In this paper we present a study on the surface acoustic wave propagation performance and coupling coefficient for a non-planar thin film Surface Acoustic Wave device (SAW). Piezoelectric Aluminum Nitride (AlN) thin film is deposited on top of the Inter Digital Transducer (IDT) by a non conformal physical vapor deposition process. Non-planarity around the transducer impedes the wave propagation, this effect is investigated using SAW delay lines.