Abstract: A system for controlling the activation/deactivation of an electromagnetic shielding screen of a porthole or a protective window of an optoelectronic equipment, which includes, a radiofrequency electromagnetic sensor, with a bandwidth adapted to a cut-off band of said shielding screen corresponding to a range of electromagnetic fields to be blocked, connected to a detector-rectifier with a sensitivity higher than a minimum value of the power of an electromagnetic field to be blocked by means of said shielding screen and a device for activating/deactivating said electromagnetic shielding screen, said detector-rectifier being configured, in the presence of the electromagnetic field with a power exceeding said minimum value, to activate said device for activating/deactivating the electromagnetic shielding screen by capturing the electromagnetic energy supplied by said electromagnetic fields with a power exceeding said minimum value.

Abstract: An optically transparent electromagnetic shielding assembly exhibiting a shielding efficiency that is increased when a conducting or polarizable fluid produces a low electrical impedance value between a periphery and a central region of a window. Such shielding assembly is useful in detection systems that are exposed to varying intensities of electromagnetic radiation, such as microwave radiation.