Precision Sensing at Selected Spectrum: A Double-Negative Low-Cost Metamaterial Sensor With Enhanced Directionality for Biomedical Applications

This paper presents a novel, low-cost, compact sensor that integrates a double-negative (DNG) metamaterial with an artificial magnetic conductor (AMC)-backed microstrip patch antenna, specifically optimized for high-precision biomedical applications in the 2–4 GHz range. Unlike prior designs, the proposed sensor leverages the simultaneous negative permittivity and permeability of the DNG structure together with the AMC layer to achieve enhanced gain, directionality, and sensitivity—key performance factors for GHz-range diagnostics. Fabricated on a cost-effective FR4 substrate with a compact footprint of 50 × 50 mm², the sensor is well-suited for scalable, real-world deployment. Full-wave simulations confirm negative refractive index characteristics within the 2.0–2.7 GHz band, and a peak gain of 7.6 dBi is achieved, surpassing comparable designs. Experimental validation in an anechoic chamber shows excellent agreement with simulation results. Benchmarking demonstrates that the sensor outperforms state-of-the-art counterparts in gain, size, and directional response. These features make it a strong candidate for biomedical applications such as wearable health monitoring, portable medical imaging, and non-invasive diagnostics including early-stage brain abnormality detection.