Chemical sensing via single input — Multi output approach

The concept of single input — multi output (SIMO) sensors is investigated for the purpose of chemical sensing and more precisely gas sensing. The measurement of a single gas is coupled to different outputs, each involving various transduction mechanisms. The concept is especially matched to gas sensing via selective adsorbing mechanism in an active layer, the mass or the electrical polarization of which both depend on the adsorbed amount. In this work, adsorbing layers are deposited on pairs of light membranes, each equipped with a meander shaped, resistive and temperature dependent layer. The latter provides heater — thermometer functions while the balanced pair assembly also makes them well matched to capacitive transduction and reading. This paper reports on such systems built either with industrial Mylar membranes or with Silicon based membranes covered with zeolite layers to introduce selectivity.