Four antenna MIMO system with compact radiator for mobile terminals

A four-antenna multiple-input multiple-output (MIMO) system with the most compact radiators for small mobile terminals is presented in this letter. The MIMO antenna has four identical elements which are positioned in each corner of the PCB board. Each antenna element consists of an L-shaped radiator and two interdigital shorting stubs, producing the 2.4/5.2/5.8 GHz wireless local area network bands with a small size of only 6.5 × 9 mm2. Two different isolation structures are introduced simultaneously to mitigate mutual coupling between various elements. Consequently, mutual coupling less than −15 dB at both lower and upper bands is achieved, leading to an envelope correlation coefficient (ECC) of less than 0.25. A prototype of the antenna has been fabricated and verified. Being equipped with small size, embeddable structure, good radiation performance, high isolation, and low ECC, the proposed antenna is very suitable for mobile terminals in wireless communication system. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1281–1286, 2015