IM3 and IM5 phase characterization and analysis based on a simplified Newton approach

A simplified Newton method is developed to deduce closed-form expressions for two-tone third- and fifth-order intermodulation magnitude and phase predictions in nonlinear microwave circuits, taking advantage of the attractive convergence properties of Newton-based algorithms. The new approach has provided theoretical data for comparison with experimental results acquired with an automated setup for the characterization of phase asymmetries in two-tone measurements. The empirical method generates the tones in a coherent form and supports the evaluation of effects dependent on baseband impedance and tone separation. A high electron-mobility transistor amplifier under two-tone excitation has been widely characterized using the experimental setup, and measurements have been compared with simulated data showing a good agreement. The theoretical method is empowered with its capability to predict fifth-order effects in a form simpler than the conventional Volterra-series approach