Electric Field Sensor Based on a Varactor Diode/MIS/MOS Structure

In this paper a voltage controlled variable capacitance is being proposed as a method for non-contacting measurement of electric fields. There are several microelectronic devices that can be utilized for that purpose: a varactor (a.k.a. varicap), a MOS (metal-oxide-semiconductor) or a MIS (metal-insulator-semiconductor) structure. The construction that has been tested and presented in this paper is based on a varactor diode. Although numerous non-contacting instrument designs are widely available, they either lack precision (meters utilizing Kerr or Pockel effect, rotating vane fieldmeters, fieldmeters with mechanically vibrating sensors) or are relatively expensive and complicated (electrostatic voltmeters). Other types of electric field meters such as capacitive coupling or induction instruments rely on variation of the electric quantity that is being measured, therefore they are not useful for detection and quantification of static (DC) electric charges and fields. The sensor used in the experiment described in this manuscript can be used for the DC and AC electric field measurements. The construction is very simple, therefore inexpensive, and it can be easily miniaturized.