There has been tremendous interest in applying the FDTD method to
microstrip circuits. Fang, Zhang, Mei, and Liu
[245,246,247] were among the first to investigate
the dispersive characteristics of microstrips using this approach.
Liang et al. [248], meanwhile, used the FDTD method
to analyze coplanar waveguides and slotlines. In 1990 Sheen et
al. [249] presented FDTD results for various microstrip
structures, including a rectangular patch antenna, a low-pass filter,
and a branch line coupler. Independently, Moore and Ling
[250] and Feix et al. [251] analyzed
microstrip bends using the FDTD method. Other early 1990's
FDTD research results for microstrips was presented by Railton and
McGeehan [118], Wu and Chang [252], Zheng and
Chen [253,254,255,256,257], and
Shibata and Sano [258,259].
Shorthouse and Railton [260] incorporated static field solutions into the FDTD method for microstrip discontinuities. Railton et al. [261] also introduced an approach to model narrow microstrip lines using the FDTD algorithm. Fang and Ren [262] have presented a locally conformable FDTD algorithm for arbitrary planar strips. Other FDTD applications to microstrip problems in the mid 1990's have been presented by Kitamura et al. [263,264], Cresson et al. [265], Qian et al. [266], Li et al. [267], and Seo [268].
Dispersive boundary conditions to terminate microstrip problems were first presented in 1992 by Bi et al. [269]. Other absorbing boundary condition techniques for terminating dispersive microstrip structures can be found in the on-line FDTD database.