Schmid G, Hirtl R, Gronau I, Meyer V, Drees K, Lerchl A. Design and Dosimetric Characterization of a Broadband Exposure Facility for In Vitro Experiments in the Frequency Range 18-40.5 GHz. Bioelectromagnetics. 2021 Oct 7. doi: 10.1002/bem.22376. Epub ahead of print. PMID: 34622469.
A novel exposure facility for exposing cell monolayers to centimeter and millimeter waves (18-40.5 GHz) used by future 5G mobile communication technology and similar applications has been developed. A detailed dosimetric characterization of the apparatus for frequencies of 27 and 40.5 GHz and 60 mm petri dishes, used in a presently ongoing study on human dermal fibroblasts and keratinocytes, was carried out. The exposure facility enables a well-defined, randomized, and blinded application of sham exposure and exposure with selectable values of incident power flux density, and additionally provides the possibility of continuous monitoring of the sample temperature during exposure while it does not require significant deviations from routine in vitro handling procedures, i.e. petri dishes are not required to be placed inside waveguides or TEM cells. Mean specific absorption rate (SAR) values inside the cell monolayer of 115 W/kg (27 GHz) and 160 W/kg (40.5 GHz) per watt antenna input power and corresponding transmitted power density (St ) values at the bottom of the cell monolayer of 65 W/m2 (27 GHz) and 70 W/m2 (40.5 GHz) per watt antenna input power can be achieved, respectively. For reasonable amounts of harvested cells (80% of petri dish bottom area), the variation (max/min) of SAR and St over the cell monolayer remains below 3.7 dB (27 GHz) and 3.0 dB (40.5 GHz), respectively.
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