In this paper, a narrow-band high-Q gas sensor is designed and verified. A single-port sensor is proposed with the Rogers RO4003C as a substrate and metal line coupled with a triple-stage split ring as a resonator. In the experiment, as ethanol gradually injects the resonance frequency shifts from 4.128 GHz to 4.068 GHz. The quality factor of the proposed sensor reaches 128 and experimental results are in good agreement with the simulations. The experiment ethanol vapor ranges from 0 to 877 ppm and the sensitivity is 0.076 MHz/ppm. The experimental results have good linearity and relatively hi...
