Electromagnetic analysis of a two-wire transmission line of parallel cylinders of unequal radii with dielectric coating

The paper presents a method for the evaluation of capacitance, characteristic impedance and velocity of propagation of a dielectric-coated two-wire transmission line of parallel cylinders of unequal radii under TEM mode approximation. A conformal transformation is used to transform the conductor and dielectric boundaries to appropriate contours extending over a fixed region along the imaginary axis in the transformed plane. Approximating the continuous curve obtained through transformation of dielectric boundaries by a very large number of discrete steps, the expression for the capacitance is derived in the form of a definite integral. Numerical data on capacitance, characteristic impedance, velocity of propagation in the absence and presence of a perfectly conducting ground plane are presented