  While piezoelectric transduction enables designing acoustic resonators
operating at multi-GHz frequencies, the deposition of piezoelectric materials
typically requires high temperature processes and specific crystallographic
orientation of substrates, thus imposing a limitation on materials that could
be used. In this paper we present a piezoelectrically transduced thickness mode
acoustic resonator that employs piezoelectric (PMNPT) nanoparticles embedded in
a polymer (SU8) matrix. This composite material is deposited using standard
resist-spin coaters and is thus compatible with a variety of substrates. The
device presented here uses a double side polished single crystal silicon wafer
as the low loss acoustic substrate for the resonator and $1.7\mu m$ thick
SU8-PMNPT composite film as the actuator, and exhibits large effective
piezoelectric coefficient $(d_{33})$ of $216pm/V$, and we experimentally
demonstrate efficient transduction of acoustic resonances at frequencies up to
$1.5GHz$.
