Through-the-wall Imagery of Human Vital Signs Using UWB MIMO Bioradar

Bioradar is an emerging concept for noncontact detection of human vital signs. In through-the-wall human imaging, ambiguities in wall parameters (thickness and dielectric constant) will degrade the focusing quality of vital signs and then signal-to-clutter ratio (SCR) of vital signs will deteriorate. In order to calibrate the influence of wall on imaging, a propagation model of electromagnetic waves for multiple-input and multiple-output (MIMO) bioradar is built and the electrical length of the transmitting path and the receiving path are respectively computed. And then, an autofocusing method is proposed. Different from the traditional autofocusing procedure, the focusing quality of imagery after change detection is evaluated to guarantee the imaging quality of vital signs. Simulated results show that the proposed method can estimate the wall parameters and effectively improve the focusing performance of human vital signs.