Diamagnetically levitating resonant weighing scale

Diamagnetic levitation offers stable confinement of an object from its environment at zero power, and thus is a promising technique for developing next generation unclamped resonant sensors. In this work, we realize a resonant weighing scale using a graphite plate that is diamagnetically levitating over a checkerboard arrangement of permanent...

Method to Determine the Closed-Loop Precision of Resonant Sensors from Open-Loop Measurements

Resonant sensors determine a sensed parameter by measuring the resonance frequency of a resonator. For fast continuous sensing, it is desirable to operate resonant sensors in a closed-loop configuration, where a feedback loop ensures that the resonator is always actuated near its resonance frequency, so that the precision is maximized even in...

A 30 ppm < 80 nJ Ring-Down-Based Readout Circuit for Resonant Sensors

This paper presents an energy-efficient readout circuit for micro-machined resonant sensors. It operates by briefly exciting the sensor at a frequency close to its resonance frequency, after which resonance frequency and quality factor are determined from a single ring-down transient. The circuit employs an inverter-based trans-impedance...

Opto-electronic MEMS oscillator for resonant pressure sensing

This thesis details the design of a self-oscillating MEMS resonator as a pressure sensor. A bi-layer circular diaphragm with a single center perforation is used as a pressure sensitive membrane which measures the absolute pressure of the surrounding medium. A novel aspect of the proposed sensor is that the resonator is made to oscillate by an...

An Energy-Efficient Reconfigurable Interface for Resonant Sensors Based On Ring-Down Measurement

This thesis discusses the theory, architecture design, circuit design and measurements of an ultra-low-energy reconfigurable interface circuit for resonant gas sensors. This interface circuit employs a transient measurement method. The resonant sensor is driven at a frequency close to its resonance frequency by an excitation source that is...

Integrated resonant magnetic field sensor