Characteristic impedance of rectangular coaxial transmission lines

EXACT mathematical relations between the characteristic impedance and the physical dimensions of circular concentric and eccentric coaxial lines, as well as of coaxial lines having square outer and circular inner conductors1 have been developed and experimentally verified. Messinger and Higgins2 were able to develop formulas for the determination of the inductance of coaxial busses composed of square tubular conductors, at power frequencies. Their calculations were based on finding the self and mutual geometric mean distances of the conductor cross sections.