Improved design techniques for the realization of linear power amplifiers for wireless transmitters

Improved power amplifier linearization techniques are required for next-generation wireless communications systems. An improved microwave feedforward amplifier (FFA) architecture has been developed, and applied to the 5.725 to 5.850 GHz ISM band (ISM-5700). This FFA is composed of a driver amplifier and a main amplifier, and the phase shift and attenuation functions are performed utilizing vector modulators. This FFA offers a 30 dB improvement in the third order carrier-to-intermodulation (C/I3) ratio performance at the rated output power level of 30 dBm and is the first demonstration of a 5 GHz FFA utilizing vector modulation.