CN215896727U - Active antenna system and base station - Google Patents

Abstract

The embodiment of the utility model provides an active antenna system and a base station. According to one embodiment, an active antenna system includes a radio frequency unit configured to generate a radio frequency signal to be transmitted through an antenna array, and the antenna array divided into a plurality of antenna sub-arrays. Each antenna sub-array includes at least one antenna element, and a feed circuit that feeds a corresponding radio frequency signal to the at least one antenna element. The plurality of antenna sub-arrays includes a first antenna sub-array and a second antenna sub-array. The active antenna system further comprises a first switching unit, a second switching unit and a control unit. The first switching unit is configured to selectively connect or disconnect a feeding circuit of the first antenna sub-array with a feeding circuit of the second antenna sub-array. The second switching unit is configured to selectively connect or disconnect the radio frequency unit to or from the feeding circuit of the first antenna sub-array. The control unit is configured to control the first switching unit and the second switching unit.

Description

Active antenna system and base station

Technical Field

Embodiments of the present invention relate generally to radio frequency and microwave equipment and, more particularly, to active antenna systems and base stations.

Background

This summary is provided to facilitate a better understanding of the utility model. Accordingly, statements in this section should not be construed as admissions about what matters belong to the prior art or what matters do not belong to the prior art.

Currently, fifth generation (5G) wireless technology is widely used in everyday communication systems. For users, 5G wireless technology implies high peak data rates, ultra-low latency, and large network capacity.

The 5G radio has higher power consumption compared to the fourth generation (4G) radio due to lower radio efficiency. This high power consumption is a critical issue in large-scale antenna systems and is a pain point for operators, as it results in high costs.

SUMMERY OF THE UTILITY MODEL

This section is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This section is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

It is an object of the present invention to provide an improved active antenna system. In particular, one technical problem to be solved by the present invention is that the configuration of the antenna array of the existing active antenna system is not flexible. Another technical problem to be solved by the present invention is that the existing partial RF channel muting method results in a reduction of antenna gain due to a reduction of antenna elements.

According to a first aspect of the present invention, an active antenna system is provided. The active antenna system includes a radio frequency unit and an antenna array. The radio frequency unit is configured to generate a radio frequency signal to be transmitted through the antenna array. The antenna array is divided into a plurality of antenna sub-arrays. Each antenna sub-array includes at least one antenna element, and a feed circuit that feeds a respective radio frequency signal to the at least one antenna element. The plurality of antenna sub-arrays includes a first antenna sub-array and a second antenna sub-array. The active antenna system further includes a first switching unit, a second switching unit, and a control unit. The first switching unit is configured to selectively connect or disconnect a feeding circuit of the first antenna sub-array with a feeding circuit of the second antenna sub-array. The second switching unit is configured to selectively connect or disconnect the radio frequency unit to or from a feeding circuit of the first antenna sub-array. The control unit is configured to control the first switching unit and the second switching unit.

According to the first aspect, since the control unit controls the switching operations of the first switching unit and the second switching unit, different operating modes of the antenna array can be realized by using hardware fixed by the active antenna system, so that the antenna array can be flexibly configured.

In an embodiment of the present invention, the control unit may switch the first antenna sub-array and the second antenna sub-array between a first operation mode and a second operation mode by controlling the first switching unit and the second switching unit. In the first operating mode, the first antenna sub-array and the second antenna sub-array receive the same radio frequency signal. In the second operating mode, only the second antenna sub-array of the first antenna sub-array and the second antenna sub-array receives the corresponding radio frequency signal.

In an embodiment of the utility model, the first switching unit is controllable to connect the feeding circuit of the first antenna sub-array with the feeding circuit of the second antenna sub-array, and the second switching unit is controllable to disconnect the radio frequency unit from the feeding circuit of the first antenna sub-array, such that the first antenna sub-array and the second antenna sub-array receive the same radio frequency signal.

In an embodiment of the utility model, the first switching unit is controllable to disconnect the feeding circuit of the first antenna sub-array from the feeding circuit of the second antenna sub-array, and the second switching unit is controllable to disconnect the radio frequency unit from the feeding circuit of the first antenna sub-array, such that only the second antenna sub-array of the first and second antenna sub-arrays receives the respective radio frequency signal.

In an embodiment of the present invention, each of the first and second switching units may include one of: a diode; a triode; a metal oxide semiconductor field effect transistor; and a micro-electromechanical system switch.

In an embodiment of the utility model, the diode may be a PIN diode.

In an embodiment of the present invention, the first switching unit and the second switching unit may be both diodes.

In an embodiment of the present invention, the control unit may control the first switching unit and the second switching unit by applying respective dc voltages to the feeding circuits of the first antenna sub-array and the feeding circuits of the second antenna sub-array, respectively.

In an embodiment of the present invention, one end of the first switching unit may be grounded through a quarter-wave line.

In an embodiment of the present invention, the first antenna sub-array and the second antenna sub-array may be arranged in a column direction or a row direction of the antenna array.

In an embodiment of the present invention, the number of the first antenna sub-array and the second antenna sub-array may be plural.

According to a second aspect of the utility model, a base station is provided. The base station comprises an active antenna system according to the first aspect described above.

Drawings

These and other objects, features and advantages of the present invention will become apparent from the following detailed description of illustrative embodiments thereof, which is to be read in connection with the accompanying drawings. It is apparent that the structural schematics in the following figures are not necessarily drawn to scale, but rather the features are presented in simplified form. Furthermore, the drawings in the following description relate to only some embodiments of the utility model and are not intended to limit the utility model.

Fig. 1 is a schematic diagram illustrating a typical application scenario of an active antenna system;

fig. 2 is a schematic diagram showing the structure of an antenna array of a conventional active antenna system;

fig. 3 is a schematic diagram for explaining the structure of an active antenna system according to an embodiment of the present invention;

fig. 4 is a schematic diagram for explaining a first operation mode of the active antenna system according to the embodiment of the present invention;

fig. 5 is a schematic diagram for explaining a second operation mode of the active antenna system according to the embodiment of the present invention;

fig. 6 is a schematic diagram for explaining a third operation mode of the active antenna system according to the embodiment of the present invention;

fig. 7 is a schematic diagram for explaining a structure of an active antenna system according to another embodiment of the present invention;

fig. 8 is a block diagram illustrating an active antenna system according to an embodiment of the present invention; and

fig. 9A to 9D are schematic diagrams illustrating different configurations that can be obtained with an active antenna system according to an embodiment of the present invention.

Detailed Description

For purposes of explanation, numerous details are set forth in the following description in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, to one skilled in the art that the embodiments may be practiced without these specific details or with an equivalent arrangement.

Currently, with the introduction of massive Multiple Input Multiple Output (MIMO) antennas into 5G radios, high power consumption is a key issue in massive MIMO systems and is a pain point for operators, as it results in high cost and energy waste.

Different approaches have been introduced to improve radio power consumption, such as muting portions of the Radio Frequency (RF) channels (or ports), employing new Power Amplifier (PA) algorithms that can achieve higher efficiency, reducing output power during idle times, and so on, where muting portions of RF channels is a common approach for 5G radios.

However, muting part of the RF channels results in a reduction in antenna gain due to fewer antenna elements, thereby shrinking the coverage area of the base station. Therefore, for operators, muting of RF channels without causing antenna gain reduction is an urgent need. In addition, in the existing antenna scheme, the configuration of the antenna array is not flexible, thereby causing a limitation to the application thereof.

Embodiments of the present invention propose an improved active antenna system and base station. Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Fig. 1 is a schematic diagram illustrating a typical application scenario of an Active Antenna System (AAS). As shown, an active antenna system 11 may be mounted on a tower and connected to a Base Band Unit (BBU)12 to form a base station (e.g., next generation node b (gnb)). For example, the active antenna system 11 may generate a narrow beam with high antenna gain to track the terminal device for better throughput, and may also implement other service modes, such as generating a macro beam (or a wide beam) to obtain traditional broadcast coverage.

Fig. 2 is a schematic diagram showing the structure of an antenna array of a conventional active antenna system. As shown, the antenna array 22 is divided into a plurality of antenna sub-arrays 221. Each antenna sub-array 221 includes a plurality of antenna elements 2211, and a feed circuit 2212 that feeds the respective radio frequency signals to the plurality of antenna elements 2211. It should be noted that fig. 2 shows only one column of the antenna array of the active antenna system for the sake of simplicity, and the number of antenna sub-arrays (i.e., 4) included in the column and the number of antenna elements (i.e., 3) included in each antenna sub-array are merely exemplary.

Fig. 3 is a schematic diagram for explaining the structure of an active antenna system according to an embodiment of the present invention. For ease of comparison, fig. 3 also shows only one column of the antenna array of the active antenna system of this embodiment, and this column also contains 4 antenna sub-arrays, each containing 3 antenna elements. In addition, the radio frequency units comprised by the active antenna system, which are configured to generate radio frequency signals to be transmitted through the antenna array 32, are omitted from fig. 3 for the sake of simplicity. As shown, the antenna array 32 is divided into a plurality of antenna sub-arrays. The plurality of antenna sub-arrays includes a plurality of first antenna sub-arrays 321 and a plurality of second antenna sub-arrays 322. Each of the first antenna sub-arrays 321 includes a plurality of antenna elements 3211, and a feed circuit 3212 that feeds a corresponding radio frequency signal to the plurality of antenna elements 3211. Each second antenna sub-array 322 includes a plurality of antenna elements 3221, and a feeding circuit 3222 that feeds respective radio frequency signals to the plurality of antenna elements 3221.

As shown, the active antenna system also includes a first diode (e.g., a PIN diode) 33 connected between the feed circuits 3212, 3222 of the first antenna sub-array 321 and the feed circuits 3222 of the second antenna sub-array 322. By applying an on-voltage or an off-voltage across the first diode 33, the first diode 33 is able to connect or disconnect the feeding circuit 3212 of the first antenna sub-array 321 and the feeding circuit 3222 of the second antenna sub-array 322, respectively.

As shown, the active antenna system further includes a second diode (e.g., a PIN diode) 34 connected between the radio frequency unit and the feed circuit 3212 of the first antenna sub-array 321 (e.g., connected between the respective antenna port and the feed circuit 3212 of the first antenna sub-array 321). By applying an on-voltage or an off-voltage across the second diode 34, the second diode 34 is able to connect or disconnect the radio frequency unit from the feeding circuit 3212 of the first antenna sub-array 321, respectively.

In addition, the active antenna system further includes a control unit for controlling the first diode 33 and the second diode 34 by applying respective on-voltages or off-voltages to both ends thereof, although the control unit is not shown in fig. 3 for the sake of brevity. This control may be achieved, for example, by applying respective dc voltages to the feed circuits 3212, 3222 of the first and second antenna sub-arrays 321, 322, respectively. As a simplest example, the applied dc voltage may be drawn from the radio frequency unit of the active antenna system. The control unit may be implemented using hardware (e.g., an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), etc.), software (e.g., software running on a processor), or a combination of hardware and software. As an illustrative example, the control unit may be implemented by adding corresponding control logic in a control module of the radio frequency unit of the active antenna system.

According to the above embodiment, since the control unit controls the switching operation of the first switching unit and the second switching unit, different operating modes of the antenna array can be realized by using hardware fixed by the active antenna system, so that the antenna array can be flexibly configured.

Alternatively, in the active antenna system, one end of the first diode 33 may be grounded through the quarter-wave line 36. Thus, on the one hand, a fixed ground voltage is provided on one side of the first diode 33 (and also on one side of the second diode 34), and the switching on and off is achieved by changing the voltage on the other side. On the other hand, the quarter-wave line is equivalent to an open circuit point on radio frequency, so that the feeding of radio frequency signals is not influenced. As shown in the figure, in order to minimize the influence on the impedance of the main path, the distance d1 between the quarter-wave line 36 and the feeding circuit 3212 of the first antenna sub-array 321 may be set as short as possible, and the distance d2 between the end of the first diode 33 close to the feeding circuit 3222 of the second antenna sub-array 322 and the feeding circuit 3222 may be set as short as possible.

The active antenna system of this embodiment may have three operation modes depending on the on or off states of the first diode 33 and the second diode 34.

Fig. 4 is a schematic diagram for explaining a first operation mode of the active antenna system of the embodiment. As shown in the left half of fig. 4, by applying a dc voltage of +5 volts to the feeding circuit 3222 of the second antenna sub-array 322, the first diode 33 is turned on, thereby connecting the feeding circuit 3212 of the first antenna sub-array 321 and the feeding circuit 3222 of the second antenna sub-array 322. By applying a dc voltage of 0 volt to the feeding circuit 3212 of the first antenna sub-array 321, the second diode 34 is turned off, thereby disconnecting the radio frequency unit from the feeding circuit 3212 of the first antenna sub-array 321. This disconnection may prevent radio frequency signals from feed circuitry 3222 from being reflected back to the frequency elements via the respective antenna ports, thereby enabling the antenna array to remain operating properly. As a result, an equivalent circuit as shown in the right half of fig. 4 can be obtained. It can be seen that in this first mode of operation, the radio frequency signals fed to the second antenna sub-array 322 are also fed to the first antenna sub-array 321, so that the first antenna sub-array 321 and the second antenna sub-array 322 receive the same radio frequency signals.

Since the first antenna sub-array 321 and the second antenna sub-array 322 receive the same radio frequency signal, which is equivalent to the first antenna sub-array 321 and the second antenna sub-array 322 forming one larger antenna sub-array as a whole, the active antenna system can achieve the same mute ratio as compared with the prior art scheme of muting one of the first antenna sub-array 321 and the second antenna sub-array 322. Meanwhile, since both the first antenna sub-array 321 and the second antenna sub-array 322 operate in the active antenna system (thereby not causing a change in the number of antenna elements in an operating state in a mute situation), a decrease in antenna gain due to a decrease in antenna elements can be avoided. That is, in the case that the number of antenna elements included in the antenna array is the same, compared with the existing muting scheme, the active antenna system of this embodiment can achieve better coverage of the base station while achieving the same muting ratio. Stated another way, the active antenna system of this embodiment can save or reduce radio power consumption under the same base station coverage while maintaining the same antenna gain.

Fig. 5 is a schematic diagram for explaining a second operation mode of the active antenna system of the embodiment. As shown in the left half of fig. 5, by applying a dc voltage of 0 volts to the feeding circuit 3222 of the second antenna sub-array 322, the first diode 33 is turned off, thereby disconnecting the feeding circuit 3212 of the first antenna sub-array 321 from the feeding circuit 3222 of the second antenna sub-array 322. By applying a dc voltage of 0 volt to the feeding circuit 3212 of the first antenna sub-array 321, the second diode 34 is turned off, thereby disconnecting the radio frequency unit from the feeding circuit 3212 of the first antenna sub-array 321. The disconnection is such that the first antenna sub-array 321 does not receive radio frequency signals. As a result, an equivalent circuit as shown in the right half of fig. 5 can be obtained. It can be seen that in this second mode of operation, only the second antenna sub-array 322 of the first antenna sub-array 321 and the second antenna sub-array 322 receives the corresponding radio frequency signal. Thus, depending on the specific requirements, the control unit may be configured to switch the first and second antenna sub-arrays between the first and second operation modes by controlling the first and second switching units. It should be noted that in the case where the first antenna sub-array and the second antenna sub-array are arranged in the column direction of the antenna array, with this second operation mode, since the number of antenna elements in the vertical plane is reduced, resulting in a reduction in the aperture in the vertical plane, a wider synthesized beam in the vertical plane can be generated.

Fig. 6 is a schematic diagram for explaining a third operation mode of the active antenna system of the embodiment. As shown in the left half of fig. 6, by applying a dc voltage of 0 volts to the feeding circuit 3222 of the second antenna sub-array 322, the first diode 33 is turned off, thereby disconnecting the feeding circuit 3212 of the first antenna sub-array 321 from the feeding circuit 3222 of the second antenna sub-array 322. By applying a dc voltage of +5 volts to the feeding circuit 3212 of the first antenna sub-array 321, the second diode 34 is turned on, thereby connecting the radio frequency unit with the feeding circuit 3212 of the first antenna sub-array 321. As a result, an equivalent circuit as shown in the right half of fig. 5 can be obtained. It can be seen that in the third operation mode, the first antenna sub-array 321 and the second antenna sub-array 322 respectively receive corresponding radio frequency signals. Therefore, depending on the specific requirements, the control unit may also be configured to switch the first and second antenna sub-arrays between the first, second and third operation modes by controlling the first and second switching units. It should be noted that the voltage values of +5V and 0V shown in fig. 4 to 6 are merely exemplary, and do not limit the present invention.

Fig. 7 is a schematic diagram for explaining the structure of an active antenna system according to another embodiment of the present invention. The embodiment of fig. 7 differs from the embodiment of fig. 3 in that in the embodiment of fig. 7 the first and second antenna sub-arrays are arranged in the row direction of the antenna array, whereas in the embodiment of fig. 3 the first and second antenna sub-arrays are arranged in the column direction of the antenna array. Similar to fig. 3, the radio frequency units included in the active antenna system, which are configured to generate radio frequency signals to be transmitted through the antenna array 72, are also omitted from fig. 7. As shown, the antenna array 72 is divided into a plurality of antenna sub-arrays. The plurality of antenna sub-arrays includes a first antenna sub-array 721 and a second antenna sub-array 722. The first antenna sub-array 721 includes a plurality of antenna elements 7211, and a feeding circuit 7212 that feeds corresponding radio frequency signals to the plurality of antenna elements 7211. The second antenna sub-array 722 includes a plurality of antenna elements 7221, and a feed circuit 7222 that feeds corresponding radio frequency signals to the plurality of antenna elements 7221.

As shown, the active antenna system also includes a first diode (e.g., a PIN diode) 73 connected between the feed circuit 7212 of the first antenna sub-array 721 and the feed circuit 7222 of the second antenna sub-array 722. By applying an on-voltage or an off-voltage to both ends of the first diode 73, the first diode 73 can connect or disconnect the feeding circuit 7212 of the first antenna sub-array 721 and the feeding circuit 7222 of the second antenna sub-array 722 accordingly.

As shown, the active antenna system also includes a second diode (e.g., a PIN diode) 74 connected between the radio frequency units and the feed circuit 7212 of the first antenna sub-array 721. By applying an on-voltage or an off-voltage to both ends of the second diode 74, the second diode 74 can connect or disconnect the radio frequency unit from the feeding circuit 7212 of the first antenna sub-array 721 accordingly.

In addition, the active antenna system further includes a control unit for controlling the first diode 73 and the second diode 74 by applying respective on-voltages or off-voltages thereto, although the control unit is not shown in fig. 7 for the sake of brevity. Alternatively, in the active antenna system, one end of the first diode 73 may be grounded through the quarter-wave line 76. The control unit and the quarter wave line 76 may be implemented similarly to the embodiment of fig. 3 and will not be described again here.

It should be noted that the utility model is not limited to the examples described above. As another example, the number of antenna elements included in each antenna sub-array is not limited to a plurality, and each antenna sub-array may include at least one antenna element. Similarly, the number of the first antenna sub-array and the second antenna sub-array may be at least one. As yet another example, the first and second switching units are not limited to diodes, but each of the two may include one or a combination of the following: diodes, transistors, Metal Oxide Semiconductor Field Effect Transistors (MOSFETs), micro-electromechanical system (MEMS) switches, and the like. Accordingly, the control unit may control its on or off operation by applying a corresponding control signal thereto. The design of the solution using diodes is simpler and the switching control is easier than the solution using other switching elements, such as transistors (requiring bias voltage and control signals).

In light of the above description, a first aspect of the present invention provides an active antenna system 80 as shown in fig. 8. The active antenna system 80 includes a radio frequency unit 81 and an antenna array 82. The radio frequency unit 81 is configured to generate a radio frequency signal to be transmitted through the antenna array 82. The antenna array 82 is divided into a plurality of antenna sub-arrays. Each antenna sub-array includes at least one antenna element (at least one antenna element 8211 for the first antenna sub-array 821; at least one antenna element 8221 for the second antenna sub-array 822), and a feeding circuit (a feeding circuit 8212 for the first antenna sub-array 821; a feeding circuit 8222 for the second antenna sub-array 822) that feeds a corresponding radio frequency signal to the at least one antenna element. The plurality of antenna sub-arrays includes a first antenna sub-array 821 and a second antenna sub-array 822. The active antenna system 80 further comprises a first switch unit 83, a second switch unit 84 and a control unit 85. The first switching unit 83 is configured to selectively connect or disconnect the feeding circuit 8212 of the first antenna sub-array 821 and the feeding circuit 8222 of the second antenna sub-array 822. The second switching unit 84 is configured to selectively connect or disconnect the radio frequency unit 81 with or from the feeding circuit 8212 of the first antenna sub-array 821. The control unit 85 is configured to control the first switching unit 83 and the second switching unit 84.

Furthermore, a second aspect of the utility model provides a base station comprising an active antenna system according to the first aspect described above. As an illustrative example, the base station may be a next generation node b (gnb). The implementation details of the other components of the base station, other than the active antenna system, are well known to those skilled in the art and therefore will not be described in detail herein.

Fig. 9A to 9D are schematic diagrams illustrating different configurations that can be obtained with an active antenna system according to an embodiment of the present invention. As shown in fig. 9A, the antenna array of the active antenna system has 96 antenna elements. Each antenna element has +/-45 ° polarization and is therefore dual polarized and has two outputs. The 96 antenna elements are divided into 32 antenna sub-arrays, each having 3 antenna elements. Accordingly, the configuration shown in fig. 9A may be represented as 192AE, 64TR, where the number of "AE" is twice the number of dual-polarized antenna elements and "TR" represents "transmitter/receiver". Since each dual-polarized antenna element has two outputs, the number of "TRs" is twice the number of antenna sub-arrays.

Fig. 9B shows the antenna array of fig. 9A in the first mode of operation described above. In this state, the 32 antenna sub-arrays in the original fig. 9A are combined into 16 larger antenna sub-arrays. Therefore, the configuration shown in fig. 9B is 192AE, 32 TR. Fig. 9C shows the antenna array of fig. 9A in the second mode of operation described above. In this state, only half of the 32 antenna sub-arrays in fig. 9A are in operation. Therefore, the configuration shown in fig. 9C is 96AE, 32 TR.

Fig. 9D shows the state of the antenna array of fig. 9A when the silence ratio is a quarter. This can be achieved by muting half of the antenna array configured in fig. 9C. Therefore, the arrangement shown in fig. 9D is 48AE, 16 TR. Therefore, the active antenna system of the embodiment can realize different antenna array configurations for different base station coverage scenes, and thus can be suitable for different base station deployment situations. It should be noted that fig. 9A-9D only show some exemplary antenna array configurations, and thus other antenna array configurations are possible depending on the specific radio requirements.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the subject invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the specification and the relevant art and will not be interpreted in an overly idealized form unless expressly so defined herein. As used herein, the statement that two or more parts are "coupled," "connected," or "cascaded" together shall mean that the parts are joined together either directly or joined through one or more intermediate components.

It is to be understood that the terms "top," "bottom," "inner," "outer," and the like are used in an orientation or positional relationship indicated in the drawings for convenience and simplicity of description only and are not intended to indicate or imply that the elements, components, or devices so referred to must be in a particular orientation, constructed and operated in a particular orientation, and thus should not be construed as limiting the present invention.

It is noted that where the term "illustrative" is used herein, particularly when it comes after a set of terms, it is merely exemplary and illustrative and should not be considered exclusive. Various aspects of the utility model may be implemented alone or in combination with one or more other aspects. In addition, the embodiments described herein are intended for illustrative purposes only and are not intended to limit the scope of the present invention.

The disclosure includes any novel feature or combination of features disclosed herein either explicitly or in any generalised form thereof. Various modifications and adaptations to the foregoing embodiments of this disclosure may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings. However, any and all modifications will still fall within the scope of the non-limiting and exemplary embodiments of this disclosure.

Claims (12)

1. An active antenna system (80) comprising:

a radio frequency unit (81) configured to generate a radio frequency signal to be transmitted by an antenna array (82); and

the antenna array (82) is divided into a plurality of antenna sub-arrays, each antenna sub-array comprises at least one antenna unit and a feeding circuit for feeding corresponding radio frequency signals to the at least one antenna unit;

it is characterized in that the preparation method is characterized in that,

the plurality of antenna sub-arrays comprises a first antenna sub-array (821) and a second antenna sub-array (822);

the active antenna system (80) further comprises:

a first switching unit (83) configured to selectively connect or disconnect a feeding circuit (8212) of the first antenna sub-array (821) and a feeding circuit (8222) of the second antenna sub-array (822);

a second switching unit (84) configured to selectively connect or disconnect the radio frequency unit (81) with or from a feeding circuit (8212) of the first antenna sub-array (821); and

a control unit (85) configured to control the first switch unit (83) and the second switch unit (84).

2. Active antenna system (80) according to claim 1, characterized in that the control unit (85) is capable of switching the first antenna sub-array (821) and the second antenna sub-array (822) between a first operating mode and a second operating mode by controlling the first switching unit (83) and the second switching unit (84);

in the first mode of operation, the first antenna sub-array (821) and the second antenna sub-array (822) receive the same radio frequency signal;

in the second mode of operation, only the second antenna sub-array (822) of the first antenna sub-array (821) and the second antenna sub-array (822) receives respective radio frequency signals.

3. Active antenna system (80) according to claim 1, characterized in that the first switching unit (83) is controllable to connect the feeding circuit (8212) of the first antenna sub-array (821) with the feeding circuit (8222) of the second antenna sub-array (822), and the second switching unit (84) is controllable to disconnect the radio frequency unit (81) from the feeding circuit (8212) of the first antenna sub-array (821) such that the first antenna sub-array (821) and the second antenna sub-array (822) receive the same radio frequency signal.

4. Active antenna system (80) according to claim 1, characterized in that the first switching unit (83) is controllable to disconnect the feeding circuit (8212) of the first antenna sub-array (821) from the feeding circuit (8222) of the second antenna sub-array (822) and the second switching unit (84) is controllable to disconnect the radio frequency unit (81) from the feeding circuit (8212) of the first antenna sub-array (821) such that only the second antenna sub-array (822) of the first antenna sub-array (821) and the second antenna sub-array (822) receives a respective radio frequency signal.

5. Active antenna system (80) according to claim 1, characterized in that each of the first switch unit (83) and the second switch unit (84) comprises one of the following:

a diode; a triode; a metal oxide semiconductor field effect transistor; and a micro-electromechanical system switch.

6. Active antenna system (80) according to claim 5, characterized in that the diode is a PIN diode.

7. Active antenna system (80) according to claim 5, characterized in that the first switching unit (83) and the second switching unit (84) are both diodes.

8. Active antenna system (80) according to claim 7, characterized in that the control unit (85) controls the first and second switching units (83, 84) by applying respective direct voltage to the feeding circuits (8212, 8222) of the first and second antenna sub-arrays (821, 822), respectively.

9. Active antenna system (80) according to claim 5, characterized in that one end of the first switching element (83) is connected to ground via a quarter-wave line.

10. The active antenna system (80) of claim 1, wherein the first antenna sub-array (821) and the second antenna sub-array (822) are arranged in a column direction or a row direction of the antenna array (82).

11. The active antenna system (80) of claim 1, wherein the number of the first antenna sub-array (821) and the second antenna sub-array (822) is plural.

12. A base station, characterized in that it comprises an active antenna system (80) according to any one of claims 1 to 11.

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