Dielectric acoustic response to microwave pulses through thermoacoustic and electrostrictive effects

摘要

Acoustic waves generated by pulsed microwaves have been cited as a mechanism for microwave hearing [1],[2],[3]. More recently it has been demonstrated that acoustic waves are transduced in dielectric objects simulating the ocular lens when exposed to pulsed microwaves [4]. The effect has also been cited as the operant mechanism for cellular damage in studies of the murine ocular lens in vitro [5]. Three theories on the microwave auditory mechanism have been reviewed and compared by Lin [6], viz., the radiation pressure theory, the electrostrictive theory, and the thermoacoustic theory. Among them it was found that only the thermoacoustic mechanism could produce elastic waves of magnitude large enough to explain the experimental observations. Comparing to the magnitude of acoustic pressure generated in typical biological tissues, the electrostrictive effect was found to be about two orders of magnitude smaller, while the radiation pressure three orders of magnitude smaller [7].