JP2016092713A - Antenna system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna system that can be made more compact.SOLUTION: An antenna system 4 includes a plurality of antenna elements 9, a transmission and reception unit 15 for making the plurality of antenna elements 9 function as active antenna, for a transmission and reception signal that is transmitted and received by a first signal system for transmitting and receiving by using the plurality of antenna elements 9, and a distribution and multiplexing circuit 16 for processing a transmission and reception signal that is transmitted and received by a second signal system having a use frequency band different from that of the first signal system. The plurality of antenna elements 9 are configured to be able to transmit and receive the transmission and reception signals of the first and second signal systems, respectively, and connected with the transmission and reception unit 15 and distribution and multiplexing circuit 16 so that the antenna elements 9 can be shared by the first and second signal systems.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an antenna system used in a base station apparatus or the like of a wireless communication system.

  Conventionally, in a base station apparatus used in a radio communication system such as a mobile phone, a radio signal processing unit (RRH: Remote Radio Head) that processes radio frequency signals and a baseband signal processing unit that performs processing related to baseband signals The structure which isolate | separated (BBU: Base Band Unit) is employ | adopted (for example, refer patent document 1).

An antenna installed outdoors is connected to the RRH via a coaxial cable or the like. A radio frequency transmission / reception signal transmitted / received by the antenna is transmitted between the RRH and the antenna via a coaxial cable or the like.
The RRH and the BBU are connected by an optical fiber cable or the like, and a digital baseband signal is transmitted between the two by optical communication or the like.

  In this way, the transmission / reception function of the base station apparatus is separated into BBU and RRH, and by installing RRH in the vicinity of the antenna, the length of the coaxial cable connecting the antenna and RRH is made as short as possible. Attenuation of radio frequency transmission / reception signals is suppressed.

JP 2012-142718 A

  In recent years, with the spread of smartphones and the like in wireless communication systems, there has been a growing demand for expansion of communication areas and expansion of communication capacity, and application of active antenna systems incorporating RRH functions to base station devices has been proposed. ing.

  The active antenna system includes a plurality of antenna elements and a plurality of radio transmission / reception units provided corresponding to the plurality of antenna elements. For this reason, the radio signal transmitted / received for each antenna element can be controlled, and the controllability is excellent, and it becomes possible to provide a new service that can improve the communication environment by using this excellent controllability. .

Here, in the wireless communication system such as the cellular phone system, when the provision of a new service is started by adopting the active antenna system or the like, the provision of the existing service to the user may have to be continued. is there.
For this reason, when starting to provide a new service, it is necessary to install an antenna system for providing a new service while maintaining the provision of the existing service.

  However, it is difficult to secure a new installation location for installing a new antenna system while keeping the antenna for providing the existing service intact. In order to be installable, it is required to be more compact.

  The present invention has been made in view of such circumstances, and an object thereof is to provide an antenna system that can be made more compact.

  An antenna system according to an embodiment includes a plurality of antenna elements as active antennas for a plurality of antenna elements and a transmission / reception signal transmitted / received by a first signal system for transmitting / receiving using the plurality of antenna elements. A plurality of antennas, comprising: a first processing circuit that performs processing to function; and a second processing circuit that performs processing of transmission / reception signals transmitted and received by a second signal system having a frequency band different from that of the first signal system. The element is configured to be able to transmit and receive transmission / reception signals of the first signal system and the second signal system, and the first signal system and the second signal system can share the antenna element. A processing circuit and the second processing circuit are connected.

  According to the antenna system of the present invention, it is possible to make it more compact.

It is a block diagram which shows a part of base station apparatus provided with the antenna system which concerns on one Embodiment. It is the block diagram which showed the functional structure of the antenna system. It is a perspective view of an antenna element. It is a side view of an antenna element. It is a front view of an antenna element. It is sectional drawing of an antenna system. It is the disassembled perspective view which showed the principal part of the antenna system.

[Description of Embodiment]

(1) An antenna system according to an embodiment includes:
A plurality of antenna elements;
A first processing circuit that performs a process of causing the plurality of antenna elements to function as an active antenna with respect to a transmission / reception signal transmitted / received by a first signal system for transmitting / receiving using the plurality of antenna elements;
A second processing circuit that performs processing on a transmission / reception signal transmitted and received by a second signal system having a different frequency band from the first signal system;
The plurality of antenna elements are configured to be able to transmit and receive transmission / reception signals of the first signal system and the second signal system, and the antenna elements can be shared by the first signal system and the second signal system. Are connected to the first processing circuit and the second processing circuit.

According to the antenna system configured as described above, the plurality of antenna elements are configured so as to be able to transmit and receive the transmission / reception signals of the first signal system and the second signal system, respectively. The number of antenna elements can be reduced as compared with the case where the antenna element is provided, and as a result, the size can be reduced.
Further, according to the present antenna system, the plurality of antenna elements are configured to be able to transmit and receive the transmission / reception signals of the first signal system and the second signal system, respectively. Transmission and reception are possible. For this reason, if this antenna system is installed in place of the existing antenna system, and the transmission / reception signal processing by the existing antenna system is assigned to the second processing circuit that performs transmission / reception signal processing by the second signal system, Service provision by the antenna system can be maintained. Furthermore, in the first signal system, a process for causing a plurality of antenna elements to function as active antennas can be performed, so that new functions and services can be added.
As described above, according to the present antenna system, even if both the function of an existing antenna system and the function of a newly added antenna system are provided, it is possible to reduce the size.

(2) The antenna system may further include an antenna sharing unit that is provided in each of the plurality of antenna elements and connects the plurality of antenna elements to the first processing circuit and the second processing circuit so as to be shared. It is preferable.
In this case, since the antenna sharing unit is provided for each antenna element, the first processing circuit of the first signal system is allowed to perform processing for causing the plurality of antenna elements to function as active antennas, while A plurality of antenna elements can be shared between the signal system and the second signal system.

(3) In the antenna system, it is preferable that the second processing circuit distributes and synthesizes transmission / reception signals by the second signal system.
In this case, in the second signal system, a plurality of antenna elements can be used as passive antennas. For example, an RRH and a passive antenna connected to the RRH are already installed as an existing antenna system. Even when this antenna system is installed, if the existing RRH and the processing unit are connected, the function of the active antenna is added by the first signal system, while the function of the existing antenna system is added by using the second signal system. The function can be maintained.

(4) Further, in the antenna system, a signal processing device installed outside the antenna system, wherein the signal processing device performs amplification and signal processing of a transmission / reception signal by the second signal system. When transmission / reception is possible, a connection terminal for connecting a signal line for transmitting / receiving a signal to / from the signal processing device may be further provided.
In this case, when the second processing circuit is connected to an RRH or the like as a signal processing device that performs amplification and signal processing of transmission / reception signals by the second signal system installed outside, the connection becomes easy.

(5) (6) The antenna system further includes a reflector disposed on a back surface of the antenna element, and the first processing circuit and the second processing circuit are disposed on a back surface side of the reflector. Further, the first processing circuit and the second processing circuit may be arranged such that the first processing circuit and the second processing circuit are located inside the edge of the reflecting plate when the reflecting plate is viewed from the front. It is preferable that they are arranged.
In this case, since the number of antenna elements can be reduced compared to the case where both systems have dedicated antenna elements, the area of the reflector is also provided with dedicated antenna elements in both systems. It can be made smaller than By disposing the first processing circuit and the second processing circuit on the back side of the reflector having a relatively small area, the antenna system can be further downsized as a whole.

(7) In the antenna system, the second processing circuit may perform a process of causing the plurality of antenna elements to function as active antennas with respect to a transmission / reception signal by the second signal system.
In this case, in both systems, the plurality of antenna elements can function as active antennas.

[Details of the embodiment]
Hereinafter, preferred embodiments will be described with reference to the drawings.
[About base station equipment]
FIG. 1 is a block diagram illustrating a part of a base station apparatus including an antenna system according to an embodiment. In the figure, a base station apparatus 1 is used as a base station apparatus in a wireless communication system for a mobile phone to which LTE (Long Term Evolution) is applied, for example, and is a mobile terminal such as a mobile phone (not shown). It has a function of performing wireless communication.
As shown in the figure, the base station apparatus 1 includes a first baseband unit (first BBU) 2, a second baseband unit (second BBU) 3, and an active antenna system 4.

The first baseband unit 2 connects a signal transmission path (an optical transmission path or an electrical transmission path) 5 extending from the first baseband unit 2 to a connection connector 5 a provided in the housing 4 a of the active antenna system 4. To the active antenna system 4 (hereinafter also simply referred to as the antenna system 4).
The first baseband unit 2 has a function of performing digital modulation processing on transmission data given from an upper network (not shown) and generating a transmission baseband signal (I / Q signal) that is a digital signal. ing.
The first baseband unit 2 gives a transmission baseband signal obtained by modulating transmission data to the antenna system 4 via the signal transmission path 5.

The first baseband unit 2 acquires a reception baseband signal (I / Q signal) that is a digital signal given from the antenna system 4 via the signal transmission path 5, and digitally outputs the reception baseband signal. It has a function of performing demodulation processing and generating received data.
The first baseband unit 2 gives received data obtained by demodulating the received baseband signal to the upper network.

The second baseband unit (second BBU) 3 is connected to the remote radio head 6 by a signal transmission path (optical transmission path or electrical transmission path) 7.
The second baseband unit 3 obtains a received baseband signal (I / Q signal) that is a digital signal provided from the remote radio head 6 via the signal transmission path 7.
The second baseband unit 3 generates reception data by performing digital demodulation processing on the reception baseband signal given from the remote radio head 6, and performs digital modulation processing on transmission data given from the higher level network. It has a function to generate a transmission baseband signal by performing.
The second baseband unit 3 gives a digital transmission baseband signal obtained by modulating transmission data to the remote radio head 6 via the signal transmission path 7 and also receives reception data obtained by demodulating the reception baseband signal. To the upper network.

The remote radio head 6 is connected to the antenna system 4 by connecting a coaxial cable 8 extending from the remote radio head 6 to a connection connector 8a provided in the housing 4a, and signal processing when transmitting / receiving a transmission / reception signal is performed. I do.
The remote radio head 6 has a function of converting it into an analog radio frequency signal by performing various kinds of signal processing on the transmission baseband signal given from the second baseband unit 3. The remote radio head 6 also includes an amplifier that amplifies the power of the transmission signal. The remote radio head 6 amplifies the converted analog radio frequency transmission signal and supplies the amplified signal to the antenna system 4 via the coaxial cable 8.
The remote radio head 6 includes an amplifier that amplifies the power of the received signal. The remote radio head 6 amplifies the received signal of the radio frequency supplied from the antenna system 4 via the coaxial cable 8 and then amplifies the received signal. It has a function of converting into a digital reception baseband signal by performing various signal processing. The remote radio head 6 gives the converted digital reception baseband signal to the second baseband unit 3 via the signal transmission path 7.

  Thus, the remote radio head 6 is installed outside the antenna system 4 and constitutes a signal processing device that performs amplification and signal processing of transmission / reception signals.

Here, the transmission / reception signal processed by the first baseband unit 2 and the transmission / reception signal processed by the second baseband unit 3 are signals that are wirelessly transmitted / received in different use frequency bands, and are transmitted by independent signal systems. It is a signal to be transmitted and received.
In other words, the antenna system 4 is connected to two signal systems, a signal system related to transmission / reception signals processed by the first baseband unit 2 and a signal system related to transmission / reception signals processed by the second baseband unit 3.
The antenna system 4 is configured to transmit and receive signals using two signal systems.
In the following description, a signal system for transmitting / receiving a transmission / reception signal processed by the first baseband unit 2 is a first signal system, and a signal system for transmitting / receiving a transmission / reception signal processed by the second baseband unit 3 is a second signal system. It is called a signal system. The first baseband unit 2 is included in the first signal system. The second baseband unit 3 and the remote radio head 6 are included in the second signal system.

The antenna system 4 includes a plurality of antenna elements 9 for transmitting and receiving radio frequency signals inside the housing 4a. The plurality of antenna elements 9 are arranged at a predetermined interval in the vertical direction and constitute an array antenna.
The antenna system 4 has a function of transmitting and receiving a radio signal related to radio communication when the base station apparatus 1 performs radio communication with a mobile terminal.
Further, the antenna system 4 of the present embodiment is configured to be able to transmit / receive two transmission / reception signals in different frequency bands, and the transmission / reception signal of the first signal system and the transmission / reception signal of the second signal system are transmitted. Transmits and receives signals from both signal systems.

As described above, each of the first signal system and the second signal system is connected to the antenna system 4.
The antenna system 4 transmits / receives transmission / reception signals by the first signal system transmitted / received by the plurality of antenna elements 9 and transmits / receives transmission / reception signals by the second signal system transmitted / received by the plurality of antenna elements 9.

  Thereby, the base station apparatus 1 of this embodiment can perform the radio communication by a 1st signal system | strain, and the radio communication by a 2nd signal system | strain.

[Functional configuration of antenna system]
FIG. 2 is a block diagram showing a functional configuration of the antenna system 4.
The antenna system 4 includes a transmission / reception processing unit 15, a distribution / synthesis circuit 16, and a plurality of duplexers 17.

  The transmission / reception processing unit 15 is connected to the first baseband unit 2 via a connection connector 5a provided on the housing 4a, and is connected to each of the plurality of antenna elements 9, and the plurality of antenna elements 9 are connected to each other. The first processing circuit has a function of amplifying a transmission / reception signal transmitted / received by the first signal system for transmitting / receiving, and constitutes a first processing circuit for performing a process of causing the plurality of antenna elements 9 to function as active antennas.

  Here, the active antenna is an antenna having a function of amplifying a signal transmitted / received by each of a plurality of antenna elements, and has a function of amplifying a transmitted / received signal transmitted / received using the plurality of antenna elements. In addition, there may be a function that can perform processing such as phase and amplitude adjustment on a transmission / reception signal for each of a plurality of antenna elements.

  The transmission / reception processing unit 15 converts a digital transmission baseband signal, which is a transmission signal by the first signal system, provided from the first baseband unit 2 into an analog radio frequency signal, and converts the converted signal into a plurality of antenna elements 9. Is transmitted as a radio signal. In addition, the transmission / reception processing unit 15 converts a reception signal by the first signal system received by the plurality of antenna elements 9 into a digital reception baseband signal, and gives the converted reception baseband signal to the first baseband unit 2.

The transmission / reception processing unit 15 includes a digital signal processing unit 20 and a plurality of transmission / reception units 21.
The digital signal processing unit 20 distributes the digital transmission baseband signal given from the first baseband unit 2 to each transmission / reception unit 21 and synthesizes the reception digital baseband signal given from each transmission / reception unit 21. Thus, the first baseband unit 2 has a function.

The transmission / reception unit 21 is provided corresponding to each of the plurality of antenna elements 9, and converts an analog radio frequency signal received by the antenna element 9 into a digital reception baseband signal, or the first baseband unit 2. 1 has a function of converting the digital transmission baseband signal given from the signal into an analog signal and giving it to the antenna element 9.
The transmission / reception unit 21 includes an amplifier, and an analog signal such as a function of amplifying an analog signal transmitted / received by the antenna element 9 and a modulation / demodulation function related to a baseband signal (I / Q signal) converted into an analog signal. It has the function to perform the process regarding.

Each transmission / reception unit 21 has a function of adjusting the phase and amplitude of an analog signal transmitted / received by the antenna element 9 by including a phase shifter, a variable attenuator, and the like.
Therefore, the transmission / reception processing unit 15 adjusts the phase and amplitude of the transmission / reception signal for each antenna element 9, so that the tilt angle of the beam formed by the antenna element 9 during transmission / reception of the signal by the first signal system, etc. Control regarding directivity can be performed.

  The beam tilt angle control by the transmission / reception processing unit 15 can be adjusted and set, for example, when the antenna system 4 is installed, or a control signal given from an interface compliant with the AISG (Antenna Interface Standards Group) standard. It is also possible to control based on this.

In the present embodiment, the case where the function of adjusting the phase and amplitude of the analog signal transmitted and received by the antenna element 9 is given to each transmitting / receiving unit 21 is described. However, the antenna element is obtained by digital signal processing by the digital signal processing unit 20. 9 can also realize a function of adjusting the phase and amplitude of an analog signal transmitted / received by the digital camera 9.
In this case, the digital signal processing unit 20 has a function of performing digital signal processing on the transmission baseband signal and the reception baseband signal. By this digital signal processing, a plurality of transmission / reception signal processing by the first signal system is performed. This is performed for each antenna element 9.
The digital signal processing unit 20 transmits each transmission baseband signal and reception baseband signal to each transmission / reception unit 21 so that the phase and amplitude of the analog signal transmitted / received by the antenna element 9 can be arbitrarily set by digital signal processing. Digital signal processing. Even in this case, similarly to the present embodiment, it is possible to control the directivity such as the tilt angle of the beam formed by the antenna element 9 when transmitting and receiving signals by the first signal system.

  As described above, the antenna system 4 functions as a plurality of antenna elements 9 as active antennas by the transmission / reception units 21 having an amplification function for transmission / reception of signals by the first signal system.

  The distribution / combination circuit 16 is connected to the remote radio head 6 via a connection connector 8a provided on the housing 4a, and is connected to each of the plurality of antenna elements 9. A second processing circuit is configured to perform processing on transmission / reception signals transmitted and received by the second signal system having different bands.

  The distribution / combination circuit 16 distributes an analog radio frequency transmission signal, which is a transmission signal of the second signal system provided from the remote radio head 6, to the plurality of antenna elements 9 and transmits the plurality of antenna elements 9. In addition, the antenna system 4 synthesizes reception signals from the second signal system received by the plurality of antenna elements 9 as radio signals, and gives the synthesized analog radio frequency signal to the remote radio head 6.

Here, the remote radio head 6 amplifies the power of the transmission signal so that it can be transmitted as radio waves from the plurality of antenna elements 9, and distributes the amplified transmission signal to the plurality of antenna elements 9.
In addition, the remote radio head 6 amplifies the power of the received signals received by the plurality of antenna elements 9 so that the power of the subsequent signal processing can be appropriately performed.

  For this reason, the distribution / combination circuit 16 does not have a function of signal amplification processing, and allows the plurality of antenna elements 9 to function as passive antennas. In other words, the antenna system 4 functions as a so-called passive antenna that performs only passive processing by the distribution / combination circuit 16 for transmission and reception of signals by the second signal system.

A plurality of duplexers 17 (antenna sharing units) are provided in each of the plurality of antenna elements 9, and the plurality of antenna elements 9 are connected to the transmission / reception processing unit 15 and the distribution / synthesis circuit 16 so as to be shared.
That is, the antenna element 9 is connected to both the transmission / reception processing unit 15 and the distribution / synthesis circuit 16 via the duplexer 17.

As described above, the transmission / reception signal by the first signal system and the transmission / reception signal by the second signal system are signals transmitted and received in different use frequency bands.
On the other hand, the plurality of antenna elements 9 are configured to be able to transmit and receive the transmission / reception signals of the first signal system and the second signal system, respectively.
That is, the plurality of antenna elements 9 are configured by using multi-frequency antenna elements that can transmit and receive signals in a plurality of frequency bands.

[Configuration of antenna element]
3 is a perspective view of the antenna element 9, FIG. 4 is a side view of the antenna element 9, and FIG. 5 is a front view of the antenna element 9.

The antenna element 9 includes a main body 30 having a plurality of radiating elements 31, 32, 33, a coaxial power supply line 40 that supplies power to a power supply point 35 of the main body 30, and a pair of first elements provided on the front side of the main body 30. 1 parasitic element 60.
This antenna element 9 is for vertical polarization, but can also be used for horizontal polarization.
In the present embodiment, in the Z-axis direction to be described later, the positive direction (upper side in FIG. 4) is referred to as “front side”, and the negative direction (lower side in FIG. 4) is referred to as “rear side”.

In addition, on the back side facing the rear side of the antenna element 9, a reflector 50 is disposed opposite to the back side of the antenna element 9.
The reflection plate 50 includes a main reflection plate 50a and a sub reflection plate 50b provided on the front side of both side edges of the main reflection plate 50a.
The coaxial feeder 40 is made of a coaxial cable, and has an inner conductor (not shown) and an outer conductor covering the outer periphery thereof. The coaxial power supply line 40 is disposed so as to reach the power supply point 35 from the reflection plate 50, and connects the duplexer 17 and the antenna element 9. The coaxial feed line 40 flows in a state where signals from the first signal system and signals from the second signal system, which are signals having different frequency bands, are mixed.
As shown in FIG. 3, in this specification, the direction in which the coaxial power supply line 40 extends is the Z-axis direction, the direction along the sub-reflection plate 50b is the X-axis direction, and both the X-axis direction and the Z-axis direction are The direction orthogonal to the Y-axis direction.

The plurality of radiating elements 31, 32, and 33 are configured to resonate at four frequencies of 0.7 GHz, 0.8 GHz, 1.5 GHz, and 2.0 GHz and radiate radio waves having those frequencies.
Among them, the second and third radiating elements 32 and 33 are arranged on the inner side of the first radiating element 31 and resonate at 1.5 GHz band and 2.0 GHz band, which are high frequencies, respectively. . Further, the first radiating element 31 is configured to resonate by itself at the other two low frequencies (0.7 GHz band and 0.8 GHz band).
Thus, the antenna element 9 is configured as a multi-frequency shared antenna element that can be used in four frequency bands of 0.7 GHz, 0.8 GHz, 1.5 GHz, and 2.0 GHz.

  Each of the radiating elements 31, 32, and 33 is electrically connected to the inner conductor of the coaxial feed line 40 and is not electrically connected to the outer conductor of the coaxial feed line 40. The second antenna portions 112, 122, and 132 are electrically connected to the outer conductor of the coaxial feeder 40 and are not electrically connected to the inner conductor of the coaxial feeder 40. The first antenna units 111, 121, and 131 and the corresponding second antenna units 112, 122, and 132 are aligned with each other in the polarization direction (X-axis direction in the present embodiment) with the feeding point 35 interposed therebetween. They are arranged and formed symmetrical to each other.

As shown in FIGS. 4 and 5, the radiating elements 31, 32 and 33 constituting the main body 30 are formed on a planar substrate 30 a. The first antenna portions 111, 121, 131 of the radiating elements 31, 32, 33 are formed on the front surface 30a1 of the substrate 30a, and the second antenna portions 112, 122, 132 are formed on the back surface 30a2 of the substrate 30a. .
The back surface 30a2 of the substrate 30a is a connection surface to which the coaxial feeder 40 is connected.
Further, the inner conductor of the coaxial feeder 40 penetrates the substrate 30a in the thickness direction and is electrically connected to the first antenna portions 111, 121, 131 on the front surface 30a1.

  The substrate 30a is supported at a predetermined interval from the reflection plate 50 by a support portion 70 attached to the reflection plate 50. In FIG. 3, the substrate 30a and the support portion 70 are omitted.

As shown in FIG. 5, among the plurality of radiating elements 31, 32, 33, the first antenna unit 111 of the first radiating element 31 corresponding to a low frequency (0.7 GHz band and 0.8 GHz band) Consists of a pair of dipole elements bent so as to approach each other.
The second antenna portion 112 of the first radiating element 31 is formed symmetrically with the first antenna portion 111 with the center line C interposed therebetween. That is, the second antenna unit 112 includes a pair of dipole elements.

A pair of lines 36 that connect the feeding point 35 and the first antenna units 111, 121, and 131 are provided on the front surface 30 a 1 of the main body 30.
In addition, a pair of lines 37 that connect the feeding point 35 and the second antenna portions 112, 122, 132 are provided on the back surface 30 a 2 of the main body portion 30.

  Of the plurality of radiating elements 31, 32, 33, the first and second antenna portions 121, 122 of the second radiating element 32 corresponding to the frequency of 1.5 GHz band are bent so that the tips thereof are close to each other. Dipole element. The first and second antenna portions 121 and 122 are formed symmetrically with respect to each other with the virtual line K in between.

  Among the plurality of radiating elements 31, 32, 33, the first antenna portion 131 of the third radiating element 33 corresponding to the highest frequency (2.0 GHz band) is a pair of dipoles whose ends are bent so as to approach each other. It consists of elements. The pair of dipole elements 131 are formed in line symmetry with respect to the virtual line K.

  The second antenna portion 132 of the third radiating element 33 is formed symmetrically with the first antenna portion 131 with the center line C interposed therebetween. That is, the second antenna unit 132 includes a pair of dipole elements.

As shown in FIGS. 4 and 5, the pair of first parasitic elements 60 provided on the front side of the main body 30 straddle the center line C, and the first and second antenna parts 121 of the second radiating element 32. , 122 are arranged so as to cover the respective straight portions 121b, 122b.
The first parasitic element 60 is formed on a substrate 61 as shown in FIG. The substrate 61 is supported at a predetermined interval from the substrate 30a by a support portion 62 attached to the front surface 30a1 of the substrate 30a on which the main body portion 30 is formed.

  Further, on the front surface 30a1 of the substrate 30a, a pair of second parasitic elements 65 are respectively disposed outside the antenna units 111 and 112 of the first radiating element 31. The pair of second parasitic elements 65 are arranged symmetrically with respect to each other in a direction orthogonal to the polarization direction across the feeding point 35. Each second parasitic element 65 is disposed outside the straight portions 111b and 112b of the antenna portions 111 and 112 at a predetermined interval, and extends in the polarization direction across the center line C.

As described above, the antenna element 9 of the present embodiment is a multi-frequency antenna that can transmit and receive signals in a plurality of frequency bands of four frequencies of 0.7 GHz, 0.8 GHz, 1.5 GHz, and 2.0 GHz. It is configured as an element.
Therefore, for example, the use frequency band used when wirelessly transmitting / receiving the transmission / reception signal by the first signal system is 0.7 GHz, and the use frequency band used when wirelessly transmitting / receiving the transmission / reception signal by the second signal system is 2. Suppose that it is 0 GHz.
In this case, the antenna element 9 of the present embodiment can transmit / receive the transmission / reception signals of the first signal system and the second signal system.

[Effect]
In a wireless communication system such as a cellular phone system, for example, when a new service is started by adopting an active antenna system or the like, it may be necessary to continue providing an existing service to a user.

  Here, in order to continue the existing service, it is conceivable to leave the existing antenna system as it is and install a newly installed active antenna system at a position different from the existing antenna system. However, the antenna system is relatively large and it is difficult to secure an installation location. Furthermore, even if the installation location can be secured, it may not be appropriate as the installation location of the antenna system.

  In addition, it may be possible to install an active antenna system at the same position as the existing antenna system (same steel tower as the existing antenna system), but many antenna systems have already been installed due to system expansion etc. In some cases, it may be difficult to additionally install a new antenna system.

  Therefore, it is conceivable to install an antenna system having both the function of the existing antenna system and the function of the active antenna system in place of the existing antenna system. If such an antenna system is used, a new service can be started while continuing an existing service.

However, even in this case, the antenna system itself may be increased in size by providing both the function of the existing antenna system and the function of the active antenna system.
For this reason, the newly installed antenna system needs to be more compact so that it can be installed in as little space as possible even if it has both the functions of the existing antenna system and the function of the active antenna system. Is done.

In this regard, according to the antenna system 4 having the above-described configuration, the plurality of antenna elements 9 are configured to be able to transmit and receive the transmission / reception signals of the first signal system and the second signal system, respectively. The number of antenna elements can be reduced as compared with the case where the elements are provided, and as a result, the size can be reduced.
Further, according to the antenna system 4, the plurality of antenna elements 9 are configured to be able to transmit and receive the transmission / reception signals of the first signal system and the second signal system, respectively. Transmission / reception of transmission / reception signals becomes possible. For this reason, if the present antenna system 4 is installed in place of the existing antenna system and the transmission / reception signal processing by the existing antenna system 4 is assigned to the second signal system, the provision of service by the existing antenna system is maintained. be able to. Furthermore, in the first signal system, a plurality of antenna elements 9 can function as active antennas, and new functions and services can be added.
As described above, according to the present antenna system, even if both the function of an existing antenna system and the function of a newly added antenna system are provided, it is possible to reduce the size.

  Further, since the antenna system 4 according to the above embodiment includes the duplexer 17 that connects the antenna element 9 to the transmission / reception processing unit 15 and the distribution / combination circuit 16 in a shared manner, the transmission / reception processing unit 15 of the first signal system is provided. Allows the plurality of antenna elements 9 to be connected between the first signal system and the second signal system while allowing processing (amplification of transmission / reception signals, etc.) to cause the plurality of antenna elements 9 to function as active antennas. Can be shared.

  In the antenna system 4 according to the above-described embodiment, the distribution / combination circuit 16 is provided as a second processing circuit that performs transmission / reception signal processing by the second signal system. Therefore, in the second signal system, a plurality of antenna elements 9 are provided. It can be used as a passive antenna. For example, when an RRH and a passive antenna connected to the RRH are already installed as an existing antenna system, and the antenna system 4 is installed instead of this, the existing RRH is also installed. And the distribution / combination circuit 16 can be used to maintain the function of the existing antenna system using the second signal system while adding the function as a new antenna system such as an active antenna by the first signal system. it can.

In the antenna system 4 according to the above-described embodiment, the distribution / combination circuit 16 is a signal processing device installed outside the antenna system 4, and performs the amplification and signal processing of transmission / reception signals by the second signal system. Signals can be exchanged with the remote radio head 6.
Accordingly, the antenna system 4 includes a connection connector 8a for connecting a coaxial cable 8 which is a signal line for transmitting and receiving signals to and from the remote radio head 6. This facilitates the connection between the antenna system 4 and the remote radio head 6.

[About the layout of each part of the antenna system]
FIG. 6 is a cross-sectional view of the antenna system 4. FIG. 7 is an exploded perspective view showing a main part of the antenna system 4. 6 and 7 show an example of an arrangement configuration when each part of the antenna system 4 is actually arranged in the housing 4a.

As shown in FIG. 6, each part of the antenna system 4 is accommodated in the housing 4a.
The casing 4a is formed in a rectangular parallelepiped shape, and the antenna elements 9 are arranged in a line in the vertical direction inside the casing 4a.

The housing 4 a includes a main body portion 23, a radome 24, and a lid portion 25.
A front opening 23 a is formed on the front side of the main body 23. Further, a back opening 23 b is formed on the back side of the main body 23. Therefore, the main body 23 is formed in a rectangular tube shape.
The antenna element 9 is disposed so that the front surface 30a1 of the substrate 30a faces the outside through the front opening 23a. Thereby, the antenna element 9 transmits and receives signals through the front opening 23a.
The radome 24 is a plate-like member fixed to the main body 23 so as to block the front opening 23a, and protects the antenna element 9 from the external environment.

The lid part 25 is fixed to the main body part 23 so as to close the back opening 23b. The lid portion 25 is a plate-like member formed using, for example, an aluminum alloy or the like, and heat radiating fins 26 are formed on the outer surface 25a facing the outside of the housing 4a.
In the lid portion 25, the transmitting / receiving portion 21 is arranged in a line in the vertical direction on the inner surface 25b facing the inside of the housing 4a.

As described above, the transmission / reception unit 21 has a function of performing processing related to an analog signal, such as amplifying the analog signal. For this reason, the transmission / reception unit 21 includes a device that generates heat, such as a power amplifier.
The transmission / reception unit 21 is fixed in a state where the heat generation portion is in contact with the lid portion 25 formed using an aluminum alloy or the like, and the generated heat can be exhausted toward the lid portion 25.
That is, the lid portion 25 has a function as a heat sink that takes away the heat generated by the transmission / reception unit 21 and radiates it from the radiation fins 26.

Inside the housing 4 a, a reflecting plate 50 disposed on the back surface of the antenna element 9 (the back surface 30 a 2 of the substrate 30 a) is fixed to the inner wall surface 23 c of the main body 23.
The reflecting plate 50 is fixed to the main body 23 in a state where the upper, lower, left and right end faces of the main reflecting plate 50a are abutted against the inner wall surface 23c. At this time, the sub-reflecting plate 50b of the reflecting plate 50 is also fixed to the main body portion 23 in a state of being in contact with the inner wall surface 23c.
The reflecting plate 50 is compared with the case where only the main reflecting plate 50a is fixed to the main body portion 23 by fixing the sub reflecting plate 50b fixed to the main reflecting plate 50a to the main body portion 23 in addition to the main reflecting plate 50a. And it is fixed more firmly.
Thus, in addition to the function as a reflecting plate, the sub-reflecting plate 50 b also has a function as a reinforcing member for more firmly fixing the reflecting plate 50 to the main body portion 23.

The reflection plate 50 is disposed so as to divide the internal space of the housing 4a into two parts.
In the space on the front surface 51 side of the reflecting plate 50, the antenna elements 9 are arranged so as to face the front opening 23a.
On the other hand, in the space on the back surface 52 side of the reflection plate 50, the duplexer 17 and the distribution / synthesis circuit 16 are disposed in addition to the transmission / reception unit 21 fixed to the lid 25.
The duplexers 17 are arranged in a line in the vertical direction in the space between the reflecting plate 50 and the transmission / reception unit 21 fixed to the lid 25. Similarly to the duplexer 17, the distribution / synthesis circuit 16 is also disposed in the space between the reflector 50 and the transmission / reception unit 21.
The duplexer 17 and the distribution / combination circuit 16 are fixed to the inner surface 25b of the lid 25 or the rear surface 52 of the reflecting plate 50 by a bracket (not shown) or the like.

  The digital signal processing unit 20 that constitutes the transmission / reception processing unit 15 together with the transmission / reception unit 21 is omitted in FIGS. 6 and 7, but similar to the duplexer 17 and the distribution / synthesis circuit 16, In the space between the transmitter / receiver 21 and the transmitter / receiver 21.

  In addition, the transmission / reception unit 21, the duplexer 17, and the distribution / combination circuit 16 are arranged so that the transmission / reception unit 21, the duplexer 17, and the distribution / synthesis circuit 16 are located inside the edge of the reflection plate 50 when the reflection plate 50 is viewed from the front. Arranged to fit.

  In the present embodiment, since the number of antenna elements can be reduced as compared to the case where both systems have dedicated antenna elements, the area of the reflector 50 is also provided with dedicated antenna elements for both systems. Compared to the case, it can be made smaller. By arranging the transmission / reception processing unit 15 (the digital signal processing unit 20 and the transmission / reception unit 21) and the distribution / combination circuit 16 on the back surface 52 side of the reflector 50 having a relatively small area, the antenna system 4 as a whole is arranged. It can be further downsized.

[Others]
The present invention is not limited to the above embodiment.
In the antenna system 4 of the above embodiment, the plurality of antenna elements 9 function as active antennas for signal transmission / reception by the first signal system, and the plurality of antenna elements 9 are passive for signal transmission / reception by the second signal system. Although the case of functioning as an antenna is illustrated, a transmission / reception processing unit capable of performing a process of causing a plurality of antenna elements 9 to function as active antennas for transmission / reception signals by the second signal system instead of the distribution / synthesis circuit 16 By providing this, the transmission / reception of signals by the second signal system may also function as an active antenna.
In this case, a plurality of antenna elements 9 can function as active antennas in both systems.

  Moreover, in the antenna system 4 of the said embodiment, although the case where each signal was transmitted / received by two signal systems like a 1st signal system and a 2nd signal system was illustrated, each signal by three or more signal systems You may comprise so that transmission / reception may be performed.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the meanings described above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 Base station apparatus 2 1st baseband unit 3 2nd baseband unit 4 Active antenna system 4a Case 5a Connection connector 5 Signal transmission path 6 Remote radio head (signal processing part)
7 Signal transmission line 8 Coaxial cable 8a Connector (connection terminal)
9 Antenna element 15 Transmission / reception processor (first processing circuit)
16 Distribution / synthesis circuit (second processing circuit)
17 Duplexer (shared antenna)
20 Digital Signal Processing Unit 21 Transmission / Reception Unit 23 Main Body 23a Front Opening 23b Rear Opening 23c Inner Wall 24 Radome 25 Lid 25a Outer 25b Inner Surface 26 Heat Dissipation Fin 30 Main Body 30a Substrate 30a1 Front 30a2 Rear 31 First Radiation Element 32 Second Radiation Element 33 Third radiating element 35 Feed point 36 Line 37 Line 40 Coaxial feed line 50 Reflector 50a Main reflector 50b Sub-reflector 51 Front face 52 Rear face 60 First parasitic element 61 Substrate 62 Support section 65 Second parasitic element 70 Support portion 111, 121, 131 First antenna portion 111 First antenna portion 111b, 112b Straight portion 112, 122, 132 Second antenna portion 121b, 122b Straight portion 131 First antenna portion 131 Dipole element 132 Second antenna portion

Claims (7)

A plurality of antenna elements;
A first processing circuit that performs a process of causing the plurality of antenna elements to function as an active antenna with respect to a transmission / reception signal transmitted / received by a first signal system for transmitting / receiving using the plurality of antenna elements;
A second processing circuit that performs processing on a transmission / reception signal transmitted and received by a second signal system having a different frequency band from the first signal system;
The plurality of antenna elements are configured to be able to transmit and receive transmission / reception signals of the first signal system and the second signal system, and the antenna elements can be shared by the first signal system and the second signal system. An antenna system connected to the first processing circuit and the second processing circuit.   2. The antenna sharing unit according to claim 1, further comprising: an antenna sharing unit that is provided in each of the plurality of antenna elements and connects the plurality of antenna elements to the first processing circuit and the second processing circuit so as to be shared. Antenna system.   The antenna system according to claim 1, wherein the second processing circuit distributes and combines transmission / reception signals by the second signal system. The second processing circuit is a signal processing device installed outside the antenna system, and can exchange signals with the signal processing device that performs amplification and signal processing of transmission / reception signals by the second signal system. And
The antenna system according to claim 3, further comprising a connection terminal for connecting a signal line for transmitting / receiving a signal to / from the signal processing device. Further comprising a reflector disposed on the back surface of the antenna element;
The antenna system according to any one of claims 1 to 4, wherein the first processing circuit and the second processing circuit are disposed on a back side of the reflector.   The first processing circuit and the second processing circuit are arranged such that the first processing circuit and the second processing circuit are arranged on an inner side of an edge of the reflecting plate when the reflecting plate is viewed from the front. 6. The antenna system according to 5.   2. The antenna system according to claim 1, wherein the second processing circuit performs a process of causing the plurality of antenna elements to function as active antennas with respect to a transmission / reception signal by the second signal system.

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