UWB textile slotted patch metamaterial antenna sensor for real-time breath monitoring

Abstract Through the Health Monitoring System (HMS), Wireless Body Area Network (WBAN) improves the quality of life. Many researchers have conducted numerous studies on the use of antennas in HMS. Several research studies proposed using an Ultrawideband (UWB) antenna sensor to monitor a patient’s health. However, each study has limitations such as narrower bandwidth (which does not cover the entire UWB frequency spectrum), lower gain which is below 4 dBi, and low flexibility, which will cause distraction for data sensing and may result in delayed data transmission. In this paper, a numerical model of a UWB textile slotted patch metamaterial antenna sensor based on Computer Simulation Technology (CST) Microwave Studio simulations is presented, as well as the result where the proposed antenna is able to achieve operating bandwidth within the range of 3.7 to 9.7 GHz with realized gain of 8.49 dBi. In addition, the radiation efficiency is more than 70%, and the bandwidth enhancement of 6 GHz is achieved. Besides, the proposed antenna sensor is also evaluated for its flat and bending conditions when placed on the body in terms of bandwidth, radiation efficiency, realized gain, and radiation pattern. In HMS, a flexible antenna is necessary for bending conditions when the antenna is positioned on the body. This research also discusses how advanced wearable antenna sensors serve critical roles in HMS, particularly in Real-Time Breathing Monitoring (RTBM). The proposed antenna sensor is able to detect and differentiate various breathing patterns, including eupnea, apnea, hypopnea, and hypernea, based on the frequency shifting technique of reflection coefficient (S11) parameters.