Decoupled Hepta-Band Antenna Array for WWAN/LTE Smartphone Applications

A wideband antenna array incorporating a neutralization line (NL) for port decoupling for smartphone applications is proposed. The U-shape NL is employed to achieve enhanced isolations for the lower band, which are better than 10 dB for 824-960 MHz. The mechanism of the NL is explained based on the S-parameters and the surface current distributions. In addition, the incorporated NL has acceptable effects on the bandwidth, while a bandstop filter and on-ground slots are utilized to realize the hepta-band coverage, covering the GSM850/900/1800/1900/UMTS/LTE2300/2500 operation. A prototype is fabricated and tested, with S-parameters, radiation efficiencies, radiation patterns, envelope correlation coefficient (ECC), and mean effective gain (MEG) presented.