Relationship between Size of Foreign Objects in Dried Parsley and Transmitted Millimeter Wave Intensity Distribution

Abstract

Target polyethylene foreign objects mixed with dried parsley were detected using transmission measurements of millimeter waves at 35 GHz (λ＝8.6 mm). Normalized Mean Square Errors (NMES) were then calculated from transmission intensities to explore the relationship between NMSE and the presence and size of the foreign objects. Results show the minimum detection limit for foreign objects was 3 mm cube. Electromagnetic field simulations were in agreement with observed diffraction patterns in the experiment, and confirm the edges of foreign objects will cause diffraction patterns. Thus, our research concludes that changes in diffraction patterns due to foreign objects can be used to detect these objects, even when they of similar or smaller size than the detection wavelength.