Anisotropic-medium PML for FETD with conjugate-scaled basis functions

A novel anisotropic-medium perfectly matched layer (PML) implementation is presented for boundary truncation in the three-dimensional (3D) finite-element time-domain (FETD) method. This approach utilizes a conjugate-scaled set of vector test and basis functions in the PML region, which recovers the usual vector basis functions in the non-PML region. Numerical examples show that the proposed PML-FETD approach has small reflection errors and no observed late-time instabilities for simulations involving up to 10⁶ time steps. By choosing the appropriate conductivity value and profile, a reflection error of -64 dB is obtained for ten layers of PML and of -80 dB is obtained for 20 layers of PML.