A compact 4 × 4 dual band-notched UWB MIMO antenna with high isolation

A compact 4 × 4 ultra-wideband (UWB) multiple-input multiple-output (MIMO) antenna is presented in this paper. The proposed UWB MIMO antenna has dual band-notched characteristic in WIMAX (3.3 - 3.8 GHz) and WLAN (5.15 - 5.35 GHz and 5.725 - 5.825 GHz) frequency with a total dimension of 56 mm × 56 mm × 0.8 mm. Meanwhile it consists of four patch antenna connected with orthogonal protruded ground parts respectively. To achieve band rejection of WIMAX frequency, a λ/4 I-shaped open slot is etched in each radiating patch. Etching a λ/2 C-shaped slot into each patch obtains notched band in WLAN frequency similarly. To meet high isolation better than 20 dB for frequency under 4.2 GHz, four rectangular and four staircase-shaped stubs are added to ground parts of the proposed UWB MIMO antenna. The simulation results show that the proposed UWB MIMO antenna operates from 3.2 to 10.7 GHz with good performance of |S11| ≤ -10 dB and high isolation of |S21| ≤ -20 dB. Therefore the proposed UWB MIMO antenna can be utilized as a promising candidate for UWB MIMO systems.