Design and Optimization of Miniaturized Co-planar Vivaldi Antennas for Enhanced Microwave Imaging in Brain Hemorrhage Detection

This paper presents an innovative design and optimization of a miniaturized coplanar Vivaldi antenna tailored for advanced microwave imaging applications in cerebral hemorrhage detection. Measuring just 80 × 80 × 1 mm³, the antenna integrates novel features such as curved radiating arms, optimized solder pads, and strategically placed metallized vias to address challenges in deep tissue imaging. These enhancements deliver outstanding broadband performance (1.6–8 GHz), exceptional impedance matching with a voltage standing wave ratio (VSWR) consistently below 1.5 in the critical 2–4 GHz range, and a reflection coefficient as low as -45 dB at 4 GHz. Notably, the gain peaks at 9.5 dB at 6.5 GHz, ensuring superior signal penetration and resolution. The innovation extends beyond design, employing ANSYS HFSS simulations and multi-layer cranial models to replicate real biological conditions. Comparative analysis of single, double, and 36-antenna arrays demonstrates the antenna's ability to achieve high-resolution imaging, even in complex tissue environments. Additionally, a novel application of real-time differential imaging and beamforming algorithms, including Delay-And-Sum (DAS) and Delay-Multiply-And-Sum (DMAS), enhances imaging clarity and detection sensitivity. The results show significant improvements in identifying hemorrhagic regions, offering crucial technical advancements for portable, non-invasive diagnostic systems. By combining miniaturization, performance optimization, and application-specific enhancements, this work establishes a transformative foundation for early stroke detection technologies.