Dual-polarization and dual-pattern planar antenna for diversity in body-centric communications

A planar three-port annular-ring slot antenna has been described. The antenna has been designed to operate at 5.725-5.825 GHz (a IEEE 802.11a frequency band). Port 1 is associated with a dipole-like radiation pattern whose radiated field is perpendicular to the antenna plane. Port 2 and 3 both radiate a broadside radiation pattern, with two orthogonal linearly polarized electric fields. The annular ring slot antenna can be useful for the implementation of a pattern/polarization receiving diversity scheme in on-body and off-body communication systems. Diversity gain measurements in both an anechoic chamber and an actual indoor environment are being performed, for different body positions and typical body movements, as already done, for a spatial diversity scheme. The most significant results of the measurement campaign will be shown at the conference. Finally, work is in progress to get a more compact layout of the slot-ring antenna, which is needed if it has to be designed for working at the 2.4-2.48 GHz frequency band.