A numerical analysis of the balanced transmission line wave sensor

A transmission line exhibiting an electric dipole moment and a magnetic dipole moment which are perpendicular has been numerically analyzed, using the Sandia National Laboratory PATCH code, to evaluate its suitability as an incident field sensor for EMP (electromagnetic pulse) measurement over the frequency range of 10 kHz to 1 GHz. Two numerical models of the antenna structure which only differ in their triangulation schemes have been developed for this study. A course model with larger triangles is used to analyze the structure for frequencies up to 100 MHz. Above 100 MHz, a fine model with smaller triangles is used. The performance of this antenna is evaluated in terms of the front-to-back ratio and its frequency response. A comparison with theoretical and measured results is made to ascertain the accuracy of the numerical study. Currents on the antenna structure are evaluated for the case of maximum sensor response as the frequency increases. The two models yield similar results. This confirms the validity of the numerical models used in the PATCH code