Calibration of high frequency MEMS microphones and pressure sensors in the range 10 kHz–1 MHz
Résumé
In the context of both nonlinear acoustics, and downscaled acoustic or aero-acoustic experiments, the
characterization of the high frequency response of microphones and pressure sensors remains a
critical challenge. In the case of the design of new MEMS microphones and shock pressure sensors
with response in the frequency range of 10 kHz–1 MHz, this question was addressed by the definition
of a new calibration method based on a spark source that generates spherical weak shock acoustic
pulse. Waves are short duration non-symmetric N-waves with duration of about 40 microseconds and
front shock rise time of the order of 0.1 microsecond. Taking advantage of recent works on the
characterization of such pressure waves using an optical interferometer, and considering non linear
propagation of weak shockwaves, we were able to estimate the incident pressure wave in the range
of 10 kHz–1MHz. Hence, from the output voltage of the microphones, the frequency response was
obtained in this range. The method applies whatever the transduction principle and the sensor
mounting. [Work supported by the French National Agency for Research (SIMI 9, ANR 2010 BLANC
0905 03, and LabEx CeLyA ANR-10-LABX-60/ANR-11-IDEX-0007).]