COMPACT DUAL-BAND MIMO ANTENNA FOR NEXT GENERATION MOBILE COMMUNICATIONS

Abstract

An extremely compact dual-band MIMO antenna for 4G USB dongle applications is proposed to operate at LTE band 13 (0.746 GHz � 0.787 GHz) and M-WiMAX band (2.5 GHz � 2.69 GHz). The proposed MIMO antenna consists of two identical elements each of which has the size of 15 mm � 13.25 mm. The minimum separation between the two elements is 0.5 mm (about 0.13% of the wavelength in free space at 0.765 GHz). An antenna element of the proposed MIMO system is composed of a feeding strip, a spiral-like radiating strip, and an L-shape parasitic strip. The radiating and L-shape strips are short-circuited to the ground plane. The radiating and parasitic strips, which are capacitively coupled to the feeding strip, do not only operate as radiators but also work as resonators to reduce the coupling between the two closely-packed input ports. The proposed MIMO antenna has a measured port-to-port isolation performance of higher than 13 dB over the frequency bands of interest. In addition, the ECCs are maintained below 0.3.