Power amplifier for amplification of an input signal into an output signal

Abstract

A power amplifier comprising a first, second and third sub-amplifier for amplification of an input signal into an output signal is disclosed. The sub-amplifiers are connected to an input network and an output network. The output network comprises a first, second and third transmission line connected to the first, second and third sub-amplifier, respectively. A difference in electrical length between the first, second and third transmission lines is an integer number of quarter-wavelengths of a center frequency of the power amplifier. A first, second and third electrical length includes the first, second and third transmission line, respectively. A longest one of the electrical lengths is at least a multiple of quarter-wavelengths of the center frequency. Furthermore, a radio network node, comprising the power amplifier, and a user equipment, comprising the power amplifier, are disclosed.

1 . A power amplifier comprising a first and a second sub-amplifier for amplification of an input signal into an output signal, wherein the first and second sub-amplifiers are connected to an input network for receiving the input signal at an input port of the input network, and the first and second sub-amplifiers are connected to an output network for providing the output signal at an output port of the output network, wherein the output network comprises a first transmission line and a second transmission line connected to the first sub-amplifier and the second sub-amplifier, respectively, wherein a difference in electrical length between the first and second transmission lines is an integer number of quarter-wavelengths of a center frequency of the power amplifier, wherein the power amplifier is characterized by further comprising:
 a third sub-amplifier for amplification of the input signal into the output signal, wherein the third sub-amplifier is connected to the input network and the output network, wherein the output network further comprises a third transmission line connected to the third sub-amplifier, wherein a first electrical length includes the first transmission line, a second electrical length includes the second transmission line, and a third electrical length includes the third transmission line, and wherein a longest one of the first, second and third electrical lengths is at least a multiple of quarter-wavelengths of the center frequency.   
     
     
         2 . The power amplifier according to  claim 1 , wherein the power amplifier is operable down to the center frequency divided by the multiple. 
     
     
         3 . The power amplifier according to  claim 1 , wherein the first and second transmission lines are connected to a first common transmission line, included in the output network, wherein the first common transmission line is common to the first and second sub-amplifiers. 
     
     
         4 . The power amplifier according to  claim 1 , further comprising a fourth sub-amplifier, wherein the fourth sub-amplifier is connected to the input network and the output network, wherein the output network further comprises a fourth transmission line. 
     
     
         5 . The power amplifier according to  claim 4 , wherein the third and fourth sub-amplifier are connected to a second common transmission line, included in the output network, wherein the second common transmission line is common to the third and fourth sub-amplifiers. 
     
     
         6 . The power amplifier according to  claim 1 , wherein the power amplifier is operable to:
 provide the output signal mainly supplied by the first sub-amplifier in a first mode;   provide the output signal mainly supplied by the second sub-amplifier in a second mode; and   provide the output signal mainly supplied by the third sub-amplifier in a third mode.   
     
     
         7 . The power amplifier according to  claim 1 , wherein the power amplifier is a composite power amplifier. 
     
     
         8 . A radio network node comprising:
 a power amplifier comprising a first and a second sub-amplifier for amplification of an input signal into an output signal, wherein the first and second sub-amplifiers are connected to an input network for receiving the input signal at an input port of the input network, and the first and second sub-amplifiers are connected to an output network for providing the output signal at an output port of the output network, wherein the output network comprises a first transmission line and a second transmission line connected to the first sub-amplifier and the second sub-amplifier, respectively, wherein a difference in electrical length between the first and second transmission lines is an integer number of quarter-wavelengths of a center frequency of the power amplifier, wherein the power amplifier is characterized by further comprising:
 a third sub-amplifier for amplification of the input signal into the output signal, wherein the third sub-amplifier is connected to the input network and the output network, wherein the output network further comprises a third transmission line connected to the third sub-amplifier, wherein a first electrical length includes the first transmission line, a second electrical length includes the second transmission line, and a third electrical length includes the third transmission line, and wherein a longest one of the first, second and third electrical lengths is at least a multiple of quarter-wavelengths of the center frequency. 
   
     
     
         9 . A user equipment comprising:
 a power amplifier comprising a first and a second sub-amplifier for amplification of an input signal into an output signal, wherein the first and second sub-amplifiers are connected to an input network for receiving the input signal at an input port of the input network, and the first and second sub-amplifiers are connected to an output network for providing the output signal at an output port of the output network, wherein the output network comprises a first transmission line and a second transmission line connected to the first sub-amplifier and the second sub-amplifier, respectively, wherein a difference in electrical length between the first and second transmission lines is an integer number of quarter-wavelengths of a center frequency of the power amplifier, wherein the power amplifier is characterized by further comprising:
 a third sub-amplifier for amplification of the input signal into the output signal, wherein the third sub-amplifier is connected to the input network and the output network, wherein the output network further comprises a third transmission line connected to the third sub-amplifier, wherein a first electrical length includes the first transmission line, a second electrical length includes the second transmission line, and a third electrical length includes the third transmission line, and wherein a longest one of the first, second and third electrical lengths is at least a multiple of quarter-wavelengths of the center frequency.