The Telegraphist's Equations at Ultra-High Frequencies

The telegraphist's or long line equations are derived from the Maxwell field equations for ultra-high frequencies. By taking into account retardation and the time rate of change of current, a new circuit parameter is obtained in addition to the four usually found in the conventional low frequency equations. This new parameter integrates into the radiation resistance of the parallel wires. The approximations involved are discussed, and application is made to a specific example.