A Compact 140-GHz Radar MMIC with I/Q Downconverter in SiGe BiCMOS Technology

A monostatic D-band Doppler radar transceiver with a newly developed diode-based mixer is proposed which provides an I/Q signal at the baseband output and thus allows to determine the relative radial direction of a moving target. The quadrature downconverter shows a simple and compact structure since no phase shifters or couplers are needed. The transmitted signal is generated by a low-noise differential voltage-controlled oscillator (VCO) with a frequency band of 136 to 146 GHz. The whole transceiver consumes 74 mA from a 3.3 V supply, with the downconverter and baseband amplifiers contributing about 2 mA. The transceiver shows reliable functionality over a wide range of silicon bulk temperature up to 125°C.