A Compact and Configurable Gasoline Detection System Using a Microwave Sensor

We propose a compact and configurable sensor system using the 4 GHz to 6 GHz frequency band. The proposed system can support three sensors and is designed to detect input samples by using intrinsic vector network analyzer (VNA) functions as well as a simple detection algorithm. The system is composed of three parts: a sensor interface, an RF resonance signal processing board and configurable graphical user interface (GUI) software for storing, processing and detecting the input signal. The resonant frequency and its root mean square (RMS) power are measured, and the margins of the frequency bandwidth and power are estimated by analyzing statistics of the measured bandwidth and power for sample detection. For evaluation of the proposed system, we used three rectangular cavity sensors for gasoline detection and obtained minimum margins of the resonant bandwidth and RMS power at 15.5 Mhz and 2.7837 dB, respectively. The subsequent experiments using the margins validated that the proposed system and algorithm flow show stable detection performance within two seconds for a maximum ten gasoline samples. Although this evaluation has been conducted for gasoline samples, it can be applied to other sensors for which resonance characteristics can be obtained within the proposed bandwidth.