A gas sensor includes a transmitter that may transmit a first radar signal, associated with a resonance peak corresponding to a first gas, through a space including the first gas and a second gas. The first gas may absorb a portion of the first radar signal to create a second radar signal. The transmitter may transmit a first infrared (IR) signal, associated with a second resonance peak corresponding to the second gas, through the space. The first gas or the second gas may absorb a portion of the first IR signal to create a second IR signal. The gas sensor may include a controller to determine a concentration of the second gas based on the second radar signal and the second IR signal.