Design of a MIMO antenna with low ECC for a 4G mobile terminal

Abstract

A MIMO antenna with low ECC is proposed for a 4G mobile terminal. Apart from the resonant mode induced by the ordinary antenna element, an additional resonant mode is generated when the double ground planes (upper and lower grounds) in the mobile terminal are excited and operate as a radiator. By combining the resonances contributed from both the antenna element and the ground plane, the proposed MIMO antenna realizes wideband over LTE band 13. An inductive coil is used to reduce the antenna volume. Moreover, the proposed MIMO antenna has an excellent ECC value below 0.1 due to the nearly orthogonal radiation patterns from different antenna elements. In addition to the MIMO system for LTE band 13, an additional antenna element is adopted to cover 2-2.7 GHz band. Finally, we suggest a general guideline for designing a small MIMO system with improved ECC and isolation.