Non-Destructive Classification of Thai Cha-Nee Durian Maturity with Near-Field Reflection Mode Measurement using a 3.4-GHz Microwave Sensor Pakornkiat Sawetmethikul (a*), Kittiwan Nimkerdphol (b)
a) Department of Industrial Education, Faculty of Technical Education, Rajamangala University of Technology Thanyaburi, Thailand
*pkkt[at]rmutt.ac.th
b) Department of Computer Engineering, Faculty of Engineering, Rajamangala University of Technology Thanyaburi, Thailand
kittiwann.n[at]en.rmutt.ac.th
Abstract
This paper proposes an investigation of Thai Cha-Nee durian maturity with reflection mode measurement using a simple microwave sensor based planar structure. The microwave sensor was a “Pencil-like shaped probe”, which were made of a FR4 laminate; dielectric constant = 4.4, dissipation factor = 0.018, substrate thickness = 1.6 mm, and copper thickness = 0.035 mm. The resonant frequency was designed at 3.4 GHz to avoid interferences from wireless communication channels. The distance between sensor and durian was recommended at less than 10 mm, due to near-field region. Referring to experimental results, durian maturity was predicted by reflection coefficient (R); R (immature) is more than 0.53, R (semi-mature) is 0.28 - 0.43, R (mature) is less than 0.19, which achieved prediction accuracy at 91.55 – 99.0 %.
