We report on an indium antimonide high electron mobility transistor with record cut-off frequency characteristics. For high frequency response it is important to minimize parasitic resistance and capacitance to improve short-channel effects. For analog applications adequate pinch-off behavior is demonstrated. For proper device scaling we need high electron mobility and high electron density. Toward this end, the device design features and simulation are carried out by the Synopsys TCAD tool. A 30 nm InSb HEMT exhibits an excellent cut-off frequency of 586 GHz. To the knowledge of the authors, the obtained cut-off frequency is the highest ever reported in any FET on any material system.