Ambiguity analysis of isolation - based multi-antenna structures on mobile terminal

This paper presents a comprehensive numerical study on the ambiguities for different isolation-based multi-antenna structures. The focus is on four-element planar inverted-F antennas (PIFA) array on a typical 100mm × 40mm mobile terminal chassis operating at 3500 MHz. The study is conducted by taking into account the effects of antenna isolation, mutual coupling between mobile terminal chassis and antenna element, and mutual coupling among antenna elements. The results show that the studied multi-antenna structures with low-isolation level, i.e. when there exist high mutual coupling among antenna elements, are less ambiguous. With such observations, a novel eight-element PIFA array has been designed for radio direction finding (RDF) applications on a mobile terminal.