Compact dual-resonator loaded band-notched MIMO antenna with high frequency selectivity and controllable bandwidth

In this paper, a compact dual-resonator loaded ultra-wideband (UWB) multiple-input-multiple-output (MIMO) antenna, which has a bandstop-filter-like response (second-order rejection band) with high frequency selectivity and controllable bandwidth at the aimed notched band, is proposed. The MIMO antenna consists of two rectangular printed monopole (PM) elements and a simple stepped ground stub to enhance wideband isolation. Compared with the traditional first-order band-rejected UWB MIMO antenna, the selectivity and bandwidth-controllability of the rejected band is greatly improved and its size is dramatically decreased to 32×26×0.8mm3 on a cost-effective FR4 substrate. The results of simulation and measurement prove a bandwidth of S11 <; -10 dB and S12 <; -15 dB at 3 GHz-12 GHz excluding the rejection band of 5 GHz-5.95 GHz. Hence, it is a good candidate for wireless portable UWB MIMO applications.