A new method to find the optimal subharmonic impedance for CDMA power amplifier with Volterra series analysis

The Volterra series method is employed in this paper to analyze the influence of the subharmonic termination. A set of formula is also deduced to calculate the optimal subharmonic impedance. With the formula, a new measurement-based method is presented to obtain the optimal subharmonic termination for the weak nonlinear condition. With this new method, the optimal subharmonic load can be easily calculated with a little amount of measurement data, while, in contrast, a great number of measurement data would be required for the conventional load pull method. The analysis result is verified with the simulation result obtained by the HB method and agrees well with the analysis.