Speaker
Description
Contactless cardiac-related chest micro-motion can be observed through the phase modulation of a reflected continuous-wave radio signal. This paper presents a bistatic software-defined radar prototype implemented with GNU Radio and an Ettus USRP B210. The RF front end uses a fabricated dual-element microstrip patch assembly on 1.8-mm FR-4, with the transmit and receive elements operating near 5.542 and 5.533 GHz, respectively. A 9MHz transmit-receive frequency offset moves the reflected tone away from the direct-conversion DC region and is removed digitally using a frequency-translating FIR filter. The processing chain performs narrowband filtering, decimation, static-clutter suppression, phase extraction, phase unwrapping, relative-displacement conversion, and parallel respiration and cardiac-band analysis. The nominal single-element simulation produced an approximately -17-dB reflection-coefficient minimum near 5.4 GHz, a 6.58-dBi realized gain, and principal-plane 3-dB beamwidths of approximately 82-95 degrees. The paper defines a reproducible experimental protocol using static and controlled-motion targets followed by synchronized human measurements with a PPG or pulse reference. The resulting platform is intended as an open GNU Radio research testbed for micro-motion sensing rather than a clinical diagnostic instrument.
| Talk Length | 15 Minutes |
|---|---|
| Acknowledge | Acknowledge In-Person |