| 摘要 |
PURPOSE:To eliminate spurious over a wide band, through the inclusion of changes in reflection to electrode finger pairs respectively, by combining the 1st electrode finger pair producing electric reflection and the 2nd electrode finger pair producing electric and acoustic reflection, on a piezoelectric substrate. CONSTITUTION:The 1st comb tooth type electrode 12a and the 2nd electrode 12b are formed on the propagating plane of surface acoustic waves of a piezoelectric substrate 11, and the electrode finger pairs are engaged with each other to form a surface acoustic wave transducer. The electrode pairs of this transducer are constituted with the 1st type electrode finger pair A generating electric reflection RB only and making acoustic reflection RA to zero, and the 2nd type electrode finger pair B producing the electroc reflection RB and the acoustic reflection RA. The crossing width of the pair B is made changed in triangle shape so that the reflections RB and RA can be made to zero along the propagating direction of the surface waves, the electrode pair A is provided at both sides of the pair B, spurious over a wide band can be eliminated and the characteristics of the transducer can be improved. |
