▎ 摘　　要

NOVELTY - The humidity sensor has a metal oxide thin film which has thickness of 10-100 nanometers. The metal oxide is selected from the group of aluminum oxide, tin oxide, titanium oxide, tungsten trioxide, and graphene oxide. The response time is 1 second and the recovery time is 3 seconds, the humidity is in the range of 3-85% humidity, and hysteresis loss is 0.3%. USE - Surface acoustic wave (SAW) humidity sensor. ADVANTAGE - Provides a metal oxide thin film based SAW humidity sensor, provides a sol gel thin film based SAW humidity sensor, and provides fast response or to reduce the response and recovery time of the humidity sensor instruments. DESCRIPTION OF DRAWING(S) - The drawing shows the scanning electron microscope image of SAW device electrode structure.