High-frequency Shock Wave Measurement Pressure Sensor

Shock wave measurement is one of the effective means to evaluate destruction of weapons, and has an important significance for the research of weapons。Dynamic pressure transducer is one of the most important matters of shock wave measurement technology research. It is premise and foundation of a accurate shock wave measurement system.There are mainly four contents in high-frequency dynamic pressure transducer research:(1) Design and technique of high natural frequency response pressure sensitive elements; (2) Research of packaging method for sensitive elements with no stress and high-frequency response; (3) Design of signal conditioning circuit; (4) Reliability improving under harsh environment as light, heat, strong shocks. This article focuses on these four issues above and the main contents as below:(1)Take an in-depth computing and research of relationships among the force-sensitive diaphragm structure, deflection, natural frequency, linearity, and range. Design pressure elements suitable for shockwave measurement by adopting the silicon piezoresistive principle and MEMS technique.(2) With silicon-glass bonding technology and Inverted-Cup structure, design a stress-free package structure to remove the cavity effect, ensuring the natural frequency of sensitive components and improve the long-term stability by reducing zero drift.(3)Design a high bandwidth DC signal conditioning circuit by two-stage amplification. The first stage amplifier for Noise suppression, and the second stage for conversion, amplification and filtering within low noise level.(4) A metal layer for protection is used on the back-side of force-sensitive chip by the method of magnetron sputtering to achieve the shielding of infrared light, visible light and ultraviolet light, solving the light interference by strong flash during detonation in the field applications. With the premise of not affect the frequency response characteristics, SOI structure is proposed to solve the interference of transient ultra-high temperature during detonation.