Microwave imaging device prototype for brain stroke 3D monitoring

This paper summarizes the development and the experimental testing of a scanning device, in the microwave range, to monitor brain stroke. The device comprehends 4 main sections: a sensors helmet, a switching matrix, a data acquisition part, and a control/processing core. The sensors in the helmet are 22 custom-made flexible antennas working around 1 GHz, placed conformally to the upper head part. A first validation of the system consists in the detection of a target in the head region. Experimental testing is performed on a single-cavity head phantom, while the target is a balloon mimicking the stroke. The shape of the balloon and phantom are extracted from medical images, and tissues properties are emulated with liquids that resemble their dielectric properties. A differential measurement approach senses the field on the antennas in two different situations, and from their difference computes a 3-D image through a singular value decomposition of the discretized scattering operator obtained from an accurate numerical model. The results verify the capabilities of the system on detecting and monitoring stroke evolution.