Uhf Feedforward Power Amplifier

In the system of modern wireless communication, the transmission ofinformation is developing toward multi-carrier, great-capacity and high-speed. This needs the RF components to provide higher linear in the systemsof communication. Especially the linearity of power amplifier will affectthe performance of the whole system. Feed-forward power amplifiers aremore concerned by RF engineers because of its high linearity and stability,and especially because it's universal to communication systems.This paper introduces the principle of the feed-forward amplifiers,studies its working process and achieves the analysis and simulation ofthe system. In the real operation, the working states are influenced bytemperature, vibration, humidity and working hours, etc. So a detectablesystem is introduced to feed-forward amplifier, which indicates theoutput distortion of the amplifier.In the paper, the application of feed-forward amplifier is described.Results are given for a series of two-tones inter-modulation distortionmeasurements. It is shown that a 26dB improvement in the inter-modulationmargin can be achieved.