W-shaped slot-loaded U-shaped low SAR patch antenna for microwave-based malignant tissue detection system

This paper describes a wideband W-shaped slot-loaded solid U-shaped rectangular patch antenna for a microwave-based head imaging application. The proposed antenna comprises a W-shaped slot-loaded solid U-shaped radiating patch and a slotted partial ground. Slots have been used to enhance efficiency, current distribution, gain, and other antenna performances. At its first resonance frequency of 1.6 GHz, the optimized electrical dimension is 0.197λ × 0.298λ × 0.085λ. The antenna is printed on a low-cost 1.6 mm-thick FR4 substrate. The antenna feeds with a 50 Ω transmission line. The assessed findings demonstrated that the stated prototype has a 1.12 GHz (1.40 - 2.52 GHz) bandwidth along with omnidirectional radiation properties. The prototype achieved a maximum gain of 3.5 dBi at 2.44 GHz and provided a maximum radiation efficiency of 95% with stable radiation characteristics. The face-to-face alignment fidelity factor (FF) is also determined to evaluate time-domain responses above 80%. Near field directivity (NFD) is also analyzed with a head model to ensure near field radiation characteristics. The SAR value reaches a < 0.3 W/kg limit over the active bandwidth. Finally, in a CST simulation platform, an array configuration with nine antenna elements is deployed in a circular arrangement around the head phantom to collect the scattered data for tumor object characterization.