Small planar UWB antennas in proximity of human head

The effects of a human head on the performance of a small planar ultra-wideband (UWB) antenna in proximity of the head are investigated. A numerical head model developed by REMCOM is used in the XFDTD software package in the study, where the frequency-dependent dielectric constant and conductivity are obtained from the average data of anatomical human heads. A planar antenna printed on a PCB is designed to cover the broad impedance bandwidth of 3.2 GHz - 12 GHz. The impedance and radiation performance of the planar antenna is examined when the antenna is placed very close to the human head. The study has shown that the effect of the human head on the impedance performance of the antenna is slight. The radiated field distribution and gain of the antenna have shown that the human head significantly blocks the radiation from the antenna so that the radiation patterns are directional in the horizontal plane and the average gain greatly decreases. This information will be helpful to the engineers who are applying UWB devices around/above human heads.