In this paper, we present an efficient and systematic algorithm for the solution of electromagnetic scattering and radiation problems over a wide frequency interval. The algorithm is based on the evaluation of the Pade approximant of the solution vector, constructed at a minimum number of expansion frequencies within the interval of interest. The bisection algorithm introduced in this paper is robust. It keeps the approximation error bounded by a predefined constant over the entire frequency band. (C) 1999 John Wiley & Sons, Inc.