Pressure Measurement Using Ultrasonic Resonance of Microcapsules

This paper describes non-invasive pressure measurement using ultrasonics. We used the method to examine the acoustic characteristics of elastic microcapsules which are dependent on the surrounding pressure with the following results: 1) The frequency characteristics of a transmission wave passing through elastic microcapsules are linearly related to the pressure. 2) The resonance frequency of elastic microcapsules depends on the material. We are therefore able to obtain the pressure by measuring certain acoustic parameters.