WO2021213407A1 - Antenna array and base station - Google Patents

Abstract

Provided in the present application are an antenna array and a base station, the antenna array comprising: a plurality of high frequency radiation units, and a first attenuator and a first phase shifter connected in series, where the first attenuator and the first phase shifter connected in series form one-to-one correspondence connections with the plurality of high frequency radiation units; among the plurality of high frequency radiation units, a portion of the high frequency radiation units make up a sub-array for radiating a low frequency signal; the antenna array further comprises a low frequency feed unit and a high frequency feed unit; the low frequency feed unit is connected to the sub-array, and the high frequency radiation units within the sub-array may form a radiation wave corresponding to a low frequency antenna by means of the first phase shifter and the first attenuator causing wave combination of the high-frequency radiation units in the sub-array. The high frequency feed unit is used for feeding power to each high frequency radiation unit. It is apparent by the description that the antenna array used in embodiments of the present application only needs to be provided with one type of radiation unit, which simplifies the antenna array when compared to the use of multiple different types of radiation units in the prior art, and can also improve radiation performance of the antenna array.

Description

Antenna array and base station

Cross-references to related applications

This application claims the priority of a Chinese patent application filed with the Chinese Patent Office, the application number is 202010321498.7, and the application name is "an antenna array and base station" on April 22, 2020, the entire content of which is incorporated into this application by reference.

Technical field

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

Background technique

For communication base stations, with the development of communication technology, 2G, 3G, 4G and other systems coexist, and base station resources are becoming more and more tense. At the same time, residents around the base station are strongly opposed to adding antennas on poles due to fear of electromagnetic radiation. , The use of multi-frequency base station antennas can reduce the number of antennas, reduce installation space, and reduce operator costs. Therefore, the study of multi-frequency base station antennas covering multiple frequency bands has very important practical value and practical significance. The 4G era requires the working bandwidth of base station antennas: low frequency band: 690MHz-960MHz, high frequency band: 1710MHz-2690MHz. The current multi-frequency antenna scheme is mainly divided into a coaxial nested form and a composite assembly form.

Existing base station technologies all use 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 antenna aperture size and its radiation efficiency, that is, when the antenna high-frequency radiation unit size is equivalent to 1/2 of the wavelength in the air, the radiation efficiency is the highest. In this way, in the 1GHz operating frequency band, the size of the low-frequency radiation unit is 300mm/1GHz/2=15mm; in the 2GHz operating frequency band, the size of the high-frequency radiation unit is 300mm/2GHz/2=7.5mm. It can be seen that the size of the low-frequency radiation unit is twice the size of the high-frequency radiation unit.

However, this combination of high and low frequency radiation units still has various serious problems. First, the physical distance between the high and low frequency radiation units is too close, and the strong mutual coupling effect between each other causes serious distortion of the far-field pattern and deteriorates the radiation performance of the array. Second, according to the basic theory of the antenna, in order to superimpose the radiated wave and the reflected wave of the antenna in phase and achieve good directional radiation characteristics, the section height of the antenna is required to be 1/4 wavelength, that is, λ/4. Since the working frequency band of the low-frequency element is low, the profile height of the low-frequency element limits the profile height of the entire array, as shown in Fig. 5, causing serious difficulties in the low profile and miniaturization of the antenna device. Third, the size of the low-frequency radiation unit is too large, which will cause the projection of the high-frequency radiation unit to overlap, or in other words, there is no design space for the high-frequency radiation unit.

Summary of the invention

The present application provides an antenna array and a base station, which are used to simplify the structure of the antenna array and improve the performance of the antenna array.

In a first aspect, an antenna array is provided. The antenna array is applied to a base station. The antenna array includes: a plurality of high-frequency radiation units arranged in an array, a first phase shifter and a first attenuator connected in series, and the series connection The first phase shifter and the first attenuator are connected to the multiple high-frequency radiation units in a one-to-one correspondence; among the multiple high-frequency radiation units, some of the high-frequency radiation units form a sub-array for radiating low-frequency signals; It also includes two feed sources, a low-frequency feed unit and a high-frequency feed unit; among them, the low-frequency feed unit is used to feed each high-frequency radiating unit in the sub-array, and also includes a control circuit for The first phase shifter is controlled to perform a phase shift of the low-frequency signal emitted by the low-frequency feed unit, and the first attenuator is controlled to perform an amplitude attenuation of the low-frequency signal, so that the sub-array is The signals emitted by all high-frequency radiating units in the above are combined into a waveform corresponding to the low-frequency signal. When the low-frequency feeding unit feeds the high-frequency radiating unit in the sub-array, the signal emitted by the high-frequency radiating unit in the sub-array can be shifted by the first phase shifter and the signal attenuated by the first attenuator, The signal waves emitted by the high-frequency radiation units in the sub-array are combined to form a waveform corresponding to the low-frequency signal. The high-frequency feed unit is used to feed each high-frequency radiation unit. It can be seen from the above description that the antenna array used in the embodiment of the present application only needs to be equipped with one type of radiating element. Compared with the use of multiple different types of radiating elements in the prior art, the antenna array is simplified, and at the same time, Improve the radiation performance of the antenna array.

In a specific implementation, the distance d between any adjacent high-frequency radiation units satisfies: 1/2λ≤d≤λ; where λ corresponds to the high-frequency signal input by the high-frequency feed unit的wavelength. Avoid crosstalk of high-frequency radiation unit signals and improve the performance of the antenna array.

In a specific implementation, d can be different distances such as 1/2λ, 3/4λ, and λ. That is, the high-frequency radiation units arranged in an array can be arranged at different intervals.

In a specific implementation, the low-frequency feed unit is connected to each high-frequency radiation unit in the sub-array through a second attenuator; the control circuit is also used to control the first attenuator The second attenuator and the second attenuator perform two amplitude attenuations on the low-frequency signal, so that the signals 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 cooperates with the first attenuator to improve the effect of combining waves to form low-frequency antenna radiation waves.

In a specific implementation, the adjustment accuracy of the first attenuator is greater than the adjustment accuracy of the second attenuator, so that coarse adjustment and fine adjustment can be achieved, so that the multiplexing can be adjusted more quickly to form low-frequency antenna radiation waves. Effect.

In a specific implementation, it further includes a power divider, the first end of the power divider is connected to the second attenuator, and the second end of the power divider is connected to each of the sub-arrays. A high-frequency radiation unit is connected. Realize the connection with each high-frequency radiation unit through the set power divider.

In a specific implementation, it further includes a second phase shifter, the second phase shifter is connected in series with the second attenuator; the control circuit is also used to control the first phase shifter and The second phase shifter shifts the phase of the low-frequency signal twice, so that the signals emitted by all high-frequency radiation units in the sub-array are combined into a waveform corresponding to the low-frequency signal. The combination of the second phase shifter and the first phase shifter improves the effect of combining waves to form low-frequency antenna radiation waves.

In a specific implementation, the adjustment accuracy of the first phase shifter is greater than the adjustment accuracy of the second phase shifter, so that the coordination of coarse adjustment and fine adjustment can be realized, so that the multiplexing can be adjusted more quickly to form a low-frequency antenna The effect of radiant waves.

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

In a specific implementation, it also includes a digital-to-analog converter, an electro-optical converter, and a high-speed single-line carrier light-speed diode; among them,

The low-frequency feed unit is connected to the digital-to-analog converter, the digital-to-analog converter is connected to the electro-optical converter, the first phase shifter is an optical phase shifter, and the first attenuator is an optical phase shifter. An attenuator, and one end of the first phase shifter and the first attenuator connected in series is connected to the electro-optical converter, and the other end is connected to the high-speed single-line carrier photodiode. Therefore, the first phase shifter and the first attenuator can be arranged at the bottom of the base station, and the weight of the radiation part of the antenna array can be reduced.

In a specific implementation, it further includes a multiplexer and a demultiplexer connected to the multiplexer; wherein, the multiplexer is connected to the plurality of first phase shifters and first attenuators connected in series. The de-wave generator is connected to the multiple high-speed single-row carrier photodiodes. Simplifies the structure of signal transmission.

In a specific implementation, when there are multiple sub-arrays, the phase centers of the multiple sub-arrays are arranged non-periodically. The high grating lobe between the antennas is reduced, and the performance of the antenna is improved.

In a specific implementation, the high-frequency radiation units in the sub-array are arranged in an irregular shape. The regular arrangement of the sub-arrays is avoided, the high grating lobes between the antennas are reduced, and the performance of the antennas is improved.

In a second aspect, a base station is provided, and the base station includes the antenna array described in any one of the foregoing. When the low-frequency feeding unit in the antenna array feeds the high-frequency radiating unit in the sub-array, the high-frequency radiating unit in the sub-array can be shifted by the first phase shifter and the signal attenuation by the first attenuator , So that the high-frequency radiation units in the sub-array combine to form a radiation wave corresponding to the low-frequency antenna. The high-frequency feed unit is used to feed each high-frequency radiation unit. It can be seen from the above description that the antenna array used in the embodiment of the present application only needs to be equipped with one type of radiating element. Compared with the use of multiple different types of radiating elements in the prior art, the antenna array is simplified, and at the same time, Improve the radiation performance of the antenna array.

Description of the drawings

FIG. 1 is a schematic diagram of an application scenario of an antenna array provided by an embodiment of the application;

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

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

FIG. 4 is a feeding structure corresponding to the first high-frequency radiation unit provided by an embodiment of the application;

Fig. 5 is a modification of the feeding structure in Fig. 4;

FIG. 6 is a feeding structure corresponding to a second type of high-frequency radiation unit provided by an embodiment of the application;

FIG. 7 is a feeding structure corresponding to a third high-frequency radiation unit provided by an embodiment of this application;

FIG. 8 is a feeding structure corresponding to a fourth high-frequency radiation unit provided by an embodiment of the application;

FIG. 9 is a modification of the feeding structure corresponding to the fourth type of high-frequency radiation unit provided by the embodiment of this application;

FIG. 10 is a schematic diagram of the connection between the fourth type of high-frequency radiation unit and the feed according to an embodiment of the application;

FIG. 11 is another arrangement of antenna arrays according to an embodiment of the application;

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

Detailed ways

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

In order to facilitate the understanding of the antenna array provided in the embodiment of the present application, firstly, an application scenario of the antenna array provided in the embodiment of the present application will be explained. The antenna array provided in the embodiment of the present application is applied to a communication base station. The communication base station mainly includes three parts: BBU (Building Baseband Unit): Baseband processing unit, which mainly completes functions such as channel coding and decoding, baseband signal modulation and demodulation, and protocol processing. Usually the BBU is under the tower and placed indoors/in the computer room. RRU (Radio Remote Unit): The remote unit of the radio frequency, mainly completes the modulation and demodulation of the radio frequency signal, amplifies the power of the radio frequency analog signal, and transmits it to the antenna feeder. The RRU is mainly installed on a pole or wall. Antenna array: Transmit or receive signals/information. As shown in Figure 1, the antenna array 1 is set on the tower 2. With the development of communication technology, communication base stations need to receive or transmit signals of different frequency bands, which requires the antenna array 1 to have radiation units matching different frequency bands. Current communication base stations cover both low frequency bands (790MHz-960MHz) and high frequency bands (1710MHz-2690MHz). Both high and low frequency high frequency radiation units of different sizes are mixed to achieve full coverage of 2G, 3G, and 4G. However, the use of low-frequency and large-size high-frequency radiation units not only interferes with high-frequency radiation units and causes pattern distortion, but also their size limits the design space of high-frequency radiation units and the cross-section of the entire array, leading to difficulties in miniaturization. For this reason, the embodiments of the present application provide an antenna array, which will be described in detail below with reference to specific drawings and embodiments.

Fig. 2 is a schematic structural diagram of an antenna array provided by 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 serves as a structure for carrying multiple high-frequency radiation units 20, and its specific shape is not limited to the rectangle shown in FIG. . The substrate 10 has a setting surface 11, and the high-frequency radiation unit 20 is fixed on the substrate 10. The specific fixing method can be a common threaded connection (bolt or screw) connection, or a fixing method such as snap connection, welding, and 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 voltage standing wave ratio VSWR≤1.5 in the whole frequency band. The space radiation performance meets the high frequency index requirements, such as the horizontal 3dB lobe width 65°, the port isolation ≥30dB, the front-to-back ratio ≥25dB, etc.

As shown in the top view of the antenna array in FIG. 3, the square in FIG. 3 represents the high-frequency radiation unit 20. To facilitate the description of the high-frequency radiation unit 20, a direction a and a direction b that are perpendicular to each other are defined, and the plane where the direction a and the direction b are located is parallel to the setting surface of the high-frequency radiation unit 20. The multiple high-frequency radiation units 20 are arranged in an array, and the multiple high-frequency radiation units 20 are arranged in rows along the direction a and in columns along the direction b on the installation surface. Exemplarily, an 8*8 antenna array as shown in FIG. 3 is formed, but the antenna array provided in the embodiment of the present application does not limit the specific number of the high-frequency radiation unit 20, and the high-frequency radiation unit 20 can be designed according to specific needs. Certainly.

When a plurality of high-frequency radiation units 20 are arranged in an array, the distance d between any adjacent high-frequency radiation units 20 satisfies: 1/2λ≤d≤λ; where λ is the high frequency input by the high-frequency feed unit The wavelength of the signal. Exemplarily, d=1/2λ, 3/4λ, 4/5λ, λ and other different distances. Any adjacent high-frequency radiation unit 20 mentioned above refers to the distance between two adjacent high-frequency radiation units 20 between any row, or two adjacent high-frequency radiation units between any two columns. 20 pitch.

In an optional solution, the distance between the high-frequency radiation units 20 between the rows is d1, and the distance between the high-frequency radiation units 20 between the columns is d2, and d1 can be greater than, equal to, or less than d2, but it needs to Ensure that 1/2λ≤d1≤λ, and 1/2λ≤d2≤λ.

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

In an optional solution, the number of high-frequency radiation units 20 between different rows may be equal or unequal, and it is not limited to the arrangement of the same number of high-frequency radiation units 20 in each row shown in FIG. 3 Way. When the number of high-frequency radiation units 20 in different rows is different, the multiple high-frequency radiation units 20 are arranged to form different shapes such as an ellipse, a pentagon, and a hexagon.

Continuing to refer to FIG. 3, in the embodiment of the present application, part of the high-frequency radiation unit 20 forms a sub-array 100 for radiating low-frequency signals. As shown in the dashed box shown in FIG. 2, the high-frequency radiation unit 20 in each dashed box constitutes a sub-array 100, which can be used to transmit low-frequency signals. In a specific implementation, each sub-array 100 contains two rows of high-frequency radiation units 20, and each row contains 4 high-frequency radiation units 20. The high-frequency radiation unit 20 of an 8*8 array is divided into 8 sub-arrays. 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 sub-arrays 100 in FIG. The number of the specific sub-arrays 100 is not limited, and all the high-frequency radiation units 20 can be divided into sub-arrays 100 as shown in FIG. 3, or part of the high-frequency radiation units 20 can be divided into sub-arrays 100.

The single high-frequency radiation unit 20 in the sub-array 100 can be used to transmit high-frequency signals. All the high-frequency radiation units 20 in the sub-array 100 can form a signal corresponding to the low-frequency signal through the superposition of the waves emitted by each high-frequency radiation unit 20. Waveform, so that the sub-array 100 can be used to transmit low-frequency signals. The power feeding of the sub-array 100 will be described in detail below.

FIG. 4 illustrates a schematic diagram of feeding power of a row of high-frequency radiating elements 20 in an antenna array provided by an embodiment of the present application. The feeding structure of the other rows in the sub-array 100 is the same as the feeding structure shown in FIG. 3, so the row of high-frequency radiation units 20 shown in FIG. 4 is taken as an example for description. The feed structure of the antenna array includes a plurality of series-connected first phase shifters 30 and first attenuators 40, and the series-connected first phase shifter 30 and first attenuator 40 and a plurality of high-frequency radiation units 20 are connected in series. One correspondence connection. As shown in FIG. 4, the first attenuator 40 and the first phase shifter 30 are connected through a feeder line, and the first attenuator 40 is connected to the corresponding high-frequency radiation unit 20 through the feeder line, and the first phase shifter 30 passes through The feeder is connected to the feed source.

In an optional manner, the first attenuator 40 is connected to the first phase shifter 30 through a feeder line, the first attenuator 40 is connected to the feed source 50 through the feeder line, and the first phase shifter 30 is connected to the corresponding feeder line through the feeder line. The high-frequency radiation unit 20 is connected.

As shown in FIG. 5 in a modification of the feeding structure in FIG. 4, one first phase shifter 30 may be used, and each row of high-frequency radiation units 20 is respectively connected with a first attenuator 40, and a plurality of first The attenuator 40 is connected to a first phase shifter 30, and after the phase weighting is performed by the first phase shifter 30, the phase weighting is performed by each first attenuator 40 respectively.

4 and 5, the feed source 50 provided by the embodiment of the present application includes two, namely a low-frequency feed unit 51 and a high-frequency feed unit 52; among them, the high-frequency feed unit 52 is used to feed each high The high-frequency radiating unit 20 can be fed by one high-frequency feeding unit 52 in a one-to-one correspondence with each high-frequency radiating unit 20, or one high-frequency feeding unit 52 can be connected to each high-frequency radiating unit through a power divider. The connection of the high-frequency radiation unit 20 is not specifically limited in this application. The low-frequency feeding unit 51 is used to feed each high-frequency radiation unit 20 in the sub-array 100 at the same time. It is used to control the first phase shifter 30 to perform a phase shift on the low-frequency signal emitted by the low-frequency feed unit, and to control the first attenuator 40 to perform amplitude attenuation of the low-frequency signal once, so that all the high-frequency radiation units in the sub-array emit The signal wave is combined into a waveform corresponding to the low-frequency signal. When the low-frequency feeding unit 51 feeds the high-frequency radiation unit 20 in the sub-array 100, the high-frequency radiation unit 20 in the sub-array 100 can be moved by the first phase shifter 30 and the first attenuator 40 The attenuation of the signal causes all the high-frequency radiation units 20 in the sub-array 100 to combine to form a radiation wave corresponding to the low-frequency antenna. When the sub-array 100 includes multiple rows of high-frequency radiation units 20, the multiple rows of high-frequency radiation units 20 are all fed by the same low-frequency feed unit 51. When in use, by adjusting the amplitude weighting of the first attenuator 40 and the phase weighting of the first phase shifter 30, the spatial composite radiation performance of the sub-array 100 meets the requirements of low frequency band indicators (horizontal 3dB lobe width 65°, port isolation Degree≥30dB, front-to-back ratio≥25dB, etc.), so that the waves emitted by the high-frequency radiation unit 20 in the sub-array 100 can be superimposed into a frequency band corresponding to the low-frequency antenna to achieve low-frequency radiation.

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

It can be seen from the above description that the antenna array provided by the embodiment of the present application abandons the low-frequency radiation unit, and is entirely composed of high-frequency radiation units 20, and some of the high-frequency radiation units 20 are formed into a sub-array 100, which is controlled by the sub-array 100. The first phase shifter 30 and the first attenuator 40 of each high-frequency radiation unit 20 in each of the high-frequency radiation units 20 construct an equivalent low-frequency radiation unit radiation pattern to complete low-frequency work. In this way, a single high-frequency radiation unit 20 can cover the high-frequency operating frequency band of 1710MHz-2690MHz, and a single sub-array 100 can cover the low-frequency operating frequency band of 790MHz-960MHz (or even 698MHz-960MHz), so that the entire array can cover the entire frequency band while solving the above The problems of mutual coupling and high profile brought by the large-size low-frequency radiating unit also bring the advantages of miniaturization and low-cost, greatly reducing the size, weight, power consumption and cost of the antenna array on the base station tower, realizing radio frequency hardware equipment and The unified utilization of fragmented spectrum achieves an increase in system throughput.

FIG. 6 shows the feeding structure corresponding to the second type of high-frequency radiation unit 20 provided by the embodiment of the present application. Part of the reference numerals in FIG. 6 can refer to the reference numerals in FIG. 4. The difference between the feeding structure shown in FIG. 6 and the feeding structure shown in FIG. 4 is that a second attenuator 60 is added, and the low-frequency feeding unit 51 passes through the second attenuator 60 and each high-frequency radiation in the sub-array 100. The unit 20 is connected. 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. When in use, the signal transmitted by the low-frequency feed unit 51 is amplitude-weighted by the second attenuator 60 (the amplitude-weighted value is

), the first phase shifter 30 performs phase weighting (the phase weighting value is ψ _l ), and the amplitude weighting is performed on the first attenuator 40 corresponding to each high-frequency radiation unit 20 (the amplitude weighting value is

). By adjusting the amplitude weighted values of the two attenuators (first attenuator 40 and second attenuator 60) at the same time

With the phase weighting value (ψ _l ) of the first phase shifter 30, the spatial composite radiation performance of the sub-array 100 meets the requirements of low frequency band indicators (horizontal 3dB lobe width 65°, port isolation ≥30dB, front-to-back ratio ≥25dB, etc. ). In the above technical solution, the control circuit controls the first attenuator 40 and the second attenuator 60 to attenuate the low frequency signal twice, and controls the first phase shifter 30 to move the low frequency signal emitted by the low frequency feed unit for the first time. Phase, so that the signals emitted by all the high-frequency radiation units in the sub-array are combined into a waveform corresponding to the low-frequency signal.

In an optional solution, the adjustment accuracy of the first attenuator 40 is greater than the adjustment accuracy of the second attenuator 60, so that coarse adjustment can be achieved by the second attenuator 60, and fine adjustment can be achieved by the first attenuator 40, thereby Coordination of coarse adjustment and fine adjustment can be realized, so that the combination of waves can be adjusted more quickly to form the effect of low-frequency antenna radiation waves.

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, the first end of the power divider is connected to the second attenuator 60, and the power divider The first end is connected to the first phase shifter 30 first, and is connected to the second attenuator 60 through the first phase shifter 30. The second end of the power splitter is connected to each high-frequency radiation unit 20 in the sub-array 100, that is, the second end is connected to the first attenuator 40 corresponding to each high-frequency radiation unit 20. Thus, the signals weighted by the first phase shifter 30 and the second attenuator 60 are sent to the first attenuator 40 corresponding to each high-frequency radiation unit 20.

In the embodiments of the present application, the power divider is not specifically limited, either a power divider with equal power division can be used, or a power divider with non-equal power division can be used, and only the high-frequency radiation unit in the sub-array 100 is required. 20 can meet the low frequency index when the wave is combined. Exemplarily, in an optional solution, the power divider is a power divider that divides the power equally.

In the antenna array shown in FIG. 6, each high-frequency radiation unit 20 is connected to a first attenuator 40, and each sub-array 100 is connected to a first phase shifter 30 and a second attenuator 60. By adjusting the first attenuator at the same time The amplitude weighted values of the first attenuator 40 and the second attenuator 60

With the phase weighting value (ψ _l ) of the first phase shifter 30, the spatial composite radiation performance of the sub-array 100 meets the requirements of low frequency band indicators (horizontal 3dB lobe width 65°, port isolation ≥30dB, front-to-back ratio ≥25dB, etc. ). In this way, a single high-frequency radiation unit 20 can cover the high-frequency operating frequency band of 1710MHz-2690MHz, and a single sub-array 100 can cover the low-frequency operating frequency band of 790MHz-960MHz (or even 698MHz-960MHz), so that the entire array can cover the entire frequency band without additional use. A large-sized low-frequency radiation high-frequency radiation unit 20.

FIG. 7 shows the feeding structure corresponding to the third high-frequency radiation unit 20 provided by the embodiment of the present application. Part of the reference numerals in FIG. 7 can refer to the reference numerals in FIG. 6. The difference between the feeding structure shown in FIG. 7 and the feeding structure shown in FIG. 6 is 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 through the cooperation of the second phase shifter 70 and the first phase shifter 30. In the above technical solution, the control circuit is used to control the first attenuator 40 and the second attenuator 60 to attenuate the low frequency signal twice, and it is also used to control the first phase shifter 30 and the second phase shifter 70 to attenuate the low frequency signal. The signal is phase-shifted twice, so that the signals emitted by all the high-frequency radiation units in the sub-array are combined into a waveform corresponding to the low-frequency signal.

In an optional solution, the adjustment accuracy of the first phase shifter 30 is greater than the adjustment accuracy of the second phase shifter 70, so that the first phase shifter 30 and the second phase shifter 70 form a hybrid phase shifting architecture. The coarse adjustment is completed by the second phase shifter 70-to achieve the larger phasor amount required for a larger frequency range; then the first phase shifter 30 completes the fine adjustment: the smaller frequency band is completed at the sub-array level Fine phase modulation needs. Thereby, it is possible to more quickly adjust the combined wave to form the effect of the low-frequency antenna radiation wave.

In a specific implementation, the first phase shifter 30 is an electrical phase shifter, and the second phase shifter 70 is an optical phase shifter. Among them, the electronic phase shifter has a narrower bandwidth and higher adjustment accuracy, and the optical phase shifter has a wider bandwidth and lower adjustment accuracy. In addition, electrical phase shifters are generally dielectric phase shifters and metal cavity phase shifters. However, these two phase shifters are not only complex in structure, but also have a very narrow working bandwidth, which cannot satisfy the full frequency band coverage of ultra-wideband. The optical phase shifter has obvious advantages in bandwidth, volume, weight, and cost. At the same time, it is an optoelectronic integrated RoF communication base station suitable for ultra-wideband and large-capacity in the future.

In an optional solution, the first phase shifter 30 and the second phase shifter 70 as shown in FIG. 7 are arranged on both sides of the second attenuator 60 respectively. Alternatively, the first phase shifter 30 and the second attenuator 60 may be arranged on both sides of the second phase shifter 70.

In the feed structure of the sub-array 100 shown in FIG. 7, the introduction of an optical phase shifter reduces the bandwidth of the electrical phase shifter, which solves the problem of ultra-wideband full-band coverage of the antenna array.

FIG. 8 shows the feeding structure corresponding to the fourth high-frequency radiation unit 20 provided by the embodiment of the present application. The following describes each functional module in detail with reference to Figure 8:

D/A: Digital-to-analog converter, which completes the conversion of baseband digital signals to analog electrical signals.

E/O: Electro-optical converter, which completes the conversion of analog electrical signals to analog optical signals.

ATT (Attenuator): Amplitude attenuator, which performs amplitude weighted tuning on optical signals.

ODL (Optical Delay Line): Optical delay line, which performs phase-weighted tuning on optical signals.

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

DE-MUX (Demultiplexer): Demultiplexer/demultiplexer, the main function is to separate multiple wavelength signals transmitted in an optical fiber. In the receiving part, a demultiplexer separates the optical carrier signals of different wavelengths, and the optical receiver performs further processing to restore the original signal. The demultiplexer (DE-MUX) is a device that reversely processes the multiplexer (MUX).

UTC-PD (Uni-Traveling-Carrier Photodiode): High-speed single-line carrier photodiode, which converts optical signals into analog electrical signals and radiates them through antennas. You can also amplify the signal. The power amplifier (electric signal amplification) and photodiode in the prior art are omitted, and the light is converted into an electric signal, and the output electric signal is amplified.

It can be seen from Figure 8 that the antenna array also includes a digital-to-analog converter, an electro-optical converter, and a high-speed single-line carrier light-speed diode; among them, the low-frequency feed unit is connected to the digital-to-analog converter, and the digital-to-analog converter is connected to the electro-optical converter. , The first phase shifter is an optical phase shifter, the first attenuator is an optical attenuator, and one end of the first phase shifter and the first attenuator connected in series is connected to the electro-optical converter, and the other end is connected to the high-speed single-line carrier photoelectric Diode connection.

In the structure shown in FIG. 9, different from the solution shown in FIG. 8, the transceiver front end adopts an all-optical architecture, and the antenna is directly driven by a single-row carrier photodiode. This can circumvent the bandwidth bottleneck of existing base station CLP devices, such as amplifiers, phase shifters, filters, etc., and realize ultra-wideband applications. At the same time, the optical domain has high isolation and is not sensitive to electromagnetic interference. After high-density integration, it can still ensure high multi-channel isolation, enabling future miniaturization and high-density multi-channel architecture. In addition, the tower will no longer have attenuators and phase shifters, which can solve the problem of the huge amount of antennas in the future Massive-MIMO system, which will cause the size/weight/power consumption of the RRU unit on the base station tower.

The above-mentioned technology of simultaneously transmitting two or more optical signals of different wavelengths in the same optical fiber is called wavelength division multiplexing, that is, WDM (Wavelength Division Multiplexing). Figure 10 illustrates the principle diagram of the wavelength division multiplexing technology. For example, a signal of λ1～λ18 is input in the MUX, and the above signal propagates in the optical fiber, and is re-separated into a signal of λ1～λ18 in the DE-MUX.

FIG. 11 illustrates another arrangement of the antenna array provided by an embodiment of the present application, and some of the reference numerals in FIG. 11 may refer to the same reference numerals in FIG. 2. The feeding structure of the high-frequency radiation unit 20 in FIG. 9 can adopt any of the feeding structures listed above.

The antenna array shown in FIG. 11 is different from the antenna array shown in FIG. 3 in that the division of the sub-array 100 is different. As shown in FIG. 11, the high-frequency radiation units 20 in the sub-array 100 are arranged in an irregular shape. In the "irregular" sub-array 100 in FIG. 11, the outer contour of the sub-array 100 composed of 8 high-frequency radiation units 20 is no longer a regular shape, but an L-shaped "Tetris". It should be understood that FIG. 11 only illustrates a specific non-cabinet arrangement sub-array 100, and the sub-array 100 provided in the embodiment of the present application may also adopt other irregular shapes.

A high grating lobe will be produced when the distance between two low-frequency antennas is greater than the low-frequency wavelength. When the sub-array 100 is used to transmit signals in the low frequency band, the phase distance 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, the high grating lobes will also be superimposed, which will affect the performance of the antenna. When multiple sub-arrays 100 are used as shown in FIG. 12, the multiple sub-arrays 100 adopt irregular shapes, so that the phase centers of the multiple sub-arrays 100 are arranged non-periodically, thereby destroying the periodic arrangement of the phases, resulting in Randomness. Furthermore, the problem of high grating lobe deteriorating radiation performance caused by the "regular" sub-array 100 form is avoided.

It can be seen from the antenna array illustrated in the above specific drawings that the antenna array provided in the embodiment of the present application constructs an equivalent low-frequency and high-frequency radiation unit 20 radiation pattern by adopting the sub-array 100 form (without additional use of actual Large-size low-frequency and high-frequency radiating unit 20), under the premise that a single high-frequency radiating unit 20 meets the requirements of high-frequency operation, an antenna array composed of a single ultra-wideband high-frequency radiating unit 20 can achieve full frequency coverage and coverage from low to high frequencies. Multi-standards are applicable. In addition, the antenna array of the embodiment of the present application abandons the low-frequency and large-size high-frequency radiation unit 20, and a single high-frequency radiation unit 20 achieves full frequency coverage, thereby solving the mutual coupling and mutual coupling of the low-frequency radiation unit and the high-frequency radiation unit 20. The problem of high profile and miniaturization of antenna arrays. The evolutionary architecture of the optoelectronic hybrid phase shifting in the antenna array can also solve the problems of narrow bandwidth, complex structure, volume, weight, and cost of electrical devices (such as electrical phase shifters, amplifiers, filters, etc.), and it is also suitable for future RoF communications Base station architecture. At the same time, the optical domain has high isolation and is not sensitive to electromagnetic interference. After high-density integration, it can still ensure high multi-channel isolation, enabling future miniaturization and high-density multi-channel architecture. As a result, the tower's hardware overhead, such as energy consumption, volume, weight, and installation and post-maintenance costs, is greatly reduced to meet the needs of future massive-MIMO deployment.

The present application also provides a base station, which includes any one of the antenna arrays described above. When the low-frequency feeding unit 51 in the antenna array feeds the high-frequency radiating unit 20 in the sub-array 100, the high-frequency radiating unit 20 in the sub-array 100 can be moved by the first phase shifter 30, and the first The attenuator 40 attenuates the signal, so that the high-frequency radiation unit 20 in the sub-array 100 combines to form a radiation wave corresponding to the low-frequency antenna. The high-frequency feeding unit 52 is used to feed each high-frequency radiation unit 20. It can be seen from the above description that the antenna array used in the embodiment of the present application only needs to be equipped with one type of radiating element. Compared with the use of multiple different types of radiating elements in the prior art, the antenna array is simplified, and at the same time, Improve the radiation performance of the antenna array.

The above are only specific implementations of this application, but the scope of protection of this application is not limited to this. Any person skilled in the art can easily conceive of changes or substitutions within the technical scope disclosed in this application, which shall cover Within the scope of protection of this application. Therefore, the protection scope of this application shall be subject to the protection scope of the claims.

Claims (11)

1. An antenna array, characterized in that it comprises:

   A plurality of high-frequency radiation units arranged in an array, a first phase shifter and a first attenuator connected in series, and the first phase shifter and first attenuator connected in series correspond to the plurality of high-frequency radiation units one-to-one Connection; among the plurality of high-frequency radiation units, some of the high-frequency radiation units form a sub-array;

   A low-frequency power feeding unit for feeding each high-frequency radiating unit in the sub-array;

   The control circuit is used to control the first phase shifter to perform a phase shift on the low frequency signal emitted by the low frequency feed unit, and to control the first attenuator to perform an amplitude attenuation of the low frequency signal, so that the Signal waves emitted by all high-frequency radiation units in the sub-array are combined into a waveform corresponding to the low-frequency signal;

   The high-frequency feed unit is used to feed each high-frequency radiation unit.
2. The antenna array according to claim 1, wherein the distance d between any adjacent high-frequency radiation units satisfies:

   1/2λ≤d≤λ; where λ is the wavelength corresponding to the high-frequency signal input by the high-frequency feed unit.
3. The antenna array according to claim 2, wherein the low-frequency feed unit is connected to each high-frequency radiating unit in the sub-array through a second attenuator;

   The control circuit is also used to control the first attenuator and the second attenuator to attenuate the low-frequency signal twice, so that the signals emitted by all the high-frequency radiation units in the sub-array are combined. Into a waveform corresponding to the low-frequency signal.
4. The antenna array according to claim 3, further comprising 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 the second attenuator. Each high-frequency radiation unit in the sub-array is connected.
5. The antenna array according to claim 3 or 4, further comprising a second phase shifter, and the second phase shifter is connected in series with the second attenuator;

   The control circuit is also used 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 The waves are combined into a waveform corresponding to the low-frequency signal.
6. The 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. The antenna array according to any one of claims 1 to 6, further comprising a digital-to-analog converter, an electro-optical converter, and a high-speed single-row carrier light-speed diode; wherein,

   The low-frequency feed unit is connected to the digital-to-analog converter, the digital-to-analog converter is connected to the electro-optical converter, the first phase shifter is an optical phase shifter, and the first attenuator is an optical phase shifter. An attenuator, and one end of the first phase shifter and the first attenuator connected in series is connected to the electro-optical converter, and the other end is connected to the high-speed single-line carrier photodiode.
8. The antenna array according to claim 7, further comprising a multiplexer and a demultiplexer connected to the multiplexer; wherein the multiplexer and the plurality of first phase shifters connected in series And the first attenuator is connected, and the de-wave is connected with the plurality of high-speed single-line carrier photodiodes.
9. The antenna array according to any one of claims 1 to 8, wherein when there are multiple sub-arrays, the phase centers of the multiple sub-arrays are arranged non-periodically.
10. The antenna array according to claim 9, wherein the high-frequency radiation units in the sub-array are arranged in an irregular shape.
11. A base station, characterized by comprising the antenna array according to any one of claims 1-10.

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