单元中,部分高频辐射单元组成用于辐射低频信号的子阵；还包括低频馈电单元及高频馈电单元；低频馈电单元与子阵连接,子阵中的高频辐射单元可以通过第一移相器及第一衰减器使得子阵中的高频辐射单元合波形成与低频天线对应的辐射波。高频馈电单元用于给每个高频辐射单元馈电。通过上述描述可以看出,本申请实施例体用的天线阵列只需要设置一种辐射单元即可,相比现有技术中采用多个不同类型的辐射单元,简化了天线阵列,同时,还可提高天线阵列的辐射性能。(The application provides an antenna array and base station, the antenna array includes: the high-frequency radiating units are connected with the first phase shifters and the first attenuators in series in a one-to-one corresponding mode; in the plurality of high-frequency radiating units, partial high-frequency radiating units form a sub-array for radiating low-frequency signals; the low-frequency power feeding unit and the high-frequency power feeding unit are also included; the low-frequency feed unit is connected with the sub-array, and the high-frequency radiation units in the sub-array can combine waves to form radiation waves corresponding to the low-frequency antenna through the first phase shifter and the first attenuator. The high-frequency feeding unit is used for feeding each high-frequency radiating unit. As can be seen from the above description, the antenna array used in the embodiment of the present application only needs to be provided with one type of radiation unit, and compared with the prior art in which a plurality of radiation units of different types are used, the antenna array is simplified, and meanwhile, the radiation performance of the antenna array can be improved.)

1. An antenna array, comprising:

the high-frequency radiating unit comprises a plurality of high-frequency radiating units arranged in an array, a first phase shifter and a first attenuator which are connected in series, wherein the first phase shifter and the first attenuator which are connected in series are connected with the high-frequency radiating units in a one-to-one correspondence manner; among the plurality of high-frequency radiating units, partial high-frequency radiating units form a sub-array;

the low-frequency feeding unit is used for feeding power to each high-frequency radiating unit in the sub-array;

the control circuit is used for controlling the first phase shifter to perform primary phase shifting on the low-frequency signal transmitted by the low-frequency feed unit and controlling the first attenuator to perform primary amplitude attenuation on the low-frequency signal so as to enable signal waves transmitted by all high-frequency radiating units in the sub-array to be combined into a wave form corresponding to the low-frequency signal;

and a high-frequency feeding unit for feeding each of the high-frequency radiating units.

2. An antenna array according to claim 1, wherein the distance d between any adjacent high-frequency radiating elements satisfies:

1/2 lambda is not less than d not more than lambda; wherein λ is a wavelength corresponding to the high-frequency signal input by the high-frequency power feeding unit.

3. An antenna array according to claim 2, wherein the low frequency feed element is connected to each high frequency radiating element in the sub-array via a second attenuator;

the control circuit is further configured to control the first attenuator and the second attenuator to perform amplitude attenuation on the low-frequency signal twice, so that signal waves emitted by all the high-frequency radiation units in the sub-array are combined into a waveform corresponding to the low-frequency signal.

4. An antenna array according to claim 3, further comprising a power divider, wherein a first end of the power divider is connected to the second attenuator, and a second end of the power divider is connected to each high-frequency radiating element in the sub-array.

5. An antenna array according to claim 3 or 4, further comprising a second phase shifter in series with the second attenuator;

the control circuit is further configured to control the first phase shifter and the second phase shifter to shift the phase of the low-frequency signal twice, so that the signal waves emitted by all the high-frequency radiation units in the sub-array are combined into a waveform corresponding to the low-frequency signal.

6. An antenna array according to claim 5 wherein the first phase shifter is an electrical phase shifter and the second phase shifter is an optical phase shifter.

7. An antenna array according to any of claims 1 to 6, further comprising a digital-to-analog converter, an electro-optic converter and a high-speed single-row carrier photo-speed diode; wherein the content of the first and second substances,

the low-frequency feed unit is connected with the digital-to-analog converter, the digital-to-analog converter is connected with the electro-optical converter, the first phase shifter is an optical phase shifter, the first attenuator is an optical attenuator, one end of the first phase shifter and one end of the first attenuator which are connected in series are connected with the electro-optical converter, and the other end of the first phase shifter and one end of the first attenuator are connected with the high-speed single-row carrier photodiode.

8. An antenna array according to claim 7, further comprising a combiner and a de-combiner connected to the combiner; wherein the combiner is connected with the plurality of first phase shifters and first attenuators connected in series, and the de-combiner is connected with the plurality of high speed single-row carrier photodiodes.

9. An antenna array according to any one of claims 1 to 8, wherein when there are a plurality of said sub-arrays, the phase centres of said plurality of sub-arrays are non-periodically arranged.

10. An antenna array according to claim 9, wherein the high frequency radiating elements in the sub-arrays are arranged in a non-regular shape.

11. A base station comprising an antenna array according to any of claims 1 to 10.

Technical Field

The present application relates to the field of communications technologies, and in particular, to an antenna array and a base station.

Background

For the communication base station, along with the development of communication technology, multiple systems such as 2G, 3G, 4G coexist, base station resources are more and more tense, and meanwhile, residents around the base station object to newly-increased antennas on the holding pole due to fear of electromagnetic radiation, the number of the antennas can be reduced by adopting the multi-frequency base station antenna, the installation space is reduced, and the cost of operators is reduced, so that the research on the multi-frequency base station antenna covering multiple frequency bands has very important practical value and practical significance. The requirement of the 4G era on the working bandwidth of the base station antenna is as follows: low frequency band: 690MHz-960MHz, high band: 1710MHz-2690 MHz. The current multi-frequency antenna scheme mainly comprises a coaxial nested form and a composite splicing form.

The existing base station technology adopts a low-frequency large-size high-frequency radiation unit and a high-frequency small-size high-frequency radiation unit to form an array. This is determined by the relationship between the size of the antenna aperture and its radiation efficiency, i.e. the highest radiation efficiency when the antenna high frequency radiation element size corresponds to 1/2 wavelengths in air. Thus, in the 1GHz working frequency band, the size of the low-frequency radiating unit is 300mm/1 GHz/2-15 mm; and in a 2GHz working frequency band, the size of the high-frequency radiating unit is 300mm/2 GHz/2-7.5 mm. It can be seen that the size of the low frequency radiating element is twice the size of the high frequency radiating element.

However, the combination of the high and low frequency radiation units still has various serious problems. The physical distance between the first high-frequency radiating unit and the low-frequency radiating unit is too close, and the strong mutual coupling effect between the first high-frequency radiating unit and the low-frequency radiating unit causes the far-field directional diagram to be seriously distorted, so that the array radiation performance is deteriorated. Secondly, according to the basic theory of antennas, in order to achieve good directional radiation characteristics by superimposing the radiation wave and the reflected wave of an antenna in phase, the height of the cross section of the antenna is required to be 1/4 wavelength, i.e., λ/4. Since the operating frequency band of the low frequency array is low, the profile height of the low frequency array limits the overall array profile height, as shown in fig. 5, which poses serious difficulties in low profile and miniaturization of the antenna device. Third, too large a size of the low frequency radiation element may cause overlapping of the high frequency radiation element projections, or no design space for the high frequency radiation element.

Disclosure of Invention

The application provides an antenna array and a base station, which are used for simplifying the structure of the antenna array and improving the performance of the antenna array.

In a first aspect, an antenna array is provided, where the antenna array is applied in a base station, and the antenna array includes: the high-frequency radiating unit comprises a plurality of high-frequency radiating units arranged in an array, a first phase shifter and a first attenuator which are connected in series, wherein the first phase shifter and the first attenuator which are connected in series are connected with the high-frequency radiating units in a one-to-one correspondence manner; among the plurality of high-frequency radiating units, part of the high-frequency radiating units form a sub-array for radiating low-frequency signals; the feed source comprises a low-frequency feed unit and a high-frequency feed unit; the low-frequency feeding unit is used for feeding each high-frequency radiating unit in the sub-array, and the low-frequency feeding unit further comprises a control circuit which is used for controlling the first phase shifter to perform primary phase shifting on a low-frequency signal transmitted by the low-frequency feeding unit and controlling the first attenuator to perform primary amplitude attenuation on the low-frequency signal, so that signal waves transmitted by all the high-frequency radiating units in the sub-array are combined into a waveform corresponding to the low-frequency signal. When the low-frequency feeding unit feeds power to the high-frequency radiating units in the sub-array, signals emitted by the high-frequency radiating units in the sub-array can move towards through the first phase shifter, and the first attenuator attenuates the signals, so that signal waves emitted by the high-frequency radiating units in the sub-array are combined to form waveforms corresponding to the low-frequency signals. And a high-frequency feeding unit for feeding each of the high-frequency radiating units. As can be seen from the above description, the antenna array used in the embodiment of the present application only needs to be provided with one type of radiation unit, and compared with the prior art in which a plurality of radiation units of different types are used, the antenna array is simplified, and meanwhile, the radiation performance of the antenna array can be improved.

In a specific embodiment, the distance d between any adjacent high-frequency radiating elements satisfies: 1/2 lambda is not less than d not more than lambda; wherein λ is a wavelength corresponding to the high-frequency signal input by the high-frequency power feeding unit. Avoid the crosstalk of high frequency radiation unit signal, improve the performance of antenna array.

In a specific embodiment, d can be 1/2 λ, 3/4 λ, and the like. That is, the high-frequency radiation units arranged in an array may be arranged at different pitches.

In a specific possible embodiment, the low-frequency feed unit is connected with each high-frequency radiating unit in the sub-array through a second attenuator; the control circuit is further configured to control the first attenuator and the second attenuator to perform amplitude attenuation on the low-frequency signal twice, so that signal waves emitted by all the high-frequency radiation units in the sub-array are combined into a waveform corresponding to the low-frequency signal. The second attenuator is matched with the first attenuator to improve the effect of combining waves to form low-frequency antenna radiation waves.

In a specific implementation mode, the adjustment precision of the first attenuator is greater than that of the second attenuator, so that the combination of coarse adjustment and fine adjustment can be realized, and the effect of forming the low-frequency antenna radiation wave by the combined wave can be adjusted more quickly.

In a specific implementation, the radio frequency module further includes a power divider, a first end of the power divider is connected to the second attenuator, and a second end of the power divider is connected to each high-frequency radiating unit in the sub-array. The connection with each high-frequency radiation unit is realized through the arranged power divider.

In a specific embodiment, the attenuator further comprises a second phase shifter, the second phase shifter being connected in series with the second attenuator; the control circuit is further configured to control the first phase shifter and the second phase shifter to shift the phase of the low-frequency signal twice, so that the signal waves emitted by all the high-frequency radiation units in the sub-array are combined into a waveform corresponding to the low-frequency signal. The effect of combining waves to form low-frequency antenna radiation waves is improved through the cooperation of the second phase shifter and the first phase shifter.

In a specific implementation, the adjustment precision of the first phase shifter is greater than that of the second phase shifter, so that the coordination of coarse adjustment and fine adjustment can be realized, and the effect of forming the low-frequency antenna radiation wave by the combined wave can be adjusted more quickly.

In a specific embodiment, the first phase shifter is an electrical phase shifter and the second phase shifter is an optical phase shifter.

In a specific implementation mode, the device further comprises a digital-to-analog converter, an electro-optical converter and a high-speed single-row carrier light speed diode; wherein the content of the first and second substances,

the low-frequency feed unit is connected with the digital-to-analog converter, the digital-to-analog converter is connected with the electro-optical converter, the first phase shifter is an optical phase shifter, the first attenuator is an optical attenuator, one end of the first phase shifter and one end of the first attenuator which are connected in series are connected with the electro-optical converter, and the other end of the first phase shifter and one end of the first attenuator are connected with the high-speed single-row carrier photodiode. The first phase shifter and the first attenuator can thus be arranged at the bottom of the base station, reducing the weight of the radiating portion of the antenna array.

In a specific implementation scheme, the system further comprises a combiner and a de-combiner connected with the combiner; wherein the combiner is connected with the plurality of first phase shifters and first attenuators connected in series, and the de-combiner is connected with the plurality of high speed single-row carrier photodiodes. The structure of signal transmission is simplified.

In a specific embodiment, when the number of the sub-arrays is plural, the phase centers of the plural sub-arrays are arranged non-periodically. High grating lobes between the antennas are reduced, and the performance of the antennas is improved.

In a specific embodiment, the high-frequency radiating elements in the sub-array are arranged in a non-regular shape. The subarrays are prevented from being regularly arranged, high grating lobes between the antennas are reduced, and the performance of the antennas is improved.

In a second aspect, there is provided a base station comprising an antenna array as claimed in any one of the preceding claims. When the low-frequency feed unit in the antenna array feeds the high-frequency radiation units in the sub-array, the high-frequency radiation units in the sub-array can move towards through the first phase shifter and the first attenuator attenuates signals, so that the high-frequency radiation units in the sub-array are combined to form radiation waves corresponding to the low-frequency antenna. And a high-frequency feeding unit for feeding each of the high-frequency radiating units. As can be seen from the above description, the antenna array used in the embodiment of the present application only needs to be provided with one type of radiation unit, and compared with the prior art in which a plurality of radiation units of different types are used, the antenna array is simplified, and meanwhile, the radiation performance of the antenna array can be improved.

Drawings

Fig. 1 is a schematic view of an application scenario of an antenna array according to an embodiment of the present application;

fig. 2 is a schematic structural diagram of an antenna array according to an embodiment of the present application;

fig. 3 is a top view of the antenna array provided by the embodiment of the present application shown in fig. 2;

fig. 4 is a feeding structure corresponding to a first high-frequency radiating element provided in an embodiment of the present application;

fig. 5 is a variant of the feed structure of fig. 4;

fig. 6 is a feeding structure corresponding to a second high-frequency radiating element provided in an embodiment of the present application;

fig. 7 is a feeding structure corresponding to a third high-frequency radiating element provided in the embodiment of the present application;

fig. 8 is a feeding structure corresponding to a fourth high-frequency radiating element provided in the embodiment of the present application;

fig. 9 is a modification of the feeding structure corresponding to the fourth high-frequency radiating element according to the embodiment of the present application;

fig. 10 is a schematic diagram of a connection between a fourth high-frequency radiating element and a feed source provided in the embodiment of the present application;

fig. 11 is an arrangement of another antenna array according to an embodiment of the present application;

fig. 12 shows the position of the phase of the sub-array.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more clear, the present application will be further described in detail with reference to the accompanying drawings.

To facilitate understanding of the antenna array provided in the embodiment of the present application, an application scenario of the antenna array provided in the embodiment of the present application is first described. The communication base station mainly comprises three parts: bbu (building base unit): the baseband processing unit mainly completes the functions of channel coding and decoding, modulation and demodulation of baseband signals, protocol processing and the like. Typically, the BBUs are all located under towers, in-house/machine rooms. RRU (radio Remote Unit): the radio remote unit is mainly used for completing modulation and demodulation of radio frequency signals, power amplification of radio frequency analog signals and transmission of the radio frequency analog signals to the antenna feeder. The RRU is mainly installed by holding poles or hanging walls. Antenna array: the signal/information is transmitted or received back and, as shown in fig. 1, an antenna array 1 is arranged on the tower body 2. With the development of communication technology, communication base stations need to receive or transmit signals of different frequency bands, which requires that the antenna array 1 has radiating elements matched with different frequency bands. The current communication base station covers a low frequency band (790MHz-960MHz) and a high frequency band (1710MHz-2690MHz), and 2G, 3G and 4G full frequency bands are covered by adopting a mode of mixing high-frequency radiating units with different sizes and high frequencies. However, the use of a low-frequency large-size high-frequency radiating element not only causes interference with the high-frequency radiating element to cause distortion of a directional pattern, but also its size limits the design space of the high-frequency radiating element and the profile of the entire array, resulting in difficulty in miniaturization. An antenna array is provided for this purpose, and is described in detail below with reference to specific figures and embodiments.

Fig. 2 is a schematic structural diagram of an antenna array according to an embodiment of the present application. The antenna array includes a plurality of high frequency radiation units 20 and a substrate 10. The substrate 10 as a structure for carrying the plurality of high-frequency radiating elements 20 is not limited to the rectangular shape shown in fig. 2, and may take other shapes such as a square, a pentagon, a circle, an ellipse, and the like. The substrate 10 has a setting surface 11, and the high-frequency radiating unit 20 is fixed on the substrate 10 by using a common screw connection (bolt or screw) or a fastening method such as snap connection, welding, or bonding.

The high-frequency radiation unit 20 provided by the embodiment of the present application satisfies the following conditions: the working bandwidth covers 500MHz-15GHz (Sub-15G), and the whole-band voltage standing wave ratio VSWR is less than or equal to 1.5. The space radiation performance meets the high-frequency band index requirements, such as the horizontal 3dB lobe width of 65 degrees, the port isolation degree is more than or equal to 30dB, the front-to-back ratio is more than or equal to 25dB, and the like.

As shown in the top view of the antenna array in fig. 3, the high frequency radiating element 20 is represented by a square in fig. 3. For convenience of description of the high-frequency radiating unit 20, a direction a and a direction b perpendicular to each other are defined, and planes in which the direction a and the direction b are located are parallel to the arrangement plane of the high-frequency radiating unit 20. The plurality of high-frequency radiating elements 20 are arranged in an array, and the plurality of high-frequency radiating elements 20 are arranged in a row in a direction a and in a column in a direction b on the installation surface. For example, an antenna array of 8 × 8 is formed as shown in fig. 3, but the antenna array provided in the embodiment of the present application is not limited to a specific number of the high-frequency radiation units 20, and the high-frequency radiation units 20 may be set according to specific requirements.

When the plurality of high-frequency radiating elements 20 are arrayed, the distance d between any adjacent high-frequency radiating elements 20 satisfies: 1/2 lambda is not less than d not more than lambda; wherein λ is a wavelength corresponding to the high-frequency signal input by the high-frequency power feeding unit. Illustratively, d is 1/2 λ, 3/4 λ, 4/5 λ, and so on. Any adjacent high-frequency radiating elements 20 mentioned above refer to the interval between two adjacent high-frequency radiating elements 20 between any one row, or the interval between two adjacent high-frequency radiating elements 20 between any two columns.

In an alternative, the distance of the spacing between the high-frequency radiating elements 20 in rows is d1, the spacing between the high-frequency radiating elements 20 in columns is d2, and d1 may be greater than, equal to, or less than d2, but it is necessary to ensure that 1/2 λ ≦ d1 ≦ λ, and 1/2 λ ≦ d2 ≦ λ.

In an alternative, the antenna array has m rows of high frequency radiation elements 20 and n columns of high frequency radiation elements 20, where m may be greater than, equal to, or less than n.

In an alternative, the number of the high-frequency radiation units 20 in different rows may be equal or unequal, and is not limited to the arrangement manner shown in fig. 3 in which the same number of high-frequency radiation units 20 are arranged. When the number of the high-frequency radiation units 20 is different, the high-frequency radiation units 20 are arranged to form different shapes such as an ellipse, a pentagon, and a hexagon.

With continued reference to fig. 3, in the embodiment of the present application, a part of the high frequency radiation units 20 is formed into a sub-array 100 for radiating low frequency signals. As shown by the dashed boxes in fig. 2, the high frequency radiating elements 20 in each dashed box form a sub-array 100, and the sub-array 100 can be used for transmitting low frequency signals. In a specific embodiment, each sub-array 100 includes two rows of the high-frequency radiating elements 20, and each row includes 4 high-frequency radiating elements 20. The high-frequency radiation units 20 in the 8-by-8 array are divided into 8 sub-arrays 100, and each sub-array 100 includes 8 high-frequency radiation units 20, it should be understood that all the high-frequency radiation units 20 are divided into the sub-arrays 100 in fig. 3, but the number of the sub-arrays 100 is not limited in this embodiment, and all the high-frequency radiation units 20 may be divided into the sub-arrays 100 as shown in fig. 3, or some of the high-frequency radiation units 20 may be divided into the sub-arrays 100.

The single high frequency radiating element 20 in the sub-array 100 may be configured to transmit a high frequency signal, and all the high frequency radiating elements 20 in the sub-array 100 may form a waveform corresponding to a low frequency signal by superposition of the waves transmitted by each high frequency radiating element 20, so that the sub-array 100 may be configured to transmit a low frequency signal. The feeding of the sub-array 100 is explained in detail below.

Fig. 4 illustrates a feeding schematic diagram of a row of high-frequency radiating elements 20 in an antenna array provided by the embodiment of the present application. The feeding structure of the other rows in the sub-array 100 is the same as that shown in fig. 3, and therefore, a row of the high-frequency radiation elements 20 shown in fig. 4 is taken as an example for explanation. The feed structure of the antenna array comprises a plurality of first phase shifters 30 and first attenuators 40 connected in series, and the first phase shifters 30 and the first attenuators 40 connected in series are connected with the plurality of high-frequency radiating elements 20 in a one-to-one correspondence manner. As shown in fig. 4, the first attenuator 40 and the first phase shifter 30 are connected by a feeder line, the first attenuator 40 is connected to the corresponding high-frequency radiation unit 20 by a feeder line, and the first phase shifter 30 is connected to the feeder line.

In an alternative mode, the first attenuator 40 and the first phase shifter 30 are connected by a feeder line, the first attenuator 40 and the feed 50 are connected by a feeder line, and the first phase shifter 30 and the corresponding high-frequency radiation unit 20 are connected by a feeder line.

As a variation of the feeding structure shown in fig. 4 shown in fig. 5, one first phase shifter 30 may be used, one first attenuator 40 is connected to each high-frequency radiation element 20, and a plurality of first attenuators 40 are connected to one first phase shifter 30, and after phase weighting is performed by the first phase shifter 30, phase weighting is performed by each first attenuator 40.

With continuing reference to fig. 4 and 5, the feed source 50 provided in the embodiment of the present application includes two low frequency feed units 51 and two high frequency feed units 52; the high-frequency feeding unit 52 is configured to feed power to each high-frequency radiating unit 20, and may be arranged in a manner that one high-frequency feeding unit 52 corresponds to each high-frequency radiating unit 20 one by one, or may be connected to each high-frequency radiating unit 20 through a power divider by using one high-frequency feeding unit 52, which is not limited in this application. The low frequency feeding unit 51 is used to simultaneously feed each high frequency radiating element 20 in the sub-array 100. The phase shifter is used for controlling the first phase shifter 30 to shift the phase of the low-frequency signal transmitted by the low-frequency feed unit for the first time, and controlling the first attenuator 40 to attenuate the amplitude of the low-frequency signal for the first time, so that the signal waves transmitted by all the high-frequency radiating units in the sub-array are combined into a waveform corresponding to the low-frequency signal. When the low-frequency feeding unit 51 feeds the high-frequency radiating elements 20 in the sub-array 100, the high-frequency radiating elements 20 in the sub-array 100 can move by the first phase shifter 30, and the first attenuator 40 attenuates the signal, so that all the high-frequency radiating elements 20 in the sub-array 100 are combined to form a radiating wave corresponding to the low-frequency antenna. When the sub-array 100 includes a plurality of rows of high-frequency radiating elements 20, the high-frequency radiating elements 20 are all fed through the same low-frequency feeding element 51. When the antenna is used, the amplitude weighting of the first attenuator 40 and the phase weighting of the first phase shifter 30 are adjusted, so that the spatial synthetic radiation performance of the sub-array 100 meets the low-frequency band index requirement (the horizontal 3dB lobe width is 65 degrees, the port isolation is not less than 30dB, the front-to-back ratio is not less than 25dB and the like), waves emitted by the high-frequency radiation units 20 in the sub-array 100 can be superposed into a frequency band corresponding to a low-frequency antenna, and low-frequency radiation is realized.

In an alternative embodiment, the control circuit may be a baseband processing unit or a radio remote unit in the antenna array.

As can be seen from the above description, the antenna array provided in the embodiment of the present application omits the low-frequency radiating elements, and is entirely composed of the high-frequency radiating elements 20, and a part of the high-frequency radiating elements 20 in the antenna array forms the sub-array 100, and the first phase shifter 30 and the first attenuator 40 of each high-frequency radiating element 20 in the sub-array 100 are controlled to construct an equivalent low-frequency radiating element radiation pattern, so as to complete the low-frequency band operation. Thus, a single high-frequency radiation unit 20 can cover a high-frequency working frequency band of 1710MHz to 2690MHz, a single subarray 100 can cover a low-frequency working frequency band of 790MHz to 960MHz (even 698MHz to 960MHz), so that the whole array can realize the coverage of the full frequency band, the problems of mutual coupling and high section brought by a large-size low-frequency radiation unit are solved, the advantages of miniaturization and low cost are brought, the size, weight, power consumption and cost of an antenna array on a base station tower are greatly reduced, the uniform utilization of radio frequency hardware equipment and fragmented frequency spectrum is realized, and the system throughput is improved.

Fig. 6 shows a corresponding feeding structure of the second high-frequency radiating element 20 provided in the embodiment of the present application. Some of the reference numbers in fig. 6 may refer to the reference numbers in fig. 4. The feed structure shown in fig. 6 differs from the feed structure shown in fig. 4 in that a second attenuator 60 is added, and the low-frequency feed unit 51 is connected to each high-frequency radiation unit 20 in the sub-array 100 through the second attenuator 60. The low frequency feed unit 51 is connected to the second attenuator 60, and the second attenuator 60 is connected to the first phase shifter 30. In use, the signal emitted by the low frequency feed element 51 is amplitude weighted by the second attenuator 60 (the amplitude weighting value being) Thereafter, phase weighting is performed by the first phase shifter 30 (phase weighting value is psi)_l) Amplitude weighting by the first attenuator 40 corresponding to each high-frequency radiating element 20(amplitude weighted value of). By adjusting the amplitude weighting values of both attenuators (first attenuator 40 and second attenuator 60) simultaneouslyAnd phase weight (psi) of the first phase shifter 30_l) The space synthetic radiation performance of the sub-array 100 meets the low frequency band index requirement (the horizontal 3dB lobe width is 65 degrees, the port isolation is more than or equal to 30dB, the front-to-back ratio is more than or equal to 25dB, and the like). In the above technical solution, the control circuit controls the first attenuator 40 and the second attenuator 60 to perform amplitude attenuation twice on the low-frequency signal, and controls the first phase shifter 30 to perform phase shifting for the first time on the low-frequency signal transmitted by the low-frequency feed unit, so that the signal waves transmitted by all the high-frequency radiating units in the sub-array are combined into a waveform corresponding to the low-frequency signal.

In an optional scheme, the adjustment accuracy of the first attenuator 40 is greater than that of the second attenuator 60, so that coarse adjustment can be realized through the second attenuator 60, fine adjustment can be realized through the first attenuator 40, and the cooperation of coarse adjustment and fine adjustment can be realized, so that the effect of combining waves to form low-frequency antenna radiation waves can be adjusted more quickly.

When the second attenuator 60 is specifically connected to the first attenuator 40, the connection is realized through a power divider, as shown in fig. 6, a first end of the power divider is connected to the second attenuator 60, and the first end of the specific power divider is first connected to the first phase shifter 30 and is connected to the second attenuator 60 through the first phase shifter 30. A second end of the power divider is connected to each high-frequency radiating element 20 in the sub-array 100, that is, the second end is connected to the first attenuator 40 corresponding to each high-frequency radiating element 20. So that the signal weighted by the first phase shifter 30 and the second attenuator 60 is transmitted to the first attenuator 40 corresponding to each high frequency radiating element 20.

In the embodiment of the present application, the power divider is not specifically limited, and may adopt a power divider with equal power division or a power divider with unequal power division, and only needs to satisfy that the high-frequency radiation unit 20 in the sub-array 100 can satisfy the low-frequency band index when combining waves. Illustratively, in an alternative scheme, the power divider is an equal power divider.

In the antenna array shown in fig. 6, a first attenuator 40 is connected to each high-frequency radiation element 20, a first phase shifter 30 and a second attenuator 60 are connected to each sub-array 100, and the amplitude weighting values of the first attenuator 40 and the second attenuator 60 are adjusted simultaneouslyAnd phase weight (psi) of the first phase shifter 30_l) The space synthetic radiation performance of the sub-array 100 meets the low frequency band index requirement (the horizontal 3dB lobe width is 65 degrees, the port isolation is more than or equal to 30dB, the front-to-back ratio is more than or equal to 25dB, and the like). Thus, a single high-frequency radiating unit 20 can cover a high-frequency working frequency band of 1710MHz-2690MHz, and a single sub-array 100 can cover a low-frequency working frequency band of 790MHz-960MHz (even 698MHz-960MHz), so that the whole array can cover the full frequency band without additionally adopting a large-size low-frequency radiating high-frequency radiating unit 20.

Fig. 7 shows a feeding structure corresponding to the third high-frequency radiating element 20 provided in the embodiment of the present application. Some of the reference numbers in fig. 7 may refer to the reference numbers in fig. 6. The feed structure shown in fig. 7 differs from the feed structure shown in fig. 6 in that a second phase shifter 70 is added. The second phase shifter 70 is connected in series with the second attenuator 60 to improve the phase weighting of the low frequency signal by the cooperation of the second phase shifter 70 with the first phase shifter 30. In the above technical solution, the control circuit is configured to control the first attenuator 40 and the second attenuator 60 to perform amplitude attenuation twice on the low-frequency signal, and is further configured to control the first phase shifter 30 and the second phase shifter 70 to perform phase shifting twice on the low-frequency signal, so that the signals emitted by all the high-frequency radiating elements in the sub-array are combined into a waveform corresponding to the low-frequency signal.

In an alternative, the adjustment accuracy of the first phase shifter 30 is greater than the adjustment accuracy of the second phase shifter 70, so that a hybrid phase shifting architecture is formed by the first phase shifter 30 and the second phase shifter 70. Coarse tuning is accomplished by a second phase shifter 70-the requirement for a large amount of phase modulation required to achieve a large frequency range; fine tuning is then accomplished by the first phase shifter 30: the fine phase modulation requirement in a smaller frequency band is fulfilled at the subarray level. Therefore, the effect of forming the low-frequency antenna radiation wave by the combined wave can be adjusted more quickly.

In a specific embodiment, the first phase shifter 30 is an electrical phase shifter and the second phase shifter 70 is an optical phase shifter. The electronic phase shifter has the advantages of narrow bandwidth, high adjustment precision, wide bandwidth and low adjustment precision. In addition, the electric phase shifter is generally a dielectric phase shifter and a metal cavity phase shifter. However, the two phase shifters have complex structures and narrow working bandwidths, and cannot meet the requirement of ultra-wideband full-band coverage. The optical phase shifter has obvious advantages in bandwidth, volume, weight and cost, and is suitable for future ultra-wideband large-capacity photoelectric integrated RoF communication base stations.

In an alternative, the first phase shifter 30 and the second phase shifter 70 as shown in fig. 7 are split on both sides of the second attenuator 60. Alternatively, the first phase shifter 30 and the second attenuator 60 may be disposed on both sides of the second phase shifter 70.

In the feed structure of the sub-array 100 shown in fig. 7, the problem of ultra-wideband full-band coverage of the antenna array is solved by introducing an optical phase shifter to solve the problem of narrow bandwidth of the electric phase shifter.

Fig. 8 shows a feeding structure corresponding to the fourth high-frequency radiating element 20 provided in the embodiment of the present application. Each of the individual functional modules is described in detail below in conjunction with fig. 8:

D/A: and the digital-to-analog converter is used for completing the conversion from the baseband digital signal to the analog electric signal.

E/O: and the electro-optical converter is used for converting the analog electric signal into the analog optical signal.

Att (atom): and the amplitude attenuator is used for carrying out amplitude weighted tuning on the optical signal.

Odl (optical Delay line): and the optical delay line is used for carrying out phase weighted tuning on the optical signal.

Mux (multiplexer): the main function of the multiplexer/multiplexer is to combine multiple signal wavelengths into one optical fiber for transmission. Since the optical carrier signals with different wavelengths can be regarded as independent of each other (when the nonlinearity of the optical fiber is not considered), the multiplexing transmission of multiple optical signals can be realized in one optical fiber.

DE-MUX (demux): the main function of the demultiplexer/demultiplexer is to separate a plurality of wavelength signals transmitted in one optical fiber. In the receiving section, a splitter separates the optical carrier signals of different wavelengths, which are further processed by an optical receiver to recover the original signal. A demultiplexer (DE-MUX) is a device that performs inverse processing on a Multiplexer (MUX).

UTC-PD (Uni-tracking-Carrier Photodiode): the high-speed single-row carrier photodiode converts an optical signal into an analog electrical signal and radiates the analog electrical signal through an antenna. Signal amplification is also possible. The power amplifier (electric signal amplification) and the photodiode in the prior art are omitted, light is converted into an electric signal, and the output electric signal is amplified.

As can be seen from fig. 8, the antenna array further includes a digital-to-analog converter, an electro-optical converter, and a high-speed single-row carrier light-speed diode; the low-frequency feed unit is connected with a digital-to-analog converter, the digital-to-analog converter is connected with an electro-optical converter, the first phase shifter is an optical phase shifter, the first attenuator is an optical attenuator, one end of the first phase shifter and one end of the first attenuator which are connected in series are connected with the electro-optical converter, and the other end of the first phase shifter and one end of the first attenuator are connected with the high-speed single-row carrier photodiode.

In the structure shown in fig. 9, unlike the scheme shown in fig. 8, the transmitting and receiving front end adopts an all-optical architecture, and the antenna is directly driven by a single-row carrier photodiode. Therefore, the bottleneck of bandwidth of electric devices in the existing base station, such as an amplifier, a phase shifter, a filter and the like, can be avoided, and the application of the ultra-wideband is realized. Meanwhile, the optical domain is high in isolation and insensitive to electromagnetic interference, high isolation of multiple channels can be guaranteed after high-density integration, and a miniaturized high-density multi-channel framework in the future can be realized. In addition, an attenuator and a phase shifter are not arranged on the tower, and the problem of size/weight/power consumption of an RRU on a base station tower caused by huge antenna quantity in a Massive-MIMO system in the future can be solved.

The above technique for simultaneously transmitting two or more optical signals with different wavelengths in the same optical fiber is called wavelength Division multiplexing (wdm). Fig. 10 illustrates a schematic diagram of a wavelength division multiplexing technique, such as inputting λ 1- λ 18 signals into MUX, propagating in the fiber, and re-splitting into λ 1- λ 18 signals in DE-MUX.

Fig. 11 illustrates another arrangement of an antenna array provided in the embodiment of the present application, and part of reference numerals in fig. 11 may refer to the same reference numerals in fig. 2. The feeding structure of the high-frequency radiation element 20 of fig. 9 may adopt any one of the feeding structures listed above.

The antenna array shown in fig. 11 differs from the antenna array shown in fig. 3 in the division of the sub-array 100. The high-frequency radiation elements 20 in the sub-array 100 are arranged in an irregular shape as shown in fig. 11. In the "irregular" subarray 100 of fig. 11, the outer contour of the subarray 100 consisting of 8 high-frequency radiation units 20 is not a regular shape, but is "russian square" like an L-shape. It should be understood that fig. 11 illustrates only one specific sub-array 100 with a non-cabinet arrangement, and that the sub-array 100 provided in the embodiments of the present application may also take other non-regular shapes.

High grating lobes are produced when the distance between the two low frequency antennas is greater than the low frequency wavelength. When the sub-arrays 100 are used to transmit signals in a low frequency band, the distance between the phases of the two sub-arrays 100 is equivalent to the distance between the two antennas. As shown in fig. 12, fig. 12 shows the position of the phase C of the sub-array 100. In addition, when the phases are arranged periodically, high grating lobes are superimposed, which affects the performance of the antenna. When a plurality of sub-arrays 100 shown in fig. 12 are used, the plurality of sub-arrays 100 are formed in an irregular shape so that the phase centers of the plurality of sub-arrays 100 are arranged non-periodically, thereby breaking the periodic arrangement of the phases and generating randomness. And further avoids the problem of radiation performance degradation caused by high grating lobes due to the "regular" sub-array 100 morphology.

As can be seen from the antenna array illustrated in the above specific drawings, in the antenna array provided in the embodiment of the present application, the radiation pattern of the equivalent low-frequency high-frequency radiation unit 20 is constructed by using the form of the sub-array 100 (without additionally using the actual large-size low-frequency high-frequency radiation unit 20), and on the premise that a single high-frequency radiation unit 20 meets the high-frequency band working requirement, the antenna array composed of a single ultra-wideband high-frequency radiation unit 20 realizes full-frequency band coverage from low frequency to high frequency and multi-system application. In addition, the antenna array for kicking the European-crown woolen cloth in the embodiment of the application abandons the low-frequency large-size high-frequency radiating unit 20, and the single high-frequency radiating unit 20 covers the whole frequency band, so that the problems of mutual coupling between the low-frequency radiating unit and the high-frequency radiating unit 20 and high section and miniaturization of the antenna array are solved. The evolution architecture of photoelectric hybrid phase shift in the antenna array can solve the problems of narrow bandwidth, complex structure, volume, weight, cost and the like of electric devices (such as an electric phase shifter, an amplifier, a filter and the like), and is suitable for the future RoF communication base station architecture. Meanwhile, the optical domain is high in isolation and insensitive to electromagnetic interference, high isolation of multiple channels can be guaranteed after high-density integration, and a miniaturized high-density multi-channel framework in the future can be realized. Therefore, hardware overhead such as energy consumption, volume, weight and installation and later maintenance cost on the tower are greatly reduced, and the future massive-MIMO deployment requirement is met.

The application also provides a base station comprising an antenna array of any of the above. When the low-frequency feeding unit 51 in the antenna array feeds the high-frequency radiating elements 20 in the sub-array 100, the high-frequency radiating elements 20 in the sub-array 100 can move by the first phase shifter 30, and the first attenuator 40 attenuates the signal, so that the high-frequency radiating elements 20 in the sub-array 100 are combined to form a radiating wave corresponding to the low-frequency antenna. And a high-frequency feeding unit 52 for feeding each of the high-frequency radiating units 20. As can be seen from the above description, the antenna array used in the embodiment of the present application only needs to be provided with one type of radiation unit, and compared with the prior art in which a plurality of radiation units of different types are used, the antenna array is simplified, and meanwhile, the radiation performance of the antenna array can be improved.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.