Design and experimental validation of a low-SAR compact UWB antenna for early breast tumor detection

Abstract

Abstract This paper presents the design, analysis, and experimental validation of a compact ultra-wideband antenna intended for microwave breast cancer imaging applications. The proposed antenna employs a modified radiating patch integrated with a partially defected ground structure and vertical slot loading to enhance bandwidth, radiation efficiency, and near-field radiation control. The antenna achieves a wide impedance bandwidth ranging from 3.03GHz to 11.24 GHz while maintaining a compact footprint of 30× 28 mm 2 . Stable radiation characteristics, high efficiency of 85.5%, and a peak gain of 5.47 dBi are obtained across the operating band. To evaluate biomedical safety performance, specific absorption rate (SAR) analysis is conducted using a multilayer breast phantom model. The proposed antenna demonstrates ultra-low SAR levels across the operating bandwidth, which are significantly below international safety limits. Microwave imaging capability is investigated through S -parameter-based tumor detection using hemispherical multilayer breast phantoms incorporating small tumor inclusions with diameters representative of early-stage cancer detection. The results demonstrate clear electromagnetic sensitivity to tumor presence while maintaining safe interaction with biological tissues. The proposed antenna is further validated through fabrication and measurement, showing good agreement between simulated and experimental results. Owing to its compact size, high efficiency, wide bandwidth, and superior safety performance, the proposed design represents a promising candidate for integration into microwave breast imaging systems.