Research On Locally One-dimensional Finite-Difference Time-domain And Its Application In Electromagnetic Compatibility Analysis

The Finite-Difference Time-Domain (FDTD) method is an important and popular numerical method in computational electromagnetics. In this thesis, an unconditionally stable FDTD method—locally one-dimensional finite-difference time-domain (LOD-FDTD) is studied. Compared with the other unconditionally stable FDTD methods (such as the alternating-direction-implicit finite-difference time-domain, ADI-FDTD), LOD-FDTD is more efficient in calculation.In this thesis, the last achievements on LOD-FDTD method are reviewed, concluded and validated. The two-dimensional and three-dimensional calculation examples are used to validate the key characters of LOD-FDTD. Then, LOD-FDTD algorithms of tiny structures such as lumped element, slot and thin wire are derived and applied into the simulation of the complex metal box.The main work and the innovative points in this thesis are summarized as followings:(1) LOD-FDTD algorithms of tiny structures such as lumped element, slot and thin wire are derived and applied into the simulation of a complex metal enclosure. The source delivered power is calculated and the calculational results agree with the result obtained by the traditional FDTD method. The error between the results of LOD-FDTD and traditional FDTD is analyzed.(2) LOD-FDTD algorithms of slot and the three-dimensional absorbing boundary LOD-PML are derived and applied into the simulation of the complex metal enclosure with slot. The source delivered power and the electromagnetics radiation are calculated and the calculational results agree with the result obtained by the traditional FDTD method. The error between the results of LOD-FDTD and traditional FDTD is analyzed.(3) The algorithm of the two-dimensional absorbing boundary LOD-PML is derived. An example of two-dimensional free space is simulated with different time steps. The reflection error of LOD-PML is analyzed .The reflection error is about -90dB.(4) The unconditional stability of the two and three-dimensional LOD-FDTD are analyzed theoretically. The examples of two and three-dimensioanl metal resonance cavities show the unconditional stability of two and three-dimensioanl LOD-FDTD, which validate the high computational efficiency of LOD-FDTD.