Physics-based propagation characterisations of UWB signals for the urine detection in human bladder.

In this paper, an IR-UWB radar for the detection of water accumulation in human bladder is presented. The goal is to monitor the level of urine in patients who suffer from urinary incontinence. This is achieved by detecting the reflected UWB signals from the boundaries of human tissues such as muscle and bladder. However, the detection ability of the UWB radar system is strongly impaired due to the high attenuation and frequency dispersion of the UWB signal in human tissues. Based on the dielectric properties of the various human tissues, the physics-based propagation characterisations of electromagnetic waves are investigated with respect to their reflection, attenuation and transmission. A model of human bladder with different tissue layers including frequency dependent dielectric properties is proposed. Furthermore, a system concept of UWB radar for the detection of water accumulation in human bladder is introduced. The UWB pulse attenuation and distortion in different human tissues are investigated and evaluated with respect to the system performance. The results show the potential of detection of urine in the human bladder, which may lead to development of new non-invasive sensors locating water accumulations in human body.