We present results and analysis of electromagnetic physical modeling of multifinger transistors, based on a newly developed time-domain numerical technique. Different examples are presented showing that accurate modeling of high-frequency devices should incorporate the effect of EM-wave propagation and electronwave interactions within and around the device. Moreover, high-frequency advantages of multifinger transistors over single-finger transistors are underlined. The objective of this paper is to report an enhanced version of a previously developed multiresolution time-domain technique and also apply it for electromagnetic-physical modeling of multifinger transistors. Work is being done now to obtain S-parameters using the proposed technique and compare it with measurements.