Compact ultra-wideband diversity antenna with a floating parasitic digitated decoupling structure

A compact planar ultra-wideband (UWB) multiple-input-multiple-output antenna array with two radiating elements is proposed in this work. Elements separation is kept at 5.5 mm and the isolation is achieved with a floating parasitic decoupling structure not known for UWB diversity antennas previously. The antenna system performs very well over the entire UWB frequency range of 3.1-10.6 GHz. The mutual coupling between the radiating elements is below -20 dB in most of the band. The decoupling structure is investigated in detail and the diversity analysis of the antenna in Rayleigh fading environment for indoor and outdoor propagations is also presented by computing envelope correlation coefficients. The proposed antenna array measures 33 x 45.5 mm(2) only and it is suitable for handheld devices, personal digital assistant (PDA)s, next generation home entertainment systems and robots.