5G Electromagnetic Field Exposure at 26 GHz: Absorbed Power Density Assessment

This article investigates the absorbed power density (APD) for a 26 GHz coaxial feed microstrip antenna with a partial ground, utilizing Rogers RT/Duroid 5880 substrate. The microstrip antenna with a dimension of 10.8 mm × 10.8 mm demonstrates excellent performances in terms of reflection coefficient, realized gain, and efficiency with values of −41.55 dB, 8.2 dBi, and 97%, respectively. The APD is assessed by determining the power density on the curve probe lines through a three-layered human head phantom, that consists of skin, fat, and muscle. The head phantom is constructed using CST voxel family data of an eight-week-old female infant and a 4-cole-cole dispersion model. In the APD assessment, the antenna is excited by 6.99 dBm (5 mW) and placed 5 mm from the phantom, and 17 curve probe lines that extend 20 mm in a perpendicular direction from the antenna, are adopted to cover the
$4\ \text{cm}^{2}$
averaging area of the phantom. The APD of
$2.09\ \mathrm{W}/\mathrm{m}^{2}$
averaged over
$4\ \text{cm}^{2}$
exposure area is obtained, which complies with the standardized limit. The proposed APD assessment method could serve as an alternative to mathematical modeling or laboratory measurement. CST Microwave Studio (MWS) is utilized for carrying out all the design and analyses.