Vivaldi Antipodal Slotted Antennas Design for Brain Anomaly Detection Systems

The use of antennas in brain anomaly detection systems has been one of the most researched areas in recent years, yielding significant results and providing more accessible and less expensive portable equipment. Also, current proposals for integrated sensing and communications systems (ISAC) aim to simultaneously use spectrum for communications and sensing of the biological and environmental surroundings. At the same time, brain sensing systems use wide bandwidths to detect anomalies with higher resolution and hence accuracy. This poses the challenge of determining the most suitable antenna whose characteristics allow its implementation in sensing systems, featuring small size, unidirectional radiation and wide spectral performance to provide better sensing of the medium under test (MUT). In this paper, four Antipodal Vivaldi Antenna (AVA) designs are proposed, with increasing complexity aimed at reducing their size and optimizing their performance through techniques such as dielectric lens and slot aggregation. Measurements were performed on a phantom with permittivity values and anomalies associated with brain tissue, highlighting the antenna's ability to detect changes in the MUT spectrum. The results mainly highlight the sensors' performance for viable use in brain anomaly detection and sensing systems, demonstrating a maximum unidirectional gain of up to 11.8 dBi, wide operating frequency ranges of up to 10 GHz and miniaturised sizes of up to 45 mm x 38 mm.