Design of a printed multiband MIMO antenna

A multiband MIMO antenna using planar technology is proposed for next generation mobile communication system. The antenna consists of two symmetrical monopole elements printed in parallel to each other at the upper and lower corners of a printed-circuit board (PCB) with a size 50×110 mm² which is similar to the side of a mobile phone. The two monopoles have two branch strips to generate two frequency bands. By using a parasitic element in each monopole, a much enhanced bandwidth in the upper band can be obtained. A lumped-impedance network is designed to enhance matching at the input ports for the two antenna elements. Computer simulation is used to study, design and optimize the antenna. Results indicate that the proposed MIMO antenna has a very bandwidth enough to cover the LTE (lower band), DCS1800, PCS1900, UMTS-2100, Wibro Band, 2.4G-WLAN, and Wimax (upper band) systems. To enhance the isolation between the two monopole elements within the desirable frequency bands, a slit is cut in the middle on the PCB ground. The MIMO antenna a very low profile and low cost which makes the design very attractive for mobile phone applications.