A study on the ground plane size for a balanced-fed dual-band antenna fabricated in a multi-layer dielectric substrate

Recently, smart phones have received increasing attention and have become equipped with several high-speed wireless systems. A built-in antenna is often placed in proximity to the printed circuit board that has several metallic electrical parts and a ground plane. The radiation characteristics of a built-in antenna are influenced by the physical shape of the ground plane, and assessing the influence is important to maximize the performance of a mobile terminal. Thus, a balanced-fed dual-band antenna was proposed, to reduce the undesired RF current along the ground plane and to contribute to stable operations. The focus of this paper is to describe the effects of the ground plane size on the radiation characteristics of a shrink balanced-fed dual-band antenna embedded in a multi-layer dielectric substrate, which is designed to reduce the required size of both the antenna and the ground plane while maintaining the stable operation of the antenna system.