Five-element inverted-F antenna array for MIMO communications and radio direction finding on mobile terminal

A five-element inverted-F antenna array on mobile terminal for both multiple input multiple output (MIMO) communications and radio direction finding (RDF) applications is presented. The multi-element antenna (MEA) system has been designed to be used in the frequency band of the future Long Term Evolution (LTE) system at 3400-3600 MHz and integrated along the edges of the upper ground plane of a clamshell type mobile terminal. Without using any specific multi-antenna isolation techniques, the antennas have been optimized to have acceptable mutual coupling and small envelope correlation in order to provide enhanced capacity with multiple input multiple output (MIMO) techniques. The ambiguities of the proposed design in RDF applications have also been investigated. A prototype has been fabricated and tested. Good agreement between numerical simulations and experimental results has validated the antenna concept.