USEFUL PATH-INDEPENDENT INTEGRALS ASSOCIATED WITH TEM-MODE TRANSMISSION-LINES AND A PROCEDURE FOR COMPUTATION OF RATE OF VARIATION OF CAPACITANCE WITH A CROSS-SECTIONAL DIMENSION

Some path-independent integrals are shown to exist in the potential fi eld of transmission lines in the TEM mode. These integrals have physic al significance that can be used effectively in design, optimisation a nd inspection. In particular, they will be useful in sensitivity analy sis of capacitance or impedance with cross-sectional dimensions, and t he ordering of relative importance of cross-sectional dimensions. Each represents the rate of decrease of potential energy of the system wit h an increase in a dimension of the conductor. In the paper, the integ rals are defined, and their relationship with line parameters such as capacitance or impedance are given. Examples are included to illustrat e the validity of path independence. An alternative method, the stiffn ess derivative procedure, for a numerical calculation of the line inte grals is also presented.