Microwave Imaging Systems for Tumor Detection: A Comprehensive Review of Antenna Designs and Imaging Algorithms.

In the past decade, microwave imaging (MWI), employing advanced antenna-based systems, has emerged as a cutting-edge, non-invasive approach for pathological diagnosis. Multiple experimental studies suggest that MWI proposes promising results for early-stage tumor diagnosis. Recent studies on MWI show the importance of antenna types and configuration. However, it is observed that a very limited research has focused on exploring the large classes of antennas used in detail. In this review, a systematic study and firsthand classification of the antennas used, as the most important aspect of an MWI system, is proposed. The classification includes fundamental antennas, microstrip antennas, metamaterial/metastructure antennas, specialized antennas, and 3D antennas. A cross-sectional study is performed to depict the potential relationship between antenna type and efficiency of the MWI systems. This goal is achieved by quantitatively analyzing the gain and operating bandwidth, antenna configuration, and application models. Further, a critical analysis is presented on different signal processing and imaging algorithms for synthetic image generation. This review presents a modular analysis of MWI systems and draws several conclusions on the effectiveness of each essential module for a reliable MWI system. It also addresses the challenges, scope of improvement in the MWI systems, and prospects for the technology's integration into clinical practice.