Design of a miniaturized UWB MIMO Vivaldi antenna with dual band-rejected performance

Abstract

A miniaturized ultra-wideband (UWB) multiple-input multiple-output (MIMO) Vivaldi antenna with dual band-rejected performance is introduced and fabricated in this letter. The method of loading absorption resistors on the ground is used to realize miniaturization. In order to improve the isolation between the two ports, a T-slot is etched between two Vivaldi elements. At last, by etching the split ring resonator (SRR) slits on the ground, and placing two split ring resonators (SRRs) near the feed balun structures, the dual band-rejected characteristics are achieved. Then the designed antenna prototype is fabricated and measured, and the measured results show that the operating frequency of the proposed antenna is 2.5-12.0 GHz, and the dual-rejected bands are 5.1-5.9 GHz and 6.6-7.1 GHz respectively, and the isolation between the two ports is more than 15 dB over the UWB range (3.1-10.6 GHz), the size of the designed antenna is only 26 × 24.5 × 0.6 mm³.