UNIDIRECTIONAL SURFACE ACOUSTIC WAVE TRANSDUCER AND SURFACE ACOUSTIC WAVE DEVICE USING THE SAME

摘要

PROBLEM TO BE SOLVED: To realize excellent group delay time deviation and small ripples in a unidirectional surface acoustic wave transducer, where a PNR (Positive and Negative Reflectivity) is arranged between excitation electrodes, and a SAW device using the unidirectional surface acoustic wave transducer. SOLUTION: The PNR type unidirectional surface acoustic wave transducer 1 is composed of the a PNR 11. The PNR 11 comprises: a split electrode 10 having a pair of negative electrode fingers T3, T4 extended from a busbar 3 grounded to positive electrode fingers T1, T2 extended from a busbar 2 connected to an external terminal 4; open type floating electrodes O1, O2 electrically connected none of the bus bars 2, 3; and short-circuiting type floating electrodes S1, S2. When the electrode cycle of the PNR 11 is set atλ1 and that of the split electrode 10 is set atλ2, an electrode cycle deflection ratio, d=(λ1-λ2)/λ1 is set at a range of 0