A multi-band isolation enhanced loaded semi-ring MIMO antenna

Due to the increasing demand of high data throughput and compact size of wireless communication devices, miniaturized multiple-input-multiple-output (MIMO) antennas are highly desirable. In addition, multiband operation is highly desirable for multitasking and covering different wireless standards. This paper presents a two element semi-ring multiband compact MIMO antenna having a total size of 32×42×1.52mm³. The natural high input impedance of the semi-ring is matched using an input lumped capacitance along with double stub matching provided by the inner half ring. The antenna can cover both 1.85GHz and 2.45GHz bands with efficiencies of 43% and 61%, respectively. The isolation at both bands is enhanced using a simple meandered defected ground structure (DGS) and is found to be more than 10dB at both bands.