Patent Publication Number: US-11043732-B2

Title: Antenna structure

Description:
FIELD 
     The subject matter herein generally relates to antenna structures, and more particularly to an antenna structure of a wireless communication device. 
     BACKGROUND 
     As electronic devices become smaller, an antenna structure for operating in different communication bands is required to be smaller. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Implementations of the present disclosure will now be described, by way of embodiments only, with reference to the attached figures. 
         FIG. 1  is a partial isometric view of an embodiment of an antenna structure in a wireless communication device. 
         FIG. 2  is an isometric view of the communication device in  FIG. 1 . 
         FIG. 3  is similar to  FIG. 2 , but showing the communication device from another perspective. 
         FIG. 4  is a diagram of the antenna structure in  FIG. 1 . 
         FIG. 5  is a diagram of a matching circuit of the antenna structure in  FIG. 4 . 
         FIG. 6  is a block diagram of a switching circuit of the antenna structure in FIG.  4 . 
         FIG. 7  is a graph of scattering values (S11 values) of the antenna structure when an electronic component is in a closed state and the switching circuit is switched to a first switching unit. 
         FIG. 8  is a graph of S11 values of the antenna structure when the electronic component is in an activated state and the switching circuit is switched to the first switching unit. 
         FIG. 9  is a graph of S11 values of the antenna structure when the electronic component is in the activated state and the switching circuit is switched to a second switching unit. 
         FIG. 10  is a graph of total radiation efficiency of a first radiating portion of the antenna structure when the electronic component is in the closed state. 
         FIG. 11  is a graph of total radiation efficiency of the first radiating portion of the antenna structure when the electronic component is in the activated state. 
         FIG. 12  is a graph of S11 values of a second radiating portion of the antenna structure. 
         FIG. 13  is a graph of total radiation efficiency of the second radiating portion. 
         FIG. 14  is a diagram of an antenna structure in accordance with another embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     It will be appreciated that for simplicity and clarity of illustration, where appropriate, reference numerals have been repeated among the different figures to indicate corresponding or analogous elements. Additionally, numerous specific details are set forth in order to provide a thorough understanding of the embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein can be practiced without these specific details. In other instances, methods, procedures and components have not been described in detail so as not to obscure the related relevant feature being described. The drawings are not necessarily to scale and the proportions of certain parts may be exaggerated to better illustrate details and features. The description is not to be considered as limiting the scope of the embodiments described herein. 
     Several definitions that apply throughout this disclosure will now be presented. 
     The term “coupled” is defined as connected, whether directly or indirectly through intervening components, and is not necessarily limited to physical connections. The connection can be such that the objects are permanently connected or releasably connected. The term “comprising” means “including, but not necessarily limited to”; it specifically indicates open-ended inclusion or membership in a so-described combination, group, series and the like. 
       FIGS. 1-3  show an embodiment of an antenna structure  100  applicable in a mobile phone, a personal digital assistant, or other wireless communication device  200  for sending and receiving wireless signals. 
     As shown in  FIG. 1 , the antenna structure  100  includes a housing  11 , a first feed portion  12 , a second feed portion  13 , a matching circuit  14 , a connecting portion  15 , and an extending portion  16 . 
     The housing  11  includes at least a border frame  110  and a backplane  111 . The border frame  110  and the backplane  111  are made of metal. The border frame  110  is hollow rectangular and is made of metal. The border frame  110  receives a display unit  201  in one side of the border frame  110  (shown in  FIG. 3 ). 
     The backplane  111  is made of metal and is mounted on a side of the border frame  110  opposite to the display unit  201 . The backplane  111  and the display unit  201  are parallel and spaced apart. In one embodiment, the backplane  111  and the border frame  110  cooperatively define an accommodating space  114 . The accommodating space  114  receives components (not shown) of the wireless communication device  200 . 
     The border frame  110  includes at least an end portion  115  (shown in  FIG. 3 ), a first side portion  116 , and a second side portion  117 . In one embodiment, the end portion  115  is a top end of the wireless communication device  200 . The first side portion  116  and the second side portion  117  face each other and are perpendicular to the end portion  115 . The end portion  115 , the first side portion  116 , and the second side portion  117  are each connected to the backplane  111  and the display unit  201 . In addition, in one embodiment, a length of each of the first side portion  116  and the second side portion  117  is longer than a length of the end portion  115 . 
     The border frame  110  includes a first gap  120 , a second gap  121 , a first slot  122 , and a second slot  123 . The first gap  120  and the second gap  121  are disposed in the end portion  115 . The first gap  120  is located adjacent to the first side portion  116 , and the second gap  121  is located adjacent to the second side portion  117 . The first slot  122  is disposed in the first side portion  116  and spaced from the first gap  120 . The second slot  123  is disposed in the second side portion  117  and spaced from the second gap  121 . 
     The first gap  120 , the second gap  121 , the first slot  122 , and the second slot  123  pass through the border frame and divide the border frame  110  into a first radiating portion A 1  and a second radiating portion A 2 . The first radiating portion A 1  is disposed in a portion of the border frame  110  between the first gap  120  and the first slot  122 . The second radiation portion A 2  is disposed in a portion of the border frame  110  between the second gap  121  and the second slot  123 . Thus, the first radiating portion A 1  and the second radiating portion A 2  are located respectively on different sides of the end portion  115 , such as two corner portion of the border frame  110 . 
     In other embodiments, the first gap  120  and the second gap  121  can be disposed in different locations of the border frame  110 . In one embodiment, the first gap  120  may be disposed in the first side portion  116 , and the second gap  121  may be disposed in the second side portion  117 , such that the first radiating portion A 1  and the second radiating portion A 2  are located respectively on opposite sides of the end portion  115 . 
     In one embodiment, the first gap  120 , the second gap  121 , the first slot  122 , and the second slot  123  are filled with insulating material, such as plastic, rubber, glass, wood, or ceramic. 
     In one embodiment, the wireless communication device  200  is about 70 mm*140 mm*8 mm in size. The wireless communication device  200  further includes a substrate  21  and an electronic component  23 . The substrate  21  is a printed circuit board made of epoxy glass fiber (FR4) or other dielectric material. The substrate  21  is received within the accommodating space  113 . At least one end of the substrate  21  is spaced from the border frame  110  and forms a clearance area  211 . 
     In one embodiment, the electronic component  23  is an optical module. The electronic component  23  is connected and electrically coupled to the substrate  21 . In one embodiment, the optical module may include at least one of a camera module, an auxiliary display screen, an ambient light sensor, and a proximity detector. In other embodiments, the electronic component  23  may be an acoustic module including at least one of a speaker, a microphone, and a vibration motor. 
     In one embodiment, the wireless communication device  200  includes a sliding structure (not shown) connected to the electronic component  23  and adapted to control the electronic component  23  to slide relative to the border frame  110 . When the electronic component  23  is in a first position, such as when the electronic component  23  is mounted within the border frame  110 , the electronic component  23  is in a closed state. When the electronic component  23  is slide to a second position, such as when the electronic component  23  is slid out of the border frame  110  such as from the end portion  115 , the electronic component  23  is in an activated state. In one embodiment, the first radiating portion A 1  and the second radiating portion A 2  are located respectively on opposite sides of the electronic component  23 . Thus, the electronic component  23  does not interfere with a resonance capacity of the first radiating portion A 1  and the second radiating portion A 2 . 
     As shown in  FIG. 4 , in one embodiment, each of the first gap  120 , the second gap  121 , the first slot  122 , and the second slot  123  has a width G The first radiating portion A 1  between the first gap  120  and the first slot  122  has a length L 1 . The second radiating portion A 2  between the second gap  121  and the second slot  123  has a length L 2 . The clearance area  211  has a width S ( FIG. 1 ). In one embodiment, G is equal to 2 mm, L 1  is equal to 34 mm, L 2  is equal to 34 mm, and S is equal to 2.5 mm. 
     In one embodiment, the first feed portion  12  is mounted within the accommodating space  113 . The first feed portion  12  may be a resilient metal piece, a screw, a feed line, a needle, or other connecting structure. One end of the first feed portion  12  is electrically coupled to a side of the first radiating portion A 1  adjacent to the first gap  120 , and a second end of the first feed portion  12  is electrically coupled through the matching circuit  14  to an end of the first feed source  212  mounted to the substrate  21  for feeding a current to the first radiating portion A 1 . A second end of the first feed source  212  is grounded. 
     The second feed portion  13  is mounted within the accommodating space  113 . The second feed portion  13  may be a resilient metal piece, a screw, a feed line, a needle, or other connecting structure. One end of the second feed portion  13  is electrically coupled to the second radiating portion A 2 , and a second end of the second feed portion  13  is electrically coupled to an end of the second feed source  213  mounted to the substrate  21  for feeding a current to the second radiating portion A 2 . A second end of the second feed source  213  is grounded. 
     The connecting portion  15  is mounted within the accommodating space  113 . The connecting portion  15  may be a resilient metal piece, a screw, a feed line, a needle, or other connecting structure. One end of the second feed portion  13  is electrically coupled to the second radiating portion A 2 , and a second end of the second feed portion  13  is electrically coupled to one end of the second feed source  213  mounted to the substrate  21  for feeding a current to the second radiating portion A 2 . A second end of the second feed source  213  is grounded. 
     The extending portion  16  is mounted within the accommodating space  113  between the second feed portion  13  and the second side portion  117 . The extending portion  16  includes a first extending section  161 , a second extending section  162 , and a third extending section  163  connected in sequence. One end of the first extending section  161  is perpendicularly connected to a side of the second feed portion  13  away from the first side portion  116  and extends parallel to the end portion  115  in a direction toward the second side portion  117 . One end of the second extending section  162  is perpendicularly connected to an end of the first extending section  161  away from the second feed portion  13  and extends parallel to the first side portion  116  and extends in a direction opposite to the end portion  115 . One end of the third extending section  163  is connected perpendicularly to an end of the second connecting section  162  away from the first extending section  161  and extends parallel to the first extending section  161  and extends in a direction toward the first side portion  116 . A second end of the third extending section  163  is grounded. 
     The first extending section  161  and the third extending section  163  are connected respectively to opposite ends of the second extending section  162  and cooperatively make a U-shaped structure. A shape of the extending portion  16  may be other shapes in other embodiments according to requirements. 
     As shown in  FIG. 5 , in one embodiment, the matching circuit  14  includes a first matching component  141 , a second matching component  142 , a third matching component  143 , a fourth matching component  144 , a fifth matching component  145 , and a sixth matching component  146 . One end of the first matching component  141  is electrically coupled to the first feed source  212 . A second end of the first matching component  141  is coupled in series to the second matching component  142  and electrically coupled to the first feed portion  12 , and then electrically coupled to the first radiating portion A 1  through the first feed portion  12 . 
     One end of the third matching component  143  is electrically coupled between the first matching component  141  and the first feed source  212 , and a second end of the third matching component  143  is grounded. One end of the fourth matching component  144  is electrically coupled between the first matching component  141  and the second matching component  142 , and a second end of the fourth matching component  144  is grounded. The fifth matching component  145  and the fourth matching component  144  are coupled in parallel. One end of the fifth matching component  145  is electrically coupled between the first matching component  141  and the second matching component  142 , and a second end of the fifth matching component  145  is grounded. One end of the sixth matching component  146  is electrically coupled between the second matching component  142  and the first feed portion  12 , and a second end of the sixth matching component  146  is grounded. 
     In one embodiment, the first matching component  141 , the fourth matching component  144 , and the sixth matching component  146  are capacitors, and the second matching component  142 , the third matching component  143 , and the fifth matching component  145  are inductors. The first matching component  141 , the fourth matching component  144 , and the sixth matching component  146  have a capacitance of 1 pF, 0.5 pF, and 3 pF, respectively. The second matching component  142 , the third matching component  143 , and the fifth matching component  145  have an inductance of 1.8 nH, 12 nH, and 6.2 nH. In other embodiments, the first matching component,  141 , the second matching component  142 , the third matching component  143 , the fourth matching component  144 , the fifth matching component  145 , and the sixth matching component  146  may have other values of capacitance, inductance, or a combination of the two. 
     When the first feed source  212  supplies a current, the current from the first feed source  212  flows through the matching circuit  14  and the first feed portion  12  to the first radiating portion A 1 . Thus, the first radiating portion A 1  forms a first antenna to excite a first resonance mode and generate a radiation signal in a first frequency band. When the second feed source  213  supplies a current, the current from the second feed source  213  flows through the second feed portion  13  to the second radiating portion A 2 . Thus, the second radiating portion A 2  forms a second antenna to excite a second resonance mode and generate a radiation signal in a second frequency band. 
     In one embodiment, the first antenna is a diversity antenna, and the second antenna is a global positioning system (GPS) antenna. The first resonance mode is a Long Term Evolution Advanced (LTE-A) low-frequency mode, and the second resonance mode is a GPS mode. The first frequency band is 700-960 MHz. The second frequency band is about 1575 MHz. 
     In one embodiment, the antenna structure  100  further includes a switching circuit  17 . The switching circuit  17  is mounted within the accommodating space  113 . One end of the switching circuit  17  is electrically coupled to the connecting portion  15  to electrically couple to the first radiating portion A 1 . A second end of the switching circuit  17  is grounded. 
     As shown in  FIG. 6 , the switching circuit  17  includes a switch  171 , a first switching unit  172 , and a second switching unit  174 . The switch  171  is electrically coupled to the connecting portion  15  to electrically couple to the first radiating portion A 1 . The first switching unit  172  includes a plurality of first switching components  173 . Each one of the plurality of first switching components  173  may be an inductor, a capacitor, or a combination of the two. The first switching components  173  are coupled together in parallel. One end of each of the first switching components  173  is electrically coupled to the switch  171 , and a second end of each of the first switching components  173  is grounded. The second switching unit  174  includes a plurality of second switching components  175 . Each of the plurality of second switching components  175  may be an inductor, a capacitor, or a combination of the two. The second switching components  175  are coupled together in parallel. One end of each of the second switching components  175  is electrically coupled to the switch  171 , and a second end of each of the second switching components  175  is grounded. 
     By controlling the switch  171 , the first radiating portion A 1  is switched to electrically couple to the first switching components  173  or the second switching components  175 . Since each of the first switching components  173  and each of the second switching components  175  include different impedances, the LTE-A low-frequency mode can be adjusted. 
     In one embodiment, the first switching unit  172  includes four switching components  173  each having a different impedance. When the electronic component  23  is in the closed state, the first radiating portion A 1  is switched to four different first switching components  173  having impedance values of 16 nH, 10 nH, 5.1 nH, and 3.3 nH to cause the antenna structure  100  to operate in a 700 MHz frequency band, an 800 MHz frequency band, an 850 MHz frequency band, and a 900 MHz frequency band, respectively. Thus, the LTE-A low-frequency mode covers the frequency band from 700-960 MHz. When the electronic component  23  is in the activated state, the radiating portion A 1  is switched to four different second switching components  175  having impedance values of 15 nH, 9.1 nH, 3.9 nH, and 1.8 nH to cause the antenna structure  100  to operate in a 700 MHz frequency band, an 800 MHz frequency band, an 850 MHz frequency band, and a 900 MHz frequency band, respectively. Thus, the LTE-A low-frequency mode covers the frequency band from 700-960 MHz. Thus, the impedance value of each of the first switching components  173  is greater than the impedance value of the corresponding second switching component  175 . 
       FIG. 7  shows a graph of scattering values (S11 values) of the first radiating portion A 1  when the electronic component  23  is in the closed state and the switching circuit  17  is switched to the first switching unit  172 . A plotline S 71  represents S11 values of the first radiating portion A 1  operating at 700 MHz when the electronic component  23  is in the closed state and the switching circuit  17  is switched to the first switching unit  172 . A plotline S 72  represents S11 values of the first radiating portion A 1  operating at 800 MHz when the electronic component  23  is in the closed state and the switching circuit  17  is switched to the first switching unit  172 . A plotline S 73  represents S11 values of the first radiating portion A 1  operating at 850 MHz when the electronic component  23  is in the closed state and the switching circuit  17  is switched to the first switching unit  172 . A plotline S 74  represents S11 values of the first radiating portion A 1  operating at 900 MHz when the electronic component  23  is in the closed state and the switching circuit  17  is switched to the first switching unit  172 . 
       FIG. 8  shows a graph of S11 values of the antenna structure  100  when the electronic component  23  is in the activated state and the switching circuit  17  is switched to the first switching unit  172 . A plotline S 81  represents S11 values of the first radiating portion A 1  operating at 700 MHz when the electronic component  23  is in the activated state and the switching circuit  17  is switched to the first switching unit  172 . A plotline S 82  represents S11 values of the first radiating portion A 1  operating at 800 MHz when the electronic component  23  is in the activated state and the switching circuit  17  is switched to the first switching unit  172 . A plotline S 83  represents S11 values of the first radiating portion A 1  operating at 850 MHz when the electronic component  23  is in the activated state and the switching circuit  17  is switched to the first switching unit  172 . A plotline S 84  represents S11 values of the first radiating portion A 1  operating at 900 MHz when the electronic component  23  is in the activated state and the switching circuit  17  is switched to the first switching unit  172 . 
       FIG. 9  shows a graph of S11 values of the first radiating portion A 1  when the electronic component  23  is in the activated state and the switching circuit  17  is switched to the second switching unit  174 . A plotline S 91  represents S11 values of the first radiating portion A 1  operating at 700 MHz when the electronic component  23  is in the activated state and the switching circuit  17  is switched to the second switching unit  174 . A plotline S 92  represents S11 values of the first radiating portion A 1  operating at 800 MHz when the electronic component  23  is in the activated state and the switching circuit  17  is switched to the second switching unit  174 . A plotline S 93  represents S11 values of the first radiating portion A 1  operating at 850 MHz when the electronic component  23  is in the activated state and the switching circuit  17  is switched to the second switching unit  174 . A plotline S 94  represents S11 values of the first radiating portion A 1  operating at 900 MHz when the electronic component  23  is in the activated state and the switching circuit  17  is switched to the second switching unit  174 . 
     As shown in  FIGS. 7-9 , when the electronic component  23  is in the activated state, the low-frequency band of the antenna structure  100  is shifted. For example, when the electronic component  23  is in the activated state and the switching circuit  17  is switched to the first switching unit  172 , the low-frequency mode of the first radiating portion A 1  is shifted about 80 MHz toward the low-frequency band. Thus, no matter whether the electronic component  23  is in the closed state or the activated state, the switching circuit  17  switches to one of the first switching components  173  or to one of the second switching components  175  to enhance the low-frequency function of the first radiating portion A 1 . 
     When the electronic component  23  is in the closed state, the inductance value of the frequency band is greater than the inductance value of the corresponding frequency band when the electronic component  23  is in the activated state. 
       FIG. 10  shows a graph of total radiation efficiency of the first radiating portion A 1  when the electronic component  23  is in the closed state. A plotline S 101  represents a total radiation efficiency of the first radiating portion A 1  operating at 700 MHz when the electronic component  23  is in the closed state. A plotline S 102  represents a total radiation efficiency of the first radiating portion A 1  operating at 800 MHz when the electronic component  23  is in the closed state. A plotline S 103  represents a total radiation efficiency of the first radiating portion A 1  operating at 850 MHz when the electronic component  23  is in the closed state. A plotline S 104  represents a total radiation efficiency of the first radiating portion A 1  operating at 900 MHz when the electronic component  23  is in the closed state. 
       FIG. 11  shows a graph of total radiation efficiency of the first radiating portion A 1  when the electronic component  23  is in the activated state. A plotline S 111  represents a total radiation efficiency of the first radiating portion A 1  operating at 700 MHz when the electronic component  23  is in the closed state. A plotline S 112  represents a total radiation efficiency of the first radiating portion A 1  operating at 800 MHz when the electronic component  23  is in the closed state. A plotline S 113  represents a total radiation efficiency of the first radiating portion A 1  operating at 850 MHz when the electronic component  23  is in the closed state. A plotline S 114  represents a total radiation efficiency of the first radiating portion A 1  operating at 900 MHz when the electronic component  23  is in the closed state. 
     As shown in  FIGS. 10-11 , no matter whether the electronic component  23  is in the activated state or the closed state, the total radiation efficiency of the first radiating portion A 1  is greater than −6 dB to satisfy requirements of a diversity antenna. 
       FIG. 12  shows a graph of S11 values of the second radiating portion A 2 . A plotline S 121  represents S11 values of the second radiating portion A 2  when the electronic component  23  is in the activated state. A plotline S 122  represents S11 values of the second radiating portion A 2  when the electronic component  23  is in the closed state. 
       FIG. 13  shows a graph of total radiation efficiency of the second radiating portion A 2 . A plotline S 131  represents a total radiation efficiency of the second radiating portion A 2  when the electronic component  23  is in the activated state. A plotline S 132  represents a total radiation efficiency of the second radiating portion A 2  when the electronic component  23  is in the closed state. 
     As shown in  FIGS. 12-13 , no matter whether the electronic component  23  is in the activated state or the closed state, the total radiation efficiency of the second radiating portion A 2  is greater than −5 dB to satisfy requirements of a GPS antenna. 
       FIG. 14  shows an embodiment of an antenna structure  100   a  applicable in a mobile phone, a personal digital assistant, or other wireless communication device  200   a  for sending and receiving wireless signals. 
     The wireless communication device  200   a  includes an electronic component  23 . The antenna structure  100   a  includes a border frame  110 , a first feed portion  12 , a second feed portion  13   a , a matching circuit  14 , a connecting portion  15   a , and a switching circuit  17 . The border frame  110  includes a first gap  120 , a second gap  121 , a first slot  122 , and a second slot  123 . The first gap  120 , the second gap  121 , the first slot  122 , and the second slot  123  separate the housing  11  into a first radiating portion A 1  and a second radiating portion A 2 . 
     A difference between the antenna structure  100   a  and the antenna structure  100  is that the connecting portion  15   a  is not directly electrically coupled to the first radiating portion A 1 , but instead is spaced from the first radiating portion A 1  to electrically couple to the first radiating portion A 1 . 
     Another difference between the antenna structure  100   a  and the antenna structure  100  is that the extending portion  16  is omitted. 
     Another difference between the antenna structure  100   a  and the antenna structure  100  is that the second feed portion  13   a  is not directly electrically coupled to the second radiating portion A 2 , but instead is spaced from the second radiating portion A 2 , such that current signals are coupled to the second radiating portion A 2  across a space. 
     Another difference between the antenna structure  100   a  and the antenna structure  100  is that the antenna structure  100   a  further includes a ground portion  18 . One end of the ground portion  18  is electrically coupled to the second radiating portion A 2  or spaced from the second radiating portion A 2  to electrically couple to the second radiating portion A 2 . A second end of the ground portion  18  is grounded to ground the second radiating portion A 2 . 
     The first radiating portion A 1  and the second radiating portion A 2  of the antenna structure  100  receive a current by direct contact, and so do not include a ground portion. The first radiating portion A 1  and the second radiating portion A 2  of the antenna structure  100   a  receive a current by current signal coupling across a space, and so the ground portion  18  is included. Thus, a resonance capability of the first antenna and the second antenna are optimized. 
     In other embodiments, positions of the first antenna and the second antenna can be switched. 
     The first antenna and the second antenna are not overlapped with the electronic component  23 . In other words, the first gap  120  and the second gap  121  are located on respective opposite sides of the electronic component  23 . 
     In other embodiments, the first antenna and the second antenna may be a WIFI antenna, a BLUETOOTH antenna, a near-field communication antenna, or other suitable antenna. 
     The antenna structure  100 / 100   a  of the wireless communication device  200 / 200   a  is disposed on opposite sides of the electronic component  23  by the first radiating portion A 1  and the second radiating portion A 2 . By appropriately adjusting the feeding, grounding, and switching circuits of the first radiating portion A 1  and the second radiating portion A 2 , characteristics such as wide frequency and good antenna efficiency can be effectively achieved. Furthermore, the antenna structure  100 / 100   a  can be applied in an environment where the antenna space is limited, and the electronic component  23  can effectively avoid overlapping with the antenna structure  100 / 100   a  while ensuring a screen integrity of the display unit  201 . Thus, a shielding effect of the antenna structure  100 / 100   a  is more beautiful and practical. 
     The embodiments shown and described above are only examples. Even though numerous characteristics and advantages of the present technology have been set forth in the foregoing description, together with details of the structure and function of the present disclosure, the disclosure is illustrative only, and changes may be made in the detail, including in matters of shape, size and arrangement of the parts within the principles of the present disclosure up to, and including, the full extent established by the broad general meaning of the terms used in the claims.