Insulated substrate impedance transducers

Abstract

The present invention provides an electronic transducer (10) and a method for detecting and/or characterizing target materials or physico-chemical stimuli in an external medium (8) using the electronic transducer (10). The electronic transducer (10) comprises a sensing element (3) featuring a variable conductance when exposed to a stimulus from the external medium and a first and second electrode (5a, 5b) spaced apart on or in a sensing material surface of a substrate, the sensing element being provided in or on the substrate and being located between the first and the second electrodes (5a, 5b) forming a pair of sensing electrodes for sensing a change in conductance of the sensing element (3) in a direction substantially parallel to the sensing material surface, at least one of the sensing electrodes (5a, 5b) being electrically insulated from the sensing element (3) by a dielectric layer (4), so as to be capacitively coupled to the sensing element (3). An insulating layer or target specific layer (7) may optionally be provided covering the sensing element (3) and optionally the sensing electrodes and being adapted for contact with the external medium (8). Electrical measurements made between the pair of sensing electrodes (5a, 5b) are influenced by the impedance of the channel (3) which is affected by the presence of the medium (8) to be tested