Method for modeling amplitude and bandwidth dependent distortion in nonlinear RF devices

A modeling procedure for identifying amplitude and bandwidth dependent distortion in nonlinear RF devices is presented. The modeling mechanism is based on removing the nonlinearity behavior from the relationship between input-output measurements and applying a linear identification procedure using ARMA models. The model parameter estimation is processed through a non-recursive procedure where an overdetermined set of linear equations is solved analytically employing QR-factorization. Results were carried out for different LDMOS transistor modules at 2.14 GHz. The model fit was in the order of 96%. The method allows the bandwidth dependent distortion to be evaluated under real operating conditions by monitoring pole and zero behavior.