This reference design demonstrates the capability of radio frequency (RF) sensors to detect various gases in automotive exhaust systems: such as NOx: CO2: O2: HC: soot: NH3 and others: to aid in the reduction of gas emissions. Previously implemented chemical-based sensor solutions had very slow response times: leading to inefficiencies in engine performance and increased emissions. RF sensing technology increases the accuracy and robustness of the system: improving the response time by several hundred times that of the conventional chemical sensing solution.