Behaviour of Leaky Surface Acoustic Wave Propagation at Discontinuous Region of Periodic Grating

Abstract

This paper describes the leaky surface acoustic wave (LSAW) propagation characteristics at a discontinuous region in a grating structure. First, the dispersion relation of LSAWs propagating under a multielectrode-type grating is analysed. Then, the LSAW propagation on the discontinuous region is characterised by simply assuming that the LSAW behaviour under periodic part of the structure is identical with that under a totally periodic grating structure. It is concluded that the phase lag considerably decreases at the discontinuous region. This suggests that the energy storing effect may be weakened at the region where the periodic structure is broken. The simulation of one-port LSAW resonators shows that device performances are sufficiently evaluated only by taking account of the constant phase lag for a simulation tool based on the coupling-of-modes theory.