Contactless Gas Mixture Measurements Using Distributed and Synchronized Low-Cost Millimeter-Wave FMCW Radar Sensors

In a multitude of industrial processes, various sensing technologies are employed to monitor gaseous substances. However, many traditional sensor types are not suitable for operation under harsh environmental conditions. Radar-based time-of-flight permittivity measurements have been proposed as alternative but suffer from high cost and limited accuracy in highly cluttered industrial plants. We propose a novel concept that utilizes two synchronized low-cost frequency-modulated continuous-wave radar sensors for a direct transmission measurement with increased robustness and accuracy. A prototype based on fully-integrated millimeter-wave radar transceivers was realized and multiple measurements demonstrate a significant improvement to previously published techniques due to higher signal-to-noise ratio and compensation of systematic setup induced errors.