In this paper, the impact of the nonlinear characteristic of the varactor capacitance on the intermodulation distortion (IMD) profiles of voltage controlled impedance transformation networks, is presented. A test set-up for dynamically measuring the Taylor series expansion coefficient is proposed, able to be extended to the evaluation of load-based envelope tracking transmitters (ET). An antiseries or back-to-back cathode configuration was implemented in order to minimize the IMD contribution. Measurements and simulations with a two tone signal validate this proposed topology for applications in high efficient load-modulated power amplifiers.