DNG Metamaterial-Inspired Slotted Stub Antenna With Enhanced Gain, Efficiency, and Distributed Current for Early Stage Bone Fracture Detection Applications

This article focuses on the computational design, prototype development, and experimental validation of a compact microwave antenna for orthopedic applications in biomedical regimes. The unique resonant structure comprises an embedded double negative (DNG) metamaterial (MTM)-inspired slotted stub, designed and simulated in the CST Microwave studio (MWS) environment, as well as verified through simulation in advanced design systems (ADS) software. This adaptation of the design technique improves the antenna’s performance, as demonstrated in the design and result analysis section of the research paper, which includes experimental comparison results from previously developed antenna prototypes. To make the design suitable for rapid industry prototyping, Rogers RT5880 substrates have been used with a standard substrate height of 0.79 mm (loss tangent of 0.009 and dielectric constant of 2.2). However, the antenna’s effectiveness was also compared with other commercially available variations of Rogers RT5880 substrate material (0.508, 4.575, and 3.175 mm) while transmitting the input power into the electromagnetic wave. Antenna performance for measuring bone tissue penetration was checked, and a gain of 3.5 dB and a distributed surface current value of 295 A/m were found to be satisfactory for the early stage bone fracture diagnosis application. The measured radiating efficiency was 97.5%. The far-field experimental measurements show an omnidirectional radiation pattern and a well-performed return loss well below −10 dB in the operating region of 3.8–4.8 GHz. During simulation, the stacked bone phantom environment’s operational characteristics demonstrated satisfactory gain, directivity, and efficiency performance, which are also compared in this research analysis.