Numerical Simulation Of Microstrip Filter By Finite-Difference Time-Domain Method

Finite Difference Time Domain Method (FDTD) is one of the most popular time domain methods in numerically solving electromagnetic problems. Firstly presented by K.S. Yee in 1966, it has grown up into a mature numerical algorithm in past thirty years. It also has wide applications in practical problems. Currently it has been used not only in electromagnetic scattering problems, electromagnetic compatibility, bioelectromagnetic problems, but also has been paid more attention by researches in antenna design, microwave technology, optoelectronics and other areas. In recent ten years, researches have applied FDTD to solve microstrip problems and there are many products and papers in that area.To solve those problems without the complexity of programming, there are many companies which have designed electromagnetic computational software. They have friendly user interface, and it is very convenient to define computational models and parameters. They have been paid more attention by many researchers. With one software, this paper aims at the trend of microstrip lines simulation and the method to simulate microstrip lines in time domain. As the basis of those, it has also been used in simulating microstrip filters which are designed by the author. By comparing measured data with the theoretic analysis and the simulated data, the feasibility of using this software to simulate microstrip filter is discussed. In this thesis, the problems such as defining model, defining stimulation, computational time and others which exist in solving those problems in stimulating microstrip such as the difficulties in defining models, the difficulties in defining stimulation, inefficient computation and so on are described. The using methods and characteristics of that software are also discussed.In general, FDTD has the advantages in simulating problems, including the good precision and using time domain computation once toreplace many times computation in frequency domain. FDTD has the distinct advantages on simulating microstrip filters in time domain. Because of the perfect functions and great capabilities, the software, which is based on FDTD, has a great future in computational electromagnetics.