Ultra performance of the feedforward linear power amplifier using error feedback technique

This paper presents the feedforward linear power amplifier (LPA) using error feedback technique to satisfy requirements of personal communications system (PCS) applications as well as GSM system. The proposed linear power amplifier is applied to feedforward technique combined with error feedback technique which has no main signal loss unlike typical feedback technique. In this case, the ultra reduction of intermodulation distortions (IMD) can be achieved. To verify ultra performance of the proposed LPA, it is designed, fabricated and measured. Two-tone signals at 1.85 GHz and 1.85125 GHz with a dBm/tone from synthesizers are injected into the LPA. The main power amplifier with gain of 30 dB and an average power of 10 W was fabricated. The proposed LPA could reduce more than 35 dB. The total IMD is more than -70 dBc.