Inductive microtransformer exploiting the magnetoelastic effect

Microtransformers built up in thin film technology lend themselves to be used as micro-strain gauges. The basic concept is to utilize the magnetoelastic effect for modulating a microtransformer coupling as a function of the strain the core is exposed to. The microtransformer consists of a pair of dual layer planar coils, coupled by two soft magnetic yokes. The microtransformer is located in the support area of a cantilever beam. The main emphasis is put on investigating the technological challenges involved in building such a device. While neither the transformer design nor the flux guide material have been yet optimized for the intended application, the investigations reveal that the basic concept is very promising. The initial test samples are reaching strain gauge k-factors substantially greater than for classic strain gauges.