Proposal of 28 GHz In Vitro Exposure System Based on Field Uniformity for Three-Dimensional Cell Culture Experiments

This paper proposes a novel in vitro exposure system operating at millimeter-wave (mmWave) 28 GHz, one of the frequency bands under consideration for fifth generation (5G) communication. We employed the field uniformity concept along cross-sectional observation planes at shorter distances from the radiation antenna for better efficiency and a small-size system. A choke-ring antenna was designed for this purpose in consideration of a wider beamwidth (BW) and a symmetric far-field pattern across three principal planes. The permittivity of Dulbecco's modified Eagle's medium solution was measured to examine the specific absorption rate (SAR) of the skin cell layer inside a Petri dish model for a three-dimensional (3D) cell culture in vitro experiment. The best deployment of Petri dishes, taking into account a geometrical field symmetry, was proposed. Local SAR values within the cell layer among the Petri dishes were determined with different polarization angles. It was determined that this polarization effect should be considered when the actual exposure and deployment were conducted. We finally proposed an in vitro exposure system based on the field uniformity including downward exposure from an antenna for 3D cell culture experiments. A small-size chamber system was obtained, and the size was estimated using the planar near-field chamber design rule. Bioelectromagnetics. 2019;40:445–457.