A Compact Quad Element Slotted Ground Wideband Antenna for MIMO Applications

A compact planar quad element wideband antenna for multiple-input-multiple-output (MIMO) system is proposed in this communication. A single element consists of a partially grounded printed monopole antenna loaded with a split ring resonator. The bandwidth of the antenna is from 2.2 to 6.28 GHz (96.2%), which covers LTE (2.2-3.8 GHz), Bluetooth (2.4 GHz), WLAN (2.4 and 5.1-5.8 GHz), WiMAX (2.3-5.7 GHz), and ISM bands (2.4/5.2/5.8 GHz). The fabricated antenna has an isolation greater than 14 dB between its elements, with a peak gain of 4 dBi and a peak efficiency of 91%. Polarization diversity is employed to accommodate four elements in an FR4 substrate, with an overall dimension of 0.33λ × 0.33λ × 0.01λ. The antenna has a simple planar design which is easy to fabricate with no intricate process involved.