Development of a fully-integrated ultrasensitive wireless sensor utilizing carbon nanotubes and surface plasmon theory

A practical application of surface plasmon resonance (SPR) for the realization of an ultrasensitive, fully-integrated, fully-packaged wireless sensor, that can operate in microwave frequencies based on the gas sensitivity of carbon nanotube (CNT) mixtures, is proposed. The sensor consists of a corrugated aluminum plate whose surface is periodically covered with a thin layer of the CNT materials. The incident TM-polarized waves on this surface excite the surface plasmon (SP) mode, thus resulting in a drop of power of the reflected wave. The change in the electrical properties of the CNT mixtures when exposed to gases results in the change of the SPR observable in the reflected waves. For the first time, a CNT-based wireless sensor has been designed to show a frequency shift of 400 MHz while operating in the 60 GHz range.