Abstract:
A high-gain multi-polarization antenna array module includes an antenna array and a plurality of Butler matrixes. The antenna array includes four antennas, and each antenna includes two feed portions. Each Butler matrix includes four 90° hybrid couplers, two phase shifters, four input ports, and four output ports, and the four output ports are respectively electrically connected to the four different antennas. The antenna array module integrates multi-polarization array antennas and base station antennas generating beam forming by using the Butler matrixes, such that beam shapes generated by the antenna array may be deflected according to a set specific angle, thereby greatly improving receiving quality of the antennas.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No(s). 098207762 filed in Taiwan, R.O.C. on May 6, 2009, the entire contents of which are hereby incorporated by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to an antenna array module, and more particularly to a high-gain multi-polarization antenna array module. 
         [0004]    2. Related Art 
         [0005]    Antennas may be categorized into omnidirectional antennas and directional antennas. The omni-directional antenna radiates energy to all directions on a plane, while the directional antenna radiates energy to a specific angle range in a centralized manner. Therefore, compared with the omnidirectional antenna, the directional antenna has a larger antenna gain in the specific range. A conventional base station uses three directional antennas, and each directional antenna covers a sector range having a horizontal angle of 120°. 
         [0006]    However, the directional antenna covering the sector range of 120° used by the conventional base station still has a problem of an excessively wide range. Due to the problem, only a small part of the energy may be correctly radiated to the direction of a user, so the energy is wasted. Meanwhile, most part of the redundant energy is radiated to other places, so as to interfere with other users. 
         [0007]    In addition, the antenna unit adopted by the conventional base station is vertically polarized or horizontally polarized, but a mobile device used by a user habitually is at an angle of 45° with the ground. The antenna design of the conventional base station does not consider the habit of using the mobile device by the user, so the antenna gain is lowered, thereby affecting the communication transmission quality. 
       SUMMARY OF THE INVENTION 
       [0008]    In view of the above problems, the present invention is a high-gain multi-polarization antenna array module, capable of integrating multi-polarization array antennas and Butler matrixes to generate beam forming, in which beam shapes generated by an antenna array may be deflected according to a set specific angle, thereby greatly improving receiving quality of the antennas. 
         [0009]    In an embodiment, the present invention provides a high-gain multi-polarization antenna array module, which comprises an antenna array, a first Butler matrix, and a second Butler matrix. The antenna array comprises four antennas, and each antenna comprises two feed portions. The first Butler matrix comprises four 90° hybrid couplers, two 45° phase shifters, four input ports and four output ports, and the four output ports are respectively electrically connected to the four different antennas. The second Butler matrix comprises four 90° hybrid couplers, two −45° phase shifters, four input ports and four output ports, and the four output ports are respectively electrically connected to the four different antennas. 
         [0010]    In another embodiment, the present invention further provides a high-gain multi-polarization antenna array module, which comprises an antenna array, a first Butler matrix, a second Butler matrix, and a third Butler matrix. The first Butler matrix comprises four 90° hybrid couplers, two 45° phase shifters, four input ports and four output ports, and the four output ports are respectively electrically connected to the four different antennas. The second Butler matrix comprises four 90° hybrid couplers, two −45° phase shifters, four input ports and four output ports, and the four output ports are respectively electrically connected to the four different antennas. The third Butler matrix comprises four 90° hybrid couplers, two phase shifters, four input ports and four output ports, a phase shift angle of the phase shifters is any angle except for 45° and −45°, and the four output ports are respectively electrically connected to the four different antennas. 
         [0011]    According to the embodiments of the present invention, the high-gain multi-polarization antenna array module according to the present invention may generate the beam forming having various different polarization directions centralized at a specific angle by using the plurality of Butler matrixes and one antenna array module. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The present invention will become more fully understood from the detailed description given herein below for illustration only, and thus are not limitative of the present invention, and wherein: 
           [0013]      FIG. 1  is a block diagram of a high-gain multi-polarization antenna array module; 
           [0014]      FIG. 2  is a schematic view of the implementation of a high-gain multi-polarization antenna array module; 
           [0015]      FIG. 3  is a block diagram of Butler matrixes; 
           [0016]      FIG. 4  is a block diagram of a high-gain multi-polarization antenna array module; 
           [0017]      FIG. 5A  is a pattern diagram of a first input port at a polarization direction of 45° and an operating frequency of 2400 MHz; 
           [0018]      FIG. 5B  is a pattern diagram of the first input port at the polarization direction of 45° and an operating frequency of 2450 MHz; 
           [0019]      FIG. 5C  is a pattern diagram of the first input port at the polarization direction of 45° and an operating frequency of 2500 MHz; 
           [0020]      FIG. 6A  is a pattern diagram of a second input port at a polarization direction of 45° and an operating frequency of 2400 MHz; 
           [0021]      FIG. 6B  is a pattern diagram of the second input port at the polarization direction of 45° and an operating frequency of 2450 MHz; 
           [0022]      FIG. 6C  is a pattern diagram of the second input port at the polarization direction of 45° and an operating frequency of 2500 MHz; 
           [0023]      FIG. 7A  is a pattern diagram of a third input port at a polarization direction of 45° and an operating frequency of 2400 MHz; 
           [0024]      FIG. 7B  is a pattern diagram of the third input port at the polarization direction of 45° and an operating frequency of 2450 MHz; 
           [0025]      FIG. 7C  is a pattern diagram of the third input port at the polarization direction of 45° and an operating frequency of 2500 MHz; 
           [0026]      FIG. 8A  is a pattern diagram of a fourth input port at a polarization direction of 45° and an operating frequency of 2400 MHz; 
           [0027]      FIG. 8B  is a pattern diagram of the fourth input port at the polarization direction of 45° and an operating frequency of 2450 MHz; 
           [0028]      FIG. 8C  is a pattern diagram of the fourth input port at the polarization direction of 45° and an operating frequency of 2500 MHz; 
           [0029]      FIG. 9A  is a pattern diagram of the first input port at a polarization direction of −45° and an operating frequency of 2400 MHz; 
           [0030]      FIG. 9B  is a pattern diagram of the first input port at the polarization direction of −45° and an operating frequency of 2450 MHz; 
           [0031]      FIG. 9C  is a pattern diagram of the first input port at the polarization direction of −45° and an operating frequency of 2500 MHz; 
           [0032]      FIG. 10A  is a pattern diagram of the second input port at a polarization direction of −45° and an operating frequency of 2400 MHz; 
           [0033]      FIG. 10B  is a pattern diagram of the second input port at the polarization direction of −45° and an operating frequency of 2450 MHz; 
           [0034]      FIG. 10C  is a pattern diagram of the second input port at the polarization direction of −45° and an operating frequency of 2500 MHz; 
           [0035]      FIG. 11A  is a pattern diagram of the third input port at a polarization direction of −45° and an operating frequency of 2400 MHz; 
           [0036]      FIG. 11B  is a pattern diagram of the third input port at the polarization direction of −45° and an operating frequency of 2450 MHz; 
           [0037]      FIG. 11C  is a pattern diagram of the third input port at the polarization direction of −45° and an operating frequency of 2500 MHz; 
           [0038]      FIG. 12A  is a pattern diagram of the fourth input port at a polarization direction of −45° and an operating frequency of 2400 MHz; 
           [0039]      FIG. 12B  is a pattern diagram of the fourth input port at the polarization direction of −45° and an operating frequency of 2450 MHz; and 
           [0040]      FIG. 12C  is a pattern diagram of the fourth input port at the polarization direction of −45° and an operating frequency of 2500 MHz. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0041]    The detailed features and advantages of the present invention are described below in great detail through the following embodiments, and the content of the detailed description is sufficient for those skilled in the art to understand the technical content of the present invention and to implement the present invention accordingly. Based upon the content of the specification, the claims, and the drawings, those skilled in the art can easily understand the relevant objectives and advantages of the present invention. The following embodiments are intended to describe the present invention in further detail, but not intended to limit the scope of the present invention in any way. 
         [0042]      FIG. 1  is a schematic block diagram of a high-gain multi-polarization antenna array module according to an embodiment of the present invention. Referring to  FIG. 1 , the high-gain multi-polarization antenna array module comprises an antenna array  14 , a first Butler matrix  16   a,  and a second Butler matrix  16   b.  In this embodiment, the antenna array comprises a first antenna  142 , a second antenna  144 , a third antenna  146 , and a fourth antenna  148 , and each antenna comprises two feed portions for feeding signals. 
         [0043]    The first Butler matrix  16   a  comprises a first 90° hybrid coupler  221   a , a second 90° hybrid coupler  222   a,  a third 90° hybrid coupler  223   a,  a fourth 90° hybrid coupler  224   a,  a first phase shifter  241   a , a second phase shifter  242   a,  a first input port  251   a , a second input port  252   a,  a third input port  253   a,  a fourth input port  254   a,  and a jumper  27   a.  The first 90° hybrid coupler  221   a  is electrically connected to the first phase shifter  241   a , and the first phase shifter  241   a  is electrically connected to the third 90° hybrid coupler  223   a.  The second 90° hybrid coupler  222   a  is electrically connected to the second phase shifter  242   a,  and the second phase shifter  242   a  is electrically connected to the fourth 90° hybrid coupler  224   a.  In addition, the first 90° hybrid coupler  221   a  is electrically connected to the jumper  27   a,  the jumper  27   a  is electrically connected to the fourth 90° hybrid coupler  224   a,  the second 90° hybrid coupler  222   a  is electrically connected to the jumper  27   a,  and the jumper  27   a  is electrically connected to the third 90° hybrid coupler  223   a.  A phase shift angle of the first phase shifter  241   a  and the second phase shifter  241   b  is 45°. The second Butler matrix  16   b  comprises a first 90° hybrid coupler  221   b,  a second 90° hybrid coupler  222   b,  a third 90° hybrid coupler  223   b,  a fourth 90° hybrid coupler  224   b,  a first phase shifter  241   b,  a second phase shifter  242   b,  a first input port  251   b,  a second input port  252   b,  a third input port  253   b,  a fourth input port  254   b,  and a jumper  27   b.  A phase shift angle of the first phase shifter  241   b  and the second phase shifter  242   b  is −45°. The connection of the second Butler matrix  16   b  is the same as that of the first Butler matrix  16   a.    
         [0044]    The first Butler matrix  16   a  further comprises a first output port  261   a , a second output port  262   a,  a third output port  263   a,  and a fourth output port  264   a,  and the second Butler matrix further comprises a first output port  261   b,  a second output port  262   b,  a third output port  263   b,  and a fourth output port  264   b.    
         [0045]    In the first Butler matrix  16   a,  the first output port  261   a  is electrically connected to the first antenna  142 , the second output port  262   a  is electrically connected to the third antenna  146 , the third output port  263   a  is electrically connected to the second antenna  144 , and the fourth output port  264   a  is electrically connected to the fourth antenna  148 . In the second Butler matrix  16   b,  the first output port  261   b  is electrically connected to the first antenna  142 , the second output port  262   b  is electrically connected to the third antenna  146 , the third output port  263   b  is electrically connected to the second antenna  144 , and the fourth output port  264   b  is electrically connected to the fourth antenna  148 . 
         [0046]      FIG. 2  is a schematic view of the implementation of a high-gain dual-polarization antenna array module according to an embodiment of the present invention, in which the antennas of  FIG. 1  are applied to a base station. Referring to  FIG. 2 , the arrangement of the antenna array  14 , the first Butler matrix  16   a,  and the second Butler matrix  16   b  is similar to the structure shown in  FIG. 1 . In this embodiment, the antenna array  14 , the first Butler matrix  16   a,  and the second Butler matrix  16   b  are disposed in a case  17 . The antenna array  14  further comprises a first antenna  142 , a second antenna  144 , a third antenna  146 , and a fourth antenna  148 . In this embodiment, the first antenna  142 , the second antenna  144 , the third antenna  146 , and the fourth antenna  148  are rectangular antennas, but the present invention is not limited to the shape, and the antennas in other shapes may also be applied in the present invention. Each antenna has a reflecting plate correspondingly disposed thereon, and the reflecting plates are respectively a first reflecting plate  182 , a second reflecting plate  184 , a third reflecting plate  186 , and a fourth reflecting plate  188 . Each antenna and each reflecting plate are spaced at a preset distance. In principle, the reflecting plates are made of a metal material. 
         [0047]    Each antenna and each reflecting plate may be fixed on the case  17  by using a plurality of support members  15 . The support members  15  may be made of metal or other similar materials, and may adopt a screw fixing manner or other manners. In an embodiment of the present invention, the antennas are applied to the base station, so a cover (not shown) is used to cover the case. 
         [0048]    The connection relations between the first Butler matrix  16   a  and the second Butler matrix  16   b  and the first antenna  142 , the second antenna  144 , the third antenna  146 , and the fourth antenna  148 , and the structure relations of the elements in the first Butler matrix  16   a  and the second Butler matrix  16   b  are as shown in the block diagram of  FIG. 1 . Here, it is too complicated to draw the connection and structure relations, so for the simplicity and clearness of illustration, the connection and structure relations are not shown. In this embodiment, the first Butler matrix  16   a  and the second Butler matrix  16   b,  and the first antenna  142 , the second antenna  144 , the third antenna  146 , and the fourth antenna  148  are connected by copper wires or wires of other materials. 
         [0049]      FIG. 3  is a schematic view of details of the Butler matrixes according to an embodiment of the present invention. The first Butler matrix  16   a  comprises a first 90° hybrid coupler  221   a,  a second 90° hybrid coupler  222   a,  a third 90° hybrid coupler  223   a,  a fourth 90° hybrid coupler  224   a,  a first phase shifter  241   a , a second phase shifter  242   a,  a first input port  251   a,  a second input port  252   a,  a third input port  253   a,  a fourth input port  254   a,  and a jumper  27   a.  The second Butler matrix  16   b  comprises a first 90° hybrid coupler  221   b,  a second 90° hybrid coupler  222   b,  a third 90° hybrid coupler  223   b,  a fourth 90° hybrid coupler  224   b,  a first phase shifter  241   b,  a second phase shifter  242   b,  a first input port  251   b,  a second input port  252   b,  a third input port  253   b,  a fourth input port  254   b,  and a jumper  27   b.  In the hybrid couplers, a signal delivery circuit is designed as a square structure. The jumper  27   a · 27   b  is an 8-shape structure. In the first phase shifter  241   a  and the second phase shifter  242   a  of the first Butler matrix  16   a,  the signal delivery circuit has a bent design, such that 45° phase delay is performed on the phase of a signal. In the first phase shifter  241   b  and the second phase shifter  242   b  of the second Butler matrix  16   b,  the signal delivery circuit has another bent design, such that −45° phase delay is performed on the phase of a signal. The connection relations of the elements are as shown in  FIG. 1 . The first Butler matrix  16   a  uses a first circuit board  28   a  as a substrate, the second Butler matrix  16   b  uses a second circuit board  28   b  as a substrate, each element is disposed on the circuit board, and the elements are connected by metal lines or other elements capable of transmitting signals. 
         [0050]    When an external signal is input to the first input port  251   a  of the first Butler matrix  16   a,  the polarization direction of the electromagnetic pattern generated by the antenna array is 45°, and the deflection angle is approximately −10°. When the external signal is input to the second input port  252   a  of the first Butler matrix  16   a,  the polarization direction of the electromagnetic pattern generated by the antenna array is 45°, and the deflection angle is approximately +30°. When the external signal is input to the third input port  253   a  of the first Butler matrix  16   a,  the polarization direction of the electromagnetic pattern generated by the antenna array is 45°, and the deflection angle is approximately −30°. When the external signal is input to the fourth input port  254   a  of the first Butler matrix  16   a,  the polarization direction of the electromagnetic pattern generated by the antenna array is 45°, and the deflection angle is approximately 10°. When the external signal is input to the first input port  251   b  of the second Butler matrix  16   b,  the polarization direction of the electromagnetic pattern generated by the antenna array is −45°, and the deflection angle is approximately −10°. When the external signal is input to the second input port  252   b  of the second Butler matrix  16   b,  the polarization direction of the electromagnetic pattern generated by the antenna array is −45°, and the deflection angle is approximately +30°. When the external signal is input to the third input port  253   b  of the second Butler matrix  16   b,  the polarization direction of the electromagnetic pattern generated by the antenna array is −45°, and the deflection angle is approximately −30°. When the external signal is input to the fourth input port  254   b  of the second Butler matrix  16   b,  the polarization direction of the electromagnetic pattern generated by the antenna array is −45°, and the deflection angle is approximately 10°. The deflection angles and the polarization directions in this embodiment are only used for illustration, and the present invention is not thus limited. Persons of ordinary skill in the art may design different deflection angles and polarization directions according to the spirit of the present invention. 
         [0051]    Further,  FIG. 4  is a block diagram of a high-gain tri-polarization antenna array module according to another embodiment of the present invention. Referring to  FIG. 4 , the high-gain tri-polarization antenna array module comprises an antenna array  34 , a first Butler matrix  36   a,  a second Butler matrix  36   b,  and a third Butler matrix  36   c.  The antenna array further comprises a first antenna  342 , a second antenna  344 , a third antenna  346 , and a fourth antenna  348 . 
         [0052]    In the first Butler matrix  36   a,  a first output port  361   a  is electrically connected to the first antenna  342 , a second output port  362   a  is electrically connected to the third antenna  346 , a third output port  363   a  is electrically connected to the second antenna  344 , and a fourth output port  364   a  is electrically connected to the fourth antenna  348 . In the second Butler matrix  36   b,  a first output port  361   b  is electrically connected to the first antenna  342 , a second output port  362   b  is electrically connected to the third square antenna  346 , a third output port  363   b  is electrically connected to the second square antenna  344 , and a fourth output port  364   b  is electrically connected to the fourth antenna  348 . In the third Butler matrix  36   c,  a first output port  361   c  is electrically connected to the first antenna  342 , a second output port  362   c  is electrically connected to the third antenna  346 , a third output port  363   c  is electrically connected to the second antenna  344 , and a fourth output port  364   c  is electrically connected to the fourth antenna  348 . 
         [0053]    The first Butler matrix  36   a  comprises a first 90° hybrid coupler  321   a,  a second 90° hybrid coupler  322   a,  a third 90° hybrid coupler  323   a,  a fourth 90° hybrid coupler  324   a,  a first phase shifter  341   a,  a second phase shifter  342   a,  a first input port  351   a,  a second input port  352   a,  a third input port  353   a,  a fourth input port  354   a,  and a jumper  37   a.  The first 90° hybrid coupler  321   a  is electrically connected to the first phase shifter  341   a,  and the first phase shifter  341   a  is electrically connected to the third 90° hybrid coupler  323   a.  The second 90° hybrid coupler  322   a  is electrically connected to the second phase shifter  342   a,  and the second phase shifter  342   a  is electrically connected to the fourth 90° hybrid coupler  324   a.  In addition, the first 90° hybrid coupler  321   a  is electrically connected to the jumper  37   a,  the jumper  37   a  is electrically connected to the fourth 90° hybrid coupler  324   a,  the second 90° hybrid coupler  322   a  is electrically connected to the jumper  37   a,  and the jumper  37   a  is electrically connected to the third 90° hybrid coupler  323   a.  The second Butler matrix further comprises a first 90° hybrid coupler  321   b,  a second 90° hybrid coupler  322   b,  a third 90° hybrid coupler  323   b,  a fourth 90° hybrid coupler  324   b,  a first phase shifter  341   b,  a second phase shifter  342   b,  a first input port  351   b , a second input port  352   b,  a third input port  353   b,  a fourth input port  354   b,  and a jumper  37   b.  The third Butler matrix further comprises a first 90° hybrid coupler  321   c,  a second 90° hybrid coupler  322   c,  a third 90° hybrid coupler  323   c,  a fourth 90° hybrid coupler  324   c,  a first phase shifter  341   c,  a second phase shifter  342   c,  a first input port  351   c,  a second input port  352   c,  a third input port  353   c,  a fourth input port  354   c , and a jumper  37   c.  The connection relations of the elements of the second Butler matrix and the third Butler matrix are the same as that of the first Butler matrix. A phase shift angle of the first phase shifter  341   a  and the second phase shifter  342   a  of the first Butler matrix  36   a  is 45°, a phase shift angle of the first phase shifter  341   b  and the second phase shifter  342   b  of the second Butler matrix  36   b  is −45°, and a phase shift angle of the first phase shifter  341   c  and the second phase shifter  342   c  of the third Butler matrix  36   c  is any angle except for 45° and −45°. 
         [0054]    When an external signal is input to the first input port  351   a  of the first Butler matrix  36   a,  the polarization direction of the electromagnetic pattern generated by the antenna array is 45°, and the deflection angle is approximately −10°. When the external signal is input to the second input port  352   a  of the first Butler matrix  36   a,  the polarization direction of the electromagnetic pattern generated by the antenna array is 45°, and the deflection angle is approximately +30°. When the external signal is input to the third input port  353   a  of the first Butler matrix  36   a,  the polarization direction of the electromagnetic pattern generated by the antenna array is 45°, and the deflection angle is approximately −30°. When the external signal is input to the fourth input port  354   a  of the first Butler matrix  36   a,  the polarization direction of the electromagnetic pattern generated by the antenna array is 45°, and the deflection angle is approximately 10°. When the external signal is input to the first input port  351   b  of the second Butler matrix  36   b,  the polarization direction of the electromagnetic pattern generated by the antenna array is −45°, and the deflection angle is approximately −10°. When the external signal is input to the second input port  352   b  of the second Butler matrix  36   b,  the polarization direction of the electromagnetic pattern generated by the antenna array is −45°, and the deflection angle is approximately +30°. When the external signal is input to the third input port  353   b  of the second Butler matrix  36   b,  the polarization direction of the electromagnetic pattern generated by the antenna array is −45°, and the deflection angle is approximately −30°. When the external signal is input to the fourth input port  354   b  of the second Butler matrix  36   b,  the polarization direction of the electromagnetic pattern generated by the antenna array is an angle except for −45° or 45°, and the deflection angle is approximately 10°. When the external signal is input to the first input port  351   c  of the third Butler matrix  36   c,  the polarization direction of the electromagnetic pattern generated by the antenna array is an angle except for −45° or 45°, and the deflection angle is approximately −10°. When the external signal is input to the second input port  352   c  of the third Butler matrix  36   c,  the polarization direction of the electromagnetic pattern generated by the antenna array is an angle except for −45° or 45°, and the deflection angle is approximately +30°. When the external signal is input to the third input port  353   c  of the third Butler matrix  36   c,  the polarization direction of the electromagnetic pattern generated by the antenna array is an angle except for −45°or 45°, and the deflection angle is approximately −30°. When the external signal is input to the fourth input port  354   c  of the third Butler matrix  36   c,  the polarization direction of the electromagnetic pattern generated by the antenna array is −45°, and the deflection angle is approximately 10°. 
         [0055]    In a preferred embodiment of the present invention, the four input ports are electrically connected to a switcher for being switched by the switcher, such that the antenna array is switched among beam forming of different angles. In another preferred embodiment of the present invention, a range of an operating frequency of the antenna array is from 2400 MHz to 2500 MHz. 
         [0056]      FIGS. 5A ,  5 B, and  5 C are respectively radiation patterns generated by the antenna array at the operating frequencies of 2400 MHz, 2450 MHz, and 2500 MHz and the polarization direction of 45°, when the signal is fed through the first input port  251   a  of the first Butler matrix  16   a  in  FIG. 1 .  FIGS. 6A ,  6 B, and  6 C are respectively radiation patterns generated by the antenna array at the operating frequencies of 2400 MHz, 2450 MHz, and 2500 MHz and the polarization direction of 45°, when the signal is fed through the second input port  252   a  of the first Butler matrix  16   a  in  FIG. 1 .  FIGS. 7A ,  7 B, and  7 C are respectively radiation patterns generated by the antenna array at the operating frequencies of 2400 MHz, 2450 MHz, and 2500 MHz and the polarization direction of 45°, when the signal is fed through the third input port  253   a  of the first Butler matrix  16   a  in  FIG. 1 .  FIGS. 8A ,  8 B, and  8 C are respectively radiation patterns generated by the antenna array at the operating frequencies of 2400 MHz, 2450 MHz, and 2500 MHz and the polarization direction of 45°, when the signal is fed through the fourth input port  254   a  of the first Butler matrix  16   a  in  FIG. 1 . 
         [0057]      FIGS. 9A ,  9 B, and  9 C are respectively radiation patterns generated by the antenna array at the operating frequencies of 2400 MHz, 2450 MHz, and 2500 MHz and the polarization direction of −45°, when the signal is fed through the first input port  251   b  of the second Butler matrix  16   b  in  FIG. 1 .  FIGS. 10A ,  10 B, and  10 C are respectively radiation patterns generated by the antenna array at the operating frequencies of 2400 MHz, 2450 MHz, and 2500 MHz and the polarization direction of −45°, when the signal is fed through the second input port  252   b  of the second Butler matrix  16   b  in  FIG. 1 .  FIGS. 11A ,  11 B, and  11 C are respectively radiation patterns generated by the antenna array at the operating frequencies of 2400 MHz, 2450 MHz, and 2500 MHz and the polarization direction of −45°, when the signal is fed through the third input port  253   b  of the second Butler matrix  16   b  in  FIG. 1 .  FIGS. 12A ,  12 B, and  12 C are respectively radiation patterns generated by the antenna array at the operating frequencies of 2400 MHz, 2450 MHz, and 2500 MHz and the polarization direction of −45°, when the signal is fed through the fourth input port  254   b  of the second Butler matrix  16   b  in  FIG. 1 .