In this paper, key design considerations in self-demodulators at millimeter wave range for short-range software-defined transceivers are presented. Oscillator-less demodulators are used to achieve a wide operating range with low power consumption. The proposed demodulator, featured with a new single-input differential-output low noise amplifier and implemented in 0.18- μm SiGe BiCMOS technology, is able to demodulate Gb/s data signal with a minimum sensitivity of -43 dBm from a carrier frequency of 40-60 GHz, while consuming 12 mW from a 1.5 V supply.