Over-the-Air Measurements for Mm-Wave Body-Centric Wireless Communication

A preliminary study of the applicability of mm-waves for future body-centric wireless communication systems is presented. The loss levels associated with body-centric wireless propagation at lower mm-wave frequencies are quantified by over-the-air measurements of a propagation scenario, in which a custom-made human-head phantom is placed between two antennas to obstruct the line of sight. Both passive and active measurements witin the frequency ranges 1–18 GHz and 22–30 GHz, respectively, are presented. The approximate loss levels for the passive measurements were found to be about 10 dB for the vertical polarization and more than 30 dB for the horizontal. The loss variation for the active measurements was high—between 10 and 50 dB, depending on the polarization, antenna aperture separation distance, and degree of obstruction by the phantom.