Unconditionally stable FDTD formulation with UPML-ABC

A new unconditionally stable finite-difference time-domain (US-FDTD) formulation is established in combination with the uniaxial anisotropic perfectly matched layer absorbing boundary condition. This approach exhibits improved absorbing performance yet maintains unconditional stability. Numerical results show that the reflection error of this scheme is limited even when the time-step size is beyond the Courantndash;Friedrichndash;Levy stability bound, and the absorbing performance is better than that of the US-FDTD with the dispersive boundary condition.