Patent Publication Number: US-8525738-B2

Title: Wireless communication device and method thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of Taiwan application serial No. 99104483, filed on Feb. 1, 2010. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a wireless communication device. More particularly, the present invention relates to a wireless communication device including a retractable antenna. 
     2. Description of Related Art 
     With development of wireless communication technology, wireless communication devices are widely used in various occasions and applications thereof are diversified. For example, various portable wireless communication devices such as mobile phones, smart phones, multimedia players, personal digital assistants (PDA) and satellite navigators, etc. are developed and become commonly used electronic products in people&#39;s daily life. 
     Generally, regarding a method for the wireless communication device receiving and processing a signal, an antenna is first used to receive the signal, and then the signal received by the antenna is transmitted to a circuit for a series of processing. Therefore, design of the antenna in the wireless communication device is very important. 
     In the related art, the conventional wireless communication device requires two antennas to simultaneously support global positioning system (GPS) signals and a digital video broadcasting-T/H (DVB-T/H) system, wherein one antenna is used for supporting the GPS signals, and another antenna is used for supporting the DVB-T/H system, so that a cost of the wireless communication device is increased, and a utilization convenience thereof is reduced. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a wireless communication device and a wireless communication method, in which a single antenna is used to transceive a first signal and a second signal respectively corresponding to a first radio frequency system and a second radio frequency system. 
     The present invention provides a wireless communication device. The wireless communication device includes a system ground surface and a retractable antenna. The system ground surface includes a feed point. The retractable antenna is coupled to the feed point. When the retractable antenna is configured to be a first length, the wireless communication device transceives a first signal of a first bandwidth range through the retractable antenna for a first radio frequency (RF) system. When the retractable antenna is configured to be a second length, the wireless communication device transceives the first signal of the first bandwidth range and a second signal of a second bandwidth range through the retractable antenna respectively for the first RF system and a second RF system. A center frequency of the first bandwidth range is substantially a first odd multiple of a reference frequency, and a center frequency of the second bandwidth range is substantially a second odd multiple of the reference frequency, wherein the first odd multiple is different to the second odd multiple. 
     In an embodiment of the present invention, the second length is greater than the first length. 
     In an embodiment of the present invention, the system ground surface further includes a ground point. When the retractable antenna is configured to be the first length, the ground point is coupled to the retractable antenna, and when the retractable antenna is configured to be the second length, the ground point is not coupled to the retractable antenna. 
     In an embodiment of the present invention, the wireless communication device further includes a conductive material. When the retractable antenna is configured to be the first length, the conductive material is coupled between the ground point and the retractable antenna, and when the retractable antenna is configured to be the second length, the conductive material is coupled to the ground point. 
     In an embodiment of the present invention, the first RF system is a global positioning system (GPS), and the second RF system is a digital video broadcasting (DVB-T/H) system. 
     In an embodiment of the present invention, the wireless communication device further includes a GPS chip set and a DVB-T/H system chip set. The GPS chip set is coupled to the feed point, and the DVB-T/H system chip set is coupled to the feed point. 
     In an embodiment of the present invention, the retractable antenna further includes a pivot structure, and the pivot structure is used for changing a direction of the retractable antenna. 
     In an embodiment of the present invention, the wireless communication device further includes a matching circuit, and the matching circuit is used for adjusting the first bandwidth range. 
     In an embodiment of the present invention, a resonant frequency of the retractable antennal is an odd multiple of the reference frequency. 
     The present invention provides a wireless communication method, which is adapted to a wireless communication device, wherein the wireless communication device includes a system ground surface and a retractable antenna. The wireless communication method can be described as follows. The retractable antenna is configured to be a first length, so that the wireless communication device transceives a first signal of a first bandwidth range for a first radio frequency (RF) system. The retractable antenna is configured to be a second length, so that the wireless communication device transceives the first signal and a second signal of a second bandwidth range respectively for the first RF system and a second RF system. A center frequency of the first bandwidth range is substantially a first odd multiple of a reference frequency, and a center frequency of the second bandwidth range is substantially a second odd multiple of the reference frequency, wherein the first odd multiple is different to the second odd multiple. 
     In an embodiment of the present invention, the wireless communication method further includes adjusting the first bandwidth range through a matching circuit. 
     According to the above descriptions, in the present invention, the retractable structure of the retractable antenna of the wireless communication device can be used to change the length of the retractable antenna, so that the wireless communication device can use a single retractable antenna to support the first RF system and the second RF system. 
     In order to make the aforementioned and other features and advantages of the present invention comprehensible, several exemplary embodiments accompanied with figures are described in detail below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
         FIGS. 1A-1C  are schematic diagrams illustrating a wireless communication device according to an embodiment of the present invention. 
         FIGS. 2A-2C  are schematic diagrams illustrating a wireless communication device according to an embodiment of the present invention. 
         FIGS. 3A-3C  are diagrams illustrating relationships between frequency and return loss of signals received by a wireless communication device according to an embodiment of the present invention. 
         FIGS. 4A and 4B  are flowcharts respectively illustrating a wireless communication method according to an embodiment of the present invention. 
         FIGS. 5A-5C  are schematic diagrams illustrating radiation patterns of signals transceived by a wireless communication device according to an embodiment of the present invention. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     A conventional wireless communication device requires two antennas to simultaneously support global positioning system (GPS) signals and a digital video broadcasting (DVB-T/H) system, so that a cost of the wireless communication device is increased, and a utilization convenience thereof is reduced. 
     Accordingly, embodiments of the present invention provide a retractable antenna having a retractable structure, which is mainly used for changing a radiator length of the retractable antenna. The radiator length of the retractable antenna is referred to as an antenna length hereinafter. When the retractable antenna is accommodated within the wireless communication device, the antenna length of the retractable antenna is configured to be a first length, and the wireless communication device transceives a first signal of a first bandwidth range through the retractable antenna for a first radio frequency (RF) system. When the retractable antenna is pulled out from the wireless communication device, the antenna length of the retractable antenna is configured to be a second length, and the wireless communication device transceives the first signal and a second signal of a second bandwidth range through the retractable antenna respectively for the first RF system and a second RF system. 
     In detail, when the retractable antenna is configured to be the first length, the wireless communication device can provide a good signal-receiving quality to the first signal of the first bandwidth range. When the retractable antenna is configured to be the second length, the wireless communication device can provide a good signal-receiving quality to the first signal of the first bandwidth range and the second signal of the second bandwidth range. Therefore, only a single retractable antenna is used in the wireless communication device of the embodiments to simultaneously support the GPS signals and the DVB-T/H system, so as to effectively reduce a cost of the wireless communication device and improve the utilization convenience. 
     Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements or steps throughout. 
     First Embodiment 
       FIGS. 1A-1C  are schematic diagrams illustrating a wireless communication device according to an embodiment of the present invention. The wireless communication device of the present embodiment can be a smart phone, a personal digital assistant (PDA), a GPS device, a smartbook, a netbook, a notebook, an ultra-mobile personal computer (UMPC), etc., as long as it can simultaneously support the GPS signals and the DVB-T/H system. 
     Referring to  FIGS. 1A-1C , the wireless communication device  1000  is, for example, a smart phone, in which only a single retractable antenna is used to simultaneously support the GPS signals and the DVB-T/H system, so as to effectively reduce a cost of the wireless communication device and improve the utilization convenience. The wireless communication device of a portrait mode is illustrated in  FIGS. 1A-1B , and the wireless communication device of a landscape mode is illustrated in  FIG. 1C . 
     The wireless communication device  1000  includes a system ground plane  1100  and a retractable antenna  1200 A,  1200 B or  1200 C. The system ground plane  1100  is, for example, a plane of a printed circuit board (PCB). The retractable antenna is, for example, disposed on a substrate. The system ground plane  1100  includes a feed point  1110 . The retractable antenna  1200 A,  1200 B or  1200 C is coupled to the feed point  1110 . The retractable antenna  1200 A,  1200 B or  1200 C includes a retractable structure (not shown), and the retractable structure is used for changing a radiator length of the retractable antenna. For simplicity&#39;s sake, the radiator length of the retractable antenna is referred to as an antenna length. It should be noticed that the retractable antennas  1200 A- 1200 C are the same retractable antenna, though it is marked with different reference numbers for the sake of simplicity. Moreover, the retractable antenna also includes a pivot structure  1220 . 
       FIG. 4A  is a flowchart illustrating a wireless communication method according to an embodiment of the present invention. Referring to  FIG. 1A  and  FIG. 4A , the wireless communication method  2000 A includes steps S 2100 -S 2200 . A user uses the wireless communication device  1000  in the portrait mode, and accommodates the retractable antenna  1200 A within the wireless communication device  1000 . Now, in the step S 2100 , the retractable antenna  1200 A is configured to be the first length, which is, for example, between 3.5 cm and 5.5 cm, and is preferably 4.5 cm. The first length is a corresponding length of 0.25 times of a resonance wavelength (λ) when the wireless communication device  1000  is operated at a GPS frequency (1575 MHz). The wireless communication device  1000  transceives a first signal of a first bandwidth range through the retractable antenna  1200 A for a first RF system. The first signal is, for example, a GPS signal, the first bandwidth range is, for example, between 1572 MHz and 1578 MHz, and the first RF system is, for example, the GPS system. 
     Referring to  FIG. 1B  and  FIG. 4A , the user uses the wireless communication device  1000  in the portrait mode. Now, in the step S 2200 , the retractable antenna  1200 B is configured to be the second length, which is, for example, between 14 cm and 16 cm, and is preferably 15.7 cm. The second length is a corresponding length of 0.25 times of a resonance wavelength (λ) when the wireless communication device  1000  is operated at a DVB-T/H frequency (500 MHz). Moreover, the user can also use the wireless communication device  1000  in the landscape mode, and when the retractable antenna  1200 C is configured to be the second length, lengths of the retractable antennas  1200 B and  1200 C are the same, and only shapes thereof are different, wherein the retractable antenna  1200 C has an L-shape, and the retractable antenna  1200 B has a linear-shape. The first length is, for example, between 7 cm and 9 cm, which is preferably 8.7 cm, and the second length is, for example, between 14 cm and 16 cm, which is preferably 15.7 cm. 
     The wireless communication device  1000  transceives the first signal and a second signal of a second bandwidth range through the retractable antenna respectively for the first RF system and a second RF system. The second RF system is, for example, the DVB-T/H system, and the second bandwidth range is, for example, between 450 MHz and 800 MHz. A center frequency of the first bandwidth range is substantially a first odd multiple of a reference frequency, and a center frequency of the second bandwidth range is substantially a second odd multiple of the reference frequency, wherein the first odd multiple is different to the second odd multiple. The first odd multiple is about 3, and the second odd multiple is about 1. The reference frequency is, for example, 500 MHz. It should be noticed that in the present embodiment, the first odd multiple is about 3, and the second odd multiple is about 1, though the present invention is not limited thereto. In the other embodiments, the reference frequency can be 1000 MHz, and the second odd multiple can be about 5, so that the center frequency of the second bandwidth range can be 5000 MHz. In the present embodiment, the wireless communication device  1000  receives signals from two different bandwidth ranges, though the present invention is not limited thereto. In the other embodiments, if center frequencies of bandwidth ranges in different RF systems are substantially odd multiples of the reference frequency, the wireless communication device  1000  can receive signals from other different RF systems. Moreover, a resonant frequency of the retractable antenna  1200 A,  1200 B or  1200 C is an odd multiple of the reference frequency rather than an even multiple of the reference frequency. When the retractable antenna  1200 B or  1200 C is configured to be the second length, the wireless communication device  100  can be applied to the DVB-T/H system of about 500 MHz, and can also be applied to the GPS of about 1500 MHz. In detail, the retractable antenna  1200 B or  1200 C is, for example, a single-dipole retractable antenna, and in the present embodiment, the resonant frequency thereof is designed to be about 500 MHz, which can support the DVB-T/H system. Moreover, in case of such antenna length, based on the resonance phenomenon of the frequency, a triple harmonic resonance thereof is about 1500 MHz, which is rather close to a GPS usage band (1575 MHz), so that a suitable matching circuit can be used to shift the resonant frequency to the GPS usage band. Therefore, when the retractable antenna  1200 B or  1200 C is configured to be the length of 15.7 cm, the wireless communication device  1000  can simultaneously support the DVB-T/H system and the GPS signals. 
     Accordingly, in the present embodiment, the retractable structure of the retractable antenna  1200 A,  1200 B or  1200 C of the wireless communication device  1000  can be used to change the length of the retractable antenna  1200 A,  1200 B or  1200 C, and in collaboration with a characteristic that the resonant frequency of the retractable antenna  1200 A,  1200 B or  1200 C is an odd multiple of the reference frequency rather than an even multiple of the reference frequency, the wireless communication device  1000  can use a single retractable antenna to simultaneously support the GPS signals and the DVB-T/H system, so as to effectively reduce a cost of the wireless communication device and improve the utilization convenience. 
     Moreover, in the present embodiment, the second length of the retractable antennal  1200 B or  1200 C is greater than the first length of the retractable antenna  1200 A. The wireless communication device  1000  further includes a GPS chip set  1140  and a DVB-T/H system chip set  1150 . The GPS chip set  1140  and the DVB-T/H system chip set  1150  are all coupled to the feed point  1110  through a matching circuit  1130 , so as to process the GPS signals and DVB-T/H system signals transceived by the retractable antenna  1200 B or  1200 C. The device may further include other components, such as a diplexer (not shown) electrically connected between the matching circuit and these two chip sets, though the disclosure is not limited thereto. 
     Although a possible pattern of the wireless communication device has been described in the above embodiment, it should be understood by those skilled in the art that the design of the wireless communication device varies along with different manufacturers, thus, application of the present invention should not be limited to the possible pattern. In other words, the spirit of the present invention is met as long as a single retractable antenna is used in the wireless communication device to simultaneously support two or more RF systems. Several embodiments are provided below to provide a further understanding of the invention for those skilled in the art. 
     Second Embodiment 
       FIGS. 2A-2C  are schematic diagrams illustrating a wireless communication device according to an embodiment of the present invention. The wireless communication device  1000  of  FIGS. 2A-2C  is similar to the wireless communication device  1000  of  FIGS. 1A-1B , so that detailed descriptions of the similar components are not repeated. 
     Referring to  FIGS. 2A-2C , the system ground plane  1100  of the wireless communication device  1000  of  FIGS. 2A-2C  further includes a ground point  1120 . When the retractable antenna  1200 A is configured to be the first length, the ground point  1120  is coupled to the retractable antenna  1200 A. When the retractable antenna  1200 B or  1200 C is configured to be the second length, the ground point  1120  is not coupled to the retractable antenna, wherein a total length of the retractable antenna  1200 B is the same to that of the retractable antenna  1200 C, and only shapes thereof are different. The retractable antenna  1200 C has an L-shape, and the retractable antenna  1200 B has a linear-shape. The first length is, for example, between 7 cm and 9 cm, which is preferably 8.7 cm, and the second length is, for example, between 14 cm and 16 cm, which is preferably 15.7 cm. A distance between the feed point  1100  and the ground point  1120  can be adjusted, so that when the ground point  1120  is coupled to the retractable antenna  1200 A, a quality of the first signal transceived by the wireless communication device  1000  is improved. For example, a dot line R is taken as a benchmark, a distance between the feed point  1100  and the dot line R is between 1.5 cm and 3 cm, which is preferably 2.1 cm, and a distance between the ground point  1120  and the dot line R is between 7 cm and 9 cm, which is preferably 8.7 cm, and is a corresponding length of 0.5 times of a resonance wavelength when the wireless communication device  1000  is operated at the GPS frequency (1575 MHz). In other words, assuming a distance between the feed point  1100  and the ground point  1120  is d, an optimal transceiving quality is achieved when the distance d is close to 6.6 cm. When the distance d&gt;6.6 cm, an operating frequency of the wireless communication device  1000  is shifted to be lower than the GPS frequency (1575 MHz), and when the distance d&lt;6.6 cm, the operating frequency of the wireless communication device  1000  is shifted to be higher than the GPS frequency (1575 MHz). Therefore, the quality of the first signal transceived by the wireless communication device  1000  can be improved by adjusting the distance d between the feed point  1100  and the ground point  1120 . 
     It should be noticed that in the present embodiment, the reference frequency can be adjusted by moving a position of the ground point. Moreover, while the length of the retractable antenna is changed, a configuration of the retractable antenna is changed to adjust an operation bandwidth range. 
     The wireless communication device  1000  of  FIGS. 2A-2C  further includes a conductive material  1300 . The user uses the wireless communication device in the portrait mode, and accommodates the retractable antenna  1200 A within the wireless communication device  1000 . When the retractable antenna  1200 A is configured to be the first length, the conductive material  1300  is coupled between the ground point  1120  and the retractable antenna  1200 A. The conductive material  1300  is, for example, a metal spring, a pogo pin or other conductive materials, which is used for electrically connecting the retractable antenna  1200 A and the ground point  1120 . When the retractable antenna  1200 B is configured to be the second length, the conductive material  1300  is coupled to the ground point  1120 , and the ground point  1120  is not coupled to the retractable antenna  1200 B or  1200 C. Moreover, the retractable antenna also includes the pivot structure  1220 . 
     Moreover, in the present embodiment, the wireless communication device  1000  further includes the matching circuit  1130 . The matching circuit  1130  is used for adjusting the first resonant frequency of the retractable antenna configured to the second length. For example, when the user pulls out the retractable antenna  1200 B or  1200 C from the wireless communication device  1000 , the retractable antenna  1200 B or  1200 C is not only adapted to the first bandwidth range, for example, about 1500 MHz, but is also adapted to the second bandwidth range, for example, about 500 MHz. The matching circuit  1130  can fine-tune the first bandwidth range to shift the first bandwidth range to the GPS usage band. Therefore, the quality of the first signal transceived by the wireless communication device  1000  can be improved through the matching circuit  1130 . 
     Accordingly, in the present embodiment, the distance between the feed point  1100  and the ground point  1120  in the wireless communication device  100  can be adjusted, so that when the ground point  1120  is coupled to the retractable antenna  1200 A, the resonant frequency of the first signal transceived by the wireless communication device  1000  is adjusted. Moreover, when the ground point  1120  is not coupled to the retractable antenna  1200 A, the quality of the first signal transceived by the wireless communication device  1000  can be improved through the matching circuit  1130 . 
       FIGS. 3A-3C  are diagrams illustrating return loss of signals received by the wireless communication device according to an embodiment of the present invention. The return loss is generally represented by a voltage standing wave ratio (VSWR). 
     Referring to  FIG. 2A  and  FIG. 3A ,  FIG. 3A  is diagram illustrating a relation between frequency and return loss measured when the retractable antenna  1200 A is configured to be the first length, wherein the wireless communication device  1000  has the portrait mode. The first length is, for example, 8.7 cm. The frequency of the first signal is 1575 MHz, and the VSWR is 1.516 as that shown by a point VSWR_A of  FIG. 3A . 
     Referring to  FIGS. 2B and 3B ,  FIG. 3B  is a diagram illustrating a relation between frequency and return loss measured when the retractable antenna  1200 B is configured to be the second length, wherein the wireless communication device  1000  has the portrait mode. The second length is, for example, 15.7 cm. The frequency of the first signal is 1575 MHz, and the VSWR is 2.105 as that shown by a point VSWR_B 1  of  FIG. 3B . The frequency of the second signal is 500 MHz, and the VSWR is 1.9 as that shown by a point VSWR_B 2  of  FIG. 3B . 
     Referring to  FIGS. 2C ,  3 C and  4 B,  FIG. 3C  is a diagram illustrating a relation between frequency and return loss measured when the retractable antenna  1200 C is configured to be the second length.  FIG. 4B  is another flowchart illustrating a wireless communication method according to an embodiment of the present invention. The wireless communication method  2000 B includes steps S 2100 -S 2300 . The user uses the wireless communication device  1000  in the landscape mode, and pulls out the retractable antenna  1200 C from the wireless communication device  1000 . In the step S 2300 , the pivot structure  1220  is used to change a direction of the retractable antenna  1200 C. For example, the direction of the retractable antenna of  FIGS. 2A and 2B  is approximately perpendicular to the direction of the retractable antenna of  FIG. 2C . The second length is, for example, 15.7 cm. The frequency of the first signal is 1575 MHz, and the VSWR is 1.778 as that shown by a point VSWR_C 1  of  FIG. 3C . The frequency of the second signal is 500 MHz, and the VSWR is 1.6 as that shown by a point VSWR_C 2  of  FIG. 3C . Therefore, by using the pivot structure  1220  to change the direction of the retractable antenna  12000 , the qualities of the first signal and the second signal transceived by the wireless communication device  1000  in the landscape mode can still be maintained. In other words, regardless that the user uses the wireless communication device in the portrait mode or the landscape mode, the design of the retractable antenna of the present embodiment can ensure the wireless communication device simultaneously supporting the GPS signals and the DVB-T/H system. 
       FIGS. 5A-5C  are schematic diagrams illustrating radiation patterns of signals transceived by the wireless communication device according to an embodiment of the present invention.  FIG. 5A  illustrates a radiation pattern of the wireless communication device  1000  of  FIG. 2A , wherein the radiation pattern of a direction Z is relatively intense.  FIG. 5B  illustrates a radiation pattern of the wireless communication device  1000  of  FIG. 2B , wherein the radiation pattern of the direction Z is relatively intense.  FIG. 5C  illustrates a radiation pattern of the wireless communication device  1000  of  FIG. 2C , and since the pivot structure  1220  is used to change the direction of the retractable antenna  1200 C, the radiation pattern of a direction Y is relatively intense. 
     A difference between the first embodiment and the second embodiment lies in different lengths of the retractable antenna accommodated in the wireless communication device, and the length is determined according to whether there is the ground point. As described in the first embodiment, when the retractable antenna is accommodated within the wireless communication device, it has a corresponding length X 1  of 0.25 times of a resonance wavelength (λ) when the wireless communication device is operated at the GPS frequency (1575 MHz). In the second embodiment, since there is the ground point, a required length of the resonant wavelength can be adjusted, so that the wireless communication device can be operated at the GPS frequency, and a length X 2  of the retractable antenna accommodated within the wireless communication device is greater than the length X 1 , and the ground point is also different. 
     In summary, in the embodiments of the present invention, the retractable structure of the retractable antenna of the wireless communication device can be used to change the length of the retractable antenna, and in collaboration with the characteristic that the resonant frequency of the retractable antenna is an odd multiple of the reference frequency rather than an even multiple of the reference frequency, the wireless communication device can use a single retractable antenna to simultaneously support the GPS signals and the DVB-T/H system, so as to effectively reduce a cost of the wireless communication device and improve the utilization convenience. In the embodiments of the present invention, the distance between the feed point and the ground point in the wireless communication device can be adjusted, so that in case of the first antenna length, the ground point is coupled to the retractable antenna, the antenna length of the wireless communication device is adjusted to change the resonant frequency of the retractable antennal, so as to transceive the first signal. Moreover, in case of the second antenna length, the quality of the first signal transceived by the wireless communication device can be improved through the matching circuit. In the embodiments of the present invention, the pivot structure is used to change the direction of the retractable antenna, so that the wireless communication device in the landscape mode can still maintain the qualities of the transceived first signal and second signal, so as to facilitate the user using the wireless communication device. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.