Nouveaux résonateurs haute-fréquence à Ondes de Volume dans les films minces piézoélectriques pour les Applications sources Embarquées

摘要

This work consist in development of high stability and spectral purity oscillators for the X-band applications which imposes to have high resonators with high quality factor hardly compatible with the feed back electronics developed by the partners of the NOVAE project. Our approach consist in privileging the realization of overtone resonators so called HBAR (High-overtone Bulk Acoustic Resonator) allying the interest of the piezoelectric thin film layers for the excitement of high frequency and the acoustic waves propagation in the high quality crystalline materials. HBAR Resonator based on LiNbO3/LiNbO3 but also LiNbO3/Sapphir was integrated in Colpitts oscillator, and their phase noise then compared with that of the oscillators stabilized by surface acoustic waves resonators of the market. Thus we show that the very strong quality factor measured for the niobate-on-niobate solution allow to reach noise levels comparable or better than those obtained with surface acoustic waves resonators. The manuscript shows the interest of high overtone bulk acoustic waves resonators (HBAR) in terms of ease of implementation and quality of the resonances obtained for high order tones. Also we were able to show that it was reasonably simple to reach the 1,5 GHz band with high quality factors (superior to 10000) for couplings however not over some per thousand.