A Portable Terahertz/Millimeter-Wave Spectrometer Based on SiGe BiCMOS Technology for Gas Sensing Applications

We present a compact 45 x 60 cm² breadboard gas sensor system based on 220 to 270 GHz SiGe BiCMOS transmitter and receiver chips and a circular multi-pass gas absorption cell. To demonstrate sensitive gas detection capabilities, we measured gas mixtures of acetaldehyde and air with different concentration ratios. From that, we derive a detection limit of 20 ppm/sqrt(Hz) for acetaldehyde.