Dual-Band Stable Resonant Microwave Sensor for Dielectric Characterization

A microwave planar sensor working at two industrial, scientific and medical (ISM) frequency bands (i.e. 0.92 GHz and 2.45 GHz) is proposed. The sensor stability in terms of Q-factor parameter, is preserved designing the sensor when it works in direct contact to a reference material with known dielectric properties. The dual resonance behavior is achieved by exploiting a shorting pin loaded effect in a simple microstrip structure. The numerical analysis effectively confirms that the proposed designed procedure is able to provide a sensor with a stable resonant behavior (stable Q-factor) and the ability to discriminate different types of investigated materials.