Design and development of a 2.45 GHz slot loaded SIW microwave applicator for soil treatment

Abstract This paper presents the design and application of a planar H-plane horn antenna for agricultural purposes, specifically for the treatment of loamy wet soil using microwave radiation. The antenna is designed using Substrate Integrated Waveguide (SIW) technology resonated at 2.45 GHz, having a size of 1.37 λ 0 × 1.04 λ 0 × 0.012 λ 0 . To achieve a unidirectional radiation pattern on an ultrathin substrate of 0.012 λ 0 , two exponential slots are incorporated on the top and bottom of the substrate. The gain of the antenna is further enhanced using the interdigital capacitance concept. The proposed antenna is tested for its efficacy in soil disinfection by treating loamy wet soil contained in a pot with dimensions of 150 × 150 × 150 mm 3 . The applicator’s performance is analyzed by performing both steady state and transient analysis on both homogeneous and heterogeneous soil model. In homogeneous soil, 80 °C is reached with 18 W (RMS) in 3384 s, while heterogeneous soil requires 24 W (RMS) and 4644 s. Experimentally, at a low input power of 28 watts (RMS), the maximum soil temperature achieved is 76.6 °C, with the time taken to reach this temperature being 5400 s. The lowest temperature of 70 °C is observed at a depth of 4.5 cm. This temperature range is effective for soil treatment, ensuring the eradication of soil-borne pathogens and pests. The findings demonstrate that the planar H-plane horn antenna is effective in uniformly distributing microwave radiation for soil treatment at lower power levels. This innovative approach offers a promising solution for sustainable soil management and enhanced agricultural productivity, highlighting the potential of advanced antenna designs in agricultural applications.