Radio frequency signal processing circuit and quadrature power amplifier

Abstract

A quadrature power amplifier capable of operating in a single-output mode and a multiple-output mode. When operating in the single-output mode, a first quadrature coupler receives a first input signal, and splits and phase-shifts the first input signal into two first split signals. A first power amplifier receives and amplifies one of the two first split signals to generate a first amplified signal. The second power amplifier receives and amplifies the other one of the two first split signals to generate a second amplified signal. The second quadrature coupler receives the first amplified signal and the second amplified signal, and phase-shifts and combines the first amplified signal and the second amplified signal into a first output signal.

1 . A quadrature power amplifier, capable of operating in a single-output mode and a multiple-output mode, comprising:
 a first quadrature coupler, when operating in the single-output mode, receiving a first input signal, splitting and phase-shifting the first input signal into two first split signals, which are phase-shifted substantially 90 degrees from each other;   a first power amplifier, coupled to the first quadrature coupler for receiving and amplifying one of the two first split signals to generate a first amplified signal;   a second power amplifier, coupled to the first quadrature coupler for receiving and amplifying the other one of the two first split signals to generate a second amplified signal; and   a second quadrature coupler, receiving the first amplified signal and the second amplified signal, and phase-shifting and combining the first amplified signal and the second amplified signal into a first output signal.   
     
     
         2 . The quadrature power amplifier as claimed in  claim 1 , wherein when operating in the multiple-output mode,
 the first quadrature coupler further receives a second input signal, and splits and phase-shifts the second input signal into two second split signals, which are phase-shifted substantially 90 degrees from each other;   the first power amplifier further receives and amplifies one of the two second split signals to generate a third amplified signal;   the second power amplifier further receives and amplifies the other one of the two second split signals to generate a fourth amplified signal; and   the second quadrature coupler further receives the third amplified signal and the fourth amplified signal, and phase-shifts and combines the third amplified signal and the fourth amplified signal into a second output signal.   
     
     
         3 . The quadrature power amplifier as claimed in  claim 1 , wherein the first output signal is an amplified version of the first input signal with a predetermined phase difference. 
     
     
         4 . The quadrature power amplifier as claimed in  claim 2 , wherein the first output signal is an amplified version of the first input signal with a first predetermined phase difference, and the second output signal is an amplified version of the second input signal with a second predetermined phase difference. 
     
     
         5 . The quadrature power amplifier as claimed in  claim 4 , wherein the first predetermined phase difference equals to the second predetermined phase difference. 
     
     
         6 . The quadrature power amplifier as claimed in  claim 2 , wherein when the first input signal and the second input signal have substantially the same phase, the first output signal and the second output signal have substantially the same phase, and when the first input signal and the second input signal have different phases, the first output signal and the second output signal have different phases. 
     
     
         7 . A radio frequency (RF) signal processing circuit, coupled between a transceiver module and at least a first antenna and a second antenna, comprising:
 a quadrature power amplifier, capable of operating in a single-output mode and a multiple-output mode, and comprising a first input terminal and a second input terminal coupled to the transceiver, and a first output terminal coupled to the first antenna and a second output terminal coupled to the second antenna,   wherein when operating in the single-output mode, the quadrature power amplifier receives a first input signal from the transceiver module via the first input terminal, splits and phase-shifts the first input signal into two first split signals, and further amplifies and combines the two first split signals to generate a first output signal, which is an amplified version of the first input signal with a predetermined phase difference and is output to one of the first and the second antennas.   
     
     
         8 . The RF signal processing circuit as claimed in  claim 7 , wherein when operating in the multiple-output mode, the quadrature power amplifier further receives a second input signal from the transceiver module via the second input terminal, splits and phase-shifts the second input signal into two second split signals, and further amplifies and combines the two second split signals to generate a second output signal, which is an amplified version of the second input signal with the predetermined phase difference, and outputs the second output signal to the other one of the first and the second antennas. 
     
     
         9 . The RF signal processing circuit as claimed in  claim 7 , further comprising:
 a switch device, coupled between the quadrature power amplifier and the transceiver module, for selectively passing the first input signal to the first input terminal or the second input terminal in response to an antennal selection signal indicating which antenna is selected when operating in the single-output mode.   
     
     
         10 . The RF signal processing circuit as claimed in  claim 8 , wherein the quadrature power amplifier further comprises:
 a first quadrature coupler, coupled to the first input terminal and the second input terminal;   a first power amplifier, coupled to the first quadrature coupler;   a second power amplifier, coupled to the first quadrature coupler; and   a second quadrature coupler, coupled between to the first power amplifier, second power amplifier, the first output terminal and the second output terminal.   
     
     
         11 . The RF signal processing circuit as claimed in  claim 10 , wherein
 when operating in the single-output mode, the first quadrature coupler receives the first input signal, and splits and phase-shifts the first input signal into the two first split signals, which are phase-shifted substantially 90 degrees from each other; and   when operating in the multiple-output mode, the first quadrature coupler further receives the second input signal, and splits and phase-shifts the second input signal into the two second split signals, which are phase-shifted substantially 90 degrees from each other.   
     
     
         12 . The RF signal processing circuit as claimed in  claim 11 , wherein
 when operating in the single-output mode, the first power amplifier receives and amplifies one of the two first split signals to generate a first amplified signal, and the second power amplifier receives and amplifies the other one of the two first split signals to generate a second amplified signal; and   when operating in the multiple-output mode, the first power amplifier further receives and amplifies one of the two second split signals to generate a third amplified signal, and the second power amplifier further receives and amplifies the other one of the two second split signals to generate a fourth amplified signal.   
     
     
         13 . The RF signal processing circuit as claimed in  claim 12 , wherein
 when operating in the single-output mode, the second quadrature coupler receives the first amplified signal and the second amplified signal, and phase-shifts and combines the first amplified signal and the second amplified signal into the first output signal; and   when operating in the multiple-output mode, the second quadrature coupler further receives the third amplified signal and the fourth amplified signal, and phase-shifts and combines the third amplified signal and the fourth amplified signal into the second output signal.   
     
     
         14 . A radio frequency (RF) signal processing circuit, coupled between a transceiver module and at least a first antenna and a second antenna, comprising:
 a quadrature power amplifier, comprising a first input terminal and a second input terminal coupled to the transceiver, and a first output terminal coupled to the first antenna and a second output terminal coupled to the second antenna,   wherein when the quadrature power amplifier receives a first input signal and a second input signal from the transceiver module respectively via the first input terminal and the second input terminal, the quadrature power amplifier splits, and phase-shifts the first input signal and the second input signal into two first split signals and two second split signals, respectively, and further amplifies and combines the two first split signals and the two second split signals to respectively generate a first output signal, which is an amplified version of the first input signal with a first predetermined phase difference, and a second output signal, which is an amplified version of the second input signal with a second predetermined phase difference, and outputs the first output signal to the second antenna and the second output signal to the first antenna.   
     
     
         15 . The RF signal processing circuit as claimed in  claim 14 , wherein when the quadrature power amplifier receives only the first input signal from the transceiver module via one of the first input terminal and the second input terminal, the quadrature power amplifier outputs only the first output signal to one of the first and the second antennas. 
     
     
         16 . The RF signal processing circuit as claimed in  claim 15 , further comprising:
 a switch device, coupled between the quadrature power amplifier and the transceiver module, for selectively passing the first input signal to the first input terminal or the second input terminal in response to an antennal selection signal indicating which antenna is selected to transmit the first output signal.   
     
     
         17 . The RF signal processing circuit as claimed in  claim 14 , wherein when the first input signal and the second input signal have substantially the same phase, the first output signal and the second output signal have substantially the same phase, and when the first input signal and the second input signal have different phases, the first output signal and the second output signal have different phases.