Design and Optimization of an UWB Monopole Antenna with a Two-Branch Feeding Strip for Brain Stroke Detection

An ultra-wideband (UWB) monopole antenna excited by a two-branch feeding strip is proposed for detecting both types of human brain stroke called hemorrhagic stroke and ischemic stroke. With the proposed feeding strip, the antenna achieves an ultra-wide impedance bandwidth of 3.85 GHz which is nearly twice the bandwidth obtained with a simple feeding strip. The operating frequency of the antenna lies in the range between 3.08 GHz and 6.93 GHz. Besides, a gain of 2.05 dB and a radiation efficiency of 78.76 % are obtained. The proposed antenna possesses a compact dimension of 30×20×1.5 mm
³
. The antenna is designed on a 1.5 mm thick Rogers RO3003 dielectric substrate having a relative permittivity of 3 as it is suitable for high frequency applications. Furthermore, a six-layer human head phantom model consisting of skin, fat, bone, dura, cerebrospinal fluid (CSF) and brain is proposed in which a hemorrhagic stroke and an ischemic stroke of 5 mm radius is individually inserted for assessing antenna performance. The safety level of specific absorption rate (SAR) is retained in each case to avoid health risk. The detection of hemorrhagic stroke is confirmed with an excess of current density and SAR while ischemic stroke with a deficit of current density compared to the healthy brain.