In this paper a monostatic frequency-modulated continuous-wave (FMCW) radar system around a center frequency of 24 GHz with a wide tuning range of 8 GHz (≈33%) is presented. It is based on a fully integrated single-channel SiGe transceiver chip. The chip architecture consists of a fundamental VCO, a receive mixer, a divider chain, and coupling/matching networks. All circuits, except for the divider, are designed with the extensive use of on-chip monolithic integrated spiral inductors. The chip is fabricated in a SiGe bipolar production technology which offers an fT of 170 GHz and fmax of 250 GHz. The phase noise at 1 MHz offset is better than −100 dBc/Hz over the full-tuning range of 8 GHz and a phase noise of better than −111 dBc/Hz is achieved at 27 GHz. The peak output power of the chip is −1 dBm while the receive mixer offers a 1 dBm input referred compression point to keep it from being saturated. The chip has a power consumption of 245 mW and uses an area of 1.51 mm2. The FMCW radar system achieves a power consumption below 1.6 W. Owing to the high stability of the sensor, high accuracy mesaurements with a range error <±250 µm were achieved. The standard deviation between repeated measurements of the same target is 0.6 µm and the spatial resolution is 28 mm.
Coherent 24 GHz FMCW radar system for micro-Doppler studies