Micromachined thermal conductivity sensor for the liquid phase

Due to the small thermal masses and reduced conductivities, membrane-based micromachined thermal sensors offer features superior to those provided by comparable macroscopic measurement setups. In this contribution such a device is applied to determine the thermal transport properties of various liquids. By sinusoidally exciting a heater that is placed on a membrane and recording the resulting temperature in a specified distance, both, the thermal conductivity and the diffusivity of the liquid can be determined by means of amplitude and phase measurements.