Representation of an Arbitrary-Radius Wire for FDTD Calculations in the 2-D Cylindrical Coordinate System

We have shown that a perfectly conducting wire has an equivalent radius,
a

₀
= 0.135 Delta
r
(Delta
r
is the lateral side length of rectangular cells used), if the tangential components of electric field along the wire axis are forced to zero in finite-difference time-domain (FDTD) calculations in the 2-D cylindrical coordinate system. Further, we have shown that the technique proposed by Noda and Yokoyama to represent a wire having an arbitrary radius in the 3-D Cartesian coordinate system can be applied successfully to representing such a wire in the 2-D cylindrical coordinate system if 0.135 Delta
r
is used instead of 0.230 Delta
r
for
a

₀
.