New Materials and new Devices for Filtering in Radio-communication Systems

There is now a large market for the UHF filters made with piezoelectric resonators due to their large use in radio-communication systems. These filters are presently built with materials presenting only a moderate coupling coefficient and using very similar circuit topologies. In this contribution we demonstrate that this lead to a limitation of their performances and we discuss solutions to improve them. These solutions are found considering alternative filter topologies and/or other materials and/or new kinds of devices (resonators or monolithic filters)