Abstract:
A wireless communication device includes a housing, an antenna, and a transceiver for transmitting and receiving wireless signals through the antenna. The wireless communication device also includes a first hinge connecting the antenna to the housing for allowing the antenna to rotate about a first axis with respect to the housing, a first motor for rotating the antenna about the first axis with respect to the housing, and a control circuit for controlling the first motor to rotate the antenna for scanning reception of wireless signals as the antenna is rotated at different angles.

Description:
BACKGROUND OF INVENTION 
     1. Field of the Invention 
     The present invention relates to an antenna for a wireless local area network (WLAN), and more specifically, to a wireless antenna that can be rotated by a motor for improving signal reception of the antenna. 
     2. Description of the Prior Art 
     In recent years, wireless communication networks have experienced great growth. In addition to mobile phone networks, wireless computer networks are now rapidly gaining in popularity. While cable has traditionally been used for wiring local area networks (LANs), the introduction of the wireless LAN (WLAN) has allowed users to freely carry computing devices around within the area of the WLAN while still being connected to the network. 
     Please refer to FIG.  1 . FIG. 1 is a diagram of a host computer  10  connected to a WLAN according to the prior art. The host computer  10  may be any computing device that is able to connect to a network, such as a notebook computer, desktop computer, or a PDA. The host computer  10  is connected to a wireless communication card  20  for allowing the host computer  10  to communicate with the WLAN. The wireless communication card  20  comprises a housing  22  and an antenna  30  disposed on the housing  22 . The housing  22  may be connected to the host computer  10  through a PCMCIA slot, a USB port, etc. The antenna  30  is disposed on the housing  22  in such a way that the antenna  30  is approximately perpendicular to a surface that the host computer  10  is placed on. 
     Please refer to FIG.  2 . FIG. 2 is a functional block diagram of the wireless communication card  20  connected to the host computer  10  according to the prior art. The wireless communication card  20  contains a transceiver  26  electrically connected to the antenna  30  for transmitting and receiving wireless signals through the antenna  30 . A signal sensor  28  is electrically connected to the transceiver  26  for detecting strength of wireless signals received by the wireless communication card  20 . The signal sensor  28  will output a feedback signal FD to a controller  24  for notifying the controller  24  of the strength of the received wireless signals. According to the strength of the signal detected by the signal sensor  28 , the controller  24  will vary the magnitude of a control current i c . For instance, if the signal sensor  28  detects a weak signal, the controller  24  will then increase the magnitude of the control current i c  for increasing the strength of the wireless signals. 
     Inserting the wireless communication card  20  into the host computer  10  allows the host computer  10  to quickly connect to a WLAN. Unfortunately, the antenna  30  of the wireless communication card  20  is fixed, and cannot be repositioned for improving the strength of wireless signals transmitted and received by the wireless communication card  20 . 
     Please refer to FIG.  3  and FIG.  4 . FIG.  3  and FIG. 4 are perspective diagrams of a WLAN stick  40  according to the prior art. The WLAN stick  40  comprises a housing  42  and a connector  44  formed on the housing  42 . The connector  44 , such as a USB connector, is used for connecting the WLAN stick  40  to a host computer and allowing the host computer to communicate with the WLAN through the WLAN stick  40 . The WLAN stick  40  also includes an antenna  50  connected to the housing  42  with a rotatable hinge  48 . As shown in FIG. 3, the antenna  50  is rotated outwards from the housing  42  of the WLAN stick  40  for improving the reception of wireless signals. The antenna  50  can also be rotated towards the housing  42  until the antenna  50  rests in a cavity  46  of the housing  42 , as shown in FIG.  4 . Rotating the antenna  50  along the hinge  48  allows the antenna  50  to positioned at an angle which provides optimum strength of signals transmitted to and received from the WLAN. 
     Unfortunately, the antenna  50  can only be rotated about one axis, which prevents the antenna  50  from being rotated about other axes for further improving the signal strength. Also, the antenna  50  has to be rotated manually, and a user of the WLAN stick  40  has a hard time knowing exactly what the optimum angle of the antenna  50  is. A trial and error process is usually required, with the user positioning the antenna  50  at a chosen angle, determining if the resulting signal strength is sufficient, and repositioning the antenna  50  if necessary. 
     SUMMARY OF INVENTION 
     It is therefore a primary objective of the claimed invention to provide a wireless communication device with a motorized rotatable wireless antenna in order to solve the above-mentioned problems. 
     According to the claimed invention, a wireless communication device includes a housing, an antenna, and a transceiver for transmitting and receiving wireless signals through the antenna. The wireless communication device also includes a first hinge connecting the antenna to the housing for allowing the antenna to rotate about a first axis with respect to the housing, a first motor for rotating the antenna about the first axis with respect to the housing, and a control circuit for controlling the first motor to rotate the antenna for scanning reception of wireless signals as the antenna is rotated at different angles. 
     It is an advantage of the claimed invention that the wireless communication device has the first motor for rotating the antenna about the first axis for automatically scanning signal strength when the antenna is positioned at different angles, and for rotating the antenna to an angle that provides best signal strength. 
     These and other objectives of the claimed invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment, which is illustrated in the various figures and drawings. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 is a diagram of a host computer connected to a WLAN according to the prior art. 
     FIG. 2 is a functional block diagram of a wireless communication card connected to the host computer according to the prior art. 
     FIG.  3  and FIG. 4 are perspective diagrams of a WLAN stick according to the prior art. 
     FIG. 5 is a functional block diagram of a WLAN stick connected to a host computer according to the present invention. 
     FIG. 6, FIG. 7, and FIG. 8 show perspective, top, and side views of the WLAN stick, respectively. 
     FIG. 9 shows the WLAN stick being inserted into the host computer. 
     FIG.  10  through FIG. 13 shows the WLAN stick being rotated along first and second hinges. 
     FIG. 14 is a flowchart illustrating scanning wireless signals with the present invention WLAN stick. 
    
    
     DETAILED DESCRIPTION 
     Please refer to FIG.  5  through FIG.  8 . FIG. 5 is a functional block diagram of a WLAN stick  60  connected to a host computer  55  according to the present invention. FIG. 6, FIG. 7, and FIG. 8 show perspective, top, and side views of the WLAN stick  60 , respectively. The WLAN stick  60  connects with the host computer  55  through a connector  61  formed on one end of the WLAN stick  60 . In the preferred embodiment of the present invention, the connector  61  is a USB connector, but other connectors such as IEEE 1391 and PCMCIA connectors are also within the scope of the present invention. Also, the host computer  55  may be a notebook computer, a desktop computer, or any other computing device that can communicate with a WLAN. 
     Like the prior art wireless communication card  20  shown in FIG. 2, the WLAN stick  60  contains a transceiver  66  electrically connected to an antenna  68  for transmitting and receiving wireless signals through the antenna  68 . A signal sensor  64  is electrically connected to the transceiver  66  for detecting strength of wireless signals received by the WLAN stick  60 . The signal sensor  64  will output a feedback signal FD to a controller  62  for notifying the controller  62  of the strength of the received wireless signals. 
     Different from the prior art wireless communication card  20 , the WLAN stick  60  of the present invention contains a first motor  92  and a second motor  94 , each of which is controlled by the controller  62 . The first motor  92  rotates the WLAN stick  60  along a first hinge  82  for rotating the WLAN stick  60  about the x-axis. Therefore, the first motor  92  can rotate the WLAN stick  60  in the directions shown by arrows  101  and  102 . Likewise, the second motor  94  rotates the WLAN stick  60  along a second hinge  84  for rotating the WLAN stick  60  about the y-axis in the directions shown by arrows  111  and  112 . The first and second motors  92  and  94  are preferably step motors or DC motors. 
     The controller  62  controls the first motor  92  and the second motor  94  to rotate the WLAN stick  60  in three main situations: when the WLAN stick  60  is initially inserted into the host computer  55 , during a periodic signal scan, and when the feedback signal FD received from the signal sensor  64  indicates that the signal strength is low. These three situations serve only as examples, and are not intended to limit the scope of the present invention. As shown in FIG. 7, the antenna  68  is formed in an upper portion of the WLAN stick  60  above the first hinge  82  and the second hinge  84 , for allowing the antenna  68  to be rotated about the x-axis and y-axis. By rotating the antenna  68  about the x-axis and y-axis, the WLAN stick  60  can always achieve optimum signal strength for both transmission and reception of wireless signals. 
     Please refer to FIG.  9  through FIG.  13 . FIG. 9 shows the WLAN stick  60  being inserted into the host computer  55 . FIG.  10  through FIG. 13 shows the WLAN stick  60  being rotated along the first and second hinges  82  and  84 . In FIG. 9, the connector  61  of the WLAN stick  60  is inserted into the host computer  55  for allowing the host computer  55  to communicate with the WLAN through the WLAN stick  60 . FIG. 10 shows the WLAN stick  60  after insertion into the host computer  55 . As shown in FIG.  9  and FIG. 10, the WLAN stick  60  is roughly parallel with a surface that the host computer  55  is placed on. For improving the transmission and reception signal strength, the WLAN stick  60  may be rotated along the first hinge  82  and the second hinge  84 . 
     FIG. 11 shows the WLAN stick  60  after being rotated along the first hinge  82  by a small angle in the direction shown by arrow  101 . FIG. 12 shows the WLAN stick  60  after being further rotated along the first hinge  82  in the direction shown by arrow  101 . At this point, the WLAN stick  60  is roughly perpendicular to the surface that the host computer  55  is placed on. FIG. 13 shows the WLAN stick  60  after being rotated along the second hinge  84  by a small angle in the direction shown by arrow  111 . Although FIG.  11  through FIG. 13 show the WLAN stick  60  being rotated in only one direction at a time, it is also possible to rotate the WLAN stick  60  about the x-axis and y-axis at the same time. 
     Please refer to FIG.  14 . FIG. 14 is a flowchart illustrating scanning wireless signals with the present invention WLAN stick  60 . Steps contained in the flowchart will be explained below. 
     Step  150 : Insert the WLAN stick  60  into the host computer  55 ; 
     Step  152 : Perform a signal scan process while the first and second motors  92  and  94  rotate the WLAN stick  60  for determining which position of the WLAN stick  60  provides optimal signal strength; 
     Step  154 : The host computer  55  communicates with the WLAN through the WLAN stick  60 ; 
     Step  156 : Determine if a predetermined time has elapsed; if so, the WLAN stick  60  should do a periodic signal scan, go to step  152 ; if not, go to step  158 ; 
     Step  158 : The signal sensor  64  provides the feedback signal FD to the controller  62  for indicating the strength of transmitted and received signals; and 
     Step  160 : Determine if the signal strength is below a threshold value; if so, the WLAN stick  60  should perform another signal scan, go to step  152 ; if not, go to step  154 . 
     Compared to the prior art WLAN stick  40  shown in FIG. 3, the present invention WLAN stick  60  is capable of using motors to automatically rotate the WLAN stick  60  about two axes for maintaining optimal transmission and reception signal strength. The WLAN stick  60  is automatically rotated during a scanning process, eliminating the need for a user to manually adjust the angle of the antenna. Therefore, even if the user decides to move the host computer  55  to a different location, the WLAN stick  60  can still maintain a reliable connection with the WLAN. 
     The controller  62  may also integrate with a vibration detection circuit (like the vibration responsive circuit shown in U.S. Pat. No. 4,974,850) to detect the vibration generated when the user is moving the host computer  55  to a different location. Therefore, even the WLAN stick  60  is always inserted in the host computer  55 , when the host computer  55  is moved to the new location and the vibration stops, the controller  62  will automatically trigger the WLAN stick  60  to perform the step  152  rotation and scanning process. 
     Those skilled in the art will readily observe that numerous modifications and alterations of the device may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.