Ground Current Modification of Mobile Terminal Antennas and Its Effects

In this letter, a dual-band parasitic radiator is de signed and optimized to modify the current distribution on the ground plane of a handheld terminal. Using a variable-length dual-band parasitic radiator, the ground current distribution is controlled, and low specific absorption rate (SAR) and high radiation efficiency at 900 and 1880 MHz are obtained. The proposed antenna scheme consisting of a dual-band parasitic element and a driven dual-band antenna reduces the peak SAR by 50% and 40% at 900 and 1880 MHz, respectively, compared to a conventional dual-band antenna. Significant increase in radiation efficiency is also obtained.