Design of a Planar Microstrip Multi-Input Multi-Output Antenna for LTE Applications

A compact multiple-input–multiple-output (MIMO) antenna is presented for Long Term Evolution (LTE) applications. The antenna consists of a common square patch for ports and two ground plane with two separated microstrip feed lines. The antenna feed lines are placed perpendicularly to each other to obtain high isolation, and a T-shaped slot is added to reduce the mutual coupling of antenna elements in the operating frequency band. In this design two L-shaped radiator-elements are used for exiting two resonance frequencies that have connected to the patch by two metalized vias.  The proposed MIMO antenna has a compact size of 38×37.5 mm, and the antenna prototype is fabricated and measured. The measured results show that the proposed antenna design achieves an impedance bandwidth of larger than 1.92–2.67 GHz for port-1 and 1.69-2.96 GHz for port-2, low mutual coupling of less than 10 dB, and a low envelope correlation coefficient across the frequency band, which are suitable for portable LTE applications.