  The propagation of the Lamb modes along a-SiC/ZnO thin supported composite
structures was simulated for different ZnO and a-SiC layer thicknesses and
electrical boundary conditions. The phase and group velocity, the field profile
and the electroacoustic coupling coefficient dispersion curves of the Lamb
modes travelling along the composite plate were calculated for different layers
thicknesses. Zero group velocity (ZGV) points were identified which group
velocity vanishes while the phase velocity remains finite, at specific layers
thickness values. ZGV resonators (ZGVRs) were designed that consist in only one
interdigital transducer (IDT) and no grating reflectors at its sides. The
finite element method analysis was performed to investigate the strain, stress
and internal pressure the a-SiC/ZnO plate experiences when subjected to an
external uniform differential pressure in the 1 to 10 kPa range. The ZGVR
pressure sensitivity, i.e. the relative frequency shift per unit pressure
change, was found to be mostly affected by the change in the membrane thickness
induced by the pressure. A pressure sensitivity of 9 ppm/kPa, in the 4 to 10
kPa range, was predicted for the a-SiC(1{\mu}m)/ZnO(1{\mu}m) ZGV-based pressure
sensor. The feasibility of high-frequency micro-pressure sensors based on a-SiC
and ZnO thin film technology was demonstrated by the present simulation study.
