Development of a novel microwave planar sensor for the fruit quality detection using free space transmission method

Time-effective and accurate characterization of the dielectric constant of the fruit sample is important to gauge its quality. For this purpose, the present work aims design and simulation of a radio frequency probe structure. For testing of the structures, apple and pear fruits are selected. Initially, their sugar content level is measured with the Brix meter. The novelty in the design is added with the radiation structure at another end. Further, a design and fabrication of single port planar sensor has been performed. The novel simulated sensor is fabricated and used in array structure to test quality of the fruit sample kept in-between them, and results of S₁₁ and S₂₁ is obtained. Additional arrangements are made to rotate the fruit sample from 0 to 360° with the increment of 5° using microcontroller set up and stepper motor controller unit. The proposed novel sensor structure has applications in microwave-assisted sensing of quality parameters fruit for maintaining quality and safety and as protection against insects.