A super-regenerative oscillator circuit operating in the 60 GHz band is designed and characterized for use as an active reflector tag for civil automotive FMCW radar applications. The circuit is a proof of principle based on the cross-coupled topology with switchable tail current for oscillator quenching. The circuit is fabricated in a 130-nm SiGe BiCMOS technology with fmax of 450 GHz, and occupies a total area of 0.87 mm2. The super-regenerative oscillator circuit achieves a maximum gain of80.5 dB at a dc power dissipation of 25 mW with a measured output power up to 3.1 dBm. It integrates an on-chip load transformation network and a Marchand balun for interfacing with a single-ended 50 Ω load.