Broadband Disposable Biosensors Based on Dielectric Waveguide Ring Resonators

This paper presents a broadband, 3D-printed disposable biosensor based on a dielectric waveguide ring resonator (DWGR) fabricated from high-impact polystyrene (HIPS). The sensor is specifically designed to quantify trace amounts of water in oil, a critical indicator of fluid degradation and maintenance requirements. The sensor operates in the D-Band in a frequency range of 110-170 GHz, and is designed for high-precision permittivity sensing. Key design and post-processing steps are shown, including a resonance-minima extraction framework enabling accurate material characterization. A proof of concept is presented using a vector network analyzer (VNA). After this further measurements confirming the accurate detection of known reference materials are presented. Furthermore, the sensor’s capability to detect oil degradation through water contamination is also demonstrated. Overall, the proposed approach enables high-resolution permittivity sensing over a broad frequency range and represents promising results for future disposable fluid condition monitoring.