High-linearity CMOS feedforward power amplifier for WiMAX application

A high-linearity CMOS feedforward power amplifier has been proposed. The class-C and class-AB amplifiers were combined to perform a differential circuit, which was utilized as the error amplifier to cancel the third-order nonlinear signal with the main amplifier. Therefore, the linearity of the feedforward power amplifier was improved. At the operation frequency of 2.6 GHz, the measured output IP3 and ACPR are 33.2 dBm and -59 dBc, respectively. Thus, the feedforward architecture is very suitable for high linear power amplifier design.