In this paper, a patch resonator is presented that operates in the Industrial, Scientific, Medical (ISM) band at 2.45–2.48 GHz, when placed on a four-layered (skin, fast, blood, and muscle) tissue. The patch resonator was simulated on a square digital phantom and, for a more realistic scenario, on the digital human phantom ‘Hugo’. To ensure that the resonator is in contact with the voxelized model, a superstrate with the permittivity and conductivity of skin was placed on top of the resonator. The relative permittivity of the blood tissue was decreased and the input impedance matching of the resonator monitored for each case. The results show that the resonator input impedance is sensitive to the changes in the blood tissue of a realistic human model. The fields around the resonator were also simulated.