Mitigation of the finger loading effect in handset antennas

Abstract

The effect of the human body over the radiation of handset antennas is a critical issue that have to be considered to ensure a good handset antenna performance. Among the human body effect, the finger is of particular interest since it is usually placed over the antenna area which may cause detuning and/or reduction of the efficiency. To mitigate the finger loading effects, a novel handset antenna consisting of two small antennas distributed along the ground plane is proposed. The distributed antenna system is compared with a single antenna having a broadband matching network, so both designs feature enough bandwidth to cover the GSM850 (824-890MHz) and GSM900 (880-960MHz) communication systems. The finger effect is analyzed in terms of efficiency using a phantom hand. Efficiency is measured for different finger locations concluding that the distributed antenna system is more robust to the finger loading effect.