An Improved Uniaxial Perfectly Matched Layer Based on Finite Element Method for Hyperbolic Media

Recently, hyperbolic media (HM) has attracted considerable interest due to their open isofrequency contour (IFC) and high-k modes, while their numerical computational methods in infinite space are challenging. Although the uniaxial perfectly matched layer (UPML) has been successfully utilized, its failure in absorbing electromagnetic waves with HM has been shown in recent research. In this work, the reason for the failure is thoroughly analyzed, and an improved UPML is proposed based on the frequency domain finite element method (FEM) to truncate the unbound hyperbolic computational domain. Finally, the excellent absorption effect of the improved UPML is verified by representative examples such as an infinite HM, a linear-crossing metamaterial, and a Bessel beam.