Title :
High velocity pseudosurface waves (HVPSAW)
Author :
Da Cunha, Mauricio Pereira ; Adler, Eric L.
Author_Institution :
Dept. of Electr. Eng., McGill Univ., Montreal, Que., Canada
Abstract :
Current interest in low-loss UHF filters for use in mobile and personal communication systems has led to a number of pseudo-SAW (PSAW) and SH mode based SAW devices. These filters can operate at higher frequencies than SAW-based ones for a given line-width because PSAW and SH mode velocities can be significantly higher than corresponding SAW velocities. Furthermore for certain orientations the attenuation of the PSAW is acceptably small. In this paper the existence of an independent high-velocity pseudo-SAW (HVPSAW) mode is discussed. The HVPSAW is shown to have a phase velocity close to the longitudinal bulk wave velocity and to be quasi-longitudinally polarized. The nature of this HVPSAW mode is described for both electrically open-circuited and layered metallic short-circuited conditions for several piezoelectric materials. Numerical and experimental data are presented which discuss the existence and properties of these high-velocity pseudosurface waves.<>
Keywords :
piezoelectric materials; surface acoustic wave devices; surface acoustic waves; GaAs; Li/sub 2/B/sub 4/O/sub 7/; LiNbO/sub 3/; LiTaO/sub 3/; Poynting vector declination; SiO/sub 2/; electrically open-circuited condition; high velocity pseudosurface waves; high-velocity pseudo-SAW mode; insertion loss frequency response; layered metallic short-circuited condition; longitudinal bulk wave velocity; low-loss UHF filters; numerical data; phase velocity; piezoelectric materials; quartz delay line; quasi-longitudinal polarization; Attenuation; Brillouin scattering; Filters; Frequency; Piezoelectric materials; Piezoelectric polarization; Propagation losses; Surface acoustic wave devices; Surface acoustic waves; Surface waves;
Journal_Title :
Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on
