Everyone knows the importance of sensors in our society and the huge attempt to improve their properties in order to obtain better sensitivity and selectivity. In this paper, we are more particularly focused on gas sensors based on surface acoustic waves (SAW) device. In a previous work, we have developed and studied a structure composed of a 90° rotated ST quartz crystal covered with a ZnO layer. By developing inter-digital transducers (IDT) on this structure, we can generate different types of acoustic waves. Love waves which are confined near the surface are known to be very sensitives to fluids (liquids or gases). The aim of this work is to present the way we have developed this optimal structure and to test it with a specific polymer. This polymer is polyaniline (PANI). Its main advantage is that it should be deposited by cold pulsed plasma process.