Enhanced T-Resonator with Blazed Grating for Accurate Powder Material Characterization

This paper proposes an enhanced microwave T-resonator technique for powder material characterization using a blazed grating. The main advantage of this technique is the high sensitivity and non-invasive measurement such that it can be integrated easily for sensing applications. The non-invasive measurement is achieved by implementing powder container into the sensing area of the sensor, thus avoiding the need to deal with the cross error of directly contact measurement. The proposed sensor is designed at around 2.5 GHz resonant frequency and fabricated on a 0.787 mm-thickness Roger 5880 substrate. To validate the sensitivity of the proposed sensor, six common powder materials of different weights are tested. It is found the sensitivity achieved $11.96MHz/\Delta\varepsilon$ and the frequency is shifted between 23 and 56.6 MHz for all measured cases at 1-gram weight. This work will lead to a promising cost-effective sensor with compactness in size, ease of fabrication and small amount of the tested preparation for industrial applications that required advance sensing technique in quality control of the food industry.