Model for Fields Coupling With Two Connected Transmission Lines With Different Reference Planes

This paper studies external fields coupling with two connected transmission lines over different reference planes and develops a new model for this problem. The proposed model is the same with that of the two connected transmission lines over the same reference plane except the connection condition. Two connected transmission lines with different reference planes can be equivalent to two transmission lines over the same reference plane along with an additional voltage at the connection. The results obtained by the proposed model are in a good agreement with those of the full wave method while the approximate method, where the transmission line models of the two lines are connected directly, has large errors. The feature selective validation evaluation results show that the proposed model is “Very good” or “Good.” The proposed model can be applied to analyze fields coupling with connected lines, which are on different walls in a cavity. It is also convenient to be combined with circuit analysis to study electromagnetic pulse effects on circuits on different cavity walls connected by transmission lines.