A fluidic bridge based MEMS paramagnetic oxygen sensor

This paper describes a new paramagnetic oxygen sensor based on the combination of a fluidic and an electric bridge fabricated in MEMS technology. In the sensor the gas mixture to be analysed is injected across an unguided flow section, where it is subjected to an in-plane magnetic field gradient, originating from a small permanent magnet placed at the side, followed by three parallel channels. The channel arrangement consists of a centre channel, guiding an undisturbed flow, a measurement channel close to the magnet and a reference channel on the opposite side of the centre channel. The sensor principle relies on the attraction of the paramagnetic oxygen into the measurement channel by the high strength magnetic field and corresponding distraction from both, the main and the reference channel. The change in flow is measured via integrated thermoanemometers.