Abstract-Analysis of Human Breath by Millimeter-Wave/Terahertz Spectroscopy

Nick Rothbart,  Olaf Holz, Rembert Koczulla, Klaus Schmalz,  Heinz-Wilhelm Hübers

https://www.mdpi.com/1424-8220/19/12/2719/pdf

Breath gas analysis is a promising tool for medical research and diagnosis. A particularly powerful technological approach is millimeter-wave/terahertz (mmW/THz) spectroscopy, because it is a very sensitive and highly selective technique. In addition, it offers the potential for compact and affordable sensing systems for wide use. In this work, we demonstrate the capability of a mmW/THz spectrometer for breath analysis. Samples from three volunteers and a sample from ambient air were analyzed with respect to 31 different molecular species. High-resolution absorption spectra were measured by scanning two absorption lines from each species. Out of the 31, a total of 21 species were detected. The results demonstrate the potential of mmW/THz spectroscopy for breath analysis.

Abstract- Gas Spectroscopy System for Breath Analysis at mm-wave/THz Using SiGe BiCMOS Circuits

 Klaus Schmalz,   Nick Rothbart ,  Philipp F.-X. Neumaier,  Johannes Borngräber,   Heinz-Wilhelm Hübers,  Dietmar Kissinger

http://ieeexplore.ieee.org/document/7836317/

The unique fingerprint spectra of volatile organic compounds for breath analysis and toxic industrial chemicals make an mm-wave (mmW)/THz gas sensor very specific and sensitive. This paper reviews and updates results of our recent work on sensor systems for gas spectroscopy based on integrated transmitter (TX) and receiver (RX), which are developed and fabricated in IHP's 0.13 μm SiGe BiCMOS technology. In this paper, we present an mmW/THz spectroscopic system including a folded gas absorption cell of 1.9 m length between the TX and RX modules. We discuss the results and specifications of our sensor system based on integrated TX and RX. We demonstrate TXs and RXs with integrated antennas for spectroscopy at 238-252 GHz and 494-500 GHz using integer-N phase-locked loops (PLLs). We present a compact system by using fractional-N PLLs allowing frequency ramps for the TX and RX, and for TX with superimposed frequency shift keying or reference frequency modulation. In another configuration, the voltage controlled oscillators of the TX and RX local oscillator are tuned directly without PLLs by applying external voltages. Further developments of our system are aimed at realizing an even wider frequency span by switching between frequency bands, and to use a more compact gas absorption cell.