Reducing the interaction between user and mobile terminal antenna based on antenna shielding

Reducing the effect of the hand and the head of a user on the operation of mobile terminal antennas is investigated with simulations and measurements. The study is made at 900 and 2000 MHz. The shielded antenna structure consists of two antenna elements. Non-self-resonant antenna elements are required to obtain an improved antenna performance. Depending on the use position, the better-performing antenna element is selected and the other is acting as a shield. It is shown that the proposed structure can improve the total efficiency with hand and head by 5.0 dB and decrease the maximum specific absorption rate (SAR) in the head by 81% at 900 MHz compared to the traditional single element structure. At 2000 MHz, the benefits are 2.1 dB and 43%, respectively. The shielding structure can be used also to significantly decrease the SAR in the hand.