A Monostatic D-Band Doppler MMIC With Very Compact I/Q Mixer Realization in SiGe BiCMOS Technology

A novel concept to realize a highly compact low-cost ${I}/{Q}$ radar transceiver for Doppler radar measurements is presented. Based on a diode mixer approach, no couplers are needed to realize both its monostatic structure and the quadrature downconverter to generate the ${I}/{Q}$ phase shift at the baseband output, which is connected to on-chip buffer amplifiers. An on-chip push–push ${D}$ -band voltage-controlled oscillator (VCO) generates a transmitted signal with an output power of about −1.5 dBm within an operating bandwidth of 134–146 GHz. The total current consumption amounts to 75 mA from a 3.3-V supply, with the downconverter and baseband amplifiers only contributing about 3 mA, which makes the presented principle very suitable for applications, where low power consumption is important. The transceiver exhibits a noise figure of 14.9 dB including the integrated buffer amplifiers and shows reliable functionality over a wide range of silicon bulk temperature up to 125 °C. Despite its simple structure, it demonstrates high capability for continuous wave radar applications.