The DC and microwave characteristics of Lg=50nm T-gate InAlN/AlN/GaN High Electron Mobility Transistor (HEMT) on SiC substrate with heavily doped n+ GaN source and drain regions have demonstrated using Synopsys TCAD tool. The proposed device features an AlN spacer layer, AlGaN back-barrier and SiN surface passivation. The proposed HEMT exhibits a maximum drain current density of 1.8A/mm, peak transconductance (gm) of 650mS/mm and ft/fmax of 118/210GHz. At room temperature, the measured carrier mobility, sheet charge carrier density (ns) and breakdown voltage are 1195cm2/Vs, 1.6 ×1013cm−2 and 18V respectively. The superlatives of the proposed HEMTs are bewitching competitor for future monolithic microwave integrated circuits (MMIC) applications particularly in W-band (75–110GHz) high power RF applications.