Compact UWB-MIMO antenna with band-rejection in WLAN

A compact multiple-input-multiple-output (MIMO)/ diversity ultra-wideband (UWB) antenna with planar structure is presented in this paper. It comprises of two modified rectangular slot antennas excited by microstrip transmission lines. An inverted U-shaped slot is inserted in the feeding transmission line to create a band-rejection at WLAN band (5.15-5.825 GHz). The mutual coupling between the two antenna elements is decreased by introducing T-shaped slot and a rectangular slot between them. The rectangular slot reduces the coupling at lower frequencies i.e. 3-5 GHz while T-shaped slot maintains good isolation at higher frequencies i.e. 5-10.6 GHz. The proposed antenna has a bandwidth of 7.5 GHz and operates at 3.1-10.6 GHz. It occupies a space of 22 × 26 mm² and achieves minimum isolation of 20 dB between its antenna elements over the whole operating band. The small size, good isolation and stable radiation patterns of the proposed antenna make it suitable candidate for UWB diversity applications.