Electric field measurement using a non-perturbative method based on a calibrated electric potential sensor

We present results of finite element analysis for simple test structures which demonstrate clearly that the measurement situation is complex. The test structure consists of an open geometry parallel plate capacitor within a screened enclosure. Indeed, the presence of earthed objects, even at considerable distances, is shown to have a significant effect on the field geometry close to the source. These simulations are compared with field measurements made using an ultra-high input impedance sensor, the Electric Potential Sensor. A single experimentally determined calibration factor is all that is required to achieve excellent agreement between experimental measurements and the results of the simulations. Given this, the sensor is capable of mapping accurately, and in a non-perturbative manner, the spatial potential both within and outside of the test structure.