Coupled lines perpendicular to their cylindrical ground plane embedded in a
cylindrical structure are proposed and analyzed CAD-oriented analytic form
ulas for investigating the quasistatic mode parameters and the coupling pro
perties are derived with the even-odd mode analysis method based on the qua
si-TEM approximation. Calculated mode impedances and coupling coefficients
are observed to be sensitive to cylindrical curvature, especially for large
r values of the spacing in the ground plane. Calculated results are compare
d,vith those obtained for a corresponding planar coupling structure. (C) 19
99 John Wiley & Sons, Inc.