A Wideband Quad-Antenna System for Mobile Terminals

Abstract

A wideband quad-antenna system for mobile terminals is studied. Because a quad-antenna system could consist of two dual-antenna systems, the dual-antenna systems in the open literature are utilized as a fundamental building block. The mutual coupling between them is analyzed, and a decoupling method is adopted. To validate the design, a wideband quad-antenna system, consisting of two symmetry wideband dual-antenna systems and a decoupling element, is fabricated and tested. Its measured ${-}$ 10-dB impedance bandwidth is 1.17 GHz (1.7–2.87 GHz), and measured mutual couplings among the four elements are all below ${-}$ 15 dB at the 1.7–2.74-GHz band. It covers the GSM1800, GSM1900, UMTS, LTE2300, LTE2500, and 2.4-GHz WLAN bands for 2G/3G/4G mobile terminal applications. The radiation patterns are measured. The antenna gains and efficiencies are provided.