Passive Wireless Sensor System Utilizes Piezoelectric MEMS Resonator

Abstract

Researchers at the University of Central Florida have invented a passive wireless sensor system that includes a piezoelectric microelectromechanical systems (MEMS) resonator that can be configured to sense one or more physical parameters such as temperature, pressure, viscosity and mass. This system is complementary metal oxide semiconductor based, which uses silicon substrates and fab line processing techniques, and is thus significantly less expensive than other MEMS sensors. Additionally, this invention is smaller, typically less than a few square micrometers, and can potentially be used as medical implants. Compared to LC tank technology, this system provides measurements with higher resolutions and can be utilized at higher resolution and operating ranges. Due to their small size, these sensors do not waste any of the received energy to power up electronic circuitries.

Most commercial sensors need batteries to operate which, in turn, limits their life spans. The UCF device is wireless, requires no regular maintenance, and has no required minimum power for operation. Because of these features, the sensors can be placed on moving parts located inside an engine and inside rotating objects such as tires. Along with its antenna, this sensor system can be configured to operate at most common desired frequencies, based on the application. Furthermore, several separate sensors with multiple frequencies and independent measurements can be assembled onto one substrate.

Technical Details

The UCF invention includes a base unit (or a transceiver) and a lateral-extensional MEMS resonator (sensing element) connected directly to an antenna with no additional components or power source. The base unit wirelessly transmits an RF signal to the sensor and analyzes the received signal. It harvests energy from the received RF signal to operate and then transmits the data back to the base unit within a few microseconds.

Benefit

Market Application