Breath activity monitoring by means of a UWB radar with automatic range detection

A ultra-wideband (UWB) radar with automatic range detection for breath activity monitoring is presented. The radar has been designed in hybrid technology that allows a compact and cheap realization. The radiofrequency part of the radar is based on step recovery and Schottky diodes. A varactor controlled delay line has been implemented in the low frequency section. The radar operation is regulated by a microcontroller based on a 32 bit ARM Cortex-M4 architecture. Preliminary results indicate that the proposed radar is able to track the thorax wall and to monitor its movements for distances between 15 cm and 150 cm.