A temperature compensated magnetic field sensor based on the combination of CoFeB ferromagnetic thin films and Quartz/ZnO Love waveguide platform is developed and optimized. The Love wave is a shear horizontal guided wave and therefore provides an optimal interaction with magnetisation in the magneto-elastic thin film resulting in higher acoustic wave magneto-elastic coupling compared to the conventional Rayleigh wave based devices. ST-cut Quartz was chosen as substrate, ZnO as insulating layer for Love wave generation and temperature coefficient of frequency (TCF) compensation and CoFeB as the magnetostrictive layer sensitive to magnetic field. Experimental results show a magneto-acoustic sensitivity of 15.53 MHz/T with almost zero TCF.

Sensors based on "resonance phenomenon" span a broad spectrum of important current applications including detection of biological and chemical agents, and measurements of physical quantities. Resonance phenomena occur with all types of waves: electromagnetic, optic, and acoustic. This review reports about the most recent advances in the design and applications of resonant "passive" sensors, i.e. resonant sensors able to operate with a distant power source and/or able to communicate with a distant transceiver. The sensors considered in this review include acoustic, magnetoelastic, and electromagnetic transducers. They are presented through their relevant technological aspects and through they major advantages which include their integrability within embedded systems and/or systems requiring energy autonomy. Furthermore, the use of these resonant sensors is illustrated in a large variety of applications, ranging from environmental monitoring, structural health monitoring, food packaging monitoring, wearable or implanted sensors for the monitoring of physiological parameters in healthcare related applications, to IoT and future industry monitoring applications.