Design and development of SIW based H-plane horn applicator for sustainable agriculture applications

Abstract

Traditional weed control methods often depend on chemical herbicides, raising ecological and health hazards which are introducing unsustainable practices in agriculture. This study explores electromagnetic (EM) wave-based soil sterilization as a sustainable alternative. A substrate-integrated waveguide (SIW) horn applicator, operating at 2.45 GHz, is proposed for efficient weed mitigation. The applicator is designed on an ultrathin substrate with a thickness of λ₀/10 at 2.45 GHz, providing improved gain and maintaining a compact, low-profile design. The proposed antenna incorporates Vivaldi-shaped flaring to enhance radiation performance, specifically in terms of directivity and gain. Further optimizations include the introduction of reflector nails, substrate extension, and refined flaring geometry, which improve EM radiation performance. Experimental validation indicates that with 25 watts of power, the soil temperature can be raised to 68.6°C within 60 min, sufficient to thermally eradicate most weed species. Comprehensive thermal simulations were conducted to assess the antenna's efficacy in diverse soil conditions, such as wet and loamy soils, examining heat distribution by changing loss tangent of soil. The nutrient values such as NPK, PH and electric conductivity of soil also been measured with both controlled and treated soil. Results indicates a promising value across all the measured parameters. These analyses demonstrate the thermal impact of the SIW horn antenna and its potential for localized soil heating. The results provide critical insights into the use of EM waves for soil sterilization, offering a sustainable, non-chemical approach to weed management, with potential implications for both agricultural practices and environmental conservation.