摘要 |
The guided acoustic wave resonant device has a differentiation layer (CDf2,CDf3) formed on one acoustic wave resonator (R11,R12,R21,R22,R31,R32) of each filter (F1-F3) and combined with the period of inter-digitized electrodes to modify the coupling coefficient of the acoustic wave resonator, such that the useful band and the central frequency determined by the resonant frequencies and the coupling coefficients of the resonators may obtain determined useful bandwidths. |