On the study of skin-effect and dispersion of heavily lossy transmission lines

A special case of a circular coaxial cable with heavy conduction loss was studied by full-wave analysis, and compared with the quasi-transverse electromagnetic (TEM) solutions. It was found that at high frequencies the tangential electrical fields will be much greater than the values reported in the literature. Despite relatively strong longitudinal E-fields and radial currents, the comparison revealed that, provided the circuit parameters are properly evaluated, the errors introduced by a simple distributed circuit model under the quasi-TEM assumption are not excessively large. Therefore, the telegraphist´s equations may give good results up to frequencies of 10 GHz or higher for transmission lines of small geometries commonly found in microelectronics packaging. A second case of three coupled microstrips of rectangular cross-section was also analyzed and compared with network measurements. It was found that the dispersion occurring in microelectronics packaging interconnects at frequencies up to the microwave band is anomalous