Patent Publication Number: US-9905910-B2

Title: Electronic device and multi-band antenna

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to Chinese Patent Application No. 201510488121.X filed on Aug. 11, 2015, the contents of which are incorporated by reference herein. 
     FIELD 
     The subject matter herein generally relates to wireless communications. 
     BACKGROUND 
     Electronic devices can be equipped with multiple antennas for radiating different signal types. However, multiple antennas occupy a large area of the electronic device, and electromagnetic interference may be generated among the multiple antennas. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       Implementations of the present disclosure will now be described, by way of example only, with reference to the attached drawing. 
       The FIGURE shows an embodiment of a multi-band antenna employed in 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 shows an embodiment of a multi-band antenna  20  employed in an electronic device  100 . The electronic device  100  can be a mobile phone, a tablet, or any other suitable electronic device with communication functions. The electronic device  100  further includes a circuit board  30  for the mounting of the multi-band antenna  20 . 
     In at least one embodiment, the multi-band antenna  20  can include, but is not limited to, a first antenna frame  21 , a second antenna frame  22 , and a switching unit  23 . In at least one embodiment, the switching unit  23  is located between the first antenna frame  21  and the second antenna frame  22 . In at least one embodiment, the first antenna frame  21  and the second antenna frame  22  each has two end portions. A first feed point  211  is located at one end portion of the first antenna frame  21 . A second feed point  222  is located at one end portion of the second antenna frame  22 , and a ground point  221  is located at the other end portion of the second antenna frame  22 . Multiple electrical connection points  223  are located between the two end portions of the second antenna frame  22 . 
     In at least one embodiment, the switching unit  23  includes multiple connecting terminals. The multiple connecting terminals include a first connecting terminal  230  and multiple second connecting terminals  231 . The first connecting terminal  230  can be connected to the other end portion of the first antenna frame  21 , and each of the multiple second connecting terminals  231  is connected to one of the multiple electrical connection points  223 . When the switching unit  23  is controlled to connect the other end portion of the first antenna frame  21  to one of the multiple electrical connection points  223  of the second antenna frame  22 , a pathway is defined between the first feed point  211  of the first antenna frame  21  and the ground point  221  of the second antenna frame  22 . In the illustrated embodiment, three electrical connection points  223  are located on the second antenna frame  22 , and the switching unit  23  can be a single pole triple throw switch. 
     In at least one embodiment, the circuit board  30  can include a control module  31 , a communication module  32 , a first antenna diplexer  33  and a second antenna diplexer  34 . The control module  31  is electrically connected to the switching unit  23 , and the communication module  32  can send a command to close or open the switching unit  23 . The control module  31  can be a central processing unit (CPU), or a microprocessor. If the control module  31  controls the switching unit  23  to close, the other end portion of the first antenna frame  21  can be electrically connected to one of the multiple electrical connection points  223 . In at least one embodiment, the communication module  32  can be a 2G/3G/4G communication module. For example, the 2G communication module can be a Global System for Mobile Communications (GSM) module, the 3G communication module can be a Universal Mobile Telecommunications System (UMTS) module, and the 4G communication module can be a Long Term Evolution (LTE) module. 
     In at least one embodiment, the first antenna diplexer  33  is electronically coupled between the first feed point  211  and the communication module  32 . In the illustrated embodiment, the first antenna diplexer  33  can receive different commands from the control module  31 , and tune the antenna frequency to a predetermined frequency band. 
     For example, if the other end portion of the first antenna frame  21  is electrically connected to a first electrical connection point  223  that is farthest away from the ground point  221 , a first radiating element formed between the first feed point  211  and the ground point  221  is enabled by the first antenna diplexer  33 . The first antenna diplexer  33  can tune the antenna frequency of the first radiating element to a first predetermined frequency band. Thus, the first radiating element can be operated in a first magnetic resonance mode to radiate signals in the first predetermined frequency band. In at least one embodiment, the first predetermined frequency band can be a low frequency band having frequency between 700˜960 MHz, a middle frequency band having frequency between 1710˜2170 MHz, or a high frequency band having frequency between 1710˜2700 MHz. 
     In one embodiment, if the other end portion of the first antenna frame  21  is electrically connected to a second electrical connection point  223  that is nearest to the ground point  221 , a second radiating element formed between the first feed point  211  and the ground point  221  is enabled by the first antenna diplexer  33 . The first antenna diplexer  33  can tune the antenna frequency of the second radiating element to a second predetermined frequency band. Thus, the second radiating element can be operated in a second magnetic resonance mode to radiate signals in the second predetermined frequency band. In at least one embodiment, the second predetermined frequency band can be a low frequency band having frequency between 700˜960 MHz, a middle frequency band having frequency between 1710˜2170 MHz, or a high frequency band having frequency between 1710˜2700 MHz. 
     In at least one embodiment, if the other end portion of the first antenna frame  21  is electrically connected to the remaining one of the multiple electrical connection points  223  (not the first electrical connection point  223  or the second electrical connection point  223 ), a third radiating element formed between the first feed point  211  and the ground point  221  is enabled by the first antenna diplexer  33 . The first antenna diplexer  33  can tune the antenna frequency of the third radiating element to a third predetermined frequency band. Thus, the third radiating element can be operated in a third magnetic resonance mode to radiate signals in the third predetermined frequency band. In at least one embodiment, the third predetermined frequency band can be a low frequency band having frequency between 700˜960 MHz, a middle frequency band having frequency between 1710˜2170 MHz, or a high frequency band having frequency between 1710˜2700 MHz. 
     In at least one embodiment, the frequencies belonging to the first predetermined frequency band are lower than the frequencies belonging to the second predetermined frequency band. The frequencies belonging to the third predetermined frequency band are higher than those of the first predetermined frequency band, and are lower than those of the second predetermined frequency band. 
     In at least one embodiment, a first length from the first electrical connection point  223  to the ground point  221  is not more than a first difference value. The first difference value is a distance which is between a quarter of a wavelength of a first predetermined frequency and a length of the first antenna frame  21 , the first predetermined frequency belonging to a frequency band that is available for the first radiating element and the first antenna frame  21 . A second length from the second electrical connection point  223  to the ground point  221  is a distance not more than a second difference value, the second difference value being a distance which is between a quarter of a wavelength of a second predetermined frequency and a length of the first antenna frame  21 , the second predetermined frequency belonging to a frequency band that is available for the second radiating element and the first antenna frame  21 . A third length from the remaining one of the multiple electrical connection points  223  to the ground point  221  is not more than a third difference value. The third difference value is a distance which is between a quarter of a wavelength of a third predetermined frequency and a length of the first antenna frame  21 , the third predetermined frequency belonging to a frequency band that is available for the third radiating element and the first antenna frame  21 . 
     In at least one embodiment, the second antenna diplexer  34  is electronically coupled between the second feed point  222  and the control module  31 . The second antenna diplexer  34  can receive command from the control module  31 , and tune the antenna frequency to a fourth predetermined frequency band. Thus, the second antenna frame  22  can be operated on a fourth magnetic resonance mode to radiate signals in the fourth predetermined frequency band. In at least one embodiment, a length of the second antenna frame  22  is not more than a distance equal to a quarter of the wavelength of the frequency belonging to the fourth predetermined frequency band. In at least one embodiment, the fourth predetermined frequency band can be a low frequency band having frequency between 700˜960 MHz, a middle frequency band having frequency between 1710˜2170 MHz, or a high frequency band having frequency between 1710˜2700 MHz. 
     For example, the first predetermined frequency band can be the low frequency band of the 2G/3G/4G communication system, the second predetermined frequency band can be the middle frequency band of the 2G/3G/4G communication system, and the fourth predetermined frequency band can be the high frequency band of the 2G/3G/4G communication system. Then, the first feed point  211  can be configured to receive and/or transmit middle or low frequencies and the second feed point  222  can be configured to receive and/or transmit high frequencies. Thus, the antenna  20  can provide long-distance transmission of the 2G/3G/4G signals. 
     In other embodiments, the first predetermined frequency band, the second predetermined frequency band, the third predetermined frequency band, and the fourth predetermined frequency band or any of them can be a Near Field Communication (NFC) frequency band, or a Wireless Power Transmission (WPT) frequency band, or WIFI frequency band, or BLUETOOTH frequency band. Thus, the antenna  20  can provide short-distance transmission of the NFC/WPT/WIFI/BLUETOOTH signals. 
     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 can be made in the detail, including in particular the matters of shape, size, and arrangement of 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.