In this paper, electromagnetic topology (EMT) was used to analyze the electromagnetic compatibility (EMC) of RF circuits including passive and active components. It is difficult to obtain usable results for problems relating to electromagnetic coupling in complex systems when using conventional numerical or experimental methods. Thus it is necessary to find a new methodology for analyzing EMC problems in complicated electromagnetic environments. In order to consider the nonlinear characteristics of active components, a SPICE diode model was used. A power detector circuit and the receiver circuit of a radio control (RC) car were analyzed and experimented in order to verify the validity of this method.