A D-Band total power radiometer, implemented in an advanced 90 nm SiGe BiCMOS technology is presented. The passive imager front-end consists of D-Band LNA followed by a HBT-based power detector. The LNA achieves 30 dB gain over 28 GHz bandwidth with measured noise figure lower than 7.5 dB. The square-law power detector achieves responsivity of 14.5 kV/W and noise equivalent power (NEP) <1.5 pW/√Hz. The receiver shows record bandwidth of 20 GHz, peak responsivity of 14 MV/W and NEP of 4.3 fW/√Hz at nominal bias. It's small footprint, and low power consumption (40 mW) make it suitable for large-scale imaging arrays.