Performance comparison of a symmetrical folded dipole antenna for mobile terminals and its metal bezel extension

This paper studies the performance of a symmetrical folded dipole antenna for mobile terminals and compares the results to a metal bezel antenna. The symmetrical folded dipole is an antenna structure where two folded dipoles are implemented against each other as a mirror image to create a magnetic boundary condition between the dipoles. The metal bezel presented in this paper is an extension of the symmetrical folded dipole with a ground plane extended in width and bent up on both sides. The metal bezel structure is considered here as an antenna closer to a practical implementation. The excitations and the impedance matching of the symmetrical folded dipole and the metal bezel are implemented by using cascaded LC-baluns. The method is offering equal amplitude and phase for both RF-sources used in one antenna structure. The values of the discrete components in the implemented LC-baluns are presented in table form as well. The paper compares the two aforementioned antenna structures in terms of measured impedance matching, measured total efficiency, measured radiation patterns, and measured SAR-values.