Highly coupled resonator based on ridge-shaped periodically poled materials for radio-Frequency applications

Surface Acoustic Wave (SAW) and Bulk Acoustic Wave (BAW) devices are largely used in telecommunication for radio Frequency (RF) signal processing. Nevertheless, these devices are limited by various factors such as short-circuit between electrodes for SAW and precise thickness control for BAW. This paper shows the interest of a new kind of transducer using Periodically Poled Lithium Niobate (PPLN) developed to overcome SAW and BAW technological limits. A former PPLN-based wave-guide was presented some years ago exploiting planar technologies. The novelty of the present work lies in the 3D structuring of the transducer allowing for very high aspect ratio structures exhibiting a theoretical electromechanical coupling about 20% and a phase velocity up to 20 km.s^-1.