SURFACE ACOUSTIC WAVE TWO-TERMINAL RESONATOR

摘要

PURPOSE:To decrease the length of the resonator by connecting electrically a block of a split electrode structure transducer and a block of a normal type transducer in parallel so as to decrease the energy loss leaked from both ends of the resonator. CONSTITUTION:The surface acoustic wave resonator is constituted into three resonance blocks C4-C6. The C5 is constituted by the normal type transducer, and the C4 and C6 at the outside are constituted by the split electrode structure transducer. The three resonator blocks are arranged while keeping a prescribed block interval and they are connected in parallel. A current flowing to each electrode finger of the C5 is four times a current flowing to the C4 and C6. Thus, the amplitude of the surface acoustic wave excited by the C5 is four times the amplitude of the surface acoustic wave excited by the C4 and C6. The Q(=2piXenergy stored in the resonator/leakage loss of resonator) due to the length of the resonator and the leakage loss is increased in increasing the number of pairs of the electrode fingers of the C5 in the surface acoustic wave resonator. Thus, the length of the resonator is decreased when the Q of the resonator is the same.