مشخصات پژوهش

This paper presents a novel single-port microwave sensor designed for measuring glucose concentration in distilled water and saline solutions. The sensor was built on an FR4 substrate and incorporates an interdigital capacitor along with complementary split-ring resonators in a tank circuit configuration. The single-port sensor operates by canceling the reflection signal from the open end of the circuit using the input signal. At the sensing frequency band, the inherent losses within the sensor play a significant role in absorbing the input power. To achieve the highest possible quality factor, which impacts the sensitivity of the sensor, it is essential to avoid any additional sources of loss, such as termination loss. Furthermore, the sensor may be designed to fully absorb the input power through the inherent loss mechanism, resulting in minimal reflection power detected at the input. Simulation-based optimizations using COMSOL and MATLAB with a genetic algorithm were conducted to achieve an optimal dip null within the 1.6 GHz to 1.8 GHz range. Experimental results confirmed consistent resonance frequency shifts with varying glucose concentrations, demonstrating strong linear relationships and high correlation coefficients. These results validate the accuracy of the sensor for glucose detection. This study emphasizes the performance of single-port sensors, potentially paving the way for cost-effective microwave sensors in biomedical and industrial applications.