Log-periodic dipole array-based MIMO antenna for the mobile handsets

A novel design of multiple input-multiple output (MIMO) antenna based on the log-periodic dipole array (LPDA) for the mobile handsets is presented. The antenna operates in a wide frequency range of 1.86-3.84GHz compatible with GSM, LTE, WLAN, and WiMAX. The MIMO design consists of two symmetrical and orthogonal radiating elements and a neutralization line (NL). The radiating element comprises a LPDA having a series of printed dipoles connected together with a microstrip line. Triangular and rectangular cuts on ground plane are carried out in accordance with the LPDAs so as to increase the impedance bandwidth and isolation. The antenna elements are linked with the NL to further enhance the isolation between the radiating elements. The performance of the MIMO antenna is analyzed in terms of S-parameters, radiation pattern, gain, total efficiency, envelope correlation coefficient, mean effective gain, multiplexing efficiency; and then it is verified through the measurements. The results demonstrate that the proposed MIMO antenna has good characteristics of wideband, gain, radiation pattern, isolation, and diversity.