On the convergence of zero-order harmonics in the analysis of eigenmodes in open uniform multiwire lines

Limits of applicability are determined for methods used in the analysis of quasi-TEM eigenmodes in uniform multiwire lines; the methods are based on t he widely used assumption that the current distribution in the line wires i s axially symmetric, i.e., when the effect of closeness is not taken into a ccount. It is shown that, for symmetric lines, an analytical solution to th is problem can be obtained.