Closely Spaced Dual Band-Notched UWB Antenna for MIMO Applications

A closely spaced dual-band notched UWB MIMO antenna is proposed in this paper. A traditional semi-circular monopole with ultra-wideband operation is chosen as an element of the proposed MIMO antenna. When two of the UWB monopoles are put together closely, the mutual coupling between them is apparently strong. To reduce the coupling between the antenna elements, a T-shaped branch is inserted between them, which reduces the mutual coupling obviously over the entire operating band. Also, the T-shaped branch can perform as a compensating radiator which can lower the operating frequencies of the proposed antenna. In order to achieve dual band-notched characteristics, meandering slots are cut in the patches, and symmetrical C-shape strips are nearly placed to the monopoles’ feed-lines. The meandering slot is for lower band notch (WiMAX, 3.3–3.7GHz) while the C-shape strips are for upper band (WLAN, 5.15–5.825 GHz). The measured radiation efficiencies, peak gains and radiation patterns are illustrated and show good agreement as anticipated.