Rapid 3-D electromagnetic simulation of quasi-periodic structures

We describe a new 3-D electromagnetic simulation technique capable of fast, accurate modeling of complex cavity/waveguide structures. The method subdivides the structure into sections that can be analyzed independently, using 3-D finite element modeling then reassembled to compute a reduced-order matrix representation of Maxwell´s equations. Eigensolutions of the reduced order matrix equations correspond to eigenmodes of the complete 3-D structure, but total solution time can be orders of magnitude less than direct simulation for large complex structures. We demonstrate the method using examples in both 2-D and 3-D, having up to 50 cavities with non-uniform properties. The technique is shown to be numerically robust, even when strong losses exist in the system.