Abstract:
The present invention relates to a base station antenna for mobile communication, the antenna, equipped with vertically arranged radiating elements and connected to a base station system, comprising: a reflective plate disposed in the interior of the antenna; a plurality of radiating elements disposed on the planar surface of the reflective plate; and a moving unit for moving the plurality of radiating elements vertically within the range of the planar surface of the reflective plate.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of International Application No. PCT/KR2014/001809 filed on Mar. 5, 2014, which claims priority to Korean Application No. 10-2013-0024044 filed on Mar. 6, 2013, which applications are incorporated herein by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates to a base station antenna for mobile communication and, more specifically, to an antenna equipped with vertically arranged radiating elements that can adjust the vertical arrangement of the radiating elements thereof 
       BACKGROUND ART 
       [0003]    In recent years, mobile communication service providers have provided a multi-service band to mobile communication subscribers, and, accordingly, broadband antennas that have a wide frequency range have been required in mobile communication antenna markets. 
         [0004]    Conventional broadband antennas developed in response to the requirement have been designed to operate in a broad band. However, radiating elements thereof are vertically arranged at moderate intervals rather than optimal intervals so that the radiating elements fail to optimally operate in actual frequencies. 
         [0005]    For example, since all code division multiple access (CDMA) types of base stations use the same frequency assignment (FA), optimization to adjust at least four or five base stations on a cluster basis is consistently required to reduce inter-cell pseudo-noise (PN) interference. 
         [0006]    Although the gain of an antenna increases by about 3 dB (twice) in the same structure as a frequency band used for mobile communication rises from 800 MHz to 2 GHz, free space loss decreases by about 8 dB so that the service coverage is substantially reduced to about half. 
         [0007]    Further, antenna optimization technology is required in order to solve the problem of increasing loss, such as a decrease in a diffraction property, air, rainfall, forest, etc. 
         [0008]    Accordingly, in order to solve the aforementioned problems, a technology is required in which a broadband antenna receives information on a frequency environment of the installation area thereof from a base station and adjusts the vertical arrangement of radiating elements thereof by itself in order to achieve optimal antenna performance in the installed frequency environment. 
         [0009]    (Patent Document 1) Korean Patent Application No. 10-2003-0027727 (filed on Apr. 30, 2003 and entitled “Antenna system for controlling horizontal beam and vertical beam of antenna radiation pattern and control method for antenna system using same”; inventors Hyo-Jin Lee and Sang-Gi Kim; applicants LG Telecom, Ltd. and Gamma Nu, Inc.) 
       SUMMARY 
       [0010]    An aspect of the present invention is to provide an antenna equipped with vertically arranged radiating elements that can control the vertical arrangement of the radiating elements thereof. 
         [0011]    Another aspect of the present invention is to provide an antenna equipped with vertically arranged radiating elements that can group the radiating elements on a column basis and uniformly control the vertical arrangement of the radiating elements thereof. 
         [0012]    Another aspect of the present invention is to provide an antenna equipped with vertically arranged radiating elements that can individually control the radiating elements in the control of the vertical arrangement of the radiating elements thereof. 
         [0013]    In accordance with one aspect of the present invention, an antenna equipped with vertically arranged radiating elements, which is connected to a base station system, includes: a reflective plate installed in the interior of the antenna; a plurality of radiating elements installed on a planar surface of the reflective plate; and a moving unit that moves the plurality of radiating elements upwards or downwards on the planar surface of the reflective plate. 
         [0014]    The antenna may further include: an antenna state detector that detects the state of the connection with the base station system and the operating state of the antenna and creates antenna information; a radio frequency signal detector that measures the strength of a radio frequency signal currently being provided in the area where the antenna has been installed, and creates radio frequency signal information and frequency band information; a controller that creates interval control information; and an interval adjustment driving unit that adjusts the vertical intervals between the plurality of radiating elements according to the interval control information. 
         [0015]    The interval control information may be created using service band information received from the base station system or the frequency band information. 
         [0016]    Based on at least one of the plurality of radiating elements, the moving unit may move the remaining radiating elements upwards or downwards. 
         [0017]    The base station antenna may move the plurality of radiating elements upwards or downwards with respect to the longitudinal center of the reflective plate. 
         [0018]    Among the plurality of radiating elements, the radiating elements other than the uppermost or lowermost radiating element may be moved upwards or downwards. 
         [0019]    Two or more of the plurality of radiating elements may be simultaneously moved upwards or downwards, or the radiating elements may be individually moved upwards or downwards. 
         [0020]    The antenna equipped with vertically arranged radiating elements, according to the embodiment of the present invention, can control the vertical arrangement of the radiating elements thereof in order to adjust side-lobe among beam characteristics of the antenna, thereby achieving beam efficiency for minimizing interference between a macro base station and small base stations that are intermingled with each other. 
         [0021]    Furthermore, even if a frequency environment around the area where the antenna has been installed changes, the antenna can adapt to the changed frequency environment in order to achieve an optimal performance by controlling the vertical arrangement of the radiating elements thereof. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]      FIG. 1  is a block diagram of an antenna that includes vertically arranged radiating elements according to an embodiment of the present invention; 
           [0023]      FIG. 2  is a schematic diagram illustrating an exemplary structure of a moving unit of an antenna that includes vertically arranged radiating elements, according to an embodiment of the present invention; and 
           [0024]      FIG. 3  is a schematic diagram illustrating an exemplary operation of the antenna that includes the vertically arranged radiating elements, according to an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0025]    Hereinafter, an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings. Although particular matters such as specific configuration elements are shown in the following description, it will be obvious to those skilled in the art to which the present invention pertains that the particular matters are provided only to help a comprehensive understanding of the present invention, and various modifications and changes can be made within the scope of the present invention. 
         [0026]    Further, in the accompanying drawings and the following description, identical elements are provided with the same reference numeral where possible. 
         [0027]      FIG. 1  is a block diagram of an antenna that includes vertically arranged radiating elements according to an embodiment of the present invention. 
         [0028]    The antenna that includes the vertically arranged radiating elements, according to the embodiment of the present invention, is a base station antenna  20  connected to a base station system  10  equipped with broadband communication devices. 
         [0029]    The base station system  10  refers to a wireless communication base station of a mobile communication service provider, and may be equipped with various bands of communication devices. Here, examples of the various bands include the 800 MHz band or the 900 MHz band (e.g., 698 to 960 MHz) which is a relatively low frequency band, or the 1.8 MHz band or the 2.1 GHz band (e.g., 1.7 to 2.17 GHz) or the 2.3 GHz band (e.g., 2.3 to 2.7 GHz) which is a relatively high frequency band. 
         [0030]    The base station system  10  provides information on a service band of an area where the base station antenna  20  has been installed to a controller  220  included in the base station antenna  20 , which will be described below. 
         [0031]    The base station system  10  receives, from the base station antenna  20 , antenna status information that contains information necessary for identifying whether the base station antenna  20  has been normally connected with the base station system  10  through a wired line, a wireless line, or a combination of wired and wireless lines. 
         [0032]    The base station system  10  may receive, from the base station antenna  20 , antenna status information containing information necessary for identifying whether the normally connected base station antenna  20  normally operates as a service band corresponding to a service area in the installation area thereof. 
         [0033]    The base station antenna  20  is a broadband antenna and is always connected with the base station system  10  through a wired line, a wireless line, or a combination of wired and wireless lines. 
         [0034]    The base station antenna  20  receives service band information of the installation area thereof from the base station system  10 . 
         [0035]    In cases where the base station antenna  20  fails to receive the service band information of the installation area thereof from the base station system  10 , the base station antenna  20  acquires the service band information of the current installation area thereof by itself through a radio frequency (RF) signal detector  212  included in a detection unit  210 , which will be described below. 
         [0036]    The base station antenna  20  includes the detection unit  210  for detecting the state of the antenna, the controller  220  for controlling the antenna to operate at optimal performance, and an interval adjustment driving unit  230  for adjusting intervals between the plurality of radiating elements that are vertically arranged in the broadband antenna. 
         [0037]    The detection unit  210  includes an antenna state detector  211  and the radio frequency signal detector  212 . 
         [0038]    The antenna state detector  211  performs functions of detecting the overall connection state and operating state of the base station antenna  20  and transferring the detection results to the controller  20 . Here, the functions of detecting the connection state and the operating state may be defined as follows. 
         [0039]    The function of detecting the connection state means a function of detecting whether the base station antenna  20  and the base station system  10  have been normally connected to each other and providing the corresponding information to the controller  220 , which will be described below. 
         [0040]    The function of detecting the operating state means a function of detecting whether the elements constituting the base station antenna  20  operate normally and providing the corresponding information to the controller  220 , which will be described below. 
         [0041]    The radio frequency signal detector  212  detects service band information currently being provided in the area where the base station antenna  20  has been installed and provides the detected information to the controller  220  which will be described below. 
         [0042]    The base station antenna  20  measures a radio frequency (RF) signal in a service band currently being used, and provides the measured RF signal strength to the controller  220 . 
         [0043]    The controller  220  processes various types of information in order to provide a service at an optimal performance in the service band corresponding to the area where the base station antenna  20  has been installed. 
         [0044]    In order to provide a service at optimal performance, the controller  220  receives information on the service band corresponding to the installation area from the base station system  10 , and provides optimized interval adjustment control information to the interval adjustment driving unit  230  in the corresponding service band extracted from the received information. 
         [0045]    In cases where the controller  220  fails to receive the information on the service band from the base station system  10 , the controller  220  makes a request for information on a service band in which a service is currently provided through the base station antenna  20  to the radio frequency signal detector  212  included in the detection unit  210  to receive the information, and calculates optimized interval adjustment control information for the corresponding service band from the received information to provide the calculated information to the interval adjustment driving unit  230 . 
         [0046]    The interval adjustment driving unit  230  adjusts the intervals between the plurality of radiating elements, which are vertically arranged in the broadband antenna, according to the interval adjustment control information received from the controller  220 . 
         [0047]      FIG. 2  is a schematic diagram illustrating an exemplary structure of a moving unit of an antenna that includes vertically arranged radiating elements, according to an embodiment of the present invention, and  FIG. 3  is a schematic diagram illustrating an exemplary operation of the antenna that includes the vertically arranged radiating elements, according to an embodiment of the present invention. 
         [0048]    Referring to  FIG. 2 , the moving unit  30  includes a reflective plate  340 , a plurality of radiating elements  310  ( 310   a ,  310   b ,  310   c ,  310   d , and  310   e ) vertically arranged on the reflective plate  340 , moving support parts  320  ( 320   a ,  320   b ,  320   d , and  320   e ) on opposite sides (e.g., the left and right sides) of the radiating elements  310   a ,  310   b ,  310   d , and  310   e  other than the radiating element  310   c  which functions as a reference for the adjustment of intervals, a power generation unit  330  (e.g., a motor) for providing power for the adjustment of the intervals, and an interval adjustment driving unit  230  for controlling the power generation unit  330  according to interval adjustment control information. 
         [0049]    The moving support parts  320  make the plurality of radiating elements  310  easily move in the vertical direction, and secure the plurality of radiating elements  310  to the reflective plate  340  when the intervals between the radiating elements are completely adjusted. 
         [0050]    The power generation unit  330  is connected to the plurality of radiating elements  310  or the moving support parts  320  through a rack and pinion gear, a link structure, various gear connection structures, a guide and slide structure, etc. in order to provide power for interval adjustment. 
         [0051]    The interval adjustment driving unit  230  adjusts the intervals between the plurality of radiating elements  310 , which are installed in the vertical array on the reflective plate  340  of the broadband antenna, according to interval adjustment control information. 
         [0052]    Here, as illustrated in  FIG. 2 , the intervals between the radiating elements  310  may increase, or may alternatively decrease. 
         [0053]    When the intervals are adjusted, one of the plurality of radiating elements  310  is selected to be a reference, and the intervals between the radiating elements  310  may be adjusted by moving the radiating elements other than the reference up and down. 
         [0054]    Referring to  FIG. 3 , when the intervals between the radiating elements are adjusted, the radiating element  310   c  installed in the center of the reflective plate  340  is selected to be a reference, and the remainder is categorized into the radiating elements  310   a  and  310   b  above the radiating element  310   c  and the radiating elements  310   d  and  310   e  below the radiating element  310   c . For example, in cases where the intervals between the radiating elements  310  increase, the radiating elements  310   a  and  310   b  above the radiating element  310   c , which is installed in the center of the reflective plate  340 , are moved upwards, and the radiating elements  310   d  and  310   e  below the radiating element  310   c  are moved downwards. Here, it can be identified that the intervals  1   a ′,  1   b ′,  1   c ′, and  1   d ′ between the radiating elements after the interval adjustment are greater than the intervals  1   a ,  1   b ,  1   c , and  1   d  between the radiating elements before the interval adjustment. 
         [0055]    In contrast, in cases where the intervals between the radiating elements  310  decrease, the radiating elements  310   a  and  310   b  above the radiating element  310   c , which is installed in the center of the reflective plate  340 , are moved downwards, and the radiating elements  310   d  and  310   e  below the radiating element  310   c  are moved upwards. 
         [0056]    Although the plurality of radiating elements  310  are arranged to be perpendicular to the horizontal plane with respect to the longitudinal center of the reflective plate  340  in  FIGS. 2 and 3 , the present invention is not limited thereto, and even if the plurality of radiating elements  310  are vertically arranged in any place of the reflective plate  340 , the intervals between the radiating elements  310  may be adjusted while one of the plurality of radiating elements  310  is selected to be a reference. For example, in cases where the intervals between the radiating elements  310  increase with respect to the uppermost radiating element  310   a  among the radiating elements  310  installed on the reflective plate  340 , the intervals between the radiating elements  310  may be increased by moving the radiating elements  310   b ,  310   c ,  310   d , and  310   e  other than the reference radiating element  310   a  downwards (toward the ground). In contrast, in cases where the intervals between the radiating elements  310  are decreased with respect to the radiating element  310   a , the intervals between the radiating elements  310  may be decreased by moving the radiating elements  310   b ,  310   c ,  310   d , and  310   e  other than the reference radiating element  310   a  upwards. 
         [0057]    Furthermore, in cases where the intervals between the radiating elements  310  are increased with respect to the lowermost radiating element  310   e  among the radiating elements  310  installed on the reflective plate  340 , the intervals between the radiating elements  310  may be increased by moving the radiating elements  310   a ,  310   b ,  310   c , and  310   d  other than the reference radiating element  310   e  upwards. In contrast, in cases where the intervals between the radiating elements  310  are decreased with respect to the radiating element  310   e , the intervals between the radiating elements  310  may be decreased by moving the radiating elements  310   a ,  310   b ,  310   c , and  310   d  other than the reference radiating element  310   e  downwards. 
         [0058]    Also, the intervals between the radiating elements  310  may be adjusted by moving the radiating elements above a reference radiating element and the radiating elements below the reference radiating element upwards or downwards with respect to a vertical line on the reflective plate  340  in addition to the longitudinal center of the reflective plate  340 . That is, the reference is not limited to the longitudinal center of the reflective plate. 
         [0059]    Although the plurality of radiating elements  310 , which are vertically arranged, are all controlled at one time in the above described method of adjusting the intervals between the radiating elements, the present invention is not limited thereto, and the intervals between the radiating elements may be adjusted by individually controlling the radiating elements, or by selecting one or more of the plurality of radiating elements  310  and then simultaneously moving the selected radiating elements upwards or downwards. This is because each radiating element can be accurately controlled according to a selection of the base station system or the controller included in the base station antenna after the intervals between the radiating elements are uniformly adjusted. 
         [0060]    Through the interval adjustment described above, the broadband antenna can achieve the best performance in a frequency band currently being used in the area where the broadband antenna has been installed. This is because the broadband antenna can achieve performance specialized for service frequencies in a specific band as the intervals between the plurality of radiating elements  310  installed in the vertical array form in the broadband antenna are increased or decreased. 
         [0061]    As a result, among the beam characteristics of the broadband antenna that includes the vertically arranged radiating elements, according to the present invention, side-lobe is controlled through the adjustment of the intervals between the radiating elements  310 . 
         [0062]    Although a broadband antenna, according to the related art, cannot provide an optimal service in an area having a frequency environment in which a macro base station and small base stations are intermingled with each other, the antenna that includes the vertically arranged radiating elements, according to the present invention, can enhance beam efficiency of the broadband antenna while minimizing interference between the base stations even if being installed in the area having the above-described frequency environment. 
         [0063]    In addition, the present invention can also be applied to inter-cell interference coordination (ICIC) technology. 
         [0064]    Although the present disclosure has been described with reference to the embodiments shown in the drawings, it should be understood by those skilled in the art that various changes and modifications may be made thereto and other embodiments equivalent thereto are possible. Accordingly, the scope of the present disclosure is not limited to the above-described embodiments and should be determined by the appended claims and their equivalents.