Circularly polarized flexible antennas for near field breast cancer sensing in a smart bra monitoring system

This paper is developing a wearable device for breast cancer detection using four elements of circularly polarized (CP) sensors. The proposed CP sensors are integrated as a smart bra to provide a wearable breast cancer detection system. The proposed antenna-based sensor consists of a flexible Roger 3003 substrate with a thickness of 0.17 mm, an etched trapezoidal slot, and a CPW trapezoidal-shaped monopole antenna with an overall compact size of as 0.2 λ_o × 0.2 λ_o m². The proposed sensors provide conformal construction for biological structures and biocompatibility and sufficiently extended bandwidth from 1.8 to 8 GHz at |S₁₁| ≤ −10 dB. To guarantee safety, the specific absorption rate (SAR) of 0.789 W/kg at 20 dBm and 5.8 GHz has been computed and measured for the proposed sensor. CP sensors provide significant advantages in near-field applications compared to linear polarized sensors validated by fidelity parameter calculation and image construction for proposed sensors for image reconstruction applications. This paper also includes an analysis of bending, SAR, and heat effects. Measurements for transmission and reflection parameters without and with tumors at different positions in breast phantom are also recorded and presented