Construction of device performance models using adaptive interpolation and sensitivities

The performance of a device can be obtained as a continuous function of design parameters by repeated finite element analysis (FEA) followed by interpolation. Since FEA can provide sensitivities at little extra cost, interpolation schemes should make use of them. The scheme proposed here is adaptive and uses radial basis functions (multiquadrics) and pseudo data points. Results are presented for some artificial test problems and for the interpolation of the reflection coefficient of a partial height metallic post in a rectangular waveguide, found by three-dimensional FEA. In every case, the new scheme gives greater accuracy than the equivalent scheme that does not use sensitivities.