Performance Evaluation of Rectangular Slot Microstrip Patch Antenna Under Variable Conditions for Real-Time Microplastic Detection and Classification

Microplastics present a severe ecological threat by spreading throughout waterways, soils and air systems which endanger both human wellbeing and environmental stability. Microscopic particles less than 5 millimeters gather in water bodies where they become part of the food chain and affect apex predators. Effective mitigation depends on precise detection methods and ongoing monitoring practices. FTIR and Raman spectroscopy deliver precise results yet remain expensive and inefficient for real-time or widespread application monitoring. New detection technologies including optical probes and microwave-based systems together with Terahertz (THz) spectroscopy show potential as real-time and non-destructive alternatives. Microwave antennas hold promise for microplastic detection at low concentrations through resonance methods but face ongoing issues with calibration and environmental noise. The research proposes adopting rectangular slot microstrip patch antennas which simplify fabrication while providing a budgetfriendly alternative. Through simulations it was demonstrated that the sensing antenna can detect and classify microplastic particles smaller than a 5 mm radius. The study indicates that microparticles smaller than $874 \mu ~\mathrm{m}$ cannot be classified by this antenna design. The material's dielectric constant displayed a strong correlation with resonance frequency shifts. To combat global microplastic pollution we must focus on creating affordable portable technology alongside unified methods.