Patent Publication Number: US-9847575-B2

Title: Electronic device and antenna thereof

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This Application claims priority of Taiwan Patent Application No. 105104433, filed on Feb. 16, 2016, the entirety of which is incorporated by reference herein. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to an antenna, and in particular to an antenna disposed in an electronic device. 
     Description of the Related Art 
     A conventional antenna includes a system ground, a short pin, and a radiator. Conventionally, an antenna is H-shaped with a signal source and a ground line. Due to its being shielded by an extending ground and being influenced by a reversed current from the extending ground, the performance of the antenna is deteriorated. This is particularly true when an interference element (for example, an amplifier) is disposed above the antenna and shields the antenna, causing the performance of the antenna to be greatly reduced. 
     BRIEF SUMMARY OF THE INVENTION 
     In one embodiment of the invention, an antenna is provided. The antenna includes a first radiator, a second radiator, a third radiator, a ground portion, and a short structure. The first radiator extends in a first direction. The second radiator extends in a second direction. The first direction is opposite to the second direction. The short structure is coupled to the ground portion. The first radiator, the second radiator and the third radiator are connected to the short structure. The short structure defines an L-shaped groove. 
     In one embodiment, the third radiator extends in the second direction. 
     In one embodiment, the first radiator and the second radiator commonly transmit a high-band signal, and the third radiator transmits a low-band signal. 
     In one embodiment, the first radiator and the third radiator commonly transmit a high-band signal, and the second radiator transmits a low-band signal. 
     In one embodiment, the short structure comprises a feed section, an extending section and a short section, the extending section connects the feed section to the short section, a signal source is connected to the feed section, and the feed section has a curved structure. 
     In one embodiment, the feed section comprises a first end and a second end, the signal source is connected to the first end, the third radiator is connected to the first end, and the extending section is connected to the second end. 
     In one embodiment, the feed section comprises a first end, a second end and the curved portion, the signal source is connected to the first end, the third radiator is connected to the curved portion, and the extending section is connected to the second end. 
     In one embodiment, the extending section comprises a third end and a fourth end, the feed section is connected to the third end, the second radiator is connected to the third end, the short portion is connected to the fourth end, and the first radiator is connected to the fourth end. 
     In one embodiment, the extending section comprises a third end and a fourth end, the feed section is connected to the third end, the second radiator is connected to the third end, the short portion is connected to the fourth end, the short section comprises a fifth end and the sixth end, the fifth end is connected to the extending section, the sixth end is connected to the ground portion, and the first radiator is connected to the short section and is located between the fifth end and the sixth end. 
     In one embodiment, the feed section comprises a first section, a second section and a third section, the first section and the third section are connected to two respective ends of the second section, the signal source is connected to the first section, the extending section is connected to the third section, the second section is parallel to the extending section, and the first section and the third section are perpendicular to the second section. 
     In one embodiment, the feed section comprises a first section and a second section, the first section is parallel to the extending section, the signal source is connected to the first section, and the second section connects the extending section to the first section. 
     In one embodiment, an electronic device is provided. The electronic device includes a circuit board and an antenna. The antenna is coupled to the circuit board. The antenna includes a first radiator, a second radiator, a third radiator, a ground portion and a short structure. The first radiator extends in a first direction. The second radiator extends in a second direction. The first direction is opposite to the second direction. The short structure is coupled to the ground portion. The first radiator, the second radiator and the third radiator are connected to the short structure. The short structure defines an L-shaped groove. 
     In one embodiment, the electronic device further comprises an electronic element, wherein the electronic element overlaps the short structure, the first radiator, the second radiator and the third radiator of the antenna. 
     In one embodiment, the electronic element is an amplifier. 
     In one embodiment, the short structure comprises a feed section, an extending section and a short section, the extending section connects the feed section to the short section, a signal source is connected to the feed section, and the feed section has a curved structure. 
     Utilizing the antenna of the embodiment of the invention, by modifying the current distribution, the antenna radiation concentrated on the end of the antenna is decreased. Simultaneously, interference from the neighboring element (for example, amplifier) to the antenna is reduced. Utilizing the antenna of the embodiment of the invention, even with the neighboring electronic element (for example, an amplifier) shielding the antenna, the antenna provides favorable transmission in the high-band (5.3 G˜5.6 G) and the low-band (2.4 G˜2.48 G). 
     A detailed description is given in the following embodiments with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein: 
         FIG. 1  shows an antenna of a first embodiment of the invention; 
         FIG. 2  shows the antenna of the embodiment of the invention disposed in an electronic device; 
         FIG. 3  shows the return loss of the antenna of the electronic device of the embodiment of the invention; 
         FIG. 4  shows an antenna of a second embodiment of the invention; 
         FIG. 5  shows an antenna of a third embodiment of the invention; 
         FIG. 6  shows an antenna of a fourth embodiment of the invention; and 
         FIG. 7  shows an antenna of a fifth embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the appended claims. 
       FIG. 1  shows an antenna  1  of a first embodiment of the invention. The antenna  1  includes a first radiator  10 , a second radiator  20 , a third radiator  30 , a ground portion  40  and a short structure  50 . The first radiator  10  extends in a first direction (X). The second radiator  20  extends in a second direction (−X). The first direction (X) is opposite to the second direction (−X). The short structure  50  is coupled to the ground portion  40  (in the embodiments of the invention, to clarify the description, the short structure  50  is represented by a dotted area). The first radiator  10 , the second radiator  20  and the third radiator  30  are connected to the short structure  50 . The short structure  50  defines an L-shaped groove  59 . 
     With reference to  FIG. 1 , in this embodiment, the third radiator  30  extends in the second direction (−X). The first radiator  10  and the second radiator  20  have a common surface-current path to commonly transmit a high-band signal. In this embodiment, the lengths of the first radiator  10  and the second radiator  20  are about a quarter of the wavelength of the high-band signal. The third radiator  30  transmits a low-band signal. In one embodiment, the length of the third radiator  30  is about a quarter of the wavelength of the low-band signal. The dimensions and shape of the first radiator  10  and the second radiator  20  can be utilized to modify the frequency of the high-band signal. Similarly, the dimensions and shape of the third radiator  30  can be utilized to modify the frequency of the low-band signal. 
     With reference to  FIG. 1 , the short structure  50  comprises a feed section  51 , an extending section  52 , and a short section  53 . The extending section  52  connects the feed section  51  to the short section  53 . A signal source S is connected to the feed section  51 , and the feed section  51  has a curved structure. Specifically, the feed section  51  comprises a first end  511  and a second end  512 . The signal source S is connected to the first end  511 , the third radiator  30  is connected to the first end  511 , and the extending section  52  is connected to the second end  512 . In one embodiment, the feed section  51  comprises a first section  513 , a second section  514  and a third section  515 . The first section  513  and the third section  515  are connected to two respective ends of the second section  514 . The signal source S is connected to the first section  513 . The extending section  52  is connected to the third section  515 . The second section  514  is parallel to the extending section  52 . The first section  513  and the third section  515  are perpendicular to the second section  514 . 
     With reference to  FIG. 1 , in this embodiment, the extending section  52  comprises a third end  521  and a fourth end  522 . The feed section  51  is connected to the third end  521 . The second radiator  20  is connected to the third end  521 . The short portion  53  is connected to the fourth end  522 . The first radiator  10  is connected to the fourth end  522 . In one embodiment, the first radiator  10 , the extending section  52  and the second radiator  20  are located on the same straight line. However, the disclosure is not meant to restrict the invention. In other embodiments, the radiators are not necessarily on the same straight line as the extending section. 
     With reference to  FIG. 1 , in this embodiment, a notch  539  is formed on the short section  53 . The location, dimensions, and shape of the notch  539  can be utilized to modify the impedance matching of the antenna. 
     Utilizing the antenna of the embodiment of the invention, by modifying the current distribution, the antenna radiation concentrated on the end of the antenna is decreased. Simultaneously, interference from the neighboring element (for example, the amplifier) to the antenna is reduced. With reference to  FIG. 2 , the antenna  1  of the embodiment of the invention is adapted to be disposed in an electronic device E (For example, cell phone or tablet), which includes a circuit board P and the antenna  1  mentioned above. The antenna  1  is coupled to the circuit board P. In one embodiment, the electronic device E further comprises an electronic element A, wherein the electronic element A overlaps the short structure  50 , the first radiator  10 , the second radiator  20  and the third radiator  30  of the antenna  1 . In one embodiment, the electronic element A is an amplifier.  FIG. 3  shows the return loss of the antenna  1  of the electronic device E of the embodiment of the invention. With reference to  FIG. 3 , utilizing the antenna  1  of the embodiment of the invention, even with the electronic element A shielding the antenna, the antenna  1  provides favorable transmission in the high-band (5.3 G˜5.6 G) and the low-band (2.4 G˜2.48 G). In this embodiment, the bandwidth of the high-band (5.3G˜5.6G) is 320 MHz, and the bandwidth of the low-band (2.4 G˜2.48 G) is 100 MHz. The antenna  1  of the embodiment of the invention can satisfy Wi-Fi and Bluetooth transmission requirements. 
       FIG. 4  shows an antenna  2  of a second embodiment of the invention, wherein the first radiator  10  and the third radiator  30  commonly transmit a high-band signal, and the second radiator  20  transmits a low-band signal. 
       FIG. 5  shows an antenna  3  of a third embodiment of the invention, wherein the feed section  51 ′ comprises a first end  511 ′, a second end  512 ′ and the curved portion  513 ′. The signal source S is connected to the first end  511 ′, the third radiator  30  is connected to the curved portion  513 ′, and the extending section  52  is connected to the second end  512 ′. In this embodiment, the third radiator  30  has a curved structure to reduce the dimensions of the antenna. The feed section  51 ′ comprises a first section  514 ′ and a second section  515 ′. The first section  514 ′ is parallel to the extending section  52 . The signal source S is connected to the first section  514 ′, and the second section  515 ′ connects the extending section  85  to the first section  514 ′. In this embodiment, the second section  515 ′ extends outward and is tilted. 
       FIG. 6  shows an antenna  4  of a fourth embodiment of the invention. Compared to the third embodiment, the shape of the short structure  50  of the antenna  4  differs from that of the third embodiment. In this embodiment, the second section  515 ′ is perpendicular to the extending section  52 . Additionally, the first radiator  10  is moved to the same straight line with the third radiator  30 . In this embodiment, the short section  53  comprises a fifth end  531  and a sixth end  532 . The fifth end  531  is connected to the extending section  52 . The sixth end  532  is connected to the ground portion  40 . The first radiator  10  is connected to the short section  53  and is located between the fifth end  531  and the sixth end  532 . In this embodiment, the first radiator  10  and the third radiator  30  commonly transmit a high-band signal, and the second radiator  20  transmits a low-band signal. 
       FIG. 7  shows an antenna  5  of a fifth embodiment of the invention. Compared to the embodiment of  FIG. 6 , the first radiator  10  and the second radiator  20  of the antenna  5  commonly transmit a high-band signal, and the third radiator  30  of the antenna  5  transmits a low-band signal. 
     Use of ordinal terms such as “first”, “second”, “third”, etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having the same name (but for use of the ordinal term). 
     While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.