Dielectric-Filled Circular Waveguide Design for Localized 2.45 GHz Microwave Corn Drying

Abstract

This study presents an optimized microwave dryer design for industrial food drying
applications, operating at the target frequency of 2.45 GHz. By integrating a short-circuited circular
waveguide filled with dielectric materials (porcelain, ε=6), the design achieves localized microwave
energy delivery, addressing key challenges of conventional systems such as energy loss and uneven
heating. Numerical simulations using Finite Element Method demonstrated a resonant frequency of 2.451
GHz with a reflection coefficient of -29.7 dB, indicating minimal power reflection (<0.1%) and near
optimal impedance matching. Electromagnetic field analysis revealed concentrated energy distribution,
with electric field strengths exceeding 1000 V/m near the microwave source and ~100 V/m across the
corn surface (ε=55.57), ensuring efficient moisture removal while mitigating overheating risks. The
geometry, optimized for aluminum (σ=3.56×10⁷ S/m) and copper (σ=5.8×10⁷ S/m) components, enables
focused forward field propagation, validated by vertical energy localization in the drying chamber.
Despite minor non-uniformities, the system outperforms traditional designs by balancing high-efficiency
power transfer (via N-type connector) and material-specific adaptability. These results highlight the
potential of the proposed waveguide structure as a scalable solution for rapid, energy-efficient food
drying, providing a foundation for further refinements in cavity geometry and dielectric-material
interactions to enhance processing uniformity.