A NEW METHOD OF CALCULATING THE CHARACTERISTIC IMPEDANCES OF TRANSMISSION LINES
传输线特性阻抗的一个新计算方法

Utilizing a theorem from the variational principles, after transforming boundaries of a transmission line into simpler ones, we can find upper and lower bounds to the correct value of the characteristic impedance of the line, so that the lengthy calculation in the ordinary variational method is avoided. Impedances of the rectangular line with central cylindrical inner conductor, the trough line with the slab line as a special case and the multi-conductor cable are calculated.