WideBand CPML Optimization Using Artificial Bees Algorithm

Document Type : Original Article

Authors

1 PhD student, Babol Noshirvani University of Technology, Babol, Iran

2 Professor, Babol Noshirvani University of Technology, Babol, Iran

3 Associate Professor, Babol Noshirvani University of Technology, Babol, Iran

Abstract

FDTD (Finite Difference Time Domain) numerical method is capable of modeling complex electromagnetic phenomena by calculating electric and magnetic fields using Yee's algorithm. In this method it is possible to model unbounded media using convolutional perfectly matched layer (CPML) absorber But the use of CPML for broadband applications faces a fundamental challenge, and that is the strong reflection of low-frequency harmonics from CPML absorber layers into the FDTD space; Therefore, it is necessary to design the parameters of the CPML absorber accurately in order to prevent the reflection of low frequency harmonics into the simulation space. In this paper, CPML parameters are designed by optimizing a cost function, which is based on reflection coefficient, cutoff frequency and attenuation of CPML layers. The optimization of this cost function is done using the artificial bee algorithm. Result of this algorithm are compared with a conventional values for CPML parameters, which shows more than 15 dB improvement of wave reflection from CPML layers. Also wave incidence modeling for Impulse signals is done using TFSF, so that the scattered fields can be calculated easily.

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