A Small-Size Ultrawideband MIMO Antenna with Triple Band-Notched Function and High Isolation

In this paper, a small-size ultra-wideband (UWB) multiple-input-multiple-output (MIMO) antenna with triple notched bands and a high isolation, is proposed. Its size is dramatically decreased to 30x26x0.8 mm(3) on a cost-effective FR4 substrate. It consists of two rectangular printed monopole (PM) elements and a simple stepped ground stub to enhance wideband isolation. For two different rejected bands of the wireless local area network (WLANs) covering 5.15-5.35 and 5.725-5.825 GHz, four parasitic C-shaped split-ring resonators (PCSRR) are placed on either side of feed line. By etching two inverted U-shaped slots on the center of radiators, the notched frequency at 4 GHz C-band (3.7-4.2 GHz) of satellite communication systems is obtained. Simulated and measured results prove a bandwidth of S-11 <-10dB and S-12 <-21dB at 3.1-11.2 GHz excluding three independently adjustable rejection bands. Hence, the proposed UWB MIMO antenna has a very small size, a simple structure, a higher isolation and three narrower notched bands which effectively save more useful frequencies. Moreover, it is a good candidate for wireless portable UWB MIMO applications.