The objective of this paper is to extend the dosimetric assessment of 35mm Petri dishes exposed in the standing wave of R18 waveguides operated at 1950MHz for a medium-oil two-layer configuration for cells in monolayer and suspension. The culture medium inside the Petri dish is covered by oil that prevents evaporation and seals the cells below in the medium. The exposure of the cells was analyzed for one suspension-medium configuration, two different suspension-multilayer configurations, and one monolayer-multilayer configuration. The numerical dosimetry is verified by dosimetric temperature measurements. The non-uniformity of the specific absorption rate (SAR) distribution is 30% for monolayer, and 59-75% for suspension configurations. The latter should be taken into account when biological experiment is performed.