Real Time Monitoring and Detection of Alcohol Using Microwave Sensor Technology

The detection of ethanol in water/ethanol mixtures has been tested using an electromagnetic wave non-invasive sensor operating at frequencies ranging from 1G HZ to 10 GHz (microwave frequency domain) and using very low power <1 mW. The sensor is composed by a tuned cavity operating in reflection mode (S11 parameter). The cavity has a standard WG9A size and is working in the TE10 mode. The tests have been realized using samples of water/ethanol mixtures going from 0% ethanol (pure water) until 100% ethanol. Every sample alcohol concentration is determined by its unique frequency, its magnitude, its phase and depending on the temperature. By looking at these four properties, we would be able to recognize each sample.