4H-SiC based semicircular electrode metal-semiconductor-metal (SEMSM), triangular electrode MSM (TEMSM) and conventional electrode MSM (CEMSM) ultraviolet (UV) sensors have been modeled, investigated and characterized with numerical simulator ISE-DESSIS. By comparing with relevant experimental data, the model correctness is verified. The electrical and optical features of these sensors are simulated and calculated to character the effect of the novel electrode on performance enhancement. In contrast to CEMSM device, the SEMSM and TEMSM sensors show an outstanding superiority in terms of higher photocurrent, comparable low dark current and excellent quantum efficiency. At a bias of 30 V, the dark currents of SEMSM and TEMSM sensors are below 3.5 pA and the photocurrents are 20.7 nA and 23.7 nA under 310 nm UV illumination, respectively. Furthermore, the peak responsivity is estimated to be larger than 0.135 A/W, 0.156 A/W at 290 nm and maximum quantum efficiency at 280 nm is 58.8% and 67.7% for semicircular and triangular electrode structure, respectively.