Magnetic-Feedback-Based Predistortion Method for Low-Noise Amplifier Linearization

A predistortion method for CMOS low-noise amplifiers (LNAs) to be used in broadband wireless applications is presented. The method is based on the nulling of the third-order intermodulation distortion of the main amplifier by a highly nonlinear predistortion branch. Maximum nonlinearity product cancellation is ensured by a transformer feedback method. The technique improves linearity in a wide range of input power without significant gain and noise figure (NF) degradation. Simulation results on a 1-V LNA indicate a 10.3-dB improvement in the third-order input intercept point with a degradation of only 1 and 0.44 dB in amplifier gain and NF, respectively. The design is based on a 0.13-mum CMOS technology