Optically interrogated MEMS pressure sensor array

A novel pressure measurement technique is presented for wireless recording of time-averaged surface pressure distributions in wind tunnel surveys. An array of silicon micro-plate resonators acts as pressure sensing element. The pressure is recorded by measuring the sensor diaphragms’ resonance frequency using optical interferometry. Dependent on the quasi-static deflection caused by a pressure load, the resonance frequency varies with an average pressure sensitivity of 3 Hz/Pa in a frequency range between 30 and 150 kHz. A smart-pixel CMOS camera, narrow-band acoustic noise excitation and a specific sensor surface structure allow for the interrogation of a large number of sensors in parallel without the need for alignment between sensor and detector. Experimental tests reveal increased sensing performance with acoustic excitation of the higher vibration modes.