A Planar H-Shaped Directive Antenna and its Application in Compact MIMO Antenna

A compact multiple-input multiple-output (MIMO) antenna with planar H-shaped directive antenna elements for WLAN/WiMAX application is presented. A printed H-shaped antenna without any reflectors and directors is applied as antenna element of the proposed MIMO antenna, but the radiation pattern of it exhibits high front-to-back ratio in the azimuthal plane. Four those H-shaped antennas with compact size and directive radiation pattern are placed in a square loop array to obtain nearly orthogonal patterns. Therefore, a compact MIMO antenna with high isolation among those four elements is achieved. A laboratory model has been characterized experimentally, and the effectiveness of the proposed design in terms of theoretical achievable capacity is demonstrated. Measurement agrees well with simulation.