Contactless determination of gas concentration and pressure based on a low jitter mmWave FMCW radar

In this contribution a novel approach on the determination of gas concentration and pressure is presented. Dielectric mixing equations are shown that explain the relation of permittivity and gas concentration. By means of the mixing equation's edge case, an approximation for dielectric behavior of pure gas pressures is affiliated. A test container and a highly precise mmWave radar system enable the establishment of a fast and precise time domain measurement, named pseudo transmission measurement, for gas measuring tasks. Measurements that were performed on the test setup prove the suggested dielectric gas-theory and are discussed in detail.