Feedforward linearized traveling wave tube satellite transponder

In order to keep the nonlinear distortion at a level acceptable to frequency division multiple access carriers in a satellite transponder, the output traveling wave tube must be operated several dB below its full output power capability. In the paper it is shown that when feedforward linearization is applied to the transponder output stage, the output power for a given communication performance may be increased by 2 to 4 dB, depending on the linearity requirement. Based on analytical and experimental investigations of the linearizer sensitivity to TWT RF parameters it is concluded that such linearizers may be operated over wide bandwidth and lifetimes of 5-7 years in the 4 GHz frequency range.