A Sensitive Resonant Gas Sensor Based on Multimode Excitation of a Buckled Beam

We report a new gas sensing technique based on the simultaneous tracking of multiple modes of vibration of an electrothermally heated bridge resonator operated near the buckling point. The proposed technique maximizes the sensitivity of the sensor to the change in the gas concentration and enables the identification of the gas type without the need for selective coating. Under the same gas concentration value, the reported measurements demonstrate a 200% change in the frequency in contrast to 0.5% using the conventional technique based on resistance measurements. The proposed method is simple in principle and design and is promising for achieving practical low-cost gas sensors.