International audienceA new generation of passive gas sensors that works at millimeter-wave frequency (50 to 70 GHz) incorporating sensitive material is presented. The sensor uses a microwave planar dielectric resonator operating with whispering gallery-modes. The dielectric resonator (DR) is covered by SnO2 thin film as sensitive layer. A gas adsorption makes the SnO2 effective dielectric parameters changing namely its permittivity. Such changing modifies the resonance frequency of the resonator. Here, the proof of concept is demonstrated thorough full wave simulations. This sensor is a passive circuit and has great potential for wireless sensing network applications