A conductivity sensor with two active parts made by sputtering with interdigitated structure of electrodes

The sensor is formed on a corundum ceramic base. Onto this surface two interdigitated structures of electrodes are applied. The electrodes are applied by sputtering. At the end of the sensor there is a contact which is connected with the active part by the gold conducting path which is covered by a polymer dielectric protection layer. A bio-chemically active substance can be immobilised on the electrodes, one interdigitated structure, the second structure is reference.