Integrated passive and wireless sensor for magnetic fields, temperature and humidity

This paper presents a surface acoustic wave-based passive and wireless sensor that can measure magnetic field, temperature and humidity. A thin film giant magnetoimpedance sensor, a thermally sensitive LiNbO
₃
substrate and a humidity sensitive hydrogel are integrated together with a surface acoustic wave transducer to realize the multifunctional sensor. The device is characterized using a network analyzer under sequentially changing humidity, temperature and magnetic field conditions. The first hand results show the sensor response to all three sensing parameters with small temperature interference on the magnetic signals.