Abstract:
A signal matching module for single or multiple systems is disclosed, thereby enhancing the flexibility in using a communication module, and the performance of each subsystem. Further, a fine-tuning function is introduced into a selective matching circuit for the case that the inner matching components in the communication module cannot reach a required matching. Still further, a multi-stage matching circuit is used to reach a required Q-value (quality factor) for the matching circuit, thereby tuning the bandwidth. One of the preferred embodiments is to provide a unit cell which is used to connect with one or multiple subsystems, and a feeding point disposed outside the matching circuit to generate a better impedance matching and bandwidth.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention discloses a signal matching module for single or multiple systems, more particularly to dispose the signal matching module in the module of the signal or multiple systems, so as to reach a required matching without performance loss. 
         [0003]    2. Description of Related Art 
         [0004]    In the field of wireless communication, interference amid noise signals and circuits in high-frequency communication often occurs and further affects the performance of wireless communication. Especially if a communication module couples to multiple systems, such as WiFi, Bluetooth, GSM, WiMAX (Worldwide Interoperability for Microwave Access) and the like, many unpredictable interferences may be generated. 
         [0005]    For example, in a wireless communication device with a high-frequency module and several wireless communication networks installed, such as Bluetooth, GSM and WiMAX, a switch or a circulator is usually used for switching the transmitted or received signal. 
         [0006]    An exemplary embodiment relating to the mentioned circulator is such as a the circulator used for a high-frequency amplifier disclosed in U.S. Pat. No. 6,894,562 which is issued on May 17, 2005. In which, a divider divides an input high-frequency signal into two output signals, and the circulator adjusts an effect for amplifying the signal. Reference is made to  FIG. 1 , a high-frequency signal is fed into an input terminal  1 , and outputted from a output terminal  2 . A divider  3  divides the high-frequency signal fed from the input terminal  1  into two signaling directions, wherein one direction passes through a primary amplifier  4 , and another one direction passes through a secondary amplifier  5 . A circulator  6  is provided to transfer the high-frequency signal from the secondary amplifier  5  to the output terminal of the primary amplifier  4 , such as the dotted line shown in the diagram. The high-frequency signal outputted from the primary amplifier  5  is transferred to the output terminal  2 , such as the solid line shown in the diagram. Therefore, the circulator is used to generate variant effects on amplifying. 
         [0007]    In a related technology regarding to a module having multiple wireless communication subsystems, the mentioned switch is often used to switch the communication signals among the variant subsystems.  FIG. 2  shows a schematic diagram of the mentioned communication module of the subsystem. The communication device includes a first communication module  25  and a second communication module  26 . The first communication module  25  utilizes a bidirectional transmission line to perform the signal reception and transmission (RX/TX). The second communication module  26  utilizes a transmission line for signal reception (RX) and another transmission line for signal transmission (TX). Both the communication modules use a coupler  22  to couple with the transmission lines of the first communication module  25  and the second communication module  26 , thereby to insulate the other signals and allocate the direction for each signal. After that, the switch  20  switches the signal allocated by the coupler  22  and the transmission signal of the second communication module  26 , and then sent to the antenna  21  for signal reception and transmission. 
         [0008]    Reference is made to the exemplary embodiment shown in  FIG. 2 . The first communication module  25  can be implemented as a Bluetooth module that features a bidirectional transmission line for transmitting and receiving signals. The second communication module  26  can be a wireless network (WiFi) module that features a transmission line for respectively transmitting and receiving signals. The switch  20  is used for switching the signals received from the antenna  21  to each communication module based on the types therefor. Further, the coupler  22  is used to guide the signals to each communication module. And vice versa, the signals sent transmitted from each communication module are transmitted via the coupler  22 , switch  20  and the antenna  21 . 
         [0009]    With the development of the technologies, many wireless communication systems can be installed in one module—including the mentioned wireless communication network, Bluetooth, GSM and WiMAX. In view of in this module having multiple subsystems, one system probably interferes with the other system when those subsystems operate at the same time. Especially under consideration of capacity and cost, probably only one common port configured to an I/O port for each subsystem is installed. Therefore, the performance of communication could drop if there is no special design for the communication module. 
       SUMMARY OF THE INVENTION 
       [0010]    According to the foregoing shortcomings of a conventional communication module used for the subsystem, one common port adopted for the system will produce interference among the subsystems and affect the performance of communication. However, the present invention provides a signal matching module for single or multiple systems, which implements a flexible use of the communication module by means of a multiple or single I/O port without any change to the conventional communication module components and circuits. 
         [0011]    Additionally, the signal matching module for single or multiple systems provides an optional matching circuit. An external circuit can be used to fine tune the module when the inner matching component of the module fails to reach a required matching impedance. The optional matching circuit can utilize a means for multiple matching to achieve a required quality factor (Q-value) when the inner matching component can be tuned to a required impedance. Thus, the bandwidth of the matching is tunable. 
         [0012]    The preferred embodiment of the single or multiple systems of the present invention functions as a communication module for single or multiple subsystems. The system includes a unit cell is included connecting with the single or multiple subsystems, and the unit cell has a plurality of interconnected electronic components or transmission lines. Further, one or a plurality of communication ports inside the signal matching module of the single or multiple systems are connected with the external signals, and provide tuning interfaces for the inner circuits of the signal matching module. Therefore no extra loading is received by the inner circuit of the signal matching module by the connected devices, and direct interference or signal loss can be avoided. 
         [0013]    In the other embodiment of the present invention, a multi-order matching is realized by combining the mentioned plurality of unit cells, so as to reach a required quality factor (Q-value) and bandwidth. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    The foregoing aspects and many of the attendant advantages of this invention will be more readily appreciated as the same becomes better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein: 
           [0015]      FIG. 1  shows a schematic diagram of a circular for the prior art; 
           [0016]      FIG. 2  shows a schematic diagram of the multiple subsystems of the prior art; 
           [0017]      FIG. 3  shows a schematic diagram of a unit cell of signal matching module for the single or multiple systems of the present invention; 
           [0018]      FIG. 4A  and  FIG. 4B  shows a schematic diagram of the unit cell of the signal matching module of the present invention; 
           [0019]      FIG. 5A  and  FIG. 5B  are the chart showing curves between the frequencies and insertion losses for the unit cell that connects with two subsystems; 
           [0020]      FIG. 6A  and  FIG. 6B  show the schematic diagram of the unit cell of the signal matching module of the present invention; 
           [0021]      FIG. 7A  and  FIG. 7B  are charts showing the curve between the frequencies and losses for the unit cell that connects with two subsystems; 
           [0022]      FIG. 8  shows a Smith Chart for a multi-order matching; 
           [0023]      FIG. 9A  through  FIG. 9C  are charts showing a curve between the frequencies and insertion losses provided by the present invention; 
           [0024]      FIG. 10  shows a schematic diagram of the signal matching module of the embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0025]    The present invention is illustrated with a preferred embodiment and attached drawings. However, the invention is not intended to be limited thereby. 
         [0026]    The present invention provides a signal matching module for single or multiple systems for a communication module of single or multiple subsystems rather than a common communication port, thus solving the problem of the interference among the subsystems. A selective matching circuit is provided for the signal matching module, thereby to tune an inner matching component to reach a required matching impedance. Moreover, if the inner component of the signal matching module reaches the required matching impedance, the selective matching circuit uses a multi-order matching to achieve the required quality factor (Q-value) for tuning the bandwidth therefor. 
         [0027]    Reference is made to  FIG. 3 , which shows a schematic diagram of a unit cell in the signal matching module of the preferred embodiment. The unit cell is used to connect to multiple subsystems, or to one subsystem in another embodiment. The unit cell is implemented as an interface apparatus connecting with each subsystem. The unit cell  32  electrically connects to an internal communication port of one or a plurality of signal matching module, or to an external communication port thereof. This exemplary embodiment shows one external communication port of the signal matching module. Further, each communication port electrically connects to the unit cell. The communication port connecting with the external signaling source embodies one or a plurality of external feeding point of the module. The unit cell  32  at least includes the interconnected electronic components or transmission lines, and connects to the external signaling source through the external communication port installed outside the signal matching module. For example, the external signaling source can be a device that produces communication signals. The unit cell  32  also provides a tuning interface for the inner circuit. Therefore, no extra loading will be received by the inner circuit from the signaling source, and the direct interference or signal loss can be avoided. 
         [0028]    Such as the embodiment shown in the diagram, the unit cell  32  at least includes a first component A, second component B, third component C, and fourth component D. Each block shown in the diagram, including the first component A, the second component B, the third component C, the fourth component D, a fifth component E and a sixth component F, can be a general passive component such as a circuitry having resistor, capacitor and inductor, and also can be a transmission line. In the diagram, at least one connecting terminal ( 301 ,  303 ,  305 ,  307 ) used to connect with other module, circuit or ground is mounted above a reference plane  30  presented by dotted line. Those connecting terminals  301 ,  303 ,  305  and  307  can connect to another communication port, circuit, module or ground. 
         [0029]    Further, a communication port  31  for each subsystem is mounted above the reference plane  30 . The communication port  31  electrically connects to the unit cell  32  that forms one or more external feeding points of the signal matching module. Thereby the unit cell  32  can process tuning externally, and no extra loading is produced for the inner circuitry. Further, the inner matching component can be fine tuned and easily reach the required matching. In addition, two other communication ports  33 ,  35  are mounted below the reference plane  30 , thereby to connect the communication module disposed inside the other device. 
         [0030]    The combination of the plurality of unit cell  32  in another embodiment form a multi-order matching circuit. The multi-order signal matching is tuned to achieve the object of the present invention, that is to reach the required quality factor (Q-value), and then the bandwidth can be tuned by the matching. 
         [0031]    The signal matching module for the multiple systems shown in  FIG. 3  is a preferred embodiment of the present invention. In particular, the communication port  31  that connects to the external communication module can process the tuning externally, and it won&#39;t cause the loss, interference or other influence of the inner circuitry. 
         [0032]    Next,  FIG. 4A  and  FIG. 4B  show a schematic diagram of a unit cell of the signal matching module for the single or multiple systems of the present invention. Such as the embodiment shown in  FIG. 4A  describing a unit cell without any external communication port installed, a horizontal dotted line presents a reference plane  30 , and the inner components of the signal matching circuit are disposed underneath the reference plane  30 . In particular, a first port P 1 , third port P 3  and fourth port P 4  therein are used to connect with other modules. For example, the ports connect with variant subsystems, especially to the wireless communication systems—including WiFi, Bluetooth, GSM, UWB (Ultra Wide Band), DVB (Digital Video Broadcasting), GPS, 3G and WiMAX. Moreover, a second port P 2  is disposed above the reference plane  30  for connecting with other circuit or module.  FIG. 4B  shows a schematic diagram of another unit cell. The unit cell has a fifth port P 5 , sixth port P 6  and seventh port P 7  which are disposed underneath the reference plane  30 . 
         [0033]    The mentioned reference plane  30  is to distinguish the inner circuit and outer circuit of the signal matching module. In an embodiment of the communication system, a feeding point is disposed outside the module, such as the second port P 2  shown in  FIG. 4A , and a selective matching circuit is electrically connected. If the inner matching component in the module fails to reach a required matching, the signal matching module can be tested and tuned externally through the feeding point, so that the loss, interference or other influences can be avoided. Even though the inner component of the module reaches the required matching, the selective matching circuit adopts a multi-order matching to reach the required quality factor (Q-value), thereby to be tuned to the required bandwidth. 
         [0034]    According to the exemplary embodiment of  FIG. 4A , the first port P 1 , third port P 3  and fourth port P 4  of the inner circuit, and the second port P 2  outside the module are included. Next,  FIG. 5  shows a chart having a curve presenting the relation between insertion loss and frequency as the signals are transmitted among the ports in an ideal circuit. In which, a default insertion loss of the inner circuit is set −3 dB. The chart shown in  FIG. 5  presents a curve of S-parameter that is a basic measurement tool in the process of RF design, thereby to simulate the behavior of an electronic component under different frequencies. 
         [0035]    The curve S 43  presents the insertion loss of the signal emitted from the third port P 3  and received via the fourth port P 4  in a subsystem. Since the third port P 3  and the fourth port P 4  are the communication ports that are disposed internally, the insertion loss is about −3.01 dB, the default value. That is at the frequency 2.45 GHz that is the experiment of the present invention concerns. 
         [0036]    The curve S 12  presents the insertion loss of the signal emitted from the second port P 2  outside the circuit, and received through the first port P 1  disposed inside the circuit in another subsystem. Obviously, the insertion loss at point  1  of curve S 12  that presents frequency 2.45 GHz is better than the insertion loss for curve S 43 . Ideally, the insertion loss at point  1  is 0.00 dB. Therefore, the signal matching module for the single or multiple systems of the present invention has better performance because there is a matching circuit disposed outside the module that won&#39;t cause loss on the inner circuit. 
         [0037]    According to the embodiment shown in  FIG. 4B ,  FIG. 5B  shows a curve presenting the relation between the insertion loss and frequency as signaling among the ports in an ideal circuit. In which, a default loss for the inner circuit is set −3 dB. 
         [0038]    The curve S 76  presents the insertion loss of the signal emitted from the sixth port P 6  disposed inside the circuit, and received through the seventh port P 7  in a subsystem. Since the default loss for the inner circuit is set about −3 dB, the insertion loss has no much change at the point  1  presenting −3.01 dB under frequency 2.4 GHz. 
         [0039]    The curve S 75  presents the insertion loss of the signal emitted from the fifth port P 5  and received via the seventh port P 7  in another subsystem. Since there is more complex influence from the circuit between the two ports, a larger insertion loss is produced. But the loss is still around the default loss at point  2  presenting −3.16 dB under frequency 2.4 GHz. 
         [0040]    In proof of the above-mentioned experiment in  FIG. 4A , the external signal feeding point can be used to achieve the lowest insertion loss without any change of the inner circuit of the signal matching module, ideally the insertion loss is zero. More, a resonance effect can be used to function the similar filtering means. In an exemplary embodiment of the dual-subsystem module shown in  FIG. 4B , there is no difference between their characteristics. That is, the insertion loss at each feeding point has no too much difference. 
         [0041]    Therefore, the selective matching circuit provided by the signal matching module of the present invention can reduce insertion loss and prevent the interference caused by the inner circuit. More, the present invention can reduce the interference occurred among the subsystems if it is applied to the multiple subsystems. 
         [0042]      FIG. 6A  and  FIG. 6B  show a block diagram of the signal matching module with a transmission line effect for the single or multiple systems. The FR4 stripline transmission line with dielectric coefficient 4.4 is under consideration in the exemplary embodiment, and also considering the coupling effect and dielectric loss among the transmission lines. 
         [0043]    In the embodiment of the unit cell shown in  FIG. 6A , an external communication port above the reference plane  30 , that is a second port P 2 , is shown. The inner circuit still has a first port P 1 , a third port P 3  and a fourth port P 4  above the reference plane  30 . Beside the ordinary components in the circuit, the transmission line effect is under consideration. Such as a first transmission line module  601  and a second transmission line module  602  are appended to the unit cell for connecting to the line between the inner circuit and the outer circuit. Further, not only the transmission line itself affects the circuit, but also the coupling effect between the first transmission line  601  and the second transmission line  602  affects the circuit. For example, the un-matching impedance or the effect between the two transmission lines forms the mentioned dielectric loss. 
         [0044]    Next,  FIG. 6B  has no the external communication port disposed, but the fifth port P 5 , the sixth port P 6  and the seventh port P 7  are disposed in the inner circuit for connecting with the subsystems. Similarly in the circuit, the effect between the first transmission line module  601  and the second transmission line module  602  is under consideration. 
         [0045]    Furthermore,  FIG. 7A  and  FIG. 7B  show the curves presenting the relation between the insertion loss and frequency in consideration of the transmission line effect. In this exemplary embodiment, the default loss set for the transmission line effect is −3 dB. 
         [0046]      FIG. 7A  shows a curve representing the insertion loss between two subsystems of the embodiment shown in  FIG. 6A . In which, point  1  and point  2  presenting the loss around frequency 2.45 GHz. In this embodiment, the curve S 12  indicates the behavior of the signals transmitted from the second port P 2  disposed outside the circuit and received by the first port P 1  disposed inside the module. Regarding the peak at point  1  that has only loss value −0.80 dB, which means this outside communication port, that is the feeding point, is suitable for the communication module. The curve S 34  indicates the behavior of the signals transmitted from the fourth port P 4  and received by the third port P 3 . Since the ports P 3  and P 4  are used to connect to the inner circuit, the loss therefor is close to the insertion loss in consideration of the transmission line effect, such as the loss value −3.01 dB shown in point  2  at frequency 2.50 GHz. 
         [0047]    On the other hand,  FIG. 7B  shows the curves representing the insertion loss for each communication port of the embodiment shown in  FIG. 6B . In this embodiment, the curve S 76  indicates the behavior of the insertion loss for the subsystem interconnected between the sixth port P 6  and the seventh port P 7 . The signals are transmitted from the sixth port P 6  and received by the seventh port P 7 . Since the subsystem is in the inner circuit, the insertion loss is similar with the default loss value −3 dB in consideration of the transmission line effect. In which, there is no many variances at each frequency, such as the point  1  presenting loss value −3.01 dB at frequency 2.50 GHz. The curve S 75  indicates the behavior of the signals transmitted from the fifth port P 5  and received by the seventh port P 7 .  FIG. 6B  shows that more interferences occurred between the ports P 5  and P 7 . The point  2  indicates loss value −3.30 dB at frequency 2.50 GHz. However, a high insertion loss, where a loss value −17 dB is produced around the frequency 5 GHz, occurs at higher frequency in consideration of the transmission line effect. Otherwise, a fine behavior of insertion loss happens around frequency 2.5 GHz. 
         [0048]    According to the experimental result shown in  FIG. 7A  and  FIG. 7B  as considering the transmission line effect, the second port P 2  shown in  FIG. 6  forms a feeding point of the embodiment. Accordingly, a lower insertion loss (0.8 dB in this embodiment) achieves through this feeding point without any change of the inner circuit of the module even. Further, a resonance effect can be used to achieve the like filtering. Nevertheless, if the approach is merely used for a dual subsystem embodied in  FIG. 6B , the above-mentioned property has no many variances, such as the embodiment shown in  FIG. 7B . Therefore, the external selective matching circuit provided by the signal matching module for the single or multiple systems of the present invention can reduce the insertion loss effectively and present the interference caused by the inner circuit. Similarly, the interference occurred among the subsystems can be reduced if the invention is applied to the multiple subsystems. 
         [0049]    Reference is made to the Smith Chart shown in  FIG. 8 . The mentioned external selective matching circuit is further used to perform a multi-order matching, so as to reach a required quality factor (Q-value) and to tune the bandwidth. 
         [0050]      FIG. 8  shows a sawtooth-shaped track of the impedance, that combines the result of the multi-order matching generated by the plurality of unit cells. The track shifts in a range of 0.5 of the Q-value, that is to tune the value back and forth around the curve  801  indicating 0 and the curve  802  indicating 0.5. For example, one time back-and-forth tuning means it uses the unit cell shown in  FIG. 3  to tune the impedance matching in the circuit. The plurality of unit cells are used to tune to the required impedance and bandwidth one order by one order. In this exemplary embodiment, the object is to reach the middle point  803  by means of the plurality of unit cells. 
         [0051]    According to the S-parameter shown in the mentioned Smith Chart and the curve presenting the insertion loss, the Q-value can be controlled under value 0.5 by means the multi-order matching circuit. In the meantime, the reflective value, that is the insertion loss, can be controlled at −20 dB, and the bandwidth can reach 1.9 GHz. 
         [0052]    Reference is made to  FIG. 9A , that shows a curve presenting the relation of bandwidth and insertion loss of a conventional art that uses a general matching circuit. In which, the insertion loss is controlled to −20 dB and its bandwidth is about 1 GHz. In contradistinction,  FIG. 9B  shows an embodiment with the insertion loss being controlled to around −20 dB, the Q-value being smaller than 0.5, and the bandwidth being around 1.35 GHz by utilizing a matching circuit formed by a unit cell. Further,  FIG. 9C  utilizes the mentioned multi-order matching circuit to control the Q-value being under 0.5, the insertion loss being around −20 dB, and the bandwidth being around 1.9 GHz. 
         [0053]    Based on the experiment, the signal matching module of the present invention can flexibly tune the impedance matching of the entire communication module so as to reach the required matching. Obviously, the performance of the bandwidth provided by the signal matching module of the present invention is better than the bandwidth provided by the conventional art. More, the multi-order matching circuit is more effective. 
         [0054]    The preferred embodiment of the signal matching module of the present invention is shown in  FIG. 10 . A circuit having multiple wireless communication subsystems, including a first communication module  25  and a second communication module  26 , is provided. A switch  20  is used to switch the communication signals among the systems. The first communication module  25  is used to operate reception and transmission (RX/TX) via a duplex transmission line. The communication module  26  uses a transmission line with reception (RX) and another transmission line with transmission (TX). These two communication modules utilizes a coupler  22  to couple with the RX/TX transmission line of the first communication module  25  and the transmission line with reception of the second communication module  26 . A splitter  10  is used to discriminate the signals, and further to dispatch the transmission direction. After that, the signals are switched and coupled to an antenna  21  for transmitting or receiving. In the embodiment, the signal matching module is used to connect with the transmission line coupling with each electronic component, such as a first matching module  101  disposed on the transmission line between the splitter  10  and the second communication module  26 , and a second matching module  102  between the splitter  10  and the first communication module  25 , and a third matching module  103  between the splitter  10  and the coupler  22 . In the preferred embodiment of the present invention, the mentioned first communication module  25  can be, but not limited to, a Bluetooth module that features the duplex transmission line. The second communication module  26  can be, but not limited to, a WiFi module that has two separate transmission line. 
         [0055]    To sum up, the signal matching module for the single or multiple systems of the present invention can enhance the flexibility in use of a communication module, and performance for each subsystem. The selective matching circuit provided by the present invention can offer a tuning function to required matching if in need. If the inner circuit can be tuned to required matching, the multi-order matching circuit can further reach the require Q-value, and tune the bandwidth. More, a resonance effect can achieve the like filtering for helping the development of future design of the module. 
         [0056]    While the invention has been described by means of a specification with accompanying drawings of specific embodiments, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope and spirit of the invention set forth in the claims.