Development of a device for measuring the sensitivity area of coil arrays for magnetic induction measurements

Combining single coils to form a coil array provide advantages for magnetic induction measurements of breathing or heart activity. The main goal for such combination could be a coil configuration which makes the whole measurement system less sensitive for moving artifacts of the patient due to the capability of using many coils for signal acquisition. Such setup could be designed and tested with FEM software. But in most cases, the technical realization differs from theoretical, for instance due to cable effects or the presence of amplifiers attached very close to the coils. Thus, a measurement system for detecting the sensitive area of real arrays is required. In this article, such a device is presented. Based on a crane construction, it is well suited for testing arrays which are built for an integration under a bed or within an incubator for vital parameter monitoring. We will describe the construction as well as first example measurements of a test array.