This article presents a threat detection system for Unmanned Aerial Vehicles (UAVs) designed to enhance operational security in high-risk environments. The system employs Frequency Modulated Continuous Wave (FMCW) radar, optimized to detect UAVs with a radar cross section (RCS) as small as 0.01 m², exemplified by models such as the DJI Phantom 3 and Phantom 4. Operating at 2.45 GHz, the radar achieves a maximum detection range of 300 meters and is implemented on the USRP B210 Software Defined Radio (SDR) platform, with real-time signal processing enabled through GNU Radio and integrated GPU resources. The transmission module includes a 100-watt Power Amplifier (PA) and dual-parabolic unidirectional antennas, while the receiver employs a Band-Pass Filter (BPF) and a Low Noise Amplifier (LNA) with a gain of 20 dB to improve sensitivity to reflected signals. The USRP B210 handles signal acquisition and processing, applying two-dimensional Fast Fourier Transform (FFT) techniques to extract doppler shift information. The processed data is visualized as a range-doppler map, facilitating effective target tracking. The system's modular architecture and parallel processing capability enable precise and efficient detection of low-RCS UAVs, even in cluttered environments. This work demonstrates a practical, cost-effective radar solution for security-sensitive applications, offering advantages in performance, adaptability, and real-time capability over traditional radar systems.

Several recent studies have found that measuring the dielectric permittivity of soil can be used to determine the level of environmental pollution. However, there is limited research on the measurement of dielectric properties in soil contaminated with biodiesel-diesel blends from Thailand. This paper presents to monitor the dielectric properties of soil contaminated with biodiesel-diesel blends. Specifically, we use the commercial grade diesel B7 to contaminate a sample of sand soil. We also study the measurement of dielectric properties in contaminated soil with the diesel B7 using a dual electrode plate-based radio frequency (RF) heating system. This allows us to observe the behavior of the contaminated soil before and after RF heating treatment. The experimental result showed that the dielectric properties of uncontaminated and contaminated soil were different. In addition, the RF heating system utilizing the electric field intensities of 450 kV/m resulted in the dielectric properties of the contaminated soil becoming similar to those of uncontaminated soil. These findings suggest that using RF heating on contaminated soil samples improve the air in the pore space compared to unheated contaminated soil. This approach may be effective for the treatment of soil in Thailand using an RF heating system with dual electrode plates.

This research investigated the effectiveness of radio frequency (RF) heating as a treatment for lead-contaminated soil, assessing its impact through dielectric constant measurements. Using water-soluble lead (II) acetate trihydrate, the study analyzed the impact of RF heating on soil dielectric properties under various soil moisture conditions (high, medium, and low) and electric field strengths (112.5, 150, 225, and 450 kV/m). The results indicated that soil temperature increased with lead concentration, highlighting significant changes in soil thermodynamics. Under high-humidity conditions, temperature increases were more pronounced, suggesting that higher lead concentrations elevate soil temperatures. Moreover, RF heating consistently reduced the dielectric constant as lead concentration increased, which was especially evident at higher electric field strengths. The study found that the soil resistivity approached that of uncontaminated soil, particularly at 450 kV/m electric field strength, with the highest removal rate of 46.154%. This investigation provides valuable insights into the application of RF heating for soil quality improvement in lead-contaminated environments, demonstrating how dielectric properties can reflect those of uncontaminated soil.

This study investigates the potential of Plasma-Activated Water (PAW) technology for the production of nitrate fertilizer, focusing on the dielectric properties of plasma-treated water, such as the dielectric constant and dielectric loss factor. The research aims to elucidate the impact of plasma treatment and varying water flow rates on these properties. An experimental approach was employed wherein ion-free water was subjected to plasma treatment at different flow rates (0.5, 1.0, and 2.0 L/min) and durations (1, 2, and 3 h). The results reveal a marked enhancement in the dielectric properties of the water following plasma treatment, with the most significant improvements observed at a flow rate of 0.5 L per minute and a treatment duration of 3 h, and dielectric efficiencies of 97.82%, 97.21%, and 96.61% achieved at flow rates of 0.5, 1.0, and 2.0 L/min, respectively. These findings demonstrate that PAW technology enhances the efficiency of nitrate fertilizer production by optimizing energy storage and reducing energy losses. The study underscores the potential of PAW as a sustainable, environmentally benign alternative to conventional chemical fertilizers, contributing to more efficient and sustainable agricultural practices.

Rapid and reliable detection of pesticide residues in vegetables is essential for food safety and sustainable agriculture. This work presents a four-port closed-loop ring resonator (CLRR) sensor for quantitative detection of carbamate residues in leafy vegetables. Operating through the S₃₁ transmission path, the sensor enhances electric-field coupling and sensing resolution in the high-field region. Four resonance modes were identified at 1.05, 2.10, 3.12, and 4.11 GHz, with the third mode (3.12 GHz) showing the most stable and linear response. Vegetable extracts of Chinese kale and Choy sum were prepared with carbamate concentrations of 0–8% (w/v). Increasing concentration caused a red-shift in resonance frequency corresponding to a reduction in dielectric constant. Regression analysis revealed a strong linear correlation between frequency shift and concentration (R² = 0.9855–0.9988). The CLRR achieved average normalized sensitivities of 6.39% and 6.54% per unit dielectric variation, outperforming most planar and metamaterial sensors. Fabricated on a single-layer FR-4 substrate, the sensor combines high sensitivity, low cost, and excellent repeatability, offering a practical, label-free, non-destructive tool for on-site monitoring of pesticide contamination in leafy vegetables.

Liver fluke infections, especially those induced by Opisthorchis viverrini, pose considerable health and economic difficulties in aquaculture, particularly in Southeast Asia. Traditional approaches for parasite elimination, including chemical treatments and freezing, exhibit constraints regarding efficacy, environmental sustainability, and practicality. This research investigates an improved dielectric heating system utilizing a 2.45 GHz horn antenna for the selective thermal targeting of parasite-associated regions in Cirrhinus microlepis (small-scale mud carp). The dielectric characteristics of fish tissues, encompassing scales, skin, and muscle, were analyzed utilizing an open-ended coaxial probe technique. Simulation and experimental evaluations were performed to improve energy absorption, heating uniformity, and a particular absorption rate to enable precise thermal localization while preserving the integrity of fish tissue. The findings demonstrate that dielectric heating can specifically elevate the temperature of fish scales, where parasites predominantly inhabit, to levels beyond 70 degrees Celsius, while reducing thermal impact on the underlying muscle tissue. The application of a salt coating on fish scales markedly increased their dielectric loss, exceeding that of muscle tissue, thus enhancing selective heating efficiency and supporting targeted thermal treatment. The ideal distance from the antenna to the sample was established as ranging from 6 to 9 cm, ensuring a balance between energy efficiency and homogeneous heating. This work illustrates the efficacy of dielectric heating as a novel and non-chemical approach for thermal management of parasite-prone tissues in aquaculture, providing a sustainable and viable substitute for traditional treatments.