Model of the mu-flown microphone

We present an analytical model of the microflown (mu -flown) sensor which o perates as a microphone measuring particle velocity instead of pressure. A 3-dimensional temperature distribution induced by the heater in the rectang ular channel is calculated. Correction to the temperature arising due to co nvection under acoustic wave propagating in the channel is found. Using thi s information difference in the sensor temperatures, which is proportional to the signal from the device, is evaluated. It is shown that there are two reasons for sensitivity loss of such a microphone at high frequencies. The first one is finite velocity of the heat transport and the second reason i s finite heat capacity of the sensors. Comparison with the experimental dat a is given and it is demonstrated that the model is adequate to the real de vice. (C) 2000 Elsevier Science B.V. Ail rights reserved.