Microwave auditory perception

The microwave acoustic effect may be defined as the auditory perception of microwave radiation which is a form of electromagnetic energy which occupies the part of spectrum between ordinary radio waves and infrared and optical waves. This definition may... 

It appears reasonable to argue that the auditory perception of pulsed microwave is due to thermoelastic expansion. This view receives strong support from several avenues of evidence which I will presently summarize. 

There are three widely accepted routes by which bone-conducted sound stimulates the cochlea. These are the compres-sional, inertial and osseotympanic theories of bone conduction (12). Compressional bone conduction implies that the cochlear shell is compressed slightly in response of the pressure variation caused by a sound. Inertial bone conduction alludes to a relative motion between the ossicular chain and the temporal bone for low frequency vibrations. The osseotympanic theory denotes a mechanism by which relative movement of the skull, with respect to the mandible, sets up pressure variation in the air present in the auditory meatus. Since perception of microwave pulses are correlated with the capacity to hear high-frequency sound, it rules out inertial or osseotympanic bone conduction as potential mechanisms for microwave acoustic effect. 

It should be mentioned that a recent publication (H ) showed that the pitch (frequency) of sound induced by microwave pulses of widths less than 50 ps persisted as the subject s head was lowered into saline water, while the loudness diminished roughly in proportion to the depth of immersion. Upon complete immersion, auditory sensation disappeared. For pulse widths longer than 50 ps, even partial immersion resulted in loss of perception. This was interpreted as being at odds with the thermoelastic theory. There is, however, an explanation that does seem to fit the data. 

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