A Noninvasive Microwave Imaging System for Breast Tumor Detection Using a High-Gain Vival-di Antenna Array Sensor

This article presents a high-gain, noninvasive Vivaldi antenna array sensor for microwave breast tumor imaging, operating over a wide frequency range of 3.2–7.8 GHz with a compact footprint of $1.2\times 0.9\lambda _{g}$ . The antenna features a simplified microstrip-fed design that achieves a peak gain of 10 dBi while maintaining strong sensitivity in differentiating between healthy and malignant breast tissues. A key innovation of this work is the development of a realistic, biomimetic breast phantom modeled in CST Microwave Studio, whose anatomical shape, closely resembling an actual human breast, has not been previously reported in the literature. Comprehensive performance evaluation includes both simulated and measured S-parameters, along with specific absorption rate (SAR) analysis conducted at multiple tumor locations and sizes. The SAR results reveal significant contrasts between healthy and tumor-embedded regions, validating the sensor’s ability to detect tumors accurately. Additionally, power distribution analysis (PDA) is performed across each layer of the multilayer phantom over the entire operational bandwidth, offering detailed insight into the incident, reflected, and absorbed electromagnetic power. Experimental validation corroborates the simulation outcomes, demonstrating the proposed sensor’s potential for early-stage breast cancer detection through its high gain, broadband operation, and enhanced tissue sensitivity. Finally, a detailed implementation of the confocal microwave imaging (CMI) algorithm is presented, which reconstructs a high-contrast 2-D image that accurately localizes the tumor within the phantom.