Abstract: With stretched coordinate perfectly matched layer (SC-PML) formulations and Z-transform method,an efficient and unsplit-field implementation of higher-order PML scheme with more than one pole is proposed which truncates finite-difference time-domain (FDTD) lattices.The higher-order PML has advantages of both conventional PML and complex frequency shifted PML (CFS-PML) in terms of absorbing performances.A numerical validation of the proposed formulations is provided through a 2D TE-polarized electromagnetic wave interaction with an infinitely long perfectly electric conductor (PEC) sheet with finite width.It is shown that the proposed PML formulations with higher-order scheme are efficient in terms of attenuating low-frequency propagating waves and evanescent waves and reducing late-time reflections.It has better absorbing performances than conventional SC-PML and convolutional PML (CPML) with CFS scheme.

Key words: perfectly matched layer (PML), finite-difference time-domain (FDTD), Z-transform method