Abstract :
Recently, Riblet has given the exact dimensions of a family of rectangular coaxial lines with given impedance by conformal mapping. Before then the same problem was treated in [3], [4]. However, the previous literature does not include the case when the side of the outer and inner rectangle are in the ratio 2:1 both in width and in height: if in [1, eq. (11)] we put OA = DE or EO = AB, modulus k coincides with modulus h and the rectangular line becomes a square coaxial section, which is a special case of Bowman.
