Adaptive Solution Space Projection for Fast and Robust Wideband Finite-Element Simulation of Microwave Components

A fast and robust wideband finite element method (FEM) is presented for simulation of various microwave components. Port boundary conditions are derived by means of the eigenfunction expansion and then incorporated into the functional, which is discretized and solved by the high-order FEM. To achieve an efficient and reliable wideband simulation, a multipoint model order reduction technique, called the solution space projection method, is applied. The method requires neither the construction of a port-boundary-condition matrix polynomial, nor the calculation of frequency derivatives of solution vectors in its basic version. Thus, the method not only saves memory, but also can deal with various kinds of boundary conditions that may have arbitrary frequency dependence or are described by a set of discrete vectors over the frequency band.