New acoustic resonator based on a ridge built in a periodically poled ferroelectric material for RF applications

The development of transducers alternative to usual surface acoustic wave (SAW) and bulk acoustic wave (BAW) devices for RF signal processing is strongly motivated by the need for improved operating characteristics to face modern telecommunication challenges. This paper shows the interest of a new concept of periodically poled transducers (PPT) on Lithium Niobate (LiNbO₃). This new kind of transducer has been developed to overcome technological limits of SAW inter-digitated transducers (short-circuits between electrodes for instance) or precise thickness control of BAW devices piezoelectric material. The novelties of the structure compared to already achieved work on PPT lies in the 3D structuring of the transducer. High aspect ratio ridges are achieved on PPT plates and an adapted metallization allows for the excitation of modes exhibiting theoretical electromechanical coupling in excess of 20% with predicted phase velocities close to 18000m.s^-1.