Contactless electrode for sensing physiological electrical activity

A contactless system for sensing biopotentials in an individual, the system comprising:

• an electrode for generating a sensing signal indicative of a biopotential at a location on a body of the individual, the electrode comprising:
• an electrically conductive sensing layer having a sensing surface, an opposing surface which opposes the sensing surface and one or more edge surfaces extending between the sensing surface and the opposing surface, the sensing surface capacitively coupled to an outer tissue surface of the individual and sensitive to electric field in a vicinity of the sensing surface;
• and
• an electrically conductive guard layer proximate to the opposing surface of the sensing layer and separated from the opposing surface by an electrically non-conductive layer, the guard layer electrically insulating the sensing layer from electromagnetic interference;
• and
• a high input impedance amplifier circuit
• wherein the sensing layer is electrically coupled to an input of the high input impedance amplifier circuit to condition the sensing signal into an amplifier output signal that depends at least in part on capacitive coupling between the sensing layer and the tissue surface of the individual.