Printed Polymer based Acoustic Sensor for Temperature Monitoring

A flexible printed acoustic sensor for temperature measurement is reported. The sensor is based on an acoustic resonator operating in FPW mode and is fabricated by printing silver Interdigitated transducers (IDTs) on 0-3 lead zirconate titanate (PZT)- poly dimethylo siloxane (PDMS) composite thin film. IDTs are designed with a wavelength of 800 microns and aperture of 12 mm. A temperature variation changes the FPW velocity and thereby the resonant frequency of the FPW resonator. Therefore, temperature of the environment can be monitored by measuring the change of sensor's resonant frequency. Results obtained for the sensor exhibited a linear relationship between the resonant frequency of the sensor and temperature over a over 25 to 120°C temperature range with a sensitivity of 18.111 kHz/°C. The high piezoelectric charge constant of the composite results in a low attenuation of the acoustic resonator. The sensor can be useful where low cost flexible temperature sensing is required.