A classical synthesis of microwave filters is based on a coupling matrix approach in which the matrix coefficients determine the filter topology. The first part of this eSeminar will focus on the conversion of the matrix into a 3D model. A typical workflow will describe the relevant modeling features available in CST MICROWAVE STUDIO® (CST MWS). Two filter synthesis options will be described in detail. The new link between CST MWS and NuHertz allows the user to automatically generate CST® models of filters generated by NuHertz. In addition, we will present a specialized built-in macro for automatic band-pass filter synthesis and construction. The second part of the eSeminar will discuss suitable numerical approaches to the simulation itself, as well as the various tuning techniques – direct 3D simulation, space mapping techniques, group delay, and inverse Chirp-Z transformation – that can be applied in the design environment of CST STUDIO SUITE®. Finally, the modeling possibilities for thermal and mechanical analysis of high power filters, and multipacting issues for space-borne components, will be briefly discussed. Real world design examples will be used throughout.