Substrate Integrated Waveguide Phase Shifter for Hydrogen Sensing

This letter presents a novel environmental sensor for hydrogen detection. The new sensor is based on a passive microwave substrate integrated phase shifter in which the phase shift of the output signal varies in function of the hydrogen gas concentration. The proposed structure uses tin oxide (SnO2) micro powder as a hydrogen-sensing material and exhibits a phase variation of 19.5° in the hydrogen range of 0 to 1.6%. The substrate integrated sensor presents a new solution for environmental sensing which has the advantage of being passive and having a simple and low-cost manufacturing process.