Electromagnetic effects on transmission lines

Electromagnetic fields can generate interference on intersystem wiring and cabling. Often this interconnection is in the form of cables and other forms of transmission lines. The simplest model for the system interconnections is a two wire transmission line. Even such a simple case is complex when the wavelength approaches the spacing between the conductors. In such a case one needs to use the full set of Maxwell's equations. Such calculations are computationally expensive. The general solution to this problem provides more information than is needed. A simpler approach is to compute the resonant frequency amplitudes using a modified transmission line model which includes a radiation resistance term. We have obtained a closed form solution of the modified transmission line model with radiation resistance. We compare the results of this solution with computational solutions obtained from a Maxwell equation solver. We conclude that under some conditions, the model is sufficiently accurate at wavelengths larger than 5 times the separation of the wires on the transmission line