Super-UWB MIMO Antenna With Dual Band-Notched and High Gain

A 2 × 2 multiple-input multiple-output (MIMO) antenna with super-ultra wideband (super-UWB), dual band-notched characteristics and high gain is proposed. The antenna element consists of a circular slot shape radiator fed by a tapered feedline on the top side of the substrate, whereas defected ground structure (DGS) is etched on the bottom ground plane. The DGS and tapered feedline has been designed to produce the super-UWB performance. Dual-band notch is achieved by etching a J-shape slot in the radiator and an I-shape slot at the edges of the ground plane. The dual-band notch prevents the electromagnetic interference allocated for other wireless applications. High isolation is realized by incorporating a plus-shape decoupling structure with four small arm shape stubs at the center of the ground plane. A prototype was fabricated to verify the simulated and measurement results. The proposed design achieves a super-ultra wide bandwidth of 165% (3.4 ∼ 35 GHz), isolation of 21 dB, and a peak gain of 13 dBi. The notched bands are at 6.6 and 10 GHz. The envelope correlation coefficient is less than 0.01. The overall size of the MIMO design is 0.58λ_0L × 0.34λ_0L (λ_0L is the free-space wavelength at the lowest operating frequency).