STW Resonators with the High Quality Factor and Reduced Sizes

This paper presents the STW resonators with high Q-factor and reduced sizes on 36 degrees YX90 degrees cut quartz. The resonators are realized as 1-port scheme when an IDT is placed between 2 reflectors. The Q-factor of these resonators is determined by the reflectivity of the reflectors, propagation attenuation, conductive loss in Al electrodes of the IDT, frequency agreement of the center of stopband and maximal reflectivity of the reflectors with maximal admittance of the IDT. The constructional and topological optimization of the STW resonators with computer simulation using equivalent circuit model allows to obtain the high Q-factor and reduced sizes. The 500-1000 MHz STW resonators have shown Q-factors of 8600-9500 and were housed in the miniature 3x3x1.2 and 5x5x1.8 mm SMD package.