This paper deals with different methods to find systematically critical coupling configurations. A critical coupling configuration can appear between a cable and an antenna or cables for data and power transmission. In the later case the minimum distance between the cables or the maximum length for placement in one cable bundle must be determined. One option to find the critical parameters can be standard circuit simulation. In this case the simulation has to be repeated several times. A better approach is using a direct inverse method based on the Modified Nodal Analysis (MNA). Both approaches are discussed in this paper and critical coupling parameters are determined for several configurations.