A 94 GHz single-chip FMCW radar module for commercial sensor applications

A single-chip 94 GHz frequency modulated continuous wave (FMCW) radar module has been developed for high resolution sensoring under adverse conditions and environments. The monolithic microwave integrated circuit (MMIC) includes a varactor tuned VCO with injection port, very compact transmit and receive amplifiers and a single-ended resistive mixer. To enable bidirectional operation of a single transmit-receive antenna a combination of a Wilkinson divider and a Lange coupler was integrated. The circuit features coplanar technology and cascode HEMTs for compact size and low cost. These techniques result in a particularly small over-all chip-size of only 2 x 3 mm2. The packaged 94 GHz FMCW radar sensor achieved a tuning range of 6 GHz, an output power of 1mW and a conversion loss of 5 dB. The RF performance of the radar module was successfully verified by real-time monitoring the time flow of a gas-assisted injection molding process.