S. Amari et al., USING SELECTIVE ASYMPTOTICS TO ACCELERATE DISPERSION ANALYSIS OF MICROSTRIP LINES, IEEE transactions on microwave theory and techniques, 46(7), 1998, pp. 1024-1027
A selective asymptotic technique (SAT) to accelerate the elements of t
he impedance matrix in the conventional spectral-domain approach (SDA)
is presented. Instead of using the full asymptotic expression of the
Green's functions, only those parts which cannot be evaluated in close
d form are approximated by their asymptotic expressions. The resulting
expressions are more accurate and systematic, as no additional parame
ter is introduced. The technique is applied to determine the effective
dielectric constant of an open microstrip line to demonstrate its eff
iciency.