Design of a Skin Equivalent Phantom for Estimating Surface Temperature Elevation Due to Human Exposure to Electromagnetic Fields From 10 to 100 GHz

A semisolid human-body phantom for simulating the steady-state temperature elevation at the skin surface due to exposure to millimeter waves (MMWs) and quasi-MMWs was developed in this article. The phantom was designed by optimizing the electric constants of a mixed material consisting mainly of water and glycerin. First, the empirical equation of the complex permittivity of the phantom with respect to the composition and frequency was derived from dielectric measurements of phantoms. Then, the phantom composition used to obtain the temperature elevation equivalent to skin exposure were optimized using a computational approach. Here, the phantom composition was optimized at frequencies ranging from 10 to 100 GHz. In addition, we found that a single composition can be used for frequencies from 20 to 100 GHz. This phantom can simulate the temperature elevation due to skin exposure within the variation of the temperature elevation due to the individual differences in human tissue thickness. The developed phantom was validated by thermographic measurement using a horn antenna and an array antenna at 28 and 60 GHz, respectively. The developed phantoms are applicable to the thermal assessment of skin exposure to electromagnetic fields at MMW and quasi-MMW frequencies.