Anthropomorphic Multi-tissue Head Phantom for Microwave Imaging Devices Testing

This paper describes the realization of a versatile anthropomorphic multi-tissue head phantom for testing microwave imaging devices, employing mixtures featuring readily available, not harmful, and stable components. Considering that the evaluation of devices, such as medical ones, might require the variation of the characteristics of the tissues for their assessment, the manufacturing approaches the issue using both unalterable and adjustable components. For the former, we reproduce skin, fat, bone, grey matter, white matter, cerebellum, and ventricles using flexible and solid compounds made with proper proportions of urethane rubber, graphite powder, and salt. While for the latter, water, triton X-100, and salt are used to generate a liquid mixture to mimic cerebrospinal fluid. The anatomical structures of the tissues are faithfully rendered using 3D-printed molds and assembled without additional intermediate plastic layers. The materials' dielectric properties are measured via an open-ended coaxial probe method, investigating the frequency range of 0.5-2 GHz. The final prototype fits the nominal dielectric values in the literature, presenting stability and replicability, demonstrating its validity as a multi-purpose test object.