Abstract:
A radio frequency identification (RFID) reader includes a main body, a first connecting portion, and a second connecting portion. The first connecting portion and the second connecting portion are positioned at two sides of the main body. The first connecting portion is configured to connect to the second connecting portion of another RFID reader and interconnecting the RFID reader to another RFID reader in series.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The disclosure generally relates to radio frequency identification (RFID) technology, and particularly to a RFID reader and system. 
         [0003]    2. Description of Related Art 
         [0004]    RFID technology is an automatic identification technology based on radio frequency identification principle and is widely used in various fields to track people and articles. A RFID system commonly includes a plurality of RFID tags, a RFID reader and a data processor. Each RFID tag is configured to store article or personal information. The RFID reader communicates with the RFID tags and reads the information stored in the RFID tags. 
         [0005]    However, most RFID readers can identify and read the RFID tag in a limited effective identifying area, but there is always a “blind area”. Referring to  FIG. 4 , an effective identifying area A 10  of a typical RFID reader includes a primary identifying area A 11  and two secondary indentifying area A 12  symmetrically positioned at two sides of the primary identifying area A 11 . A blind area A 13  is formed between each secondary indentifying area A 12  and the primary identifying area A 11 . To reduce the blind area A 13 , multiple RFID readers are linearly positioned to enlarge the effective identifying areas and enhance identifying sensitivity. However, two adjacent RFID readers still cannot completely cover the blind area of each other so that a blind area A 14  still exists. 
         [0006]    Therefore, there is room for improvement within the art. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0007]    Many aspects of the present disclosure can be better understood with reference to the following drawing. The components in the drawing are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the disclosure. 
           [0008]      FIG. 1  is a block diagram of a RFID system, according to an exemplary embodiment of the disclosure. 
           [0009]      FIG. 2  is a partial circuit diagram of the RFID system of  FIG. 1 , according to an exemplary embodiment of the disclosure. 
           [0010]      FIG. 3  is a radiation pattern of RFID readers of the RFID system of  FIG. 1 , according to an exemplary embodiment of the disclosure. 
           [0011]      FIG. 4  is a radiation pattern of conventional RFID readers. 
       
    
    
     DETAILED DESCRIPTION 
       [0012]      FIG. 1  is a block diagram of a RFID system  100 , according to an exemplary embodiment of the disclosure. The RFID system  100  includes a plurality of RFID tags  10 , a plurality of RFID readers  20 , a data processor  40 , and a host terminal  50 . 
         [0013]    Each RFID tag  10  includes an RFID microchip which stores personnel information such as names, work numbers or studying numbers of workers or students, for example. 
         [0014]    Each RFID reader  20  includes a main body  21 , a first connecting portion  22 , and a second connecting portion  23 . The first connecting portion  22  and the second connecting portion  23  are positioned at two opposite ends of the main body  21 . The first connecting portion  22  and the second connecting portion  23  may be connectors. 
         [0015]    Referring to  FIG. 2 , the main body  21  of the embodiment is shown. The main body  21  includes two power supply contacts Vcc, two ground contacts GND, a first data receiving contact RX 1 , a first data transmitting contact TX 1 , a second data receiving contact RX 2 , and a second data transmitting contact TX 2 . One of the power supply contacts Vcc, one of the ground contacts GND, the first data receiving contact RX 1 , and the second data transmitting contact TX 2  form a first connecting terminal The other one of the power supply contacts Vcc, the other one of the ground contacts GND, the second data receiving contact RX, and the first data transmitting contact TX 1  form a second connecting terminal Each RFID reader  20  includes an identity (ID) number configured to distinguish the RFID reader  20  from other RFID readers  20 . 
         [0016]    The first connecting portion  21  and the second connecting portion  23  are conventional connectors configured to interconnect the RFID readers  20 . The first connecting portion  21  connects to the first connecting terminal The second connecting portion  23  connects to the second connecting terminal 
         [0017]    The RFID readers  20  are interconnected in series by a plurality of conductive lines  30 . The first connecting terminal of an initial RFID reader  20  (i.e., an RFID reader  20  positioned at an end of the serially interconnected RIFD readers  20 ) is electrically connected to the data processor  40  via the first connecting portion  21 . The second connecting terminal of the initial RFID reader  20  is electrically connected to the first connecting terminal of an adjacent RFID reader  20  (i.e., the RFID reader  20  directly connected to the initial RFID reader  20 ). The second connecting terminal of the adjacent RFID reader  20  is electrically connected to the first connecting terminal of an next RFID reader  20  (i.e., the RFID reader  20  directly connected to the adjacent initial RFID reader  20  excepting the initial RFID  20 ). The next RFID reader  20  and remaining RFID readers  20  are electrically connected in the same way similar to the adjacent RFID reader  20 . The first data transmitting contact TX 1  and the second data receiving contact RX 2  of a distal RFID reader  20  (i.e. an RFID reader  20  positioned at another end of the serially interconnected RIFD reader  20 ) are shorted by a resistor having zero ohms Thus, all RFID readers  20  are connected in series to form a data transmitting link. All the RFID readers  20  can communicate with the data processor  40  via the data transmitting link. 
         [0018]    In this exemplary embodiment, the RFID readers  20  are connected to form two data transmitting links. For the purpose of simplicity, in this exemplary embodiment, each data transmitting link includes three RFID readers  20  connected in series as one example. 
         [0019]    Referring to  FIG. 3 , each RFID reader  20  includes a substantial circle sub-identifying area. Portions of the identifying areas A 21  of two adjacent RFID readers  20  overlap and form a complete main identifying area A 20 . The complete main identifying area A 20  is an area having no blind areas between every two adjacent RFID readers  20 . Thus, the entire effective identifying area of the RFID readers  20  is effectively enlarged. Moreover, blind areas which may exist between two adjacent RFID readers  20  are reduced and can be almost eliminated. 
         [0020]    In addition, a length of each conductive line  30  interconnected two adjacent RFID readers  20  is substantially equal to a diameter of each identifying area A 20 . The length of each conductive line  30  can be adjusted to change the identifying area A 20  according to requirement to identifying ability of the RFID readers  20 . 
         [0021]    The host terminal  50  may be a computer. The host terminal  50  obtains and manages the information of the RFID tags  10  indentified and read by the RFID readers  20  and the data processor  40 . The host terminal  50  also sends commands to the RFID readers  20  by the data processor  40  to obtain information of the RFID readers  20  such as version numbers. In addition, the host terminal  50  has an identity (ID) number. The RFID readers  20  can send the information of the RFID tags  10  to the host terminal  50  according to the ID number of the host terminal  50 . 
         [0022]    To use the RFID system  100 , the RFID readers  20  connected in series can identify and read the RFID tags  10  positioned in the main indentifying areas A 20 . For example, when the initial RFID reader  20  identifies one of the RFID tags  10  and reads the original information of the RFID tag  10 , the initial RFID reader  20  processes the original information to be a data packet and transmits the data packet to the next RFID reader  20 . The data packet may include an ID number of a transmitting part (i.e., RFID reader  20  here), an ID number of a target part (i.e., the host terminal  50  here) and the original information of the RFID tag  10 . The adjacent RFID reader  20  receives the data packet. The adjacent RFID reader  20  can determine that the data packet is needed to be transmitted to the host terminal  50  according to the ID number of the target part and sends the data packet to the next RFID reader  20 . The next RFID reader  20  and remaining RFID readers  20  operates substantially similar to the adjacent RFID reader  20  until the data packet is transmitted to the host terminal  50 . 
         [0023]    In addition, the host terminal  50  can send commands to the RFID readers  20 . Each command may include an ID number of the target part (i.e., some RFID readers  20  here), command content (e.g., transmitting the version number to the host terminal  50 ), and a verifying code. For example, when the initial RFID reader  20  receives the command from the host terminal  50 , the initial RFID reader  20  determines whether the command is aimed at itself according to the ID number of the target part. If the command is aimed at the initial RFID reader  20 , the initial RFID reader  20  executes the command and transmits the command to the next RFID reader  20 . If the command is not aimed to the initial RFID reader  20 , the initial RFID reader  20  transmits the command to the next RFID reader  20  directly. The next RFID reader  20  and the remaining readers  20  operates substantially similar to the initial RFID reader  20  until the distal RFID reader  20  sends all executing data back to the host terminal  50 . 
         [0024]    In one exemplary embodiment, during the processes of transmitting the data packets and commands, to prevent signal intensities from being weakened due to transmission loss, each RFID reader  20  can strengthen the signal intensities by a voltage boosting process before transmitting the data packet and commands and weaken the signal intensities by a voltage reducing process when receiving the data packet and commands. 
         [0025]    The RFID readers  20  interconnected in series of the RFID system  100  effectively enlarge the entire identifying area and reduces the blind areas that may be formed between adjacent RFID readers  20 . Therefore, the information of the RFID tags  10  can be more accurately indentified and read the information of the RFID tags  10 . 
         [0026]    It is believed that the exemplary embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the disclosure or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the disclosure.