Results are presented from measurements and numerical simulations of Schottky Junction Transistors, a new type of micropower device capable of operating at GHz frequencies in the sub-threshold regime. Detailed measurements of the d.c. characteristics of a 2 /spl mu/m gate length device agree well with numerical simulations. Measurements of transconductance and gate capacitance suggest that this relatively long gate length device will have a cut-off frequency of 126 MHz, which is again consistent with the numerical simulations. When projected to gate lengths of 0.1 /spl mu/m cut-off frequencies in excess of 10 GHz are predicted for drain currents of less than 1 /spl mu/A//spl mu/m.