Passive monolithic microwave multisensor based on N coupled Substrate Integrated resonators for environmental detection

This work presents a novel fully passive monolithic microwave multisensor on Substrate Integrated Waveguide (SIW) technology for simultaneous detection of humidity and temperature. The proposed structure is simple and combines several resonators with well controlled coupling. Each resonator of the multisensor is capable of environmental detection. The detection principle is based on a frequency shift due to a perturbation of the effective permittivity, depending on the sensitivity of the dielectric medium to the surrounding physical variable. The presented multisensor structure operates in the frequency range from 5-9.5 GHz and exhibits a frequency shift for relative humidity in the range of 6.5-93%RH and for temperature between 23-60°C. Based on SIW technology, this new monolithic environmental solution presents the advantage of being easily integrated into planar structure, energetically efficient and low-cost for mass production application.