Decoupled Dual-Antenna System Using Crossed Neutralization Lines for LTE/WWAN Smartphone Applications

A decoupled dual-antenna system for Long Term Evolution (LTE)/Wireless Wide Area Network (WWAN) smartphone applications is presented. The proposed dual-antenna system is composed of two symmetric antenna elements and two crossed neutralization lines. The antenna element of the proposed dual-antenna system consists of a driven branch and a parasitic ground branch, generating a couple of resonant modes. The dual-antenna system incorporates two crossed neutralization lines to reduce the mutual coupling between the two closely spaced antenna elements. A measured impedance bandwidth with S11 lower than -6 dB over 702-968, 1698-2216, and 2264-3000 MHz is obtained. Within the operating bands, the measured S21 is lower than 10 dB. Based on the measured 3-D radiation patterns, several important figures of merit for the diversity performance of the dual-antenna system are calculated, including the envelop correlation coefficient, the mean effective gain, and the diversity gain, and good results are obtained.