Modularly Designed Magnetoelastic Micro Strain Gauge

A highly sensitive micro strain gauge may be created by building up a thin-film micro transformer with one leg of its flux guide made out of magnetoelastic material. Locating the magnetoelastic leg at the bottom of the micro transformer structure directly on top of the wafer lends itself for integration in a cantilever beam subjected to bending. On the other hand, putting the magnetoelastic layer on top and placing it on an external tension bar instead of integrating it into the sensor allows for strain measurement without exposing the strain gauge itself to stain. By choosing a modular design, both types of micro transformers may be fabricated in the same wafer process. This paper describes design, fabrication, and performance of such a modular system