In this paper, a network based approach to model resonant conversion systems with capacitive coupling is introduced. The modeling methodology provides an efficient tool to investigate capacitive-based wireless power transfer (WPT) systems, in particular for the output characteristics under variations of the components and the coupling parameters. The model enables to explore the dynamics as well as the intricate interactions between the multiple parameters of the systems that can be translated into guidelines in the design of compensators and operation in closed-loop. In addition, a simulation-compatible model of the capacitive coupler using a continuous-time variable capacitor has been constructed in order to provide a simulation framework for the analysis of capacitive-based WPT systems under medium variations. To validate the modeling approach, an experimental capacitive WPT prototype operating at the MHz range has been designed and examined for various air-gaps. The experimental results of the prototype are in excellent agreement with the theoretical analysis and simulations.