Patent Publication Number: US-9893433-B2

Title: Array antenna

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of International Application No. PCT/CN2014/084774, filed on Aug. 20, 2014, claims priority to Chinese Patent Application No. 201310690542.1, filed on Dec. 13, 2013, both of which are incorporated herein by reference in their entireties. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to the field of communications, and in particular, to an array antenna. 
     BACKGROUND 
     An antenna is one of the most important front-end passive components of a communications device. The antenna plays a very important role in performance of a communications product. Currently, an existing slot array antenna uses rows of through-holes provided on a surface of the slot array antenna to form a side wall of a rectangular waveguide, so that functions of a conventional rectangular waveguide are implemented. However, the antenna uses a serial feed. Due to constraints of the serial feed, bandwidth of the antenna is inversely proportional to a quantity of slots of each waveguide. Therefore, the antenna has narrow bandwidth, and cannot meet a requirement of a system for wider bandwidth. 
     SUMMARY 
     An array antenna is provided to increase bandwidth of an antenna and meet a requirement of a system for wider bandwidth. 
     According to a first aspect, an array antenna is provided and configured to receive an input signal and radiate the received input signal in a form of an electromagnetic signal. The array antenna includes a cavity power divider and a final-stage power dividing, coupling, and radiating unit assembled on the cavity power divider. The cavity power divider is configured to receive the input signal and perform power division on the input signal to output a first power-divided signal to the final-stage power dividing, coupling, and radiating unit. The final-stage power dividing, coupling, and radiating unit includes a dielectric substrate, a first metal surface layer disposed on an upper surface of the dielectric substrate, and a second metal surface layer disposed on a lower surface of the dielectric substrate. A coupling slot array is formed on the second metal surface layer to receive the first power-divided signal, a radiating slot array corresponding to the coupling slot array is formed on the first metal surface layer, and several plated through-hole units are provided on the dielectric substrate. The plated through-hole units go through the first and second metal surface layers vertically, and a range corresponding to each plated through-hole unit encloses a coupling slot in the coupling slot array and a radiating slot in the radiating slot array and corresponding to the coupling slot, so that final-stage power division is performed on the first power-divided signal received by the coupling slot array to output a second power-divided signal to the radiating slot array and that the radiating slot array radiates the second power-divided signal. 
     In a first possible implementation manner of the first aspect, the array antenna further includes a matching mechanical part, where the matching mechanical part is disposed between the cavity power divider and the final-stage power dividing, coupling, and radiating unit; the cavity power divider includes a waveguide port and a power-divided signal output port, where the waveguide port receives the input signal, so that the cavity power divider performs power division processing on the input signal, and the power-divided signal output port is configured to output the first power-divided signal; and the matching mechanical part includes a body part and a matching port formed on the body part, where the matching port corresponds to the power-divided signal output port and the coupling slot array, so that the power-divided signal output port is connected to a coupling slot of the final-stage power dividing, coupling, and radiating unit and that the first power-divided signal is transmitted to the coupling slot array. 
     With reference to the first possible implementation manner of the first aspect, in a second possible implementation manner, a quantity of the matching ports is the same as a quantity of the power-divided signal output ports and a quantity of the coupling slots in the coupling slot array, and sizes of the matching ports are the same as sizes of the power-divided signal output ports and sizes of the corresponding coupling slots in the coupling slot array. 
     In a third possible implementation manner of the first aspect, the array antenna further includes an isolating mechanical part, where the isolating mechanical part includes a board body and a through-hole array disposed on the board body; the through-hole array goes through a top and a bottom of the board body and corresponds to the radiating slot array; the bottom of the board body is disposed on the second metal surface layer; the through-hole array is interconnected with the radiating slot array; a projection of the radiating slot array on the board body is a first projection; and a projection of the through-hole array on the board body is a second projection, where the first projection overlaps the second projection or the first projection is within the second projection. 
     With reference to the third possible implementation manner of the first aspect, in a fourth possible implementation manner, both the radiating slot array and the through-hole array are 4×4 arrays, and the coupling slot array is a 2×2 array. 
     With reference to the third possible implementation manner of the first aspect, in a fifth possible implementation manner, the isolating mechanical part, the final-stage power dividing, coupling, and radiating unit, and the cavity power divider are assembled by using positioning pins. 
     With reference to the third possible implementation manner of the first aspect, in a sixth possible implementation manner, all through-holes in the through-hole array have a same size. 
     With reference to the third possible implementation manner of the first aspect, in a seventh possible implementation manner, the board body is made of a metallic material. 
     With reference to the third possible implementation manner of the first aspect, in an eighth possible implementation manner, the board body is made of a non-metallic material, and all hole walls of the through-hole array are coated with a metal layer. 
     In a ninth possible implementation manner of the first aspect, the dielectric substrate, the first metal surface layer, and the second metal surface layer are all in a square shape and have a same size. 
     The array antenna provided according to each implementation manner is configured to receive an input signal and radiate the received input signal in a form of an electromagnetic signal. The array antenna includes a cavity power divider and a final-stage power dividing, coupling, and radiating unit installed on the cavity power divider, where the cavity power divider is configured to receive the input signal and perform power division on the input signal to output a first power-divided signal to the final-stage power dividing, coupling, and radiating unit; and the final-stage power dividing, coupling, and radiating unit includes a dielectric substrate, a first metal surface layer disposed on an upper surface of the dielectric substrate, and a second metal surface layer disposed on a lower surface of the dielectric substrate, a coupling slot array is formed on the second metal surface layer to receive the first power-divided signal, a radiating slot array corresponding to the coupling slot array is formed on the first metal surface layer, and several plated through-hole units are provided on the dielectric substrate, where the plated through-hole units go through the first and second metal surface layers vertically, and a range corresponding to each plated through-hole unit encloses a coupling slot in the coupling slot array and a radiating slot in the radiating slot array and corresponding to the coupling slot, so that final-stage power division is performed on the first power-divided signal received by the coupling slot array to output a second power-divided signal to the radiating slot array and that the radiating slot array radiates the second power-divided signal. Because the cavity power divider is a shunt-fed power division feed and each plated through-hole unit of the final-stage power dividing, coupling, and radiating unit encloses a coupling slot in the coupling slot array and a radiating slot in the radiating slot array and corresponding to the coupling slot, a quantity of radiating slots corresponding to each final-stage power division is relatively small, so that the bandwidth of the array antenna is relatively wide, thereby meeting a requirement of a system for wider bandwidth. In addition, the dielectric substrate, the first metal surface layer, and the second metal surface layer of the final-stage power dividing, coupling, and radiating unit constitute a printed circuit board. Therefore, an objective of integrating functions of coupling, final-stage power dividing, and radiating is achieved by using the printed circuit board, availability is high, and costs are reduced. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       To describe the technical solutions in the embodiments of the present disclosure more clearly, the following briefly introduces the accompanying drawings required for describing the embodiments or the prior art. Apparently, the accompanying drawings in the following description show merely some embodiments of the present disclosure, and a person of ordinary skill in the art may still derive other drawings from these accompanying drawings without creative efforts. 
         FIG. 1  is a schematic breakdown diagram of an array antenna according to a first exemplary implementation manner; 
         FIG. 2  is a top view of a final-stage power dividing, coupling, and radiating unit in  FIG. 1 ; 
         FIG. 3  is a diagram of a simulated voltage standing wave ratio after a matching mechanical part is removed from the array antenna in  FIG. 1 ; 
         FIG. 4  is a diagram of a simulated voltage standing wave ratio of the array antenna in  FIG. 1 ; 
         FIG. 5  is a schematic breakdown diagram of an array antenna according to a second exemplary implementation manner; 
         FIG. 6  is a diagram of a simulated radiation pattern after an isolating mechanical part is removed from the array antenna in  FIG. 5 ; and 
         FIG. 7  is a simulated radiation pattern of the array antenna in  FIG. 5 . 
     
    
    
     DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS 
     The following clearly describes the technical solutions in the embodiments of the present disclosure with reference to the accompanying drawings in the embodiments of the present disclosure. Apparently, the described embodiments are merely some but not all of the embodiments of the present disclosure. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present disclosure without creative efforts shall fall within the protection scope of the present disclosure. 
     Referring to  FIG. 1 , a first exemplary implementation manner of the present disclosure provides an array antenna  100 . The array antenna  100  is configured to receive an input signal, and radiate the received input signal in a form of an electromagnetic signal. The array antenna  100  includes a cavity power divider  10  and a final-stage power dividing, coupling, and radiating unit  20  installed on the cavity power divider  10 . The cavity power divider  10  is configured to receive the input signal, and perform power division on the input signal to output a first power-divided signal to the final-stage power dividing, coupling, and radiating unit  20 . Referring to  FIG. 2 , the final-stage power dividing, coupling, and radiating unit  20  includes a dielectric substrate  21 , a first metal surface layer  22  disposed on an upper surface of the dielectric substrate  21 , and a second metal surface layer  23  disposed on a lower surface of the dielectric substrate  21 . A coupling slot array  232  is formed on the second metal surface layer  23  to receive the first power-divided signal. A radiating slot array  222  corresponding to the coupling slot array  232  is formed on the first metal surface layer  22 . Several plated through-hole units  212  are provided on the dielectric substrate  21 . The plated through-hole units  212  go through the first metal surface layer  22  and the second metal surface layer  23  vertically. A range  214  corresponding to each plated through-hole unit  212  encloses a coupling slot  234  in the coupling slot array  232  and a radiating slot  224  in the radiating slot array  222  and corresponding to the coupling slot  234 , so that final-stage power division is performed on the first power-divided signal received by the coupling slot array  232  to output a second power-divided signal to the radiating slot array  222  and that the radiating slot array  222  radiates the second power-divided signal. 
     The plated through-holes  212  provided on the dielectric substrate  21  and going through the first metal surface layer  22  and the second metal surface layer  23  enable the final-stage power dividing, coupling, and radiating unit  20  to implement final-stage power division with an equal amplitude and an equal phase and a symmetry in both an X-axis direction and a Y-axis direction. The X axis and Y axis are two axes of an X-Y coordinate system that is established on the surface of the dielectric substrate  21  and by using a center of the dielectric substrate  21  as an origin. The array antenna  100  is a PCB (printed circuit board) slot array antenna. The final-stage power dividing, coupling, and radiating unit  20  is a final-stage power dividing, coupling, and radiating unit of a PCB. The dielectric substrate  21 , the first metal surface layer  22 , and the second metal surface layer  23  constitute the PCB. Therefore, the final-stage power dividing, coupling, and radiating unit  20  achieves an objective of integrating the coupling, final-stage power dividing, and radiating by using the PCB. 
     In this implementation manner, the plated through-hole unit  212  is enclosed by several plated through-holes  213 . The range  214  corresponding to the plated through-hole unit  212  is enclosed by the several plated through-holes  213 . A quantity of the plated through-hole units  212  is four. The radiating slot array  222  is a 4×4 array, and the coupling slot array  232  is a 2×2 array. That is, one coupling slot  234  corresponds to four radiating slots  224 , and the range  214  corresponding to one plated through-hole unit  212  encloses one coupling slot  234  and four radiating slots  224  corresponding to the coupling slot  234 . Therefore, the final-stage power dividing, coupling, and radiating unit  20  implements final-stage one-to-four power division with an equal amplitude and an equal phase. The dielectric substrate  21 , the first metal surface layer  22 , and the second metal surface layer  23  are in a square shape and have a same size. 
     In other implementation manners, the radiating slot array  222  may also be an N×N array, where N is a natural number. However, the N×N array is extended on a basis of a most basic 2×2 subarray unit, for example, 4×4 and 8×8. That is, one coupling slot may correspond to a quantity of radiating slots that is equal to an integer multiple of 2, namely, 2N. In this way, one plated through-hole unit  212  may also enclose one coupling slot and 2N radiating slots corresponding to the coupling slot. Therefore, the final-stage power dividing, coupling, and radiating unit  20  can implement final-stage one-to-2N power division with an equal amplitude and equal phase. The type of the cavity power divider  10  may also be replaced according to an actual requirement, that is, the cavity power divider  10  may be replaced with another cavity power divider according to a requirement provided that it can implement a power division function. The shapes and sizes of the dielectric substrate  21 , the first metal surface layer  22 , and the second metal surface layer  23  may be adjusted according to an actual requirement, for example, may be circular or in an irregular shape. 
     In this implementation manner, the final-stage power dividing, coupling, and radiating unit  20  includes a dielectric substrate  21 , a first metal surface layer  22  disposed on an upper surface of the dielectric substrate  21 , and a second metal surface layer  23  disposed on a lower surface of the dielectric substrate  21 . A coupling slot array  232  is formed on the second metal surface layer  23  to receive the first power-divided signal. A radiating slot array  222  corresponding to the coupling slot array  232  is formed on the first metal surface layer  22 . Several plated through-hole units  212  are provided on the dielectric substrate  21 . The plated through-hole units  212  go through the first metal surface layer  22  and the second metal surface layer  23  vertically. A range corresponding to each plated through-hole unit  212  encloses a coupling slot  234  in the coupling slot array  232  and a radiating slot  224  in the radiating slot array  222  and corresponding to the coupling slot  234 , so that final-stage power division is performed on the first power-divided signal received by the coupling slot array  232  to output a second power-divided signal to the radiating slot array  222  and that the radiating slot array  222  radiates the second power-divided signal. Because the cavity power divider  10  is a shunt-fed power division feed and each plated through-hole unit  212  of the final-stage power dividing, coupling, and radiating unit  20  encloses a coupling slot  234  in the coupling slot array  232  and a radiating slot  224  in the radiating slot array  222  and corresponding to the coupling slot  234 , a quantity of radiating slots  224  corresponding to each final-stage power division is relatively small, so that the bandwidth of the array antenna is relatively wide, thereby meeting a requirement of a system for wider bandwidth. In addition, the dielectric substrate  21 , the first metal surface layer  22 , and the second metal surface layer  23  of the final-stage power dividing, coupling, and radiating unit  20  constitute a PCB. Therefore, the final-stage power dividing, coupling, and radiating unit  20  achieves an objective of integrating functions of coupling, final-stage power dividing, and radiating by using the PCB, availability is high, and costs are reduced. 
     Further, referring to  FIG. 1 , the array antenna  100  further includes a matching mechanical part  30 . The matching mechanical part  30  is disposed between the cavity power divider  10  and the final-stage power dividing, coupling, and radiating unit  20 . The cavity power divider  10  includes a waveguide port  11  and a power-divided signal output port  12 . The waveguide port  11  receives the input signal, so that the cavity power divider  10  performs power division processing on the input signal. The power-divided signal output port  12  is configured to output the first power-divided signal. The matching mechanical part  30  includes a body part  31  and a matching port  32  formed on the body part  31 . The matching port  32  corresponds to the power-divided signal output port  12  and the coupling slot array  232 , so that the power-divided signal output port  12  is connected to a coupling slot  234  of the final-stage power dividing, coupling, and radiating unit  20  and that the first power-divided signal is transmitted to the coupling slot array  232 . 
     A quantity of the matching ports  32  is the same as a quantity of the power-divided signal output ports  12  and a quantity of the coupling slots  234  in the coupling slot array  232 , and a size of the matching ports  32  is the same as a size of the power-divided signal output ports  12  and a size of the corresponding coupling slots  234  in the coupling slot array  232 . The matching mechanical part  30  may be made of a conducting material, for example, a metallic material. The matching mechanical part  30  may also be made of a non-conducting material, but the matching port in the matching mechanical part  30  is coated with a conducting material, for example, a metallic material. 
     Referring to  FIG. 3  and  FIG. 4 , in this implementation manner, the matching mechanical part  30  is disposed between the cavity power divider  10  and the final-stage power dividing, coupling, and radiating unit  20 . The matching port  32  corresponds to the power-divided signal output port  12  and the coupling slot array  232 , so that the power-divided signal output port  12  is connected to a coupling slot  234  of the final-stage power dividing, coupling, and radiating unit  20  and that the first power-divided signal is transmitted to the coupling slot array  232 .  FIG. 3  is a simulated voltage standing wave ratio diagram obtained when simulation is performed after the matching mechanical part  14  is removed from the array antenna in  FIG. 1 .  FIG. 4  is a simulated voltage standing wave ratio diagram obtained when simulation is performed on the array antenna according to the present disclosure. It can be known through comparison between  FIG. 3  and  FIG. 4  that the array antenna  100  in which the matching mechanical part  14  is disposed between the cavity power divider  10  and the final-stage power dividing, coupling, and radiating unit  20  has a relatively low voltage standing wave ratio. That is, the matching mechanical part  14  reduces the voltage standing wave ratio of the array antenna  100 . Therefore, the bandwidth of the array antenna  100  is increased. 
     Referring to  FIG. 5 , a second exemplary implementation manner of the present disclosure provides an array antenna  200 . The array antenna  200  provided according to the second exemplary implementation manner is similar to the array antenna provided according to the first exemplary implementation manner, with a difference in that in the second exemplary implementation manner, the array antenna  200  further includes an isolating mechanical part  40 . The isolating mechanical part  40  includes a board body  41  and a through-hole array  42  disposed on the board body  41 . The through-hole array  42  goes through a top and a bottom of the board body  41  and corresponds to the radiating slot array  222 . The bottom of the board body  41  is disposed on the second metal surface layer  23 . The through-hole array  42  is interconnected with the radiating slot array  232 . A projection of the radiating slot array  232  on the board body  41  is a first projection. A projection of the through-hole array  42  on the board body  41  is a second projection. The first projection overlaps the second projection or the first projection is within the second projection. The through-hole array  42  is configured to isolate each radiating slot  224  in the radiating slot array  232  to prevent the radiating slots  224  from affecting each other and avoid an impact on signal quality. 
     The through-hole array  42  is a 4×4 array. The isolating mechanical part  40 , the final-stage power dividing, coupling, and radiating unit  20 , and the cavity power divider  10  are assembled by using positioning pins. All through-holes in the through-hole array  42  have a same size. The through-holes are in a square shape. The board body is made of a metallic material. 
     In other implementation manners, the form of the through-hole array  42  may be changed according to a change of the radiating slot array  232 . The shape of the through-hole may also be adjusted according to an actual requirement, for example, adjusted to a circular or horn shape. The board body  41  may also be made of a non-metallic material. 
     Referring to  FIG. 6  and  FIG. 7 , in this implementation manner, the through-hole array  42  on the isolating mechanical part  40  is disposed on the second metal surface layer  23 . Each through-hole corresponds to one radiating slot  224 , so that a surface current of each radiating slot  224  can be isolated and that couplings between the radiating slots  224  can be reduced.  FIG. 6  is a simulated radiation pattern after the isolating mechanical part  40  is removed from the array antenna in  FIG. 5 .  FIG. 7  is a simulated radiation pattern of the array antenna  200  according to the present disclosure. It can be known through comparison between  FIG. 6  and  FIG. 7  that in the radiation pattern of the array antenna  200  to which the isolating mechanical part  40  is added, a grating lobe and a sidelobe of the antenna are greatly improved. Therefore, a problem that a panel antenna generally has a higher grating lobe is solved. 
     What is disclosed above is merely exemplary embodiments of the present disclosure, and certainly is not intended to limit the protection scope of the present disclosure. A person of ordinary skill in the art may understand that all or some of processes that implement the foregoing embodiments and equivalent modifications made in accordance with the claims of the present disclosure shall fall within the scope of the present disclosure.