This paper presents the electrical characteristics of the gallium nitride (GaN) current aperture vertical electron transistor (CAVET) by using two-dimensional (2-D) technology computer-aided design (TCAD) simulations. The CAVETs are considered as the alternative device due to their high breakdown voltage and high integration density in the high-power applications. The optimized design for the CAVET focused on the electrical performances according to the different gate-source length (L-GS) and aperture length (L-AP). We analyze DC and RF parameters inducing on-state current (I-on), threshold voltage (V-t), breakdown voltage (V-B), transconductance (g(m)), gate capacitance (C-gg) cut-off frequency (f(T)), and maximum oscillation frequency (f(max)).