Enhancing Ammoniacal Nitrogen Detection in Water Quality Applications Using Complementary Split-Ring Resonators: A Comparison Between Rectangular and Circular Configurations

This study investigates the sensitivity enhancement of Complementary Split-Ring Resonators (CSRR) for detecting ammoniacal nitrogen (NH3-N) in water quality applications. Detecting NH3-N at low concentrations is critical for water quality monitoring, necessitating the development of highly sensitive NH3-N sensors. A comparative analysis was performed on the performance of circular and rectangular single-ring CSRRs. These resonators were designed on an FR-4 substrate with a resonant frequency of 2.4 GHz, a relative permittivity of 4.4, and a dielectric constant of 4.3. The evaluation involved analyzing the S-parameters' responses for both CSRR configurations under unloaded and NH3-N loaded conditions. The measurement results indicated that the circular single-ring CSRR exhibited a higher quality factor compared to the rectangular counterpart. Moreover, the circular single-ring CSRR demonstrated superior sensitivity in detecting NH3-N. These findings lay the groundwork for the development of highly sensitive sensors, essential for safeguarding water resources and ensuring water quality across various applications, including environmental monitoring and public health.