Electrical Sensoring Characteristics of Pseudo-LFE Sensors with Different Single Crystals

In the present study, three pseudo-LFE devices made of (yxl)21.82° LiNbO₃, Y-cut LiTaO₃ and Y-cut langasite were investigated and compared. The coupling factors and phase velocities of all devices were calculated for device design. The sensitivity of these three devices to the electrical property changes of liquid were tested in isopropanol-water and NaCl-water solution. The results shown that (yxl)21.82° LiNbO₃ device is more sensitive to the change of liquid conductivity and Y-cut LiTaO₃ device is more sensitive to the change of liquid permittivity. For the design of polymer coated gas sensors, the choose of pseudo-LFE device determines by the characteristics of conductive-polymer.