Patent ID: 6955749

Claim:
A sensor for measuring an ion concentration or a gas concentration, the sensor comprising a substrate and a sensitive layer, the sensitive layer having a potential that depends on a surrounding gas concentration or ion concentration, the sensitive layer having a first sensitive partial area and a second sensitive partial area, the sensor further comprising a first conductive area capacitively coupled by a first air gap with the first sensitive partial area, a second conductive area capacitively coupled by a second air gap with the second sensitive partial area, wherein the capacitances of the two capacitive couplings are different and wherein the first and second air gaps are of different sizes, the first conductive area capacitively coupled by a first dielectric layer with the substrate and the second conductive area capacitively coupled by a second dielectric layer with the substrate, the sensor further comprising a comparison circuit having a first transistor connected with the first conductive area and a second transistor connected with the second conductive area, the comparison circuit having at least one output signal corresponding to the potential of the sensitive layer.