A full-wave approach based on the spectral-domain method is applied to
a cylindrical strip line and a microstrip line. The effects of the di
electric substrates and the sire of the cylinder are taken into accoun
t by the spectral-domain Green's functions. Numerical results showing
the characteristic impedance of the lines at high frequency are presen
ted. These results are compared with some available limiting cases. (C
) 1996 John Wiley & Sons, Inc.