A SiGe-Chip-Based D-Band FMCW-Radar Sensor with 53-GHz Tuning Range for High Resolution Measurements in Industrial Applications

The article presents a monostatic D -band frequency-modulated continuous-wave (FMCW) radar based on a fully integrated monostatic single-channel silicon-germanium (SiGe) transceiver (TRX) chip. The chip is fabricated in Infineon's bipolar-complementary metal-oxide-semiconductor (BiCMOS) production technology B11HFC which offers heterojunction bipolar transistors (HBTs) with an f_{mathrm {T}}/f_{mathrm {max}} of 250 GHz/370 GHz. The monolithic microwave integrated circuits (MMICs) output signal is coupled by a fully differential substrate integrated waveguide (SIW) based coupling network. The output power at the WR-6.5 antenna flange is more than -10 dBm over a bandwidth of 37.5 GHz. For a sweep within a single-loop phase-locked loop (PLL) circuit from 174.5 to 121.5 GHz, a spatial resolution of almost 3 mm with a metallic plate as the target is achieved. The radar provides a small form factor of 2 times 4 times 5 cm3 and low power consumption of 2.2 W at 5 V. Finally, t he capabilities of the sensor for non-destructive testing (NDT) are demonstrated using a millimeter scanner. With radar imaging, it was possible to measure the orientation of the fiber layers up to a depth of 7.03 mm.