New orientations for longitudinal leaky SAW with small propagation losses and high velocities in lithium niobate (LN) and lithium tantalate (LT) have been found. Their velocities are 6100 to 6500 m/s in LN and 5200 to 5800 m/s in LT. Their propagation losses are almost negligible only in the case of an Al-grating structure. For example, the Al thickness relative to the SAW wavelength must be 8.4% for 171/spl deg/YZ'-LN; for 133/spl deg/YZ'-LT, the value must be 9.2%. These propagation properties were obtained by using a simulator that combined both finite-element and analytical methods. These results were also well confirmed by measuring the impedance responses of one-port SAW resonators.
Published in:
Ultrasonics, Ferroelectrics and Frequency Control, IEEE Transactions on
(Volume:46
,
Issue:
4
)
Date of Publication: July 1999