Study on Influence of Thickness and Electromagnetic Parameter of Per- fectly Matched Layer (PML)

Perfectly matched layer (PML) absorbing boundary condition (ABC) is an important technique in finitedifference time-domain (FDTD) when simulating infinite area's electromagnetic behaviour in finite area. A big enough computational area was designed in which there is no influence of reflective wave. The radiation of sinusoidal line source in this area was the benchmark for assessment of reflectivity. The total wave with boundary condition subtracted by benchmark was reflective wave. Influences of the PML absorbing layer's thickness, electromagnetic parameter distribution and loss tangent were studied via this method. The results show that 15-mesh-layer may elaborate the PML's ability and the reflectivity may be only 0.003. Better absorbing effect can be achieved when loss tangent is distributed in second power and the corresponding loss tangent in cut off boundary is 2.5.