Abstract: The author gave an optimal perfectly matched layer (PML) method for solving the 3D time harmonic electromagnetic scattering problems. The method was based on the complex coordinate stretching in the frequency domain. The calculation of the optimal PML problem for the scattering problem was not dependent on the thickness of the PML layer by introducing a small parameter ε₀ in the absorbing function. The author proved that the numerical solution converged exponentially to the original 3D time harmonic electromagnetic scattering problems if the parameter ε₀ was sufficiently small.

Key words: exponential convergence, optimal perfectly matched layer (PML) method, 3D time harmonic electromagnetic scattering