Towards breath gas detection with a 245 GHz gas sensor based on SiGe BiCMOS technology

We present a 245 GHz gas spectroscopy system with a transmitter array and a receiver based on SiGe BiCMOS technology. Beam profiles of the transmitter array and noise sources of the system were analyzed. We demonstrate the detection of a 50 ppm mixture of ethanol in ambient air after preconcentration. With the maximum signal-to-noise ratio of 190 the resolution can be estimated to 260 ppb.