Development of a new Love wave liquid sensor operating at 2GHz achieved by electron beam lithography using an integrated micro-flow channel: The liquichip system

SAW devices based on waveguide modes with shear horizontal polarization (Love modes) are very promising for sensor applications, especially in liquid media. We present here the realization of a 2 GHz operating frequency sensor based on SiO₂/36Y-X LiTaO₃ structure with integrated PDMS micro flow channel and using electron beam lithography to realize the submicronic interdigital transducers. Using our developed sensor operating at 2 GHz, we carried out alternate cycles of nitrogen and water circulating in the PDMS micro flow channel. We measured an absolute sensitivity of -19001 Hz.mm²/ng due to the interaction of the sensor with the water. This sensitivity is higher than that of other devices operating at lower frequencies. The detection mechanism, including gravimetric and permittivity effects at high frequency will be discussed.