An apparatus for on-line measuring electric field intensity during microwave heating: a theoretical consideration

A simple minimally perturbing method and an apparatus for on‐line measuring the electric field ( E ‐field) intensity at a particular small region, or a localized point in an electromagnetic field is described. The theoretical considerations and methodology for on‐line measuring electric field intensity are presented. They are based on measurement of the differential heating of the temperature rise using a fiberoptic temperature sensor at which a selected droplet of dielectric medium is dissipated in an electromagnetic field. The performance of the apparatus was examined and verified from power dissipation calculations of the water load. There was good agreement between the experimental and predicted value of average water temperature based on electric field on‐line measurement.