An Ultra-wideband Tapered Slot Antenna for Medical Microwave Imaging Applications

In Medical Microwave Imaging (MMWI), antenna design and operation are crucial, due to their operation in proximity to the human body. This paper introduces an Ultra-Wideband (UWB) Tapered Slot Antenna (TSA) tailored for MMWI applications. With an ultra-wide operational bandwidth of 1.6 to more than 20GHz, the proposed antenna provides multi-spectral imaging capabilities. Specifically, the 170.37% fractional bandwidth covers the lower microwave frequencies that penetrate deeper anatomical regions, as well as higher resolution frequencies needed to discriminate small tumors and microstructures. This combination facilitates more accurate and reliable detection across a variety of tissue types and body areas. Furthermore, the compact footprint of 0.44λ × 0.36λ at 3GHz allows for flexible, non-intrusive positioning during scanning. Therefore, the proposed antenna is well-suited for portable and lightweight medical imaging devices. The antenna achieves the peak gain of 2.9dBi, providing the sensitivity needed for medical imaging applications. Notably, rather than traditional resistive loading techniques, this design pioneers the use of feed tapering and ground plane shaping for enhanced performance in the lower frequency bands which is essential for deep tissue diagnosis. Through parametric optimization of the radiating geometry, discontinuities have been minimized, enabling smooth lower frequency responses. The incorporation of a tapered feed and curved ground plane further refines the aperture illumination and reduces reflected waves. Comprehensive experiments validate the consistent ultra-wideband operation. This reliability combined with the compact, non-intrusive form factor demonstrates the antenna’s proficiency for portable MMWI systems. The optimized bandwidth, efficiency, and cohesive design make this an attractive solution to advance near-field microwave imaging within cost-effective and accessible medical technologies.