A preconditioner based on the pre-defined wavelet packet (PWP) basis is proposed to accelerate the convergence of iterative solvers for large-scale electromagnetic scattering problems. With the moment equations more efficiently represented using the wavelet packet bases, an effective block-diagonal preconditioner can be constructed. Simulation results show that the convergence rate for inlet-type scatterers can be significantly improved while maintaining a moderate computation cost for the preconditioning operation.
