Synthesis of Inhomogeneous Dielectric, Dispersionless TEM Lenses for High-Power Application

Abstract

A recent result showed that guided transverse electromagnetic (TEM) waves of a very general form could be propagated in an inhomogeneous isotropic dielectric medium with permittivity proportional to Psi-2, where Psi is the cylindrical radius in the usual (Psi,phi,z) cylindrical coordinate system. This has the important property that the permeability mu can be taken as mu0, a constant. Moreover, very general conductor cross sections in (z ,Psi)coordinates can be specified. This allows for the construction of dispersionless bends in high-voltage transmission systems in which the pulse rise time is small compared to transit times across the transmission-line (e.g., coax) cross section. This is important for high-power pulse sources and antennas. The analysis shows that while the permeability can be allowed to be variable, the choice of mu=mu0 allows one to specify purely dielectric lenses. Thus the generalized form of a TEM plane wave involving inhomogeneous constitutive parameters can be used for generating lens designs based on the scaling.