The identification of gases is of great interest in many fields. E.g. the analysis of human breath has a large medical potential because it contains hundreds of volatile organic compounds (VOCs) that can be attributed to certain physiological processes and pulmonary as well as non-pulmonary diseases (e.g. chronic obstructive pulmonary disease (COPD) and diabetes, respectively). Further interests arise from the detection of toxic industrial chemicals (TICs) or security-relevant gases (e.g. explosives).
With Terahertz/millimeter wave spectroscopy, gases can be identified with high sensitivity, high specificity and high selectivity due to strong rotational transitions of the molecules that exhibit distinct spectral fingerprints. Our research involves the development of a breath gas sensor based on a terahertz/millimeter wave gas spectrometer around 250 GHz which requires high sensitivity detection with gas concentration levels below 1 part per million.
N. Rothbart, K. Schmalz, J. Borngraber, D. Kissinger, and H.-W. Hübers (2016): “Gas Spectroscopy by Voltage-Frequency Tuning of a 245 GHz SiGe Transmitter and Receiver,” IEEE Sensors Journal, vol. 16, no. 24, pp. 8863–8864, Dec. 2016.
K. Schmalz, N. Rothbart, P. F.-X. Neumaier, J. Borngraber, H.-W. Hübers, and D. Kissinger (2017): “Gas Spectroscopy System for Breath Analysis at mm-wave/THz Using SiGe BiCMOS Circuits,” IEEE Transactions on Microwave Theory and Techniques, pp. 1–12, 2017.