Present and near future in the world of microwave filters

The design and realization of microwave filters (and selective combiners) has passed through a deep transformation in the last decade. Two reasons have mainly produced this fact: the first is the request of more and more performing devices for the modern communication systems; in particular, the most challenging are the devices used in mobile communications, where the coexistence of several services (and different operators) has requested filters with high selectivity, low losses and moderate size. The other reason is related to the tools today available for modelling the filters with high accuracy; these tools (based on electromagnetic full wave representation of the mechanical structure of the filters) have practically eliminated the old “cut-and-try” approach to the design, drastically reducing the time-to-market for the new products (together with the overall cost). In this presentation the modern approach to the microwave filters design is discussed with the help of several examples illustrating the possible today performances (and those presumably realizable in the near future).