A 94-GHz five-port reflectometer for measuring complex reflection coefficient using 0.13-μm SiGe HBT detectors

In this paper, the authors present an on-chip multi-probe reflectometer that is incorporated in a dielectric sensor. The designed sensor, integrated on-chip with the five-port reflectometer (FPR), is fabricated in a 0.13-μm 300 GHz-f
_T
/ 450 GHz-f
_MAX
SiGe process technology. The heterojunction bipolar transistors (HBTs), implemented as power detectors for the FPR yield a responsivity of 3.3 kV/W at 94 GHz. A 450-μm long shorted coplanar-waveguide (CPW) line was designed as the sensor to detect the phase variation in the reflection coefficient when the dielectric constant above the CPW changes. The sensor chip and the reflectometer occupies an area of 1164-μm × 410-μm and 627-μm × 410-μm respectively and the reflectometer itself consumes 6.28 mW from a 1.5 V power supply.