A theoretical analysis to reduce the human body effect on wearable PIFAs performance

The robustness of wearable UHF-band grounded antennas with respect to body-coupling effects is addressed through numerical investigations. Main goal is gaining physical insights on the relationship between the grounded antenna performance and the distribution of the electric and magnetic energy densities in the antenna near-field region close to the ground plane border. Two UHF Planar Inverted-F Antennas suggested in the open scientific literature for the implementation of Radio Frequency Identification (RFID) transponders and off-body communication systems, have here been considered as examples for the investigation. A criterion for choosing a proper shape of the antenna ground plane is specified, which can increase the antenna robustness with respect to the body-coupling effects, but with a minimal impact on the antenna size.