Electromagnetic Transmission from a Dielectric Loaded Resistive Cylindrical Pipe

Abstract

We obtained analytically closed form expressions for longitudinal electric impedance and transmission coefficient of a dielectric loaded resistive cylindrical pipe of finite thickness. These expressions are valid for an axial current in a form of a point source moving parallel to the pipe axis with an offset a. The resistive–wall impedance and the transmission coefficient have been numerically visualized for some representative machine parameters. For wall thicknesses less than the skin penetration depth, the wall becomes transparent for the excited electromagnetic fields. Very good shielding for standard operation can be achieved by thin metallic walls of thicknesses of the order of few skin penetration depths. Effects of the dielectric constant and thickness on the transmission coefficient are found to be negligibly small, while the presence of the dielectric leads to a suppression of resistive-wall impedance for large thicknesses of the dielectric layer.
Keywords: Cylindrical pipe, Electrical impedance, Transmission coefficient, Wave guides.