Patent Publication Number: US-9905911-B2

Title: Antenna for electronic device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to Chinese Patent Application No. 201510546222.8 filed on Aug. 31, 2015, the contents of which are incorporated by reference herein. 
     FIELD 
     The subject matter herein generally relates to wireless communication technology, and particularly to an electronic device having an antenna. 
     BACKGROUND 
     Existing electronic devices are equipped with multiple antennas for radiating different signal types. However, multiple antennas occupy a large area of the electronic device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
       The FIGURE is a block diagram of an embodiment of an antenna for an electronic device. 
     
    
    
     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. In addition, 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. Also, the description is not to be considered as limiting the scope of the embodiments described herein. The drawings are not necessarily to scale and the proportions of certain parts can be exaggerated to better illustrate details and features. The present disclosure, including the accompanying drawings, is illustrated by way of examples and not by way of limitation. 
     Several definitions that apply throughout this disclosure will now be presented. 
     It should be noted that references to “a/an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean “at least one.” Furthermore, 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. 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 FIGURE is a block diagram of an embodiment of an antenna  20  employed in an electronic device  100 . The electronic device  100  can be a mobile phone, a tablet, or any other suitable electronic devices with communication functions. The electronic device  100  further includes a circuit board  30  for mounting the antenna  20 . 
     In at least one embodiment, the antenna  20  can include, but is not limited to, a first antenna frame  21 , a second antenna frame  22 , a switching unit  23 , and a low-pass circuit  24 . In at least one embodiment, the first antenna frame  21  and the second antenna frame  22  have two end portions. In one embodiment, a first ground point  211  and a first feed point  212  are respectively located between the two end portions of the first antenna frame  21 . A second ground point  213  is located at one end portion of the first antenna frame  21  which is away from the switching unit  23 , and the switching unit  23  is located at the other end portion of the first antenna frame  21 . The first ground point  211  is grounded via a high-pass circuit  25 . The first feed point  212  can be configured to receive and/or transmit high-frequency signal, for example, the high-frequency signal can be 2G/3G/4G signals. The 2G signal is Global System for Mobile Communication (GSM) signal, the 3G signal is Universal Mobile Telecommunication System (UMTS) signal, and the 4G signal is Long Term Evolution (LTE) signal. 
     In at least one embodiment, a second feed point  221  and a third ground point  222  are respectively located between the two end portions of the second antenna frame  22 , a third feed point  223  is located at one end portion of the second antenna frame  22  which is away from the switching unit  23 , and the low-pass circuit  24  is located at the other end portion of the second antenna frame  22 . The third ground point  222  is grounded via a high-pass circuit  25 . The second feed point  221  can be configured to receive and/or transmit the high-frequency signal, and the third feed point  223  can be configured to receive and/or transmit low-frequency signal, for example, the low-frequency signal can be Near Field Communication (NFC) signal, or Wireless Power Transmission (WPT) signal. 
     In at least one embodiment, the low-pass circuit  24  can be electrically connected to the other end portion of the first antenna frame  21 , and the switching unit  23  can be electrically connected to the other end of the second antenna frame  22 . 
     In at least one embodiment, the second ground point  213  can be coupled to an arbitrary location between the two end portions of the first antenna frame  21 , and the third feed point  223  can be coupled to an arbitrary location between the two end portions of the second antenna frame  22 . 
     In at least one embodiment, the low-pass circuit  24  can pass signals with a frequency lower than a certain cutoff frequency and attenuate signals with frequencies higher than the certain cutoff frequency. The high-pass circuit  25  can pass signals with a frequency higher than a certain cutoff frequency and attenuate signals with frequencies lower than the certain cutoff frequency. 
     In at least one embodiment, the switching unit  23  can be electrically connected between the first antenna frame  21  and the low-pass circuit  24 , and the switching unit  23  can control an electrical connection between the first antenna frame  21  and the second antenna frame  22  to be switched on or off. The electrical connection between the first antenna frame  21  and the second antenna frame  22  is in a conducting state when the switching unit  23  is closed. The electrical connection between the first antenna frame  21  and the second antenna frame  22  is in a non-conducting state when the switching unit  23  is open. In at least one embodiment, the switching unit  23  can be a one-pole switch. 
     In at least one embodiment, the antenna  20  can receive and/or transmit high frequency signal and low frequency signal. When the electrical connection between the first antenna frame  21  and the second antenna frame  22  is in a conducting state, the low-pass circuit  24  can attenuate signals with frequencies higher than the certain cutoff frequency, and the high-pass circuit  25  can attenuate signals with frequencies lower than the certain cutoff frequency to the ground. Thus, the antenna length between the first ground point  211  and the third feeder point  223  can be motivated to receive and/or transmit low frequency signal. The length of the antenna to receive and/or transmit low frequency signal is increased. 
     In at least one embodiment, the circuit board  30  can include a communication module  31  and a control module  32 . The communication module  31  can detect a signal type that is received and/or transmitted by the antenna  20 , and send the signal type to the control module  32 . 
     In at least one embodiment, the control module  32  is electrically connected to the switching unit  23  and the first feed point  212 , the communication module  31  is electrically coupled between the control module  32  and the second feed point  221 , and the communication module  31  is electrically coupled to the third feed point  223 . The control module  32  can send a command to control the switching unit  23  to close or open after receiving the signal type. For example, if the communication module  31  detects the signal type is low-frequency signal, the control module  32  can send the command to control the switching unit  23  to close. If the communication module  31  detects the signal type is high-frequency signal, the control module  32  can send the command to control the switching unit  23  to open. 
     It should be emphasized that the above-described embodiments of the present disclosure, including any particular embodiments, are merely possible examples of implementations, set forth for a clear understanding of the principles of the disclosure. Many variations and modifications can be made to the above-described embodiment(s) of the disclosure without departing substantially from the spirit and principles of the disclosure. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims.