UWB Transmission through Human Thorax behind a Wall for Non-Invasive Cardiac Detection

The existing methods followed in several applications such as criminal investigation, defense and military usage, search and rescue activities, remote healthcare etc. are derived from the observation of the health of the heart of human beings. But they are mostly invasive as they are contact based. In the context of the above applications, the commonly employed non-invasive methods using continuous-wave (CW) Doppler radars for detection of heartbeat of the subject suffer from several limitations. The use of ultra-wideband (UWB) radars are able to overcome the limitations of the Doppler radars in detecting human heartbeat. Modeling and analysis of the UWB propagation through a human body present behind a wall is essential prior to the development of a real UWB radar. In this paper, models for UWB transmission through human thorax behind a wall made up of (i) brick and (ii) solid concrete are presented. The analysis is performed from the simulations using CST Microwave Studio (MWS) in the UWB range of 1-4 GHz. The study indicates that the transmission characteristics are related to the instantaneous sizes of the heart.