| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve a problem that an isolation characteristic is insufficient in a surface acoustic wave element, in which a transmitter-side filter and a receiver-side filter are formed on the same piezoelectric substrate. <P>SOLUTION: In the surface acoustic wave element: a transmitting side filter area 12 and a receiving side filter area 14 which are respectively provided with oscillation electrodes 3, input pad parts 5, 7 and output pad parts 6, 8 are formed on one main surface of a first substrate 2 consisting of a piezoelectric substance; one main surface of a second substrate 21 consisting of a material having a dielectric constant smaller than that of the first substrate 2 is joined with the other main surface of the first substrate; and a conductive layer 22 is formed on the whole surface of the other main surface of the second substrate 21. Consequently parasitic capacitor formed between the input pad part 5 of the transmitting side filter area 12 and the output pad part 8 of the receiving side filter area 13 can be reduced by reducing the effective dielectric constant of the substrates and the isolation characteristic can be improved. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
