Improved wideband highly dispersive absorbing boundary condition

The authors present an improved implementation of a fast, highly dispersive, absorbing boundary. The formulation is based on modal decomposition of fields, and the expansion of the impulse response of a waveguide for each mode into a series of Kautz polynomials. The condition is compared to a few recently proposed absorbing boundary conditions based on an analytic Green´s function model, Berenger´s PML, recursive schemes using Prony´s method, and a scheme with Laguerre polynomials. Using this method, a superior performance in terms of Kautz polynomials is observed.