Fast Design Optimization of Waveguide Filters Applying Shape Deformation Techniques

This paper presents an efficient design of microwave filters by means of geometry optimization using shape deformation techniques. This design procedure allows for modelling complex 3D geometries which can be fabricated by additive manufacturing (AM). Shape deforming operations are based on radial basis function (RBF) interpolation and are integrated into an electromagnetic field simulator based on the 3D finite-element method (FEM). The optimization controls two sets of design variables, i.e. the geometrical parameters of the structure and the parameters that determine the shape deformation. This approach provides great design flexibility at marginal additional cost since shape deformations require very little computational effort. A complete design procedure of a Ku-band RX waveguide bandpass filter is shown to verify this approach. The designed filter is fabricated with selective laser melting (SLM) technology. Measurements are presented in comparison with simulation.