Linearization of 1.85 GHz amplifier using feedback predistortion loop

A new feedback circuit topology was proposed for the cancelling loop of linear power amplifier. This circuit could cancel the intermodulation terms the same way as a typical feedforward technique but the tolerance of the cancellation is enhanced. To verify this circuit topology, an amplifier was designed and two tone test was performed at 1.85 GHz. This experiment showed about 20 dB reduction of intermodulation.