Title:A Bidirectional Hot-Film Anemometer Based on Micromachined aGe Thermistor TechnologyAuthor(s):Samir Cerimovic, Franz Keplinger, A. Talic, Roman Beigelbeck, Thilo Sauter, Hannes Antlinger, Bernhard JakobyAbstract:We report on simulation-based sensor design and measurement results of a bidirectional micromachined hot-film anemometer. The device is based on a thin-film thermistor made of amorphous germanium embedded in a silicon nitride membrane. The germanium structure is divided by metal-strip electrodes into four equivalent thermistor segments which are connected to form a Wheatstone bridge. The sensor combines hot-film and calorimetric transduction principles. The flow dependent cooling of the hot-film results in a unipolar, strictly monotonic transduction characteristic which is utilized for flow velocity measurements. Moreover, convective heat transfer between the hot-film segments causes thermal asymmetry yielding a bridge detuning voltage with a bipolar characteristic where its sign corresponds to the flow direction. Consequently, the sensor features a strictly monotonic transduction characteristic over a wide flow velocity range combined with simultaneous detection of the flow direction. The device was characterized in both CCA and CTA operating modes.Booktitle:The 13th Mechatronics Forum International Conference ProceedingsPublisher:Trauner VerlagEditor(s):R. Scheidl, B. JakobyPage Reference:7 page(s)Publishing:2012