Development of monopole sensors for rice quality characterization in Malaysia

Abstract

This thesis presents an innovation within the established research of monopole sensors for the determination of the characteristics of rice in Malaysia. The characteristics are usually determined based on numerical method, simulation and experimental measurement. Measurements used to describe the grades and classify types of rice available in the market are based on moisture content and composition of broken rice. To characterize the quality of rice, various types of sensors have been used. In this research, two types of sensors : monopole sensor and coupled monopole sensor on a ground plane were developed. These sensors operate within the frequency range of 1 GHz to 5 GHz for moisture content characteristics and 10 GHz to 14 GHz for broken rice composition characteristics. These two types of sensors were used to measure ten different types of rice prepared using a standard oven method with moisture contents of between 14% to 18%. Besides that, five samples of different compositions of broken rice ranging between 0 to100% were also measured. To compare the two types of monopole sensors, the reflection coefficient of each sensor was measured at the feed point of the sensors by a Vector Network Analyzer (VNA) and analyzed using MATLAB software. The coupled monopole sensor showed a higher sensitivity of moisture content in the rice grain at 3 GHz with a value of 0.16 (%-1) in comparison to the monopole moisture content with a lower value of 0.07 (%-1). In addition, the coupled monopole sensor for the composition of broken rice in the samples at 12 GHz with a value of 0.00066 (%-1) was also more sensitive than the monopole sensor which had a lower value of 0.00037 (%-1). The findings have proven that the coupled monopole sensor is more sensitive than the monopole sensor.