Nano-flow thermal sensor applying dymamic w-2w sensing method

This article presents microchannel thermal flow sensors fabricated using standard micromachining technology. The sensors comprise of a SiXNY microchannel created by etching of a poly-Si sacrificial layer. The channels are released by KOH etching through inlets and outlets etched from the backside of the substrate. Liquid flow is measured by platinum resistors deposited on top of the microchannel, while the channel is thermally isolated from the substrate by a SiXNY membrane. Flow rates of DI water in the order of nl⋅min-1 have been measured using a dynamic sensing method applying heat waves

Micro coriolis flow sensor

Keywords: Coriolis flow sensor, surface channel technolog

Modeling and characterization of the sensitivity of a hot-wire particle velocity sensor

The sensitivity of an innovative acoustic sensor composed of four hot-wires is analyzed. An analytical model is presented that describes both the air flow and the temperature distribution in and around the probe. The presence of the chip surface in the vicinity of the wires influences the acoustic flow, while it also affects the temperature distribution. Both effects result into a specific angular dependence of the sensor sensitivity.\ud Acoustic measurements are compared with theory, showing good correspondence

Interfacing of artificial hairs array for complex flow pattern recognition

In this paper we report on the latest developments in characterising and interfacing biomimetic flow-sensor array based on the flow sensitive mechano-sensors of crickets. Capacitive hair sensors have been fabricated using a surface micromachining technology and implemented to detect air flows. We have realized readout electronics to detect the movements capacitively using electrodes integrated on the membrane. A charge amplifier, which produces an output voltage representing the capacitance variation of the selected sensor, is used to pick up the signal. An array of hair sensors is implemented for better and more representative flow signals compared to single sensor measurement. Different schemes for measuring individual sensors in arrays independently are discussed. Frequency Division Multiplexing is found to be efficient for this purpose individual element measurement.\ud Key Words: Artificial hairs, capacitive readout, FD

Fully integrated three dimensional sound intensity sensor

For the first time, a complete 3-dimensional sound intensity sensor – consisting of 4 particle velocity sensors and a pressure microphone – has been integrated on a single chip, providing the possibility to do nearly point measurements of acoustic particle velocity, sound pressure, and therefore sound intensity. Principally the sensor consists of two distinct designs; a pressure sensor and particle velocity sensors. In this paper the design of the sensor, fabrication and measurement results are discussed and compared with theoretical results

Micro Coriolis mass flow sensor for chemical micropropulsion systems

We have designed a micromachined micro Coriolis flow sensor for the measurement of hydrazine (N2H4, High Purity Grade) propellant flow in micro chemical propulsion systems [1]. The sensor measures mass flow up to 6 mg/s for a single thruster or up to 24 mg/s for four thrusters. The sensor will first be used for measurement and characterization of the micro thruster system in a simulated space vacuum environment. Integration of the sensor chip within the micro thruster flight hardware will be considered at a later stage. The new chip has an increased flow range because of an integrated on-chip bypass channel

Capacitive long-range position sensor for microactuators

Design, fabrication and measurements for a capacitive long-range position sensor for microactuators are presented. The sensor consists of two periodic geometries (period ≈ 8-16 µm) on resp. a slider and a sense-structure with minimal gap-distance of ~ 1 µm. A relative displacement between the two results in a periodic change in capacitance. In open-loop operation the change in capacitance vs. slider displacement is measured using synchronous detection. Adjusting the minimal gap-distance with additional sense-actuators increases the capacitance. In closed-loop operation the position of the sense-structure is controlled to keep the sensor-capacitance at a larger constant value. Our results indicate that the position precision is increased to 18 nm in closed-loop operation compared to 70 nm in open-loop operation