In this study, an efficient modal solution for analysis of wave scattering from multiple arbitrary circular cavities placed in a perfect electric conductor (PEC) is presented. Unlike most of the existing methods that employ the Graf's addition theorem which brings serious problems, we employ the complex function method cooperating with multipolar coordinate transformation to match the fields in different analyzed regions. Finally, expansion coefficients are computed by solving the system of linear equations and the Fourier series. Some typical examples are given to verify the solution by the method of moments (MoM).
