This paper is on the use of a hybrid boundary element method/finite element method (BEM/FEM) to determine the induced electric field in several human head models exposed to high-frequency electromagnetic field (EMF). The models including the homogeneous and non-homogeneous spherical and anatomically detailed one, respectively, are irradiated by plane EM wave at several frequencies of interest, including 3500 MHz pertaining to 5G communication systems but also 6000 MHz representing the transition frequency in the EMF safety standards. The numerical results for the induced electric field along propagation axis are then post-processed using a numerical filtering technique in order to obtain the signal envelope. The results show that envelope can be subsequently utilized to correlate the exponentially decaying electric field with calculated penetration depth at the high frequency of interest.