Abstract: A compact analog predistortion circuit used to compensate the nonlinear characteristics of solidstate power amplifier (SSPA) in the satellite tracking telemetry and command system was developed. This new predistortion circuit is simple, compact and of low cost. The fundamental principle of this linearizer was analyzed and its corresponding equivalent circuit model was shown. Then, the desired nonlinear characteristics of linearizer versus different circuit parameters were simulated and discussed. Finally, this linearizer was fabricated and measured. The comparative results of both linearized and nonlinearized amplifiers show that the linearizer can significantly improve the intermodulation distortion of amplifiers by about 6dB.

Key words: intermodulation distortion (IMD, gain compression, solidstate power amplifier, satellite communication, Schottlky barrier diode (SBD)