Patent Publication Number: US-11024945-B2

Title: Antenna system and mobile terminal

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the priority benefit of Chinese Patent Applications Ser. No. 201810071729.6 filed on Jan. 25, 2018, the entire content of which is incorporated herein by reference. 
     TECHNICAL FIELD 
     Embodiments of the present disclosure relate to the field of communications technologies, and in particular, to an antenna and a mobile terminal. 
     BACKGROUND 
     With constant development of communications technologies, the fifth-generation (5G) mobile communications technology appears behind the cool and hot technologies such as virtual reality, drones, and automatic driving. The fifth-generation mobile communications technology is an extension of 4G, and is being researched. A theoretical downlink speed of a 5G network is 10 Gb/s (which is equivalent to a download speed of 1.25 GB/s). With regard to capacities, mobile data traffic of the 5G communications technology increases by 1000 times than that of 4G per unit area. While with regard to transmission rates, a typical user data rate increases by 10 times to 100 times, and a peak transmission rate can reach 10 Gbps (where a peak transmission rate of 4G is 100 Mbps). As can be seen, 5G will fully surpass 4G in all aspects and achieve a real integrated networks. 
     The International Telecommunication Union (ITU) specified the main application scenarios of 5G at the 22 nd  ITU-RWP5D Conference held in June 2015. The ITU defined three main application scenarios of 5G: enhanced Mobile Broadband (eMBB), large-scale machine Communication, and high Reliable and Low Latency Communication (HRLLC). The three application scenarios respectively correspond to different key indicators, where in the eMBB scenario, a user&#39;s peak rate is 20 Gbps, and a lowest user experience rate is 100 Mbps. 
     The inventor finds out that at least the following problems exist in the prior art: the existing mobile terminal design tends to a structure of a full screen, a ceramic or glass rear housing, and a metal middle frame. For a full-screen communications device, a conventional antenna layout space is very limited. Therefore, it is very difficult to dispose more antennas of more bands. In addition, in a multi-frequency band antenna layout, isolation and correlation requirements between antennas also need to be considered, which further increasing the design difficulty. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       One or more embodiments are exemplified by tdrawings corresponding to the accompanying drawings. The exemplary descriptions do not constitute any limitation to the embodiments. Elements with a same reference numeral in the accompanying drawings represent similar elements. Unless otherwise stated, the drawings in the accompanying drawings constitute no proportional limitation. 
         FIG. 1  is a schematic structural diagram of a mobile terminal according to a first embodiment of the present disclosure; 
         FIG. 2  is a schematic structural diagram of an antenna system according to a first embodiment of the present disclosure; 
         FIG. 3  is a schematic structural diagram of an antenna group according to a first embodiment of the present disclosure; 
         FIG. 4  is a schematic diagram of a connection between an antenna group and a circuit board according to a first embodiment of the present disclosure; 
         FIG. 5  is a schematic structural diagram of another antenna system according to a first embodiment of the present disclosure; 
         FIG. 6  is a schematic structural diagram of another antenna system according to a first embodiment of the present disclosure; 
         FIG. 7  is a waveform graph of radiation efficiency of a first antenna and a second antenna according to a first embodiment of the present disclosure; 
         FIG. 8  is a waveform graph of reverse transmission coefficients of a first antenna and a second antenna according to a first embodiment of the present disclosure; and 
         FIG. 9  is a waveform graph of Envelope Correlation Coefficient (ECC) of a first antenna and a second antenna according to a first embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     To make the objectives, technical solutions, and advantages of embodiments of the present disclosure clearer, the following further describes the embodiments of the present disclosure in detail with reference to the accompanying drawings. However, a person of ordinary skill in the art may understand that in the embodiments of the present disclosure, to make a reader understand the present disclosure better, many technical details are provided. However, various changes and modifications without these technical details and based on the following embodiments the present disclosure can also implement the technical solutions protected by the present disclosure. 
     A first embodiment of the present disclosure relates an antenna system, applied to a mobile terminal. A structure thereof is shown in  FIG. 1 . The mobile terminal includes a metal frame  40  and a metal middle frame  30  accommodated in the metal frame  40  and connected to the metal frame  40 . In  FIG. 1 , the metal frame  40  includes two opposite long sides and two short sides connecting the long sides, which are a first short side  41 , a first long side  42 , a second short side  43 , and a second long side  44 , respectively. 
     As shown in  FIG. 2 ,  FIG. 3 , and  FIG. 4 , the antenna system includes at least one antenna group  100 , and each antenna group includes a first antenna  10  and a second antenna  20 . 
     The first antenna  10  includes a first antenna slot  11  disposed at a position of the metal middle frame  30  interfacing with the metal frame  40 , a gap  12  disposed on the metal frame  40  and in communication with an end of the first antenna slot  11 , and a first radiation arm  10   a  formed on the metal frame  40 . 
     The first antenna slot  11  extends along a circumferential direction of the metal frame  40 , one end of the first radiation arm  10   a  is connected to the gap  12 , and the other end of the first radiation arm  10   a  is connected to the other end of the first antenna slot  11  away from the gap  12 . 
     The second antenna  20  includes a second antenna slot  21  disposed on the metal frame  40 , where the second antenna slot  21  includes a first slit  22  and a second slit  23  in communication with the first slit  22 , and the first slit  22  extends along the circumferential direction of the metal frame  40 , and the second slit  23  extends along a direction perpendicular to the first slit  22 , to divide the metal frame  40  located at an edge of the first slit  22  into a first branch  20   a  and a second branch  20   b.    
     The first antenna  10  and the second antenna  20  are spaced away from each other along the circumferential direction of the metal frame  40 . 
     The antenna system further includes a circuit board  50  disposed on the metal middle frame  30 , where the circuit board  50  is provided with a first feed point  51 , a second feed point  52 , and a first ground point  53 . Wherein the first feed point  51  is electrically connected to the first radiation arm  10   a , to perform feeding for the first antenna  10 . The second feed point  52  is connected to an end of the first branch  20   a  close to the second slit  23 . The first ground point  53  is connected to an end of the second branch  20   b  close to the second slit  23 , for the second antenna  20  to perform feeding and be grounded. 
     Specifically, the gap  12  of the first antenna  10  is disposed at an end of the first antenna slot  11  away from the second antenna  20 . An electromagnetic wave of the first antenna  10  is radiated through the gap  12 . Therefore, the gap  12  is provided away from the second antenna  20 , which helps improve isolation between the first antenna  10  and the second antenna  20 . It should be noted that the gap  12  may be formed in design of a mobile terminal ID, or may be formed specifically for the first antenna  10 . Therefore, the gap  12  corresponding to the first antenna  10  may be set flexibly as required. 
     A conventional main antenna, diversity antenna, GPS antenna, and Wi-Fi antenna are usually disposed on the short sides of the metal frame  40 . Therefore, in this embodiment, the first antenna  10  and the second antenna  20  are preferably disposed on the long sides, to avoid a conventional antenna area. Specifically, the first antenna  10  and the second antenna  20  both may be formed on the first long side  42 , or may be formed on the second long side  44 . 
     Specifically, the first antenna slot  11  has a width of not greater than 1 mm, and the first slit  22  and the second slit  23  both have a width of not greater than 1 mm. It should be noted that values given in this embodiment are preferable values, and the widths of the first antenna slot  11 , the first slit  22 , and the second slit  23  are not limited to the values in this embodiment. 
     In this embodiment, the antenna system is a multiple-input multiple-output (MIMO) antenna system, and the mobile terminal may be provided with at least one antenna group  100 . The metal frame  40  and the metal middle frame  30  of the mobile terminal are fully used to improve data transmission efficiency of the terminal and improve communication quality of the terminal. 
     Specifically, the mobile terminal may be provided with a plurality of antenna groups. As shown in  FIG. 5 , the antenna system is a 4*4 antenna group. A terminal frame on a left side of the figure is provided with an antenna group  200 , a terminal frame on a right side of the figure is provided with an antenna group  300 , and each antenna group has two antennas. In addition, as shown in  FIG. 6 , the antenna system may alternatively be provided with an 8*8 antenna group. Specifically, antenna groups  200  and  500  may be disposed on a left side, and antenna groups  300  and  400  are disposed on a right side. The descriptions herein are merely examples, a specific quantity and position of the antenna group may be set according to a data transmission requirement or a communication quality requirement of the terminal. Specific structures of the antenna group  200 , the antenna group  300 , the antenna group  400 , and the antenna group  500  are the same as or similar to a specific structure of the antenna group  100 . 
     Compared with the prior art, the provided antenna system can improve a data transmission capacity and increase data transmission channels without affecting an existing antenna, and each antenna group in the antenna system includes two antennas having different radiation mechanisms. In addition, the two antennas are not in contact with each other, and therefore, respective signal transmission is not affected, thereby ensuring good isolation. 
     In this embodiment, the first antenna  10  and the second antenna  20  have a same working frequency band, which covers 3300 MHz to 3600 MHz and 4800 MHz to 5000 MHz. 
     Working radiation efficiency of the first antenna  10  and the second antenna  20  are shown in  FIG. 7 . The radiation efficiency of the first antenna  10  and the second antenna  20  at working frequencies corresponding to the first antenna  10  and the second antenna  20  in the foregoing specific embodiment is relatively high, and is at least −7.5 dB. Reverse transmission coefficients of the first antenna  10  and the second antenna  20  are shown in  FIG. 8 , wherein the reverse transmission coefficients of the two antennas at the working frequencies corresponding to the first antenna  10  and the second antenna  20  in the foregoing specific embodiment are below −10 dB. An ECC (Envelope Correlation Coefficient) waveform of the first antenna  10  and the second antenna  20  is shown in  FIG. 9 . At a corresponding working frequency band, the first antenna  10  and the second antenna  20  have relative good ECCs, which are below 0.05. 
     It should be noted that in other embodiments, the first antenna  10  and the second antenna  20  may be designed as other forms of antennas, for example, dual-band mono-pole antennas. 
     It should be noted that to highlight the disclosure parts of the present disclosure, a unit not closely related to the technical problem mentioned in the present disclosure is not provided in this embodiment, but this does not indicate that there are no other units in this embodiment. 
     A second embodiment of the present disclosure relates to a mobile terminal, including the antenna system in the first embodiment, and the mobile terminal has a full screen. 
     Specifically, the mobile terminal can work at a 5G band. 
     Compared with the prior art, the embodiments of the present disclosure can improve data transmission efficiency of a terminal having a full screen, improve communication quality of the terminal, and improve user experience by adding an antenna when an existing terminal has extremely limited space. 
     Certainly, the terminal should further include hardware such as a processor and a memory, Wherein the memory and the processor are connected through a bus, and the bus may include any quantity of interconnected buses and bridges, the bus links various circuits of one or more processors and memories together. The bus may further link various other circuits, such as a peripheral device, a voltage stabilizer, and a power management circuit. These are known in the art, and therefore are not further described in the present disclosure. A bus interface provides an interface between the bus and a phased array antenna system. Data processed by the processor is transmitted on wireless medium by using the phased array antenna system. Further, the phased array antenna system further receives data and transfers the data to the processor. The processor is responsible for managing the bus and usual processing, and may further provide various functions, including timing, a peripheral interface, voltage adjustment, power management, and other control functions. The memory may be configured to store data used by the processor to perform an operation. 
     A person of ordinary skill in the art may understand that the foregoing embodiments are specific examples for implementing the present disclosure. However, in practical application, forms and details of the foregoing embodiments may be changed in various manners without departing from the spirit and scope of the present disclosure.