A compact dual band-rejected MIMO Vivaldi antenna for UWB wireless applications

Abstract

In this paper, a novel compact dual band-rejected ultra-wideband (UWB) multiple-input multiple-output (MIMO) Vivaldi antenna is introduced and fabricated. The MIMO antenna with a small size of 26 × 28mm2 contains a modified ground plane and two microstrip-slot balun structures. A T-slot is etched on the ground to achieve miniaturization and high isolation, and the simulated |S11| of −10 dB impedance bandwidth is from 2.7 to 10.9GHz. An isolation of better than 15 dB is acquired over the UWB range (3.1-10.6 GHz). Meanwhile, by introducing two split ring resonator (SRR) slits on the ground and adding two split ring resonators (SRRs) close to the microstrip-slot balun structures, dual band rejection at both WLAN (5.15-5.85 GHz) and IEEE INSAT/Super-Extended C-band (6.7-7.1GHz) can be achieved. The MIMO antenna has high gain and very low envelop correlation coefficient (ECC < 0.02). The measured results agree with the simulated ones, demonstrating that the UWB MIMO Vivaldi antenna is suitable for the UWB diversity applications.