P6G-4 High Q-factor STW-Resonators on AT-Cut of Quartz

Surface transverse wave-resonators with resonant frequency near 1900 MHz on AT-cut of quartz with different periods of interdigital transducer and reflectors are reported. It is established that for metal thickness to wavelength ratio 1.9% the use of reflectors with gradually increasing periodicity gives the highest resonance Q-factor. Application of uniform reflectors with center frequency immediately shifted down to set the resonance at the center of reflection stopband results in 9.2% decrease of Q-factor that is attributed to the bulk wave scattering at the break of periodicity. Fabricated test samples of one-port resonators show unloaded Q-factors up to 7200.