A Small-Area, Low-Power 76-81GHz HBT-based Differential Power Detector for Built-In Self-Test in Automotive Radar Applications

This paper presents a differential power detector for automotive radar applications based on the nonlinearity of a SiGe HBT. Compared to other commonly used detectors, this architecture achieves true measurement of the differential-mode power by applying the differential input signal over the base-emitter diodes of complementary bipolar transistors. A competitive dynamic range of 30 dB is reached. Because of its low power consumption of only 0.5 mW and small active area of 0.005 mm
²
, the detector is well-suited for built-in self-test applications. To the authors' best knowledge this is the only true differential power detector in the 76 GHz to 81 GHz automotive radar band. Measurements over the complete automotive temperature range and the detector's sensitivity to process variation are reported.