A switched-beam three-element printed loop antenna array for MIMO systems

In this paper, a novel switched-beam antenna is proposed to deliver high performance gains in the Multiple-Input Multiple-Output (MIMO) systems. The antenna is composed of three identical loop elements separated at 120 degrees from each other. Such an antenna is a planar structure and can rotate the beam over the whole azimuthal angle. To prove the concept, an antenna is developed and optimized to cover 3.08-3.72 GHz and 5-5.4 GHz frequency bands appropriate for the mobile WiMAX (3.5 GHz) and Wi-Fi (IEEE802.11 5.25 GHz) standards. The envelope correlation coefficient and radiation characteristics of the proposed antenna are also discussed. Its compact size and simple structure combined with low manufacture cost makes it promising solution for indoor base stations to overcome multipath problems and enhance system performance.