Abstract:
This invention relates to a board-shaped wideband dual polarization antenna whose feeding structure is simplified. Dipole antennas are prepared on both front and rear surfaces of a printed circuit board, and an electric signal is fed to the dipole antennas through via holes at the same time. Through the dipole antennas, the dual polarization antenna radiates dual polarized waves whose radiation emissions have perpendicular directions to each other. The wideband characteristics of the dual polarization antenna are improved through parasitic elements. The disclosed printed circuit board comprises: a first line hole into which a first core line (+) of a first electric cable transmitting a first electric signal is inserted; a first ground via hole through which a first ground line (−) of the first electric cable passes; a first balun hole into which a first balun cable is inserted; a second line hole into which a second core line (+) of a second electric line is inserted; is second balun hole into which a second balun cable is inserted; and a connection via-hole through which both the second core line (+) and the second balun cable pass. The first and second balun cables make a pair with the first and second electric cables respectively by being parallel to those electric cables respectively in order so perform the function of a balun. According to the invention, the dual polarization antenna is able to radiate, through the dipole antennas on both surfaces of the printed circuit boards, dual polarized waves whose radiation emissions have perpendicular directions to each other. In addition, the feeding structure can be simplified and a complex three-dimensional air-bridge structure does not need to be used in the dual polarization antenna since an electric signal is fed to the dipole antennas on both surfaces of the printed circuit board at the same time.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a board-type wideband dual polarization dipole antenna used in a base station and a repeater of a mobile communication system or a wireless communication system. 
         [0003]    2. Description of the Related Art 
         [0004]    In general, a dual polarization antenna as an antenna having two polarized waves of an inclined angle in comparison with a general antenna having a single polarized wave such as a vertical polarized wave or a horizontal polarized wave is used as an antenna for implementing the duplication of a reception path of a base station in a mobile communication system. 
         [0005]    The dual polarization antenna is used as an alternative for preventing communication deterioration by a fading phenomenon which is one of the largest causes to deteriorate communication quality instead of the existing spatial diversity antenna. 
         [0006]    In the dual polarization antenna when a horizontal polarization antenna and a vertical polarization antenna are separately installed to separately synthesize signals, an influence of fading can be reduced and the spatial utilization of the dual polarization antenna is higher than the existing spatial diversity antenna and since two different antennas of the spatial diversity antenna can be configured in one antenna, it is possible to significantly save cost. 
         [0007]      FIG. 1  is a plan view illustrating a known dual polarization wideband dipole antenna. 
         [0008]    Referring to  FIG. 1 , the known wideband dipole antenna  100  includes a ground board  101 , a feeding cable  103  and a balun cable  104  which each are mounted on the ground board  101 , a radiator  102  where a plurality of radiation pattern portions  121   a,    121   b,    121   c,  and  121   d  are formed, which is connected with the feeding cable  103  and the balun cable  104 , a radiation pattern portion connected with the feeding cable  103 , an air bridge  123  connecting the radiation pattern portion connected with the balun cable  104 , and a wideband compensation pad  125  which is etched onto the other surface of the radiator  102  to contribute to an increase of a bandwidth. 
         [0009]    The feeding cable  103  and the balun cable  104  are connected with the radiator  102  through the ground board  101  and an outer peripheral surface thereof is soldered to a soldering connector  159  mounted on the ground board  101  to be grounded. The balun cable  104  forms a pair with the feeding cable  103  to implement a balun and the air bridge  123  as a metallic material electrically connects the radiation pattern portions  121   a,    121   b,    121   c,  and  121   d  which are formed on the radiator with the feeding cable  103 . 
         [0010]    The air bridge  123  made of the metallic material electrically connects a core line  131  of the feeding cable  103  to another radiation pattern which is positioned in a direction diagonal to the radiation pattern portion connected to a shell of the feeding cable  103 . In order to prevent direct connection between the air bridge  123  and the radiation pattern portion connected to the shell of the feeding cable  103 , a dielectric  105  exits on a feeding network in a predetermined height or more. 
         [0011]    In the case of the known mobile communication system configured as described above, a radiating element as a metallic instrument is primarily etched on one surface of a planar board and a feeding structure has a 3D structure such as the air bridge  123 . 
         [0012]    Therefore, in the known dipole antenna structures, the feeding structure has a complicated shape through the air bridge and processability, and cost and workability is not good and as the radiation element is etched through one surface of the plane board, one polarized wave is radiated, such that there is a limit in improving wideband characteristics. 
       SUMMARY OF THE INVENTION  
       [0013]    In order to solve the above-mentioned problems, there is an object of the present invention to provide a board-type wideband dual polarization dipole antenna in which dipole antennas are provided on a front surface and a rear surface of a radiation board, electric power is fed to the dipole antennas on the front surface and the rear surface through a via hole, dual polarized waves whose antenna radiation directions are perpendicular (vertical) to each other are radiated through the dipole antennas on the front surface and the rear surface to simplify a feeding structure and improve wideband characteristics through parasite elements. 
         [0014]    In order to achieve the above-mentioned object, an antenna radiation board according to an exemplary embodiment of the present invention includes: a first core line hole for inserting and connecting a first core line (+) of a first feed cable transferring a first feed signal; a first ground via hole for penetratively connecting a first ground line (−) of the first feed cable; a first balun hole for inserting and connecting a first balun cable which forms a pair with the first feed cable in parallel to serve as a balun; a second core line hole for inserting and connecting a second core line (+) of a second feed cable transferring a second feed signal; a second balun hole for inserting and connecting a second balun cable which forms a pair with the second feed cable to serve as the balun; and a core line balun connection via hole for penetratively connecting the second balun cable with the second core line (+). 
         [0015]    Further, in order to achieve the above-mentioned object, in the antenna radiation board according to the exemplary embodiment of the present invention, dipole antennas are provided on a front surface and a rear surface and a feed signal is provided through a via hole of each dipole antenna at the same time. 
         [0016]    At this time, parasite elements for extending a frequency band of each dipole antenna are provided on the front surface and the rear surface. 
         [0017]    Meanwhile, in order to achieve the above-mentioned object, an antenna radiation board according to another embodiment of the present invention includes: a front part with a front dipole antenna radiating a first feed signal; a rear part with a rear dipole antenna radiating a second feed signal; a feeding part providing the first feed signal to the front part and providing the second feed signal to the rear part through a via hole; and a feed line unit transferring the first feed signal from the feeding part to the front dipole antenna and transferring the second feed signal to the rear dipole antenna. 
         [0018]    Further, the feeding part includes: includes a front feeding part receiving the first feed signal and a rear feeding part receiving the second feed signal, and a first core line hole through which a first core line (+) of a first feed cable applying the first feed signal is penetratively connected from the rear feeding part; a first ground via hole to which a first ground line (−) of the first feed cable is penetratively connected from the rear feeding part; a first balun hole into which a first balun cable which forms a pair with the first feed cable to serve as a balun is inserted and connected; a second core line hole into which a second core line (+) of the second feed cable is inserted and connected; a second balun hole into which a second balun cable which forms a pair with the second feed cable to serve as the balun is inserted and connected; and a core line balun connection via hole for connecting the second balun cable with the second core line (+) by penetrating the front feeding part and the rear feeding part. 
         [0019]    Further, the core line balun connection via hole and the second balun hole are connected to each other through a connection pattern, and the second feed signal applied to the second core line hole of the front feeding part by penetrating from the second core line hole of the rear feeding part is transferred to the core line balun connection via hole through the connection pattern and its transferred to the core line balun connection via hole of the rear feeding part by penetrating from the core line balun connection via hole of the front feeding part. 
         [0020]    In addition, in the front feeding part, the first core line hole and the first balun hole are connected to each other through a first printed circuit pattern, and the first feed signal applied to the first core line hole of the front feeding part by penetrating the first core line hole from the rear feeding part is transferred to the first balun hole through the printed circuit pattern. 
         [0021]    Moreover, parasite elements for extending frequency bands of the front dipole antenna and the rear dipole antenna are provided on the front part and the rear part. 
         [0022]    Besides, the front dipole antenna radiates a polarized wave of +45° and the rear dipole antenna radiates a polarized wave of −45°. 
         [0023]    Meanwhile, a board-type dual polarization dipole antenna according to yet another embodiment of the present invention includes: a first feed cable transferring a first feed signal; a fist balun cable which forms a pair with the first feed cable to serve as a balun; a second feed cable transferring the first feed signal and a second feed signal; a second balun cable which forms a pair with the second feed cable to serve as the balun; a support unit fixing and supporting the first feed cable and the first balun cable and the second feed cable and the second balun cable; and a radiation board in which the first feed cable and the first balun cable and the second feed cable and the second balun cable are inserted and connected and dipole antennas are provided on a front part and a rear part to radiate the first feed signal as a first polarized wave through the dipole antenna provided on the front part and radiate the second feed signal as a second polarized wave vertical to the first polarized wave through the dipole antenna provided on the rear part. 
         [0024]    Further, the radiation board includes: a feeding part providing the first feed signal from the first feed cable to the front part and providing the second feed signal from the second feed cable to the rear part; and a feed line unit transferring the first feed signal from the feeding part to the dipole antenna provided on the front part and transferring the second fed signal to the dipole antenna provided on the rear part. 
         [0025]    In addition, the feeding part includes: a first core line hole through which a first core line (+) of the first feed cable is inserted and connected; a first ground via hole to which a first ground line (−) of the first feed cable is penetratively connected; a first balun hole into which a first balun cable which forms a pair with the first feed cable to serve as a balun is inserted and connected; a second core line hole into which a second core line (+) of the second feed cable is inserted and connected; a second balun hole into which a second balun cable which forms a pair with the second feed cable to serve as the balun is inserted and connected; and a core line balun connection via hole for connecting the second balun cable with the second core line (+) by penetrating the front part and the rear part. 
         [0026]    Moreover, on the front part of the radiation board, the first core line hole and the first balun hole are connected to each other through a first printed circuit pattern, the second core line hole and the core line balun connection via hole are connected to each other by a connection pattern, and on the rear part of the radiation board, the core line balun connection vie hole and the second balun hole are connected to each other by a second printed circuit pattern. 
         [0027]    Besides, on the front part, the first feed signal is transferred from the first core line hole to the first balun hole through the first printed circuit pattern and is transferred to the dipole antenna provided on the front part from the first balun hole through the feed line unit. 
         [0028]    Further, on the rear part, the second feed signal penetrates from the second core line hole to be transferred to the second core line hole of the front part, is transferred to the core line balun connection via hole of the front part from the second core line hole of the front part through the connection pattern, penetrates from the core line balun connection via hole of the front part to be transferred to a core line balun connection via hole of the rear part, is transferred to the second balun hole from the core line balun connection via hole through the second printed circuit pattern, and is transferred to the dipole antenna provided on the rear part from the second balun hole through the feed line unit. 
         [0029]    In addition, on the radiation board, parasite elements for extending frequency bands of the dipole antenna provided on the front part and the dipole antenna provided on the rear part are provided on the front part and the rear part.            
         [0030]    According to an embodiment of the present invention, it is possible to radiate dual polarized waves whose radiation directions are perpendicular (vertical) to each other through dipole antennas which are positioned on both surfaces of a radiation board and since electric power is fed to both dipole antennas which are positioned on both surfaces through via holes, it is possible to simplify a feeding structure of the dipole antenna. 
         [0031]    Further, since electric power is fed to both dipole antennas which are positioned on both surfaces of the radiation board through the via holes, it is not necessary to use a complicated 3D air bridge structure. 
         [0032]    In addition, it is possible to wideband characteristics of a radiation signal by using a parasite element of the radiation board. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0033]      FIG. 1  is a plan view illustrating a known dual polarization wideband dipole antenna. 
           [0034]      FIG. 2  is a plan view illustrating the configuration of an antenna radiation board according to an exemplary embodiment of the present invention. 
           [0035]      FIG. 3  is a diagram illustrating the configuration of a front part and a feeding structure on an antenna radiation board according to an exemplary embodiment of the present invention. 
           [0036]      FIG. 4  is a diagram illustrating the configuration of a rear part and a feeding structure on an antenna radiation board according to an exemplary embodiment of the present invention. 
           [0037]      FIG. 5  is a plan view illustrating an operation of front part of an antenna radiation board according to an exemplary embodiment of the present invention. 
           [0038]      FIG. 6  is a diagram illustrating an operation of a rear part of an antenna radiation board according to an exemplary embodiment of the present invention. 
           [0039]      FIG. 7  is a configuration diagram illustrating the configuration of a board-type wideband duel polarization dipole antenna according to an exemplary embodiment of the present invention. 
           [0040]      FIG. 8  is a diagram illustrating a board-type wideband dual polarization dipole antenna array according to an exemplary embodiment of the present invention. 
           [0041]      FIG. 9  is a graph illustrating a VSWR measurement result of a board-type wideband dual polarization dipole antenna according to an exemplary embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0042]    A matter regarding to a configuration and an effect of the present invention will be appreciated clearly through the following detailed description with reference to the accompanying drawings illustrating preferable embodiments of the present invention. Hereinafter, an embodiment in accordance with the present invention will be described in detail with reference to the accompanying drawings. 
         [0043]      FIG. 2  is a plan view illustrating the configuration of an antenna radiation board according to an exemplary embodiment of the present invention. 
         [0044]    As a result, a front feeding part  220  and a rear feeding part  260  receive a first feed signal and a second feed signal to feed the received signals to dipole antennas  240 ,  242 ,  280 , and  282  through parallel feed line units  230  and  270  at the same time. 
         [0045]    Herein, a feed cable includes a first feed cable applying the first feed signal to the front feeding part  220  and a second feed cable applying the second feed signal to the rear feeding part  260 . The first feed cable and the second feed cable may be implemented by, for example, a coaxial cable in order to transfer electric power or a signal and is constituted by an internal conductor (core line) serving as a signal line and an external conductor serving as a ground line. 
         [0046]    Meanwhile, although described in  FIG. 7  to be shown later, a first balun cable which forms a pair with the first feed cable in parallel and a second balun cable which forms the second feed cable in parallel are inserted into and connected to the rear feeding part  260 . At this time, the first balun cable and the second balun cable serve as a balun with respect to the first feed cable and the second feed cable. Herein, the role of the balun (BALUN:Balance/Unbalance), which is a concept to allow resonance to be made by balancing a difference between a (+) feed signal and a (−) feed signal of the first feed cable and the second feed cable, is a known technology in an antenna field. 
         [0047]    The parallel feed line units  230  and  270  transfer the feed signals applied from the feeding parts  220  and  260  to the dipole antennas  240 ,  242 ,  280 , and  282 . 
         [0048]    Further, the parallel feed line units  230  and  270  has a function of converting impedance of the feeding parts  220  and  260  into impedances of the dipole antennas  240 ,  242 ,  280 , and  282  and therefore, may be referred to as an impedance converting unit. 
         [0049]    The dipole antennas  240 ,  242 ,  280 , and  282  radiates the feed signals from the feeding parts  220  and  260  through the parallel feed line units  230  and  270  to free space. 
         [0050]    At this time, the dipole antennas  240 ,  242 ,  280 , and  282  are constituted by front dipole antennas  240  and  242  that are provided on a front part  210  and rear dipole antennas  280  and  282  that are provided on a rear part  250 . 
         [0051]    Herein, the front dipole antennas  240  and  242  are constituted by a first front dipole antenna  240  and a second front dipole antenna  242  for radiating the first feed signal and the rear dipole antennas  280  and  282  are constituted by a third rear dipole antenna  280  and the fourth rear dipole antenna  282  for radiating the second feed signal. 
         [0052]    Further, the parallel feed line units  230  and  270  are constituted by a front parallel feed line unit  230  transferring the first feed signal from the front feed unit  220  to the front dipole antennas  240  and  242  and a rear parallel feed line unit  270  transferring the second feed signal from the rear feed unit  260  to the rear dipole antennas  280  and  282 . 
         [0053]    Herein, the front parallel feed line unit  230  is constituted by a first front parallel feed line portion  230   a  transferring the first feed signal from the front feed unit  220  to the first front dipole antenna  240  and a second front parallel feed line portion  230   b  transferring the first feed signal to the second front dipole antenna  242 . Further, the rear parallel feed line unit  270  is constituted by a third rear parallel feed line portion  270   a  transferring the second feed signal from the rear feed unit  260  to the third rear dipole antenna  288  and a fourth rear parallel feed line portion  270   b  transferring the second feed signal to the fourth rear dipole antenna  282 . 
         [0054]    In addition, the first front dipole antenna  240  and the second front dipole antenna  242  and the third rear dipole antenna  280  and the fourth rear dipole antenna  282  have a length of a wavelength (λ) of ½ and are spaced apart from the feeding parts  220  and  260  by a wavelength (λ) of ¼. Therefore, the front parallel feed line unit  230  and the rear parallel feed line unit  270  have a length of the wavelength (λ) of ¼. 
         [0055]    In the antenna radiation board  200  configured as described above, the first feed cable and the second feed cable and the first balun cable and the second balun cable are connected to the rear feeding part  260 , and the second feed signal by the second feed cable is applied to the rear feeding part  260  and the first feed signal by the first feed cable is applied to the front feeding part  220  from the rear feeding part  260  through via holes at the same time. 
         [0056]    Subsequently, the first feed signal is transferred to the front dipole antennas  240  and  242  from the feeding part  220  through the front parallel feeding line unit  230  and the second feed signal to the rear dipole antennas  280  and  282  from the rear feeding part  260  through the rear parallel feed line unit  270  at the same time. 
         [0057]    Therefore, as the front dipole antennas  240  and  242  radiate the first feed signal as a polarized wave of +45° and at the same time, the rear dipole antennas  280  and  282  radiate the second feed signal as a polarized wave of −45°, the antenna radiation board  200  radiates dual polarized waves which are perpendicular (vertical) to each other through the front part  210  and the rear part  250 . 
         [0058]      FIG. 3  is a diagram illustrating the configuration of a front part and a feeding structure on an antenna radiation board according to an exemplary embodiment of the present invention. 
         [0059]    Referring to  FIG. 3 , the front part  210  includes the front feeding part  220  receiving the first feed signal from the outside, the front parallel feed line unit  230  transferring the first feed signal to the front dipole antennas  240  and  242  from the front feeding part  220 , front dipole antennas  240  and  242  radiating the first feed signal to space, and front parasite elements  290   a  and  290   b  for extending frequency bands of the front dipole antennas  240  and  242 . 
         [0060]    Herein, the front feeding part  220  includes a first core line hole  310  through which a first core line (+) of the first feed cable is penetrated and connected from the rear feeding part  260 , a first ground via hole  312  through which a first ground line (−) of the first feed cable is penetrated and connected form the rear feeding part  260 , a first balun hole  314  through which the first balun which forms a pair with the first feed cable to serve as the balun is inserted and connected, a second core line hole  316  through which a second core line (+) of the second feed cable is inserted and connected, a second balun hole  318  through which the second balun cable forms a pair with the second feed cable to serve as the balun is inserted and connected, and a core line balun connection via hole  320  for connecting the second core line (+) and the second balun cable by penetrating the front feeding part  220  and the rear feeding part  260 . 
         [0061]    Further, the first core line hole  310  and the first balun hole  314  are connected to each other through a first printed circuit pattern  322  and the second core line hole  316  and the core line balun connection via hole  320  are connected to each other through a connection pattern  324 . 
         [0062]    The front dipole antennas  240  and  242  include the first front dipole antenna  240  and the second front dipole antenna  242  radiating the first feed signal as a polarized wave of +45°. Herein, the first front dipole antenna  240  is positioned spaced apart upwardly from the front feeding part  220  by the wavelength (λ) of ¼ and the second front dipole antenna  242  is positioned apart downwardly from the front feeding part  220  by the wavelength (λ) of ¼. 
         [0063]    Further, in the front parallel feed line unit  230 , two feed lines for transferring (+) current and (−) current to the front dipole antennas  240  and  242  from the front feeding part  220  are arranged in parallel. 
         [0064]    At this time, the front parallel feed line unit  230  matches impedances of the front feeding part  220  and the front dipole antennas  240  and  242 . That is, although there is a bit difference between the impedance of the front feeding part  220  and the impedances of the front dipole antennas  240  and  242 , the front parallel feed line unit  230  converts the impedance of the front feeding part  220  into the impedances of the front dipole antennas  240  and  242  while the first feed signal is transferred to the front dipole antennas  240  and  242  from the front feeding part  220  through the front parallel feed line unit  230 . 
         [0065]    Meanwhile, the first core line (+) of the first feed cable is inserted into and connected to the first core line hole  310  of the rear feeding part  260  to penetrate the first core line hole  310  and get out through the first core line hole  310  of the front feeding part  220 . At this time, the first ground line (−) is connected to a first ground via hole  312  of the rear feeding part  260 . Herein, the first ground via hole  312  is constituted by three holes, but may be properly constituted by one or more holes in accordance with an intention of a designer. 
         [0066]    Therefore, the (+) current is applied to the first core line hole  310  from the first feed cable and the (−) current is applied to the first ground via hole  312 . 
         [0067]    As a result, on the front part  210 , the (−) current of the ground via hole  312  is also applied to the front parallel feed line portions  230   a  and  230   b  while the (+) current of the first core line hole  310  is applied to the front parallel feed line portions  230   a  and  230   b  through the first printed circuit pattern  322  and the first balun hole  314 , such that the applied feed signals are transferred to both the first front dipole antenna  240  and the second front dipole antenna  242  through the front parallel feed line portions  230   a  and  230   b.    
         [0068]    Meanwhile, on the front part  210  of  FIG. 3 , a first circular circuit pattern  326  which circularly surrounds the second balun hole  318  is spaced apart from the second front parallel feed line portion  230   b  at predetermined intervals. 
         [0069]    Further, in the first front dipole antenna  240 , an antenna constituent member  240   a  which receives the (+) current and an antenna constituent member  240   b  which receives the (−) current are horizontally symmetric to each other and even in the second front dipole antenna  242 , an antenna constituent member  242   a  which receives the (+) current and an antenna constituent member  242   b  which receives the (−) current are horizontally symmetric to each other. 
         [0070]    In contrast, the first front dipole antenna  240  and the second front dipole antenna  242  are vertically symmetric to each other on the basis of the front feeding part  220 . 
         [0071]    Further, on the front part  210 , the front parasite elements  290   a  and  290   b  are arranged in parallel to the first front dipole antenna  240  and the second front dipole antenna  242 , current having the same direction as current directions of the first front dipole antenna  240  and the second front dipole antenna  242  is induced to serve to extend frequency bandwidths of the first front dipole antenna  240  and the second front dipole antenna  242 . 
         [0072]    In the case of the front part  210  configured as described above, the first core line (+) of the first feed cable is inserted into and connected to the first core line hole  310  of the rear feeding part  260  to penetrate the first core line hole  310  to be connected to the first core line hole  310  of the front feeding part  220 . Therefore, the (+) current is applied to the first balun hole  314  from the first core line hole  211  of the front feeding part  220  through the first printed circuit pattern  322  and the (+) current applied to the first balun hole  314  is transferred to the first front dipole antenna  240  and the second front dipole antenna  242  through the front parallel feed line portions  230   a  and  230   b.    
         [0073]    At the same time, on the front part  210 , the first ground line (−) of the first feed cable is connected to the first ground via hole  312  of the rear feeding part  260  and the first ground line (−) is connected to the first ground via hole  312  of the front feeding part  220  through the first ground via hole  312 . 
         [0074]    Therefore, the (−) current is transferred to the first front dipole antenna  240  and the second front dipole antenna  242  from the first ground via hole  312  of the front feeding part  220  through the front parallel feed line portions  230   a  and  230   b.    
         [0075]    Accordingly, the first front dipole antenna  240  and the second front dipole antenna  242  radiate the first feed signal to free space as the polarized wave of +45°. 
         [0076]      FIG. 4  is a diagram illustrating the configuration of a rear part and a feeding structure on an antenna radiation board according to an exemplary embodiment of the present invention. 
         [0077]    Referring to  FIG. 4 , the front part  250  according to the exemplary embodiment of the present invention includes the rear feeding part  260  receiving the second feed signal from the outside, the rear parallel feed line unit  270  transferring the second feed signal from the rear feeding part  260  to the rear dipole antennas  280  and  282 , the rear dipole antennas  280  and  282  radiating the second feed signal received from the rear parallel feed line unit  270  to the free space, and the rear parasite elements  290   c  and  290   d  for widening the bandwidth of the second feed signal. 
         [0078]    Herein, the rear feeding part  260  includes a second core line hole  316  for inserting a second core line (+) of the second feed cable, a second balun hole  318  for inserting and connecting the second balun cable which forms a pair with the second feed cable to serve as the balun, a core line balun connection via hole  320  for connecting the second balun cable with the second core line (+) inserted into the second core line hole  316 , a first core line hole  310  into which the first core line (+) of the first feed cable is inserted, a first ground via hole  312  connecting the first ground line (−) of the first feed cable, and a first balun hole  314  for inserting and connecting the first balun cable which forms a pair with the first feed cable to serve as the balun. 
         [0079]    At this time, the second balun hole  318  and the core line balun connection via hole  320  are connected to a second printed circuit pattern  420  and the second core line hole  316  is spaced apart from a part which contacts the second ground line (−) of the second feed cable by predetermined intervals. 
         [0080]    Further, the rear dipole antennas  280  and  282  include the first rear dipole antenna  280  and the second rear dipole antenna  282  which radiate the second feed signal as the polarized wave of −45°. Herein, the first rear dipole antenna  280  is positioned spaced apart to the left from the rear feeding part  260  by the wavelength (λ) of ¼ and the second rear dipole antenna  282  is positioned apart to the right from the rear feeding part  260  by the wavelength (λ) of ¼. 
         [0081]    Further, in the rear parallel feed line unit  270 , two feed lines for transferring the (+) current and the (−) current to the rear dipole antennas  280  and  282  from the rear feeding part  260  are arranged in parallel. 
         [0082]    In addition, the rear parallel feed line unit  270  matches impedances of the rear feeding part  260  and the rear dipole antennas  280  and  282 . That is, although there is a bit difference between the impedance of the rear feeding part  260  and the impedances of the rear dipole antennas  280  and  282 , the rear parallel feed line unit  270  converts the impedance of the rear feeding part  260  into the impedances of the rear dipole antennas  280  and  282  while the second feed signal is transferred to the rear dipole antennas  280  and  282  from the rear feeding part  260  through the rear parallel feed line unit  270 . 
         [0083]    Meanwhile, the second core line (+) of the second feed cable is inserted into and connected to the second core line hole  316  of the rear feeding part  260  and the second ground line (−) is spaced apart from the second core line hole  316  by a predetermined gap to contact a part which is connected with the rear parallel feed line unit  270 . Therefore, the (+) current is applied to the second core line hole  316  from the second feed cable and the (−) current is applied to the part connected with the rear parallel feed line unit  270 . 
         [0084]    As a result, on the rear part  250 , the (−) current of the second ground line is applied to the rear parallel feed line portions  270   a  and  270   b  while the (−) current of the second core line hole  316  is applied to the rear parallel feed line portions  270   a  and  270   b  through the connection pattern  324  and the core line balun connection via hole  320  of the front feeding part  220  and the second printed circuit pattern  420  and the second balun hole  318  of the rear feeding part  260 , such that the applied feed signals are transferred to both the third rear dipole antenna  280  and the fourth rear dipole antenna  282  through the rear parallel feed line portions  270   a  and  270   b.    
         [0085]    Accordingly, the third rear dipole antenna  280  and the fourth rear dipole antenna  282  radiate the second feed signal to the free space as the polarized wave of −45°. 
         [0086]    Meanwhile, on the rear part  250  of  FIG. 4 , a second circular circuit pattern  430  which circularly surrounds the first balun hole  314  is spaced apart from the first rear parallel feed line portion  270   a  at predetermined intervals. Further, a third circular circuit pattern  440  which circularly surrounds one or more first ground via holes  312  which are spaced apart from the first core line hole  310 , and the like at predetermined intervals is spaced apart from the second rear feed line portion  270   b  at predetermined intervals. 
         [0087]    Further, in the third rear dipole antenna  280 , an antenna constituent member  280   a  which receives the (+) current and an antenna constituent member  280   b  which receives the (−) current are vertically symmetric to each other and even in the fourth rear dipole antenna  282 , an antenna constituent member  282   a  which receives the (+) current and an antenna constituent member  282   b  which receives the (−) current are vertically symmetric to each other. 
         [0088]    In contrast, the first rear dipole antenna  280  and the second rear dipole antenna  282  are horizontally symmetric to each other on the basis of the rear feeding part  260 . 
         [0089]    Further, on the rear part  250 , the rear parasite elements  290   c  and  290   d  are arranged in parallel to the third rear dipole antenna  280  and the fourth rear dipole antenna  282 , current having the same direction as current directions of the third rear dipole antenna  280  and the fourth rear dipole antenna  282  is induced to serve to extend frequency bandwidths of the third rear dipole antenna  280  and the fourth rear dipole antenna  282  by the induced current. 
         [0090]    On the rear part  280  configured as described above, as the second core line (+) of the second feed cable is inserted into and connected to the second core line hole  316 , the (+) current penetrates from the second core line hole  316  to be transferred to the second core line hole  316  of the front feeding part  220 , is transferred to the core line balun connection via hole  320  through the connection pattern  324  in the second core line hole  316  of the front feeding part  220 , penetrates from the core line balun connection via hole  320  to be transferred to the core line balun connection via hole  320  of the rear feeding part  260 , and is applied to the second balun hole  318  from the core line balun connection via hole  320  through the second printed circuit pattern  420  in the rear feeding part  260 , and the (+) current applied to the second balun hole  318  is transferred to the third rear dipole antenna  280  and the fourth rear dipole antenna  282  through the rear parallel feed line portions  270   a  and  270   b,  respectively. 
         [0091]    At the same time, the (−) current is transferred to the third rear dipole antenna  280  and the fourth rear dipole antenna  282  from the second ground line (−) of the second feed cable through the rear parallel feed line portions  270   a  and  270   b.    
         [0092]    Accordingly, the third rear dipole antenna  280  and the fourth rear dipole antenna  282  radiate the second feed signal to the free space as the polarized wave of −45°. 
         [0093]      FIG. 5  is a plan view illustrating an operation of a front part of an antenna radiation board according to an exemplary embodiment of the present invention. 
         [0094]    Referring to  FIG. 5 , on the front cart  210  of the antenna radiation board  200  according to the exemplary embodiment of the present invention, since the first core line (+) of the first feed cable penetrates from the first core line hole  310  of the rear feeding part  260  to be connected to the first core line hole  310  of the front feeding part  220 , the (+) current is applied to the first balun hole  314  from the first core line hole  310  of the front feeding part  220  through the first printed circuit pattern  322  and is transferred to the first front dipole antenna  240  and the second front dipole antenna  242  through the front parallel feed line unit  230  in the first balun hole  314 . Therefore, the (+) current has a current direction which faces the front dipole antennas  240  and  242  from the first balun hole  314  of the front feeding part  220  through the front parallel feed line unit  230 . 
         [0095]    At the same time, the first ground line (−) of the first feed cable penetrates from the first ground via hole  312  of the rear feeding part  260  to be connected to the first ground via hole  312  of the front feeding cart  220 , such that the (−) current is transferred to the front dipole antennas  240  and  242  from the first ground via hole  312  through the front parallel feed line unit  230  to have a direction of current which flows into the first ground via hole  312  from the front dipole antennas  240  and  242  through the front parallel feed line unit  230 . 
         [0096]    Meanwhile, the front parallel feed line unit  230  is connected the centers of the front dipole antennas  240  and  242 . 
         [0097]    As a result, since the (+) current is applied to the centers of the dipole antennas  240  and  242  from the front parallel feed line unit  230  and the (−) current is transferred to the front parallel feed line unit  230  from the centers of the front dipole antennas  240  and  242 , the front dipole antennas  240  and  242  have a direction of current which flows from the right side to the left side as shown in  FIG. 5 . 
         [0098]    At this time, on the front part  210 , the front parasite elements  290   a  and  290   b  which are spaced part from the front dipole antennas  240  and  242  at predetermined intervals are arranged in parallel to the front dipole antennas  240  and  242 . 
         [0099]    Therefore, the current is induced, which flows from the right side to the left side in the same manner as the current direction of the front dipole antennas  240  and  242  even in the front parasite elements  290   a  and  290   b  which are arranged in parallel to the front dipole antennas  240  and  242 . Herein, frequency bandwidths of the front dipole antennas  240  and  242  are extended by the current induced to the front parasite elements  290   a  and  290   b.    
         [0100]      FIG. 6  is a diagram illustrating an operation of a rear part of an antenna radiation board according to an exemplary embodiment of the present invention. 
         [0101]    Referring to  FIG. 6 , on the rear part  250  of the antenna radiation board  200  according to the exemplary embodiment of the present invention, the second core line (+) of the second feed cable penetrates from the second core line hole  316  of the rear feeding part  260  to be connected to the second core line hole  316  of the front feeding part  220 , is transferred to the core line balun connection via hole  320  through the connection pattern  324  in the second core line hole  316  of the front feeding part  220 , penetrates from the core line balun connection via hole  320  of the front feeding part  220  to be transferred to the core line balun connection via hole  320  of the rear feeding part  260 , and is applied to the second balun hole  318  from the core line balun connection via hole  320  through the second printed circuit pattern  420  in the front feeding part  260 , and the (+) current applied to the second balun hole  318  is transferred to the third rear dipole antenna  280  and the fourth rear dipole antenna  282  through the rear parallel feed line portions  270   a  and  270   b,  respectively. 
         [0102]    Therefore, on the rear part  250 , the (+) current has a current direction which faces the rear dipole antennas  280  and  282  from the second balun hole  318  of the rear feeding part  260  through the rear parallel feed line unit  270 . 
         [0103]    At the same time, since the (−) current is transferred to the rear dipole antennas  280  and  282  from the second ground line (−) of the second feed cable through the rear parallel feed line unit  270 , the (−) current has a direction of current which flows into the second core line hole  316  from the rear dipole antennas  280  and  282  through the rear parallel feed line unit  270 . 
         [0104]    Meanwhile, the front parallel feed line unit  270  is connected the centers of the front dipole antennae  280  and  282 . 
         [0105]    As a result, since the (+) current is applied to the centers of the dipole antennas  280  and  282  from the rear parallel feed line unit  270  and the (−) current is transferred to the rear parallel feed line unit  270  from the centers of the rear dipole antennas  280  and  282 , the rear dipole antennas  280  and  282  have a direction of current which flows from the lower side to the upper side as shown in  FIG. 6 . 
         [0106]    At this time, on the rear part  210 , the rear parasite elements  290   c  and  290   d  which are spaced part from the rear dipole antennas  280  and  282  at predetermined intervals are arranged in parallel to the rear dipole antennas  280  and  282 . 
         [0107]    Therefore, the current is induced, which flows from the lower side to the upper side in the same manner as the current direction of the rear dipole antennas  280  and  282  even in the rear parasite elements  290   c  and  290   d  which are arranged in parallel to the rear dipole antennas  280  and  282 . Herein, the frequency bandwidths of the front dipole antennas  280  and  282  are extended by the current induced to the rear parasite elements  290   c  and  290   d.    
         [0108]      FIG. 7  is a configuration diagram illustrating the configuration of a board-type wideband dual polarization dipole antenna according to an exemplary embodiment of the present invention. 
         [0109]    Referring to  FIG. 7 , the board-type wideband dual polarization dipole antenna  700  according to the exemplary embodiment of the present invention includes a radiation board  710 , a first feed cable  720 , a first balun cable  722 , a second feed cable  730 , a second balun cable  732 , a support unit  740 , and a ground board  750 . 
         [0110]    The radiation board  710  is constituted by the front part  210  and the rear part  250  as described through  FIGS. 2 to 4  and in  FIG. 7 , the front part  210  of the radiation board  710  is shown. Herein, since the configuration of the front part  210  is described through  FIGS. 2 and 3 , the configuration will not be described. 
         [0111]    As shown in  FIG. 7 , the front feeding part  220  includes a first core line hole  310  where a first core line (+) of the first feed cable  720  is inserted into and connected the rear feeding part  260  to penetrate the front feeding part  220 , a first ground via hole  312  where a first ground line (−) of the first feed cable  720  is connected to the rear feeding part  260  penetrate the front feeding part  220  from the rear feeding part  260 , a first balun hole  314  for inserting and connecting a first balun cable  722  which forms a pair with the first feed cable  720  to serve as the balun, a second core line hole  316  for inserting and connecting a second core line (+) of the second feed cable  730 , a second balun hole  318  for inserting and connecting a second balun cable  732  which forms a pair with the second feed cable  730  to serve as the balun, and a core line balun connection via hole  320  for penetratively connecting the second balun cable with the second core (+) of the second feed cable  730 . 
         [0112]    In  FIG. 7 , the first feed cable  720  transfers a first feed signal of (+) current received from the outside through the first core line (+) to the first core line hole  310 . 
         [0113]    The first balun cable  722  forms a pair with the first feed cable  720  to serve as the balun, and is inserted into and connected to the first balun hole  314 . 
         [0114]    The second feed cable  730  transfers a second feed signal of (+) current received from the outside through the second core line (+) to the second core line hole  316 . 
         [0115]    The second balun cable  732  forms a pair with the second feed cable  730  to serve as the balun, and is inserted into and connected to the second balun hole  318 . 
         [0116]    The core line balun connection via hole  320  is a via hole where when the second core line (+) of the second feed cable  730  inserted into the second core line hole  316  of the rear feeding part  260  penetrates from the second core line hole  316  of the rear feeding part  260  to be connected to the second core line hole  316  of the front feed unit  220 , the second core line (+) of the second feed cable  730  is connected with the second core line hole  316  of the front feeding part  220  through the connection pattern  324  and connected to the second balun hole  318  of the rear feeding part  260  through the second printed circuit pattern  420  of the rear feeding part  260  to connect the second balun cable  732  with the second core line (+) of the second feed cable  730 . 
         [0117]    At this time, on the front feeding part  220 , the first core line hole  310  and the first balun hole  314  are connected to each other through the first printed circuit pattern  322 . 
         [0118]    Meanwhile, the first feed cable  720  and the first balun cable  722  and the second feed cable  730  and the second balun cable  732  are supported and fixed to the support unit  740  by soldering, and the like. 
         [0119]    The antenna having the dipole structure essentially requires an additional structure called the balun for balancing the impedances of the (+) feed signal and the (−) feed signal at the time of feeding through the coaxial line due to its symmetric structure. Therefore, the first feed cable  720  and the first balun cable  722  and the second feed cable  730  and the second balun cable  732  are fixed to the support unit  740  which is made of a metallic material by soldering to be installed to be grounded while being balanced with each other, thereby forming the balun structure. Herein, each of the first feed cable  720  and the second feed cable  730  may be configured by using the coaxial cable. 
         [0120]    The support unit  740  may be stably coupled to the ground board  750  which is made of a conductive material by using, for example, a bolt-nut structure, and the like while the first feed cable  720  and the first balun cable  722  and the second feed cable  730  and the second balun cable  732  connected to the radiation board  710  are fixed by soldering. 
         [0121]    The first feed cable  720  and the first balun cable  722  are parallel to each other and the second feed cable  730  and the second balun cable  732  are fixed to the support unit  740  to be are parallel to each other. 
         [0122]    Meanwhile, in the board-type wideband dual polarization dipole antenna  700  according to the exemplary embodiment of the present invention, a plurality of antenna arrays may be designed on the ground board  750  which is made of the conductive material as shown in  FIG. 8 .  FIG. 8  is a diagram illustrating a board-type wideband dual polarization dipole antenna array according to an exemplary embodiment of the present invention. 
         [0123]      FIG. 9  is a graph illustrating a VSWR measurement result of a board-type wideband dual polarization dipole antenna according to an exemplary embodiment of the present invention. 
         [0124]    Referring to  FIG. 9 , the board-type wideband dual polarization dipole antenna  700  according to the exemplary embodiment of the present invention may use a wide frequency band in the range of 1.2 GHz to 3 GHz on the basis of a result of measuring a voltage standing wave ratio (VSWR) by implementing the dipole antenna on the front surface and the rear surface as a printed circuit board type. 
         [0125]    Therefore, the board-type wideband dual polarization dipole antenna  700  according to the exemplary embodiment of the present invention may use a wideband frequency of approximately 1750 to 1600 MHz including a PCS frequency band of 1750 to 1860 MHz, a USPCS frequency band of 1850 to 1960 MHz, a GSM frequency band of 1710 to 1800 MHz, a WCDMA frequency band of 1920 to 2170 MHz, a Wibro frequency band of 2300 to 2390 MHz, and a WiMAX frequency band of 2400 to 2500 MHz. 
         [0126]    As described above, according to the present invention, it is possible to implement the board-type wideband dual polarization dipole antenna in which the dipole antenna is provided on the front surface and the rear surface of the radiation board, electric power is fed to the dipole antennas on the front surface and the rear surface through the via hole, dual polarized waves whose antenna radiation directions are perpendicular (vertical) to each other are radiated through the dipole antennas on the front surface and the rear surface to simplify the feeding structure and improve wideband characteristics through the parasite elements. 
         [0127]    While certain embodiments have been described above, it will be understood to those skilled in the art that the embodiments described are by way of example only. 
         [0128]    Rather, the apparatus described herein should only be limited in light of the claims that follow when taken in conjunction with the above description and accompanying drawings. 
         [0129]    The present invention can be used in a base station antenna of a mobile communication system and can be applied to a dual polarization dipole antenna which radiates or receives a wireless signal. Further, the present invention can also be applied to a dual polarization antenna whose radiation directions of the dipole antenna are perpendicular to each other.