Unconditionally Stable Higher Order CNAD-PML for Left-Handed Materials

An unconditionally stable and efficient higher order complex frequency-shifted perfectly matched layer (CFS-PML) based on the Crank-Nicolson-approximate-decoupling (CNAD) algorithm is proposed for truncating the finite-difference time-domain (FDTD) computational domain filled with the left-handed materials (LHMs). The proposed higher order CFS-PML is implemented by the bilinear transform (BT) approach and the LHMs are solved by the trapezoidal recursive convolution (TRC) method. A numerical example is provided to validate the effectiveness of the proposed implementation. The results show that the proposed CFS-PML not only has better absorbing performance compared with the first-order CNAD CFS-PML and the alternating-direction-implicit (ADI) CFS-PML but also takes advantage of the unconditional stability of the original Crank-Nicolson algorithm.