Design and Simulation of Microstrip Based IDC Humidity Sensor

This proposed research work presents designing and simulation of Inter-Digital Capacitor (IDC) and its coupling with micro strip line. Our purpose is to identify the presence of humidity in the environment. The humidity sensor model is capable of detecting relative humidity of a sample as per change in its permittivity. The principle of humidity sensor is based on frequency shift due to change in the permittivity. The operation frequency of the proposed system is in S band around 2.8 GHz, for the Relative Humidity (RH) variation of 20- 80% is analysed. The proposed sensor is found to have substantially higher sensitivity when compared with the models available in the literature. This system has been proposed for percentage of relative humidity classification. It exhibits frequency shift of 161.1 MHz for above RH range at ambient temperature. This model is cost effective and can operate without any sensitive material. It is easier to fabricate in comparison to various microwave techniques like N coupled Substrate Cavity Resonator and Substrate Integrated Waveguide (SIW) microwave planar sensors etc. It has an excellent sensing property that can be used in various applications like in food processing, electrical equipment and chemical gas purification.