Unlike their macroscale counterparts, MEMS gyroscopes use a vibrating proof mass rather than a rotational mass to sense changes in angular rate. They are also smaller and less expensive than traditional gyroscopes. For this reason, MEMS gyroscopes are being used in many new applications, some of which include operation in harsh environments. There has been much research on the negative effects of the performance of MEMS gyroscopes in environments that experience mechanical shock, high frequency vibration, and high frequency acoustic noise in air. However, MEMS gyroscopes are beginning to be used in underwater applications such as autonomous underwater vehicles, digital compasses, and torpedo guidance systems. The results of this experiment demonstrate that MEMS gyroscopes submerged in water are susceptible to high power, high frequency acoustic noise at and near the resonant frequency of the proof mass. These effects are demonstrated using the ADXRS300 MEMS gyroscope.

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As a result of the relatively low intrinsic damping in printed circuit boards, vibration and shock loading may excite vibration modes that lead to vibration-induced damage of the PCB and attached components. An investigation of techniques to enhance the damping in printed circuit boards is conducted. Experimental evaluation of the effects of several damping treatments was performed. Of particular interest were the effects of potting materials and microfibrous metallic cloth sandwich configurations. The results from different configurations for each type of treatment are compared and the results discussed. An overall summary of the results is presented and conclusions/observations are discussed.

As a result of the relatively low intrinsic damping in printed circuit boards, vibration and acoustic energy present in the operating environment may excite vibration modes in the PCB that lead to deleterious effects in attached vibration sensitive components, such as MEMS gyroscopes. An investigation of the use of sandwiched layers of microfibrous metallic cloth in contact with the PCB to increase damping was investigated. Tests were performed for both vibration excitation and acoustic excitation. The initial results indicate that mechanical damping can be increased through this approach.

Packaging MEMS devices is challenging, especially when the MEMS device is a sensor that requires direct exposure to and simultaneous protection from the operating environment. Because E-glass PCB laminate (FR4) is often used as a substrate for electronic components, a technique for directly integrating MEMS devices onto these substrates at the die level would be useful. This has been accomplished by attaching a bare die HMX2000 MEMS humidity sensor to an FR-4 carrier by forming a Au–Sn eutectic bond between the Au stud bumped die and tin–silver coated landings on the carrier. Prototype devices were then integrated with other electronics and environmentally evaluated. Test results indicated that this packaging technique was reliable.