Direct Bandwidth Measurements of Dynamic Pressure Sensors

We present an experimental method for performing direct, high-speed dynamic pressure measurements of MEMS based sensors with bandwidths exceeding 1 MHz. We employ a focused nanosecond pulsed laser beam to produce a laser-induced spark that rapidly expands into a supersonic shock wave that stimulates the pressure transducer. A windowed chamber with an integrated heating element allows the sensor’s dynamic pressure response to be characterized at temperatures ranging from 25°C to 1000°C. A precision PID pressure control system is used to establish specific static pressure setpoints ranging from 1 Pa to 33,000Pa (absolute) that are dynamically modulated by the laser-induced shock wave. This method has significant repeatability, accuracy, and bandwidth advantages over other direct and indirect measurement methods such as employing a shock tube, ultrasonic excitation, or using a low frequency reciprocal calibration.