Impedance of rectangular eccentric transmission lines

Rectangular eccentric transmission lines are used in transmission system work, in directional couplers for monitoring power reflections, and in multiplexing and mixing. The determination of the characteristic impedance of these lines is essentially an electrostatic problem and its solution has involved a number of methods, including conformal transformation, finite elements, finite differences and integral equations. Another method is developed here for this problem, employing known field matching means as applied to eccentric geometries. This method is believed to be less involved and easier to use. Comparisons with known experimental and calculated results for rectangular eccentric lines and for strip lines have shown good agreement. Also the variation of the impedance is shown as the sizes and positions of the transmission-line conductors are changed.