Eight-element UWB-MIMO array with three distinct isolation mechanisms

An eight-element multiple-input-multiple-output (MIMO) antenna array for ultra-wideband (UWB) communication is reported. The proposed array contains eight antenna elements having annular ring slots in the middle of each element and tapered feed lines for impedance matching. The defected ground planes are introduced on the back of these antenna elements. Moreover, closed-loop frequency selective surfaces are introduced to achieve enhanced isolation between antenna pairs. A quad-strip connected circular arc decoupling structure is also used to enhance the isolation among particular antenna elements. These decoupling structures provide isolation of 20 dB over most of the desired UWB spectrum. The proposed UWB-MIMO array has dimensions of 60 × 93 mm². The proposed design is suitable for integration with system-in-package applications and provides ease of connectivity on all four sides.