The interference of humidity on a shear horizontal surface acoustic wave ammonia sensor

The interference of humidity on an ammonia sensor was studied in this work. The shear horizontal surface acoustic wave (SH-SAW) device coated with l-glutamic acid hydrochloride was fabricated and used as an ammonia sensor. The sensitivity of the SH-SAW ammonia sensor was 4.6 ppm/ppm and the mass loading dominated the perturbation in dry air at 50 °C. As the humidity rose in the environment, the perturbation was primarily from the elastic effect. This work estimated the cross-sensitivity of the interference of humidity. Finally, the neural network technique was used to identify ammonia in the environment.