Polarization-Agile Antenna for Physiological Radar Monitoring Systems

In Doppler radar systems for human respiratory motion measurement, the change in wave polarization after reflection can be critical. In this contribution, a polarization-agile antenna based on a cavity-back slot fed by stripline is proposed to improve the experimental setup to investigate polarimetric effects in such measurements. The antenna consists of a series-fed sequentially-rotated array of four elements terminated in two ports. In this way, it is demonstrated that both right-handed and left-handed circular polarizations can be received and, by combination of both, arbitrary polarization can be obtained.