Coupling and radiation problems for a pair-wire line above a conducting ground plane

The reciprocal relationship between the coupling and the radiation for a pair-wire transmission line above a conducting ground plane (PTL) is developed on the basis of a circuit concept. The line equations are derived for the PTL currents composed of balanced and unbalanced modes or differential and common modes. The reciprocal relationship between both problems for both modes is expressed by a three-terminal-pair network and, therefore, network functions for response/input for the two terminal-pairs concerned are considered to clarify both characteristics of the phenomena