The intention of this paper is to present the instantaneous electromagnetic field measurement by signature of a neutral object (MICHELSON) method. The MICHELSON method is relatively new and enables the measurement of high-level electromagnetic fields from the utilization of a target. The incident field scattering on the target allows us to move the field measurement to a new location where the scattered field can then be measured using simple equipment and without breakdown risk. This method does away with the necessity for cables in the test zone. When using small targets, the induced disturbances in the incident field are limited. The MICHELSON method is implemented to characterize high-level electromagnetic sources whereby the signals radiated can be harmonic signals as well as transient pulses.