An ultra-wideband multiple-input multiple-output antenna with dual band-notched characteristics

In this paper, an ultra-wideband multiple-input multiple-output antenna with dual band-notched characteristics is proposed. The radiating element is an octagonal structure using a tapered microstrip line to feed. A multimode resonator is introduced on one side of the microstrip feed line to achieve dual band-notched characteristics, which eliminates the interference of wireless local area network band and X satellite communication frequency band. By using a diamond-shaped defect ground structure and extending a parasitic branch at the centre axis of the ground, the mutual coupling of the antenna is reduced to −20 dB. The proposed antenna has a compact size of 30 × 35 × 0.8 mm³. The measured results are in good agreement with the simulation results. The proposed antenna covers 3.1–10.6 GHz with dual notched-band characteristics and the mutual coupling below −20 dB. The antenna has a good diversity performance as the envelope correlation coefficient <0.03. The antenna is suitable for ultra-wideband communications.