Table of Contents
International Journal of Microwave Science and Technology
Volume 2013, Article ID 459767, 6 pages
Research Article

Wideband Lithium Niobate FBAR Filters

1FEM TO-ST UMR 6174 CNRS-UFC-ENSMM-UTBM, ENSMM, 26 Chemin de l'Epitaphe, 25030 Besançon Cedex, France
2Xlim, UMR 6172 CNRS, Université de Limoges, 87060 Limoges, France
3Thales Alenia Space, CCEL/LPH/EA, Toulouse, France
4CNES, 18 Avenu Edouard Belin, 31401 Toulouse Cedex 9, France

Received 5 October 2012; Accepted 17 December 2012

Academic Editor: Priyanka Mondal

Copyright © 2013 Thomas Baron et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Filters based on film bulk acoustic resonators (FBARs) are widely used for mobile phone applications, but they can also address wideband aerospace requirements. These devices need high electromechanical coupling coefficients to achieve large band pass filters. The piezoelectric material LiNbO3 complies with such specifications and is compatible with standard fabrication processes. In this work, simple metal—LiNbO3—metal structures have been developed to fabricate single FBAR elements directly connected to each other on a single chip. A fabrication process based on LiNbO3/silicon Au-Au bonding and LiNbO3 lapping/polishing has been developed and is proposed in this paper. Electrical measurements of these FBAR filters are proposed and commented exhibiting filters with 8% of fractional bandwidth and 3.3 dB of insertion losses. Electrical measurements show possibilities to obtain 14% of fractional bandwidth. These devices have been packaged, allowing for power handling, thermal, and ferroelectric tests, corresponding to spatial conditions.