Abstract:
An all-pass wideband phase shifter is introduced. Series connections in parallel between two 3 dB hybrid couplers include combining two 90-degree phase shifters and two attenuators to form a novel phase shifter framework. Under specific controls of continuous 90-degree phase shifters and attenuators in four quadrants, 360-degree all-pass phase shifting is effected by phase shifting and vector composition.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to electronic adjustable phase shifters and more particularly to an all-pass wideband phase shifter. 
       BACKGROUND OF THE INVENTION 
       [0002]    Electronic adjustable phase shifters are widely used in phase control array antennas, radars, and phase modulation communication systems.  FIG. 1  shows a conventional switch microstrip line length phase shifter  100  inside which phase shifters are connected in series, namely a 22.5-degree phase shifter  110 , a 180-degree phase shifter  120 , a 90-degree phase shifter  130  and a 45-degree phase shifter  140 , which are arranged in sequence, started with the input end and ended at the output end. Each phase shifter has a reference line and a delay line which are connected in parallel. Specifically speaking, the 22.5-degree phase shifter  110  has a first reference line  111  and a first delay line  112  which are connected in parallel. The 180-degree phase shifter  120  has a second reference line  121  and a second delay line  122  which are connected in parallel. The 90-degree phase shifter  130  has a third reference line  131  and a third delay line  132  which are connected in parallel. The 45-degree phase shifter  140  has a fourth reference line  141  and a fourth delay line  142  which are connected in parallel. Their adjustable phases are achieved by switch microstrip line length.  FIG. 2  shows a conventional high-pass/low-pass phase shifter  200  which comprises switch high-pass and low-pass filters, advantageously characterized in that its Ka frequency band has relative small circuit dimensions as well as simple circuit and layout.  FIG. 3  shows a conventional transistor switch high-pass/low-pass phase shifter  300  whose design is simplified by the equivalent capacitance effect which occurs as a result when the transistor is turned on and turned off. 
         [0003]    In addition to the aforesaid existing designs, to further bring the phase shifter wideband performance into full play, a reflective load phase shifter  400  shown in  FIG. 4  and a phase shifter  500  synthesized by IQ phase and shown in  FIG. 5  are introduced. The reflective load phase shifter  400  comprises a 3 dB hybrid coupler  410  with its two non-input/output points connected to reflective terminating circuits  420 ,  430 , respectively. 
         [0004]    Nonetheless, the switch microstrip line length phase shifter  100  shown in  FIG. 1  and operated by conventional switch microstrip line length as well as the high-pass/low-pass phase shifter  200  and switch high-pass and low-pass filters phase shifter  300  shown in  FIGS. 2, 3  are subjected to limits on an operating bandwidth. On the other hand, those phase shifters whose design is simplified by the equivalent capacitance effect which occurs as a result when the transistor is turned on and turned off require a precise transistor model and wiring design. The reflective load phase shifter  400  shown in  FIG. 4  must be provided in the plural and connected in series in order to function as a 360-degree all-pass phase shifter, but ends up with an overly large or long circuit layout. Referring to  FIG. 5 , the phase shifter  500  synthesized by IQ phase is controlled with just two power sources under an operating voltage that is very sensitive to any phase change, and thus the phase shifter  500  is difficult to control. Moreover, despite the existing 180-degree large-range phase shifter framework, almost every phase shifter faces a challenge, that is, maintaining the same power output and achieving an accurate relative phase shift range within a wideband. 
       SUMMARY OF THE INVENTION 
       [0005]    Every conventional phase shifter is subjected to limits on available bandwidth. The objective of the present invention is to not only provide an all-pass wideband phase shifter but also attain the advantages of operating an 360-degree all-pass phase shifter by techniques related to phase shift and vector synthesis, with a view to effectuating performance enhancement in terms of the application of mobile communication technology. 
         [0006]    The objective and technical solution of the present invention are achieved as described below. The present invention provides an all-pass wideband phase shifter which comprises a first 3 dB hybrid coupler, a second 3 dB hybrid coupler, a first attenuator, a second attenuator, a first continuous phase shifter and a second continuous phase shifter. The first 3 dB hybrid coupler has a signal input end, a first grounding resistor, a first series-connection starting end and a second series-connection starting end to allow a first distribution signal to be sent from the first series-connection starting end at the first series-connection path and allow a second distribution signal to be sent from the second series-connection starting end at the second series-connection path. The second 3 dB hybrid coupler has a signal output end, a second grounding resistor, a first series-connection terminating end and a second series-connection terminating end, so as to vector synthesize the first distribution signal and the second distribution signal. The first attenuator is disposed in the first series-connection path which connects the first series-connection starting end and the first series-connection terminating end, so as to attenuate and intercept the first distribution signal. The second attenuator is disposed in the second series-connection path which connects the second series-connection starting end and the second series-connection terminating end, so as to attenuate and intercept the second distribution signal. The first continuous phase shifter is disposed in the first series-connection path which connects the first series-connection starting end and the first series-connection terminating end, so as to continuously and discontinuously adjust the phases of the first distribution signal. The second continuous phase shifter is disposed in the second series-connection path which connects the second series-connection starting end and the second series-connection terminating end, so as to continuously and discontinuously adjust the phases of the second distribution signal. An all-pass phase shift is formed by IQ phase synthesis and continuous phase shift according to the four quadrant model. 
         [0007]    The objective and technical solution of the present invention are achieved as described below. 
         [0008]    In the aforesaid all-pass wideband phase shifter, the first continuous phase shifter and the second continuous phase shifter each have a 0˜90 degrees of continuously adjustable angle. 
         [0009]    In the aforesaid all-pass wideband phase shifter, especially in first quadrant-based continuous phase shift mode, the first attenuator intercepts the first distribution signal, whereas the second continuous phase shifter adjusts 0˜90 degrees of phase of the second distribution signal; in the third quadrant-based continuous phase shift mode, the second attenuator intercepts the second distribution signal, whereas the first continuous phase shifter adjusts 0˜90 degrees of phases of the first distribution signal, wherein, in the second quadrant-based continuous phase shift mode, the first continuous phase shifter fixes the phase of the first distribution signal to the 90 degree so as for the first distribution signal to be attenuated and adjusted with the first attenuator, whereas the second continuous phase shifter fixes the phase of the second distribution signal to the 0 degree so as for the second distribution signal to be attenuated and adjusted with the second attenuator, thereby being vector synthesized in the second 3 dB hybrid coupler, wherein, in the fourth quadrant-based continuous phase shift mode, the first continuous phase shifter fixes the phase of the first distribution signal to the 0 degree so as for the first distribution signal to be attenuated and adjusted with the first attenuator, whereas the second continuous phase shifter fixes the phase of the second distribution signal to the 90 degree so as for the second distribution signal to be attenuated and adjusted with the second attenuator, thereby being vector synthesized in the second 3 dB hybrid coupler. 
         [0010]    Given the above technical solution, the present invention effectuates a wideband phase shifter. The all-pass wideband phase shifter of the present invention attains 0/180-degree wideband phase shift with two 3 dB hybrid couplers, effectuates between two couplers series connections in parallel which include combining two 90-degree phase shifters and two attenuators, and enables a 360-degree all-pass phase shifter to operate under the control of continuous 90-degree phase shifters and attenuators. Hence, the resultant novel phase shifter framework is capable of IQ phase synthesis and functioning as a 0˜90-degree continuous phase shifter to thereby effectuate the operation of the all-pass wideband phase shifter. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a schematic view of the wiring framework of a conventional switch microstrip line length phase shifter; 
           [0012]      FIG. 2  is a schematic view of the wiring framework of a conventional switch high-pass/low-pass phase shifter; 
           [0013]      FIG. 3  is a schematic view of the wiring framework of a conventional transistor switch high-pass/low-pass phase shifter; 
           [0014]      FIG. 4  is a schematic view of the wiring framework of a conventional reflective load phase shifter; 
           [0015]      FIG. 5  is a schematic view of the wiring framework of a phase shifter of a conventional IQ phase synthesis; 
           [0016]      FIG. 6  is a schematic view of the framework of an all-pass wideband phase shifter according to a preferred embodiment of the present invention; 
           [0017]      FIG. 7  is a schematic view of a phase operation mode of the all-pass wideband phase shifter in the four quadrants according to a preferred embodiment of the present invention; 
           [0018]      FIG. 8  is a graph of insertion loss against operating frequency of the all-pass wideband phase shifter according to a preferred embodiment of the present invention; and 
           [0019]      FIG. 9  is a graph of phase change against operating frequency of the all-pass wideband phase shifter according to a preferred embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0020]    The embodiments of the present invention are hereunder described with reference to the accompany drawing. Although the accompanying drawings are schematic diagrams illustrative of the framework and implementation of the present invention and thus only components and combinations thereof related to the present invention are shown, the diagrams are not drawn to scale in terms of the quantity, shape and dimensions of the components; instead, the dimensions of the components shown in the diagram may be exaggerated and diminished as needed for illustrative sake. Hence, the actual quantity, shape and dimensions of the components shown in the diagrams are attributed to design choices, and related layouts of component can be more complicated than they are shown in the diagrams. 
         [0021]    According to a preferred embodiment of the present invention, an all-pass wideband phase shifter  600  is illustrated with  FIG. 6  and  FIG. 7 .  FIG. 6  is a schematic view of the framework of an all-pass wideband phase shifter according to a preferred embodiment of the present invention.  FIG. 7  is a schematic view of a phase operation mode of the all-pass wideband phase shifter in the four quadrants according to a preferred embodiment of the present invention. As shown in the diagrams, the all-pass wideband phase shifter  600  comprises a first 3 dB hybrid coupler  610 , a second 3 dB hybrid coupler  620 , a first attenuator  631 , a second attenuator  632 , a first continuous phase shifter  641  and a second continuous phase shifter  642 . 
         [0022]    The first 3 dB hybrid coupler  610  has a signal input end  611 , a first grounding resistor  612 , a first series-connection starting end  613  and a second series-connection starting end  614 . A first distribution signal P 1  is sent from the first series-connection starting end  613  which a first series-connection path  601  starts with. A second distribution signal P 2  is sent from the second series-connection starting end  614  which a second series-connection path  602  ends at. The second 3 dB hybrid coupler  620  has a signal output end  621 , a second grounding resistor  622 , a first series-connection terminating end  623  and a second series-connection terminating end  624  so as to vector synthesize the first distribution signal P 1  and the second distribution signal P 2 . An output signal P out  sent from the second 3 dB hybrid coupler  620  through the signal output end  621  is commensurate with the phase change of the first distribution signal P 1  in different quadrants, the phase change of the second distribution signal P 2 , and is vector synthesized after being attenuated at a fixed phase of the first distribution signal P 1  and the second distribution signal P 2  as shown in  FIG. 7 . 
         [0023]    The first attenuator  631  is disposed in the first series-connection path  601  which connects the first series-connection starting end  613  and the first series-connection terminating end  623 , so as to attenuate and intercept the first distribution signal P 1 . The second attenuator  632  is disposed in the second series-connection path  602  which connects the second series-connection starting end  614  and the second series-connection terminating end  624 , so as to attenuate and intercept the second distribution signal P 2 . 
         [0024]    The first continuous phase shifter  641  is disposed in the first series-connection path  601  which connects the first series-connection starting end  613  and the first series-connection terminating end  623  so as to continuously and discontinuously adjust the phase of the first distribution signal P 1 . The second continuous phase shifter  642  is connected in the second series-connection path  602  which connects the second series-connection starting end  614  and the second series-connection terminating end  624  so as to continuously and discontinuously adjust the phase of the second distribution signal P 2 . The first continuous phase shifter  641  and the second continuous phase shifter  642  each have a 0˜90 degree of continuously adjustable angle, i.e., phase angle φ, which can be changed and adjusted within the 0˜90° range as shown in  FIG. 6 . 
         [0025]    An all-pass phase shift is formed by IQ phase synthesis and continuous phase shift according to the four quadrant model. 
         [0026]    Referring to  FIG. 7 , in the first quadrant-based continuous phase shift mode, the first attenuator  631  intercepts the first distribution signal P 1 , whereas the second continuous phase shifter  642  adjusts the 0˜90 degrees of phase of the second distribution signal P 2 ; hence, the phase angle φ of the second distribution signal P 2  equals 0˜90 degrees and is commensurate with the output signal P out . In the third quadrant-based continuous phase shift mode, the second attenuator  632  intercepts the second distribution signal P 2 , whereas the first continuous phase shifter  641  adjusts the 0˜90 degrees of phase of the first distribution signal P 1 ; hence, phase angle φ of the first distribution signal P 1  equals 0˜90 degrees and is commensurate with output signal P out . In the second quadrant-based continuous phase shift mode, the first continuous phase shifter  641  fixes the phase of the first distribution signal P 1  to the 90 degree so as for the first distribution signal P 1  to be attenuated and adjusted with the first attenuator  631 , whereas the second continuous phase shifter  642  fixes the phase of the second distribution signal P 2  to the 0 degree so as for the second distribution signal P 2  to be attenuated and adjusted with the second attenuator  632 , thereby being vector synthesized in the second 3 dB hybrid coupler  620 . Therefore, the phase angle of the first distribution signal P 1  is fixed to the 90 degree, whereas the phase angle of the second distribution signal P 2  is fixed to the 0 degree, wherein the first distribution signal P 1  and the second distribution signal P 2  are attenuated to thereby generate the output signal P out  by vector synthesis. In the fourth quadrant-based continuous phase shift mode, the first continuous phase shifter  641  fixes the phase of the first distribution signal P 1  to the 0 degree so as for the first distribution signal P 1  to be attenuated and adjusted with the first attenuator  631 , whereas the second continuous phase shifter  642  fixes the phase of the second distribution signal P 2  to the 90 degree so as for the second distribution signal P 2  to be attenuated and adjusted with the second attenuator  632 , thereby being vector synthesized in the second 3 dB hybrid coupler  620 . The phase angle of the first distribution signal P 1  is fixed to the 0 degree, whereas the phase angle of the second distribution signal P 2  is fixed to the 90 degree, wherein the first distribution signal P 1  and the second distribution signal P 2  are attenuated to thereby generate the output signal P out  by vector synthesis. 
         [0027]    Referring to  FIG. 6 , the all-pass wideband phase shifter  600  is capable of IQ phase synthesis and functioning as a 0˜90-degree continuous phase shifter. The second attenuator  632  intercepts the second distribution signal P 2 , whereas the first distribution signal P 1  undergoes continuous 0˜90 degrees of phase change (φ=0˜90°. Referring to  FIG. 7 , in the third quadrant operation mode, the first attenuator  631  intercepts the first distribution signal P 1 , whereas the second distribution signal P 2  undergoes continuous 0˜90 degrees of phase change (φ=0˜90° in the same way as the first quadrant operation mode shown in  FIG. 7 . The first distribution signal P 1  operates at the 90 degree, whereas the second distribution signal P 2  operates at the 0 degree, so as to control the attenuation of the first distribution signal P 1  and second distribution signal P 2 , respectively, and then undergoes vector synthesis, such that the output signal P out  undergoes 0˜90 degrees of continuous phase shift in the second quadrant shown in  FIG. 7 . Likewise, the first distribution signal P 1  operates at the 0 degree, whereas the second distribution signal P 2  operates at the 90 degree, so as to control the attenuation of the first distribution signal P 1  and second distribution signal P 2 , respectively, and then undergoes vector synthesis, such that the output signal P out  undergoes 0˜90 degrees of continuous phase shift in the fourth quadrant shown in  FIG. 7 . 
         [0028]    Referring to  FIG. 8 , given the phase shifter framework of the present invention, a chip capable of IQ phase synthesis and functioning as a 0˜90-degree continuous phase shifter is provided to simulate a 360-degree 5 bit operation mode such that the resultant insertion loss amounts to −8.8˜−10.9 dB or so at 38 GHz. Referring to  FIG. 9 , the largest phase error equals 5˜6 degrees whenever the operating frequency operates within a range of 4 GHz in the 38 GHz bandwidth. 
         [0029]    The present invention provides an all-pass wideband phase shifter which is capable of phase shift and vector synthesis to thereby function as a 360-degree all-pass phase shifter, thereby effectuating performance enhancement in terms of the application of mobile communication technology. 
         [0030]    The present invention is disclosed above by preferred embodiments. However, the preferred embodiments should not be interpreted as restrictive of the scope of the present invention. Hence, all equivalent changes made to the claims of the present invention should fall within the scope of the present invention.