The microwave auditory phenomenon

Abstract

When human subjects are exposed to rectangular pulses of microwave radiation, an audible sound occurs which appears to originate from within or behind the head. It has been shown that electrophysiological auditory activity may be elicited by exposing the brains of laboratory animals to rectangular pulses of microwave energy. These results suggest that a microwave auditory phenomenon is evoked by a mechanism similar to that responsible for conventional sound reception and that the primary site of interaction resides peripheral to the cochlea. A comparison of the pressure amplitudes, such as those produced in a homogeneous planar layer of brain matter that is irradiated by a microwave pulse, indicates that the peak pressure due to thermal expansion is much greater than either radiation pressure or electrostriction. Theoretical analyses for a spherical brain based on the thermoelastic mechanism of interaction were found to agree with experimentally observed characteristics and indicate also that the induced sound frequency is only a function of the size and acoustic property of the brain. A few suggestions have been made for future research aimed at furthering our knowledge on microwave auditory effect and its health implications.