| dc.description.abstract | Memscap AS have experienced an increased demand for cost-effective sensor solutions. Smaller civil aircraft do not necessarily need the high-end performance offered by Memscap’s higher-end sensors. Making a new sensor element design is time-consuming and costly. This project aims to find out if available low-cost sensor elements perform well enough to be used in aviation applications.
Different sensor elements were ordered based on datasheet specifications and discussions with manufacturers. The sensor elements were initially tested in a range of performance tests where the sensor characteristics were measured and analysed. Based on results from initial testing, two sensor elements were chosen for further use. Temperature hysteresis was the most significant contributor to the measurement error. This effects could also be difficult to compensate.
Open tooled SMD Ceramic air cavity packages were chosen as external sensor package bases. The ceramic bases have a wide operating range and match the thermal expansion of the silicon sensor elements. On the other hand, the ceramic bases do not match the CTE (coefficient of thermal expansion) of the FR4 PCB (printed circuit board). Both a leadless and a leaded type of package were included in the testing. The type of package could limit the area of application due to concerns about the longevity of the different package types. Both package types performed well with no signs of damage in the soldering joint or the package itself after temperature cycling.
A soft silicone adhesive was used as die-attach. Test results from the sensor element with die-attach are promising, indicating that the silicone adhesive absorbs/isolates the die from unwanted external stress. The project ended with two different sensor suggestions consisting of; two different sensor elements, silicone adhesive die-attach, and two different ceramic bases. With the tests performed in this project, both suggestions should be within the given performance requirements. The two different solutions have measurable differences in performance, at two different price points. | |