Local Dosimetry at Cellular and Subcellular Level in HF and Millimeter-Wave Bands

The aim of this study was to investigate quantitatively local sub-cellular power deposition at frequencies upcoming for wireless power transfer (WPT) and millimeter-wave (mmWave) technologies. The study was performed on a realistic two-dimensional keratinocyte cell model, designed based on electron microscopy images and experimental data on surface area fraction of keratinocyte to explicitly represent nucleus, mitochondria, endoplasmic reticulum, Golgi apparatus and vesicles. The average power loss density (${\boldsymbol{PLD_{\text{avg}}}}$) and electric field (${\boldsymbol{E_{\text{avg}}}}$) were computed by solving Laplace's equation under quasi-static approximation using the finite element method. The numerical results for the spherical cell model were validated with corresponding analytical solutions. The results showed that ${\boldsymbol{E_{\text{avg}}}}$ and ${\boldsymbol{PLD_{\text{avg}}}}$ inside the organelles increased with frequency. Nearly, 51.8% and 98.9% of the incident field on the cell penetrated inside the organelles at 6.78 MHz and 60 GHz, respectively. The ${\boldsymbol{PLD_{\text{avg}}}}$ within the organelles in average was 35.7% (6.78 MHz) and 1.95% (60 GHz) lower than in the cytoplasm. The ${\boldsymbol{E_{\text{avg}}}}$ induced inside nuclear pores (N$_\text{p}$) exceeded the incident field by 5 times and 1.1 times at 6.78 MHz and 60 GHz, respectively. The corresponding ${\boldsymbol{PLD_{\text{avg}}}}$ within N$_\text{p}$ was 32.7 times (6.78 MHz) and 1.2 times (60 GHz) higher than that of the cytoplasm. The enhancement of ${\boldsymbol{PLD_{\text{avg}}}}$ in N$_\text{p}$ suggests that the intracellular traffic is locally exposed to higher exposure levels compared to the background ${\boldsymbol{PLD_{\text{avg}}}}$ in cytosol.