Simulation Of Hybrid Circuit By Extended Finite-Difference Time-Domain Method

With the fast development of electronic technology, the size of electronic components is getting much smaller than the signal wavelength, we could treat these components as zero-dimensional units. However, as the signal frequency has become increasingly high, the effect of electromagnetic coupling between the components and electromagnetic radiation of the circuit can not be ignored any more. Analyzing the circuit with field theory is one of the most efficient methods to solve these problems. Among these numerical methods, the Finite-Difference Time-Domain(FDTD) method is highly considered by acdemics because of its special advantages as direct simulation in time domain, full-wave analysis and so on. In this paper, the FDTD method with the Unaxial Perfectly Matched Layer(UPML) is applied to analyze the hybrid circuit consists of microstrip and lumped element.Firstly, the paper introduces the background, characteristics and the application in circuits of FDTD method, and then reviews the basic theory, discusses absorbing boundary conditions and total field-scattered field technique.In addition, the paper proposes FDTD modeling method, derives the FDTD iterative formulas of lumped elements, simulate basic linear lumped elements and diode.At last, three practical circuits are analyzed by this method, obtains the distribution of the electromagnetic field of the circuits at different moments, which are significant factors for studying electromagnetic phenomena, and the simulation results of FDTD and commercial software are highly consistent, proved that the method is practical and effective.