Hermetically sealed inductor-capacitor (LC) resonator for remote pressure monitoring

Abstract

This paper reports an integrated inductor-capacitor (LC) resonator structure fabricated using bulk micromachining and anodic bonding technologies. In this resonator structure, pressure change monitored by a capacitive pressure sensor results in the change of resonance frequency. The resonance frequency shift is detected by inductive coupling from an external transmission coil; therefore, pressure can be monitored remotely using the passive LC resonator. The fabricated device size measures 3 mm × 3 mm × 0.6 mm, and pressure responsivity has been estimated to be 2 MHz/mmHg. This micromachined, hermetically sealed structure is suitable for biomedical applications such as intraocular, cardiovascular and brain pressure monitoring. © 1998 Publication Board, Japanese Journal of Applied Physics.