Humidity dependent permittivity characterization of polyvinyl-alcohol film and its application in relative humidity RF sensor

This work addresses the dielectric characterization of polyvinyl-alcohol (PVA) in humidity sensing applications. The PVA film is characterized in relative humidity (RH) range from 12% to 94% over a frequency span from 1 GHz to 10 GHz, and its suitability for RH sensing is verified with a sensor prototype by implementing a resonator. The characterization results of the PVA film are applied to simulate the frequency response of the sensor, and the discrepancy between the simulation and measurement is less than 8%. The maximal average sensitivity of the fabricated sensor is 42.7 MHz/%RH.