Simulation of Passive Microstrip Circuits
Some characteristics are common to all the methods of electromagnetic simulation. Among these are the space discretizations and the corresponding geometrical segmentations. The methods also share the mathematical models, which are given by wave propagation equations, such as that of Maxwell or the telegrapher, or by simple wave equations as that of Helmholtz. Of course, they share as well several of their weaknesses, including nonconvergence and numerical dispersion. Another disadvantageous peculiarity which is common to all the methods is that of providing amplitude-scaled and frequency-shifted responses (due to transitions and discontinuities) which have to be corrected to supply acceptable final results. This chapter uses FDTD method to write several programs to simulate all the microstrip circuits. After each code is implemented, its operability is validated by doing intercomparisons of its results with the previous ones obtained via the circuit analysis. The chapter discusses some theoretical and empirical shortcuts necessary to create the programs.