On the Low-Cost Production of Tissue-Mimicking Skin Phantoms Up to 40 GHz

Objectives: In this paper, a simple methodology for making skin phantoms is presented. In addition, the first millimeter (mm)-wave images in scenarios including the skin phantoms are shown. Technology or Method: Two mixtures based on the use of simple and inexpensive materials are produced and dielectrically characterized in the [0.5--40] GHz frequency range. Cole-Cole parameters are derived by the least-squares method. An inexpensive polystyrene mold to obtain morphologically compatible skin thicknesses is presented. Finally, these phantoms are used for experimental mm-wave imaging tests in two scenarios, with targets with different size and reflectivity in air and in an oil-based phantom. Results: The dielectric characteristics of the produced skin phantoms are compared with those of human skin, showing excellent agreement over the entire spectrum. Realistic and uniform thicknesses from 1 to 2.5 mm were obtained. The experimental images show the possibility of detecting targets with different reflectivity below the skin at mm- waves. Conclusions: two phantoms based on safe and low-cost materials emulating dielectric characteristics (up to 40 GHz) and morphological characteristics of the skin were proposed. One of these phantoms has been used for a number of mm-wave imaging system tests in different scenarios, and the potential of mm-waves to detect non-superficial targets even in the presence of skin is demonstrated. Clinical or Biological Impact: the results presented in this paper provide a replicable methodology for skin phantom realization and show the potential feasibility of mm-wave imaging for early detection of breast cancer.