A planar active antenna array for hybrid phased array-MIMO system

Multiple-Input-Multiple-Output (MIMO) technology plays an important role in the fourth generation and future wireless communication systems to meet the exploding capacity requirements. In conventional MIMO approaches, antenna elements are placed far away from each other to eliminate the correlation and make use of the spatial multiplexing. However, this advantage offered by the MIMO comes at the price of losing the beamforming ability in the smart antenna system. We propose a new technique for MIMO communication with active phased antenna array in each transmitter/receiver which we call hybrid phased array MIMO. Coherent processing gain can be achieved by designing a weight vector for each subarray to form a beam towards a certain direction in space. Moreover, the subarrays are treated jointly to form a MIMO system. A four-input-four-output hybrid phased array MIMO system for TD-LTE base station is designed and implemented. The measured results validate the effectiveness of the proposed system.