Development of Higher-Order CPML Boundary Conditions for the Leapfrog WCS-FDTD Method

In this communication, higher-order convolutional perfectly matched layer (HO-CPML) boundary conditions have been developed for the leapfrog weakly conditional stability finite-difference time-domain (WCS-FDTD) method. Here, the recursive convolution approach has been used to implement the higher-order CPML boundary conditions. The stability of the proposed implementation is numerically evaluated, and it is observed that the proposed higher-order CPML boundary conditions are stable for the allowed time-step size of the leapfrog WCS-FDTD method. To validate the efficacy, a numerical test has been performed where a metal plate is buried inside a dispersive medium. The proposed boundary conditions give reduced reflection error than its first-order CPML implementation. The performance of the proposed implementation is further validated by simulations of a double-T monopole antenna.