Abstract:
A phase shifter includes a metal plate, a support portion, a slot, a coupling portion, and a ground portion. The phase shifter effectively improves signal coupling efficiency, and inhibits noise generated with the change of phase shift due to signal transmission. The phase shifter is advantageous in smaller volume, easy to assemble, and low cost.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of Invention 
         [0002]    The present invention relates to a phase shifter, and more particularly to a phase shifter with slot coupling. 
         [0003]    2. Related Art 
         [0004]    With the development of wireless communication technology, wireless communication products are becoming more and more important in daily life. Moreover, people now require the communication products to be capable of transmitting video or online browsing instead of merely transmitting voice and messages. As compared with paying little attention on the appearance in the past, people now emphasizes on the products being “light, thin, short and small”, and capable of providing various communication services. As the communication products are developing in the trend of broadband and integration of multiple functions, the antennae for receiving and transmitting signals require wider bandwidth, so as to achieve high transmission speed and provide various communication services. 
         [0005]    Phase shifters are often used in the fields of communications, instruments, and control. Though having many applications, they still have quite a number of problems to solve. For example, as the phase shifters are formed with metal structures, the coupling efficiency is unsatisfactory, or as the signal transmission is done in a contact mode, noise will be generated with the change of phase shift. Moreover, normal phase shifters have large volumes, and metal structures, so it is quite complex to fabricate. 
         [0006]    Therefore, it has become a problem for researchers to solve to provide a phase shifter that effectively improves the signal coupling efficiency, effectively inhibits the noise generated with the change of the phase shift due to the signal transmission, and has a smaller volume. 
       SUMMARY OF THE INVENTION 
       [0007]    Accordingly, the present invention is directed to providing a phase shifter, which effectively realizes wide broadband, small volume, easy to assemble, and low cost. 
         [0008]    The phase shifter of the present invention includes a metal plate, having a first surface and a second surface paralleling to the first surface; a support portion, located on the first surface of the metal plate for receiving a feed-in signal from a signal feed-in end; a slot, formed on the first surface of the metal plate, for transmitting the feed-in signal received by coupling to signal output end; a coupling portion, connected to the support portion, for coupling the feed-in signal to the slot; a ground portion, located beneath the second surface of the metal plate vertically, for simplifying the architecture and reduce volume of the phase shifter. 
         [0009]    The phase shifter disclosed in the present invention couples the feed-in signal to the slot through the coupling portion, and transmitting the signal out from the slot, thereby effectively improving the signal coupling efficiency, and inhibiting noise generated with the change of phase shift due to the signal transmission, so as to realize the effect of an energy distributor. Moreover, as the support portion is movable, the phase of the signal is changed when the support portion is moved, so as to realize the effect of a phase shifter. 
         [0010]    Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    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: 
           [0012]      FIG. 1  is a schematic view of a first embodiment of the present invention; 
           [0013]      FIG. 2  is a schematic view of a second embodiment of the present invention; 
           [0014]      FIG. 3  is a schematic view of a third embodiment of the present invention; 
           [0015]      FIG. 4  is a schematic view of a fourth embodiment of the present invention; 
           [0016]      FIG. 5  is a schematic view of a fifth embodiment of the present invention; 
           [0017]      FIG. 6  shows an input return loss in an input bandwidth simulated according to the third embodiment; and 
           [0018]      FIG. 7  shows a signal loss at a signal output end obtained from simulation when the third embodiment is used as an energy distributor. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0019]      FIG. 1  is a schematic view of a first embodiment of the present invention. As shown in  FIG. 1 , the phase shifter includes a metal plate  10 , a signal transmission line  15 , a first support portion  21 , a first slot  30 , a second slot  31 , a first coupling portion  40 , and a second coupling portion  41 . 
         [0020]    The metal plate  10  has a first surface  11  and a second surface  12 . 
         [0021]    The signal transmission line  15  and the first support portion  21  are connected to two opposite edges of the first surface  11  respectively, and support the first coupling portion  40  and the second coupling portion  41  respectively. An internal signal line  16  of the signal transmission line  15  is connected to the first coupling portion  40 , and an external grounding metal sheathing  17  of the signal transmission line  15  is connected to the first surface  11  of the metal plate  10 , so as to receive a signal and feed the signal into the first coupling portion  40 . The signal transmission line  15  and the first support portion  21  can be connected to the first surface  11  by bonding or another manner. 
         [0022]    An end of the first coupling portion  40  is connected to the second coupling portion  41 , and the other end is connected to the internal signal line  16  of the signal transmission line  15 . Another end of the second coupling portion  41  is connected to the second support portion  21 . The first coupling portion  40  and the second coupling portion  41  span across the first slot  30  and the second slot  31  respectively, and couple the feed-in signal to the corresponding first slot  30  and second slot  31  respectively. The first coupling portion  40  and the second coupling portion  41  are a one-piece formed metal sheet, or are different metal sheets that are bonded together. 
         [0023]    The first slot  30  and the second slot  31  are formed on the first surface  11  of the metal plate  10 , so as to transmit the feed-in signal received by coupling to signal output portions  14 A,  14 B,  14 C, and  14 D. The signal output portions  14 A,  14 B,  14 C, and  14 D are located on two ends of the first slot  30  and two ends of the second slot  31  respectively, so as to receive the feed-in signal from the first slot  30  and the second slot  31 , and transmit the signal to the outside or to an external element. 
         [0024]    The ground portion  22  is located beneath the second surface  12  of the metal plate  10 , for electrically grounding the signal output portions  14 . 
         [0025]    When the feed-in signal is fed in through the signal transmission line  15 , the feed-in signal is transmitted to the first coupling portion  40  and the second coupling portion  41  by the use of an impedance matching design. The areas of the first coupling portion  40  and the second coupling portion  41  may be adjusted to realize the impedance matching design, and to control the energy coupled to the signal output portions  14 A,  14 B,  14 C, and  14 D. 
         [0026]    The first slot  30  and the second slot  31  on the first surface  11  are discontinuous surfaces relative to the first coupling portion  40  and the second coupling portion  41 . Therefore, as the air serves as a dielectric, the first coupling portion  40  and the second coupling portion  41  couple the feed-in signal to corresponding positions of the first slot  30  and the second slot  31  in the first surface  11  by means of radiation transmission. Then, the first slot  30  and the second slot  31  transmit the feed-in signal received by coupling to the signal output portions  14 A,  14 B,  14 C, and  14 D, and then transmit the signal to the outside. 
         [0027]    A ground portion  22  is located beneath the second surface  12  of the metal plate  10 , and is connected to the metal plate vertically, so as to electrically ground the signal output portions  14 . The ground portion  22  may be a metal sheet perpendicular to the second surface  12 , a metal bolt locked on the metal plate  10 , or the like. In addition, in order to prevent the coupling between the neighboring first slot  30  and second slot  31  caused by the closing space between the first slot  30  and second slot  31 , the space between the first slot  30  and the second slot  31  must be increased to avoid the coupling effect between the first slot  30  and the second slot  31 . However, the volume of the metal plate  10  is thus increased. At this time, as the ground portion  22  is designed isolative, the coupling between the first slot  30  and the second slot  31  may also be prevented, and the volume of the metal plate  10  will not be increased, which prevents the phase shifter from becoming larger and more costly. 
         [0028]    As the phase shifter uses the first coupling portion  40  and the second coupling portion  41  to couple the feed-in energy signal to the corresponding first slot  30  and second slot  31 , the first slot  30  and the second slot  31  will transmit the energy signal to the signal output portions  14 . As the phase shifter can distribute the energy at the input end to the corresponding output ends, it can also be regarded as an energy distributor. 
         [0029]      FIG. 2  is a schematic view of a second embodiment of the present invention. Referring to  FIG. 2 , the structure of the second embodiments of the present invention is different from that of the first embodiments of the present invention in terms that the second support portion  21  is removed. Thus, one end of the second coupling portion  41  is connected to the first coupling portion  40 , while another end is suspended above the metal plate instead of connecting to the metal plate  10 . The rest connecting methods and functions of the second embodiment are the same as those of the first embodiment, and will not be described herein again. 
         [0030]      FIG. 3  is a schematic view of a third embodiment of the present invention. As shown in  FIG. 3 , the phase shifter includes a metal plate  50 , a first support portion  61 , a second support portion  62 , a signal transmission portion  63 , a signal transmission line  64 , a first slot  70 , a second slot  71 , a first coupling portion  65 , and a second coupling portion  66 . 
         [0031]    The metal plate  50  has a first surface  51  and a second surface  52 . An internal signal line  68  of the signal transmission line  64  is connected to the signal transmission portion  63 . An external grounding metal sheathing  69  of the signal transmission line  64  is connected to the first surface  51  of the metal plate  50 , so as to transmit and couple the feed-in signal to the signal transmission portion  63 . One end of the first support portion  61  and one end of the second support portion  62  are connected to the first coupling portion  65  and the second coupling portion  66 , and another end of the first support portion  61  and another end of the second support portion  62  are located on two opposite edges of the metal plate  50  respectively. 
         [0032]    The first coupling portion  65  spans across the first slot  70 . One end of the first coupling portion  65  is connected to the first support portion  61 , and another end is connected to the signal transmission portion  63 , so as to couple the feed-in signal from the signal transmission portion  63  to the corresponding first slot  70 . The second coupling portion  66  spans across the second slot  71 . One end of the second coupling portion  66  is connected to the second support portion  62 , and another end is connected to the signal transmission portion  63 , so as to couple the feed-in signal from the signal transmission portion  63  to the corresponding second slot  71 . The signal transmission portion  63 , the first coupling portion  65 , and the second coupling portion  66  are interconnected as a whole. In another embodiment, a V-shaped notch  67  is formed at the junction of the first coupling portion  65  and the second coupling portion  66 . 
         [0033]    The first slot  70  and the second slot  71  are formed in the first surface  51  of the metal plate  50 , so as to transmit the feed-in signal received by coupling to the signal output portion  80 . 
         [0034]    Signal output ends  80 A,  80 B,  80 C, and  80 D are located on two ends of the first slot  70  and two ends of the second slot  71  respectively, so as to transmit the feed-in signals received from the first slot  70  and the second slot  71  to the outside. 
         [0035]    A ground portion  81  is located beneath the second surface  52  of the metal plate  50 , so as to electrically ground the signal output portion  80 . 
         [0036]    When the feed-in signal is fed in from the internal signal line  68  of the signal transmission line  64 , the feed-in signal is transmitted through the signal transmission portion  63  to the first coupling portion  65  and the second coupling portion  66  that are connected to the signal transmission portion  63 . At this time, the first slot  70  and the second slot  71  in the first surface  51  are discontinuous surfaces relative to the first coupling portion  65  and the second coupling portion  66 . Therefore, as the air serves as the dielectric, the first coupling portion  65  and the second coupling portion  66  couple the feed-in signal to corresponding positions of the first slot  70  and the second slot  71  in the first surface  51  by means of radiation transmission. Then, the first slot  70  and the second slot  71  transmit the feed-in signal received by coupling to the signal output portions  80 A,  80 B,  80 C, and  80 D, and then transmit the signal to the outside. 
         [0037]    The signal transmission line  64 , the first support portion  61 , and the second support portion  62  may be connected to the first surface  51  by bonding or in another manner. 
         [0038]      FIG. 4  is a schematic view of a fourth embodiment of the present invention. The structure of the fourth embodiment of the present invention is different from that of the third embodiments of the present invention in terms that the first support portion  61  and the second support portion  62  are removed. Thus, one end of the first coupling portion  65  and one end of the second coupling portion  66  are connected to the signal transmission portion  63 , while another end of the first coupling portion  65  and another end of the second coupling portion  66  are suspended above the metal plate without connecting to the metal plate  50 . The rest connecting methods and functions of the fourth embodiment are the same as those of the third embodiment, and will not be described herein again. 
         [0039]      FIG. 5  is a schematic view of a fifth embodiment of the present invention. The difference between the structures of the fifth and third embodiments of the present invention is described as follows. The ground portion  81  is removed, and the positions of the signal output portions  80 A,  80 B,  80 C, and  80 D on two ends of the first slot  70  and two ends of the second slot  71  are moved inward to positions one-fourth wavelength away from edges of the slots. 
         [0040]    When a signal is transmitted for a distance of one-fourth of its wavelength, an open loop will be formed. At this time, the first surface  51  may be regarded as three regions, namely, a region  51   a  between the first slot  70  and an edge of the first surface  51 , a region  51   b  between the first slot  70  and the second slot  71 , and a region  51   c  between the second slot  71  and the other edge of the first surface  51 . The region  51   b  between the first slot  70  and the second slot  71  may be regarded as grounded, and the region  51   a  between the first slot  70  and the edge of the first surface  51  and the region  51   c  between the second slot  71  and the edge of the first surface  51  may be regarded at the same level. At this time, as long as the signal transmission line spans across the first slot and transversely reaches the positions of the signal output ends  14  on the first slot  70  and the second slot  71 , the internal signal line of the signal transmission line is connected to the region  51   a  and the region  51   c  that are regarded at the same level. The external grounding metal sheathing of the signal transmission line is connected to the region  51   b  that is regarded as grounded. In this manner, the phase shifter is simplified and becomes smaller, and the ground portion  81  is omitted. 
         [0041]      FIG. 6  shows an input return loss of −20 dB in an input bandwidth simulated according to the third embodiment, which is smaller than the loss of −10 to −15 dB of normal phase shifters. 
         [0042]      FIG. 7  shows a signal loss at a signal output end obtained from simulation when the third embodiment is used as an energy distributor, which is in conformity with the theoretical signal loss of −6 dB at the signal output end. 
         [0043]    In the embodiments of the phase shifter of the present invention, though the long metal plate  10  and the linear slot  30  are set as an example, it should be understood that they can also be fabricated to other shapes such as round, which are not limited herein. 
         [0044]    The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.