LAUSR

The work presented in this article is focused on the design of an omni‐directional and dual‐frequency antenna for multiple input multiple output (MIMO) applications. The proposed antenna consists of a monopole with a pair of L‐shaped strips and a butterfly‐like coupling slot, excited by a coplanar waveguide and a proximity coupling, respectively. Using two completely different elements and exciting multimode orthogonal characteristics current, high isolation for two ports is achieved. To improve the stability of input impedance, a gradient arc structure between the microstrip line and monopole element is adopted. The designed MIMO antenna provides port isolation of better than −20 dB and envelope correlation of lower than 0.02, at two resonant frequencies covering WLAN/WiMAX bands.